Engineering the Space Age

A Rocket Scientist Remembers

Robert V. Brulle

Lieutenant Colonel, USAF, Retired

Air University Press

Maxwell Air Force Base, Alabama

July 2008
ii

Disclaimer

Opinions, conclusions, and recommendations expressed or implied within are solely those of the 

author and do not necessarily represent the views of Air University, the United States Air Force, 

the Department of Defense, or any other US government agency. Cleared for public release: 

distribution unlimited.

Muir S. Fairchild Research Information Center Cataloging Data

Brulle, Robert V.

Engineering the space age : a rocket scientist remembers / Robert V. Brulle.

 p. ; cm.

Includes bibliographical references and index.

ISBN 978-1-58566-184-8

1. Brulle, Robert V. 2. Aeronautical engineers—United States—Biography. 3. Rocketry—United States—Biography. 4. Renewable energy sources—Research I. Title.

629.130092—dc22

Air University Press

131 West Shumacher Avenue

Maxwell AFB, AL 36112-5962

http://aupress.maxwell.af.mil
To the Almighty and my loving wife Margaret, 

without whose help and guidance, 

I could never have experienced the excitement 

of being in the vanguard of this 

aviation and space adventure 



Contents

Chapter	 Page

DISCLAIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

DEDICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 	 iii

FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

ABOUT THE AUTHOR . . . . . . . . . . . . . . . . . . . . xiii

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . xv

Introduction . . . . . . . . . . . . . . . . . . . . . . . . xvii

 1 Aeronautical Engineering . . . . . . . . . . . . . . . . . . 1

 2 Pilots and Education . . . . . . . . . . . . . . . . . . . . . 15

 3 Aircraft Procurement . . . . . . . . . . . . . . . . . . . . . 29

 4 Aeronautics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

 5 Missiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

 6 Computer Programming . . . . . . . . . . . . . . . . . . . 113

 7 Spacefarers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

 8 Secret Missiles and Tactics . . . . . . . . . . . . . . . . . 161

 9 Space Projects . . . . . . . . . . . . . . . . . . . . . . . . . . 173

10 Pilots and Airplanes . . . . . . . . . . . . . . . . . . . . . . 183

11 Cyclogiro Aircraft . . . . . . . . . . . . . . . . . . . . . . . . 201

12 Giromill Wind Power . . . . . . . . . . . . . . . . . . . . . . 211

13 Aquagiro Water Power . . . . . . . . . . . . . . . . . . . . . 233

Appendices

 A Wing Vortex System . . . . . . . . . . . . . . . . . . . . . . 247

 B McPilot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
CONTENTS

vi

Appendices	 Page

 C Whirlpools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251

 D Diffusers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . 257

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265

Illustrations

Figures

 1 Back side of drag curve explanation . . . . . . . . . . 40

 2 Radio range operation . . . . . . . . . . . . . . . . . . . . 49

 3 New York radio range congestion . . . . . . . . . . . . 51

 4 Republic XF-103 and power plant 

operation diagrams . . . . . . . . . . . . . . . . . . . . . . . 55

 5 Wind-shear effect explanation . . . . . . . . . . . . . . . 65

 6 Performance envelopes . . . . . . . . . . . . . . . . . . . . 68

 7 Performance comparison . . . . . . . . . . . . . . . . . . 69

 8 Long-range missile trajectories . . . . . . . . . . . . . . 87

 9 NACA glide vehicle concept . . . . . . . . . . . . . . . . . 89

10 Alpha Draco glide vehicle . . . . . . . . . . . . . . . . . . 90

11 Alpha Draco configuration . . . . . . . . . . . . . . . . . 91

12 Alpha Draco trajectory . . . . . . . . . . . . . . . . . . . . 95

13 Alpha Draco range safety plot . . . . . . . . . . . . . . . 104

14 Limits of human tolerance to linear

acceleration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

15 Typical off-the-pad trajectories . . . . . . . . . . . . . . 145

16 Artist’s rendition of an in-flight ejection . . . . . . . 148

17 BGRV configuration . . . . . . . . . . . . . . . . . . . . . . 167
CONTENTS

vii

Figures	 Page

18 MDC-proposed fully reusable space shuttle . . . . 179

19 Cooper-Harper pilot rating scale . . . . . . . . . . . . . 184

20 PIO tendency rating scale . . . . . . . . . . . . . . . . . . 189

21 AFTI configuration . . . . . . . . . . . . . . . . . . . . . . . 193

22 Direct-side-force control (DSFC) modes . . . . . . . . 194

23 FIP sight HUD symbology . . . . . . . . . . . . . . . . . . 196

24 FIP bombing system . . . . . . . . . . . . . . . . . . . . . . 197

25 Cyclogiro modulation systems . . . . . . . . . . . . . . 203

26 Cycloidal propulsion pump . . . . . . . . . . . . . . . . . 205

27 Cyclogiro test aircraft . . . . . . . . . . . . . . . . . . . . . 206

28 Artist’s rendition of 120-kW Giromill . . . . . . . . . . 215

29 Rock angle variation with wind speed . . . . . . . . . 216

30 Giromill wind tunnel test results . . . . . . . . . . . . 218

31 40-kW Giromill configuration . . . . . . . . . . . . . . . 222

32 Giromill test performance . . . . . . . . . . . . . . . . . . 226

33 Aquagiro power coefficient . . . . . . . . . . . . . . . . . 238

34 Augmented Aquagiro . . . . . . . . . . . . . . . . . . . . . 242

35 Augmented Aquagiro performance . . . . . . . . . . . 243

A-1 Wing vortex system effects . . . . . . . . . . . . . . . . . 248

B-1 McPilot math function . . . . . . . . . . . . . . . . . . . . 249

C-1 Cyclogiro vortex system . . . . . . . . . . . . . . . . . . . 252

C-2 Induced velocities around orbit . . . . . . . . . . . . . . 253

C-3 Cyclogiro rotor definitions . . . . . . . . . . . . . . . . . . 253

C-4 Hover blade rock angle . . . . . . . . . . . . . . . . . . . . 254

D-1 Augmented rotor vortex system . . . . . . . . . . . . . 255
CONTENTS

viii

Photos	 Page

Capt Robert V. Brulle at the Air Force Institute 

of Technology, 1951 . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

RF-84F reconnaissance version . . . . . . . . . . . . . . . . . . 32

The first F-84F flight, 23 November 1952 . . . . . . . . . . . 35

F-84F air refueling checkout viewed from boom 

operator’s station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

RF-84F nose view . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Green Quail decoy missile . . . . . . . . . . . . . . . . . . . . . . 82

Green Quail deployed from a B-52 bomb bay . . . . . . . . 83

Alpha Draco hypersonic glider . . . . . . . . . . . . . . . . . . . 93

Cape Canaveral launch team . . . . . . . . . . . . . . . . . . . . 97

Alpha Draco launch . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Two-man Gemini space capsule . . . . . . . . . . . . . . . . . . 124

Atlas rocket boosts Mercury into orbit . . . . . . . . . . . . . . 126

Mercury manned space capsule . . . . . . . . . . . . . . . . . . 127

Titan II ballistic missile boosted Gemini to orbit . . . . . . 130

Gemini ejection seat . . . . . . . . . . . . . . . . . . . . . . . . . . 138

Live jump test of the Ballute stabilizer . . . . . . . . . . . . . 142

Final high-speed test of Gemini ejection seat . . . . . . . . 149

Balancing ejection seat to prevent 

astronaut tumbling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Astronaut Ed White made the first US space walk . . . . 155

Gemini VI and VII conduct first rendezvous 

in space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

Brulle family on flying vacation . . . . . . . . . . . . . . . . . . . 210

Giromill wind tunnel test . . . . . . . . . . . . . . . . . . . . . . . 217

Valley Industries Giromill checkout . . . . . . . . . . . . . . . . 220

Giromill at Rocky Flats Wind Energy Test Area . . . . . . . 224

Mod-1 Aquagiro test in the Missouri River . . . . . . . . . . 234
CONTENTS

ix

Photos	 Page

Aquagiro tow-tested between two canoes . . . . . . . . . . . 235

Large, float-mounted Mod-2 Aquagiro test . . . . . . . . . . 236

Mod-2 Aquagiro observed by Lyle McNair 

and the author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

Augmented Aquagiro with gin pole mounting . . . . . . . . 240

Augmented Aquagiro . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

xi

Foreword

Rarely is a reader exposed to such an extraordinary, multifaceted presentation of aerospace technology as Bob Brulle 

narrates in this book. After returning from duty as a combat 

fighter pilot in World War II, this Belgian immigrant developed 

a multitalented and innovative aerospace career path that addressed many of the aerospace professions. Along the way he 

forged a career in the aviation and space field that resulted in 

his participating in several of the most momentous aerospace 

achievements of the past century. He also expanded his education through hard work to a level at which he was qualified to 

teach graduate-level aerospace engineering courses.

It is interesting to follow how the analysis and design techniques of aerospace vehicles progressed over the years, which 

incidentally reveals the large role that the computer played in 

making that possible. The story on the early Cape Canaveral 

operations was amusing and showed that enterprising innovations played a large role in a successful undertaking. Some of 

the projects described were a surprise, as I had never heard of 

them, like reading how a pencil-shaped missile was built that 

could fly and maneuver over an intercontinental distance at a 

high hypersonic velocity. He also described how American engineers and scientists fought the Cold War battle for technological supremacy on their desks and in their laboratories.

The initiatives by which this enterprising engineer develops 

his technical approach to a project are very informative and offer the reader an insight into the workings of successful operations. He achieves an interesting behind-the-scenes look at 

how aerospace history is made by weaving in the historical significance of these projects as they are developed.

As a former aeronautical engineer at the rapidly growing McDonnell Aircraft Corporation, Bob gives us an interesting exposure to the importance of top management’s relationship with 

the workforce in a successful company. “Mr. Mac” made it a 

point to make all his employees team members by frequent 

communication and friendly association. 

From my experience in the aviation field, I find that this 

unique aviation and space history book provides a very realis-
FOREWORD

xii

tic view on the use of technology in the aviation and space 

business as it was conquered during the past half century. 

JOHN M. WILLIAMSON

Retired Vice President and Project Manager

A-10 Program, Fairchild-Hiller Corporation
xiii

Lt Col Robert V. Brulle, USAF, retired, was born in Belgium 

and immigrated with his parents to America in 1929 when he 

was six years old. He grew up in the Chicago area and became 

a P-47 fighter pilot in the US Army Air Force during World War 

II, flying 70 combat missions in Europe. 

Following the war, he acquired a bachelor of science degree 

from Aeronautical University in Chicago in 1948 and a master 

of science degree from the Air Force Institute of Technology 

(AFIT) in 1952, both in aeronautical engineering. He began PhD 

studies at Ohio State University while teaching at AFIT but 

never completed the degree. He returned to active duty in the 

Air Force, where his assignments ranged from a junior engineer to a weapons system project officer to an assistant professor of aeronautical engineering at AFIT. 

Colonel Brulle left active duty in 1957 and joined McDonnell 

Aircraft Corporation in St. Louis, Missouri, where he researched 

and designed aircraft, missiles, spaceflight vehicles, and novel 

alternative-energy wind and water current turbines. During 

the Gemini manned orbiter program, he was appointed to the 

NASA Spaceflight Committee as a member of the Trajectory 

and Orbits, Guidance and Control, Rendezvous, and Abort 

Panels. While working at McDonnell, he also taught as an adAbout the 

Author

Lt Col Robert V. Brulle, USAF, Retired
xiv

junct associate professor of mechanical engineering for the 

University of Missouri Graduate Engineering Center in St. 

Louis. He was licensed as a professional engineer in Missouri 

and Ohio, holds two US patents, and maintained membership 

in numerous professional organizations.

Retiring to southern Florida in 1988, Colonel Brulle has since 

published about a dozen aviation and historical articles in various magazines. His first book, Angels Zero—P-47 Close Air

Support in Europe, was published by the Smithsonian Institution Press in 2000. Many of the numerous technical manuals 

he has authored are listed in the bibliography of this text. He 

was married for 60 years to his late wife, Margaret, and has 

four children.

ABOUT THE AUTHOR
xv

Acknowledgments

This narrative is based on notes, drawings, and reports from 

the many projects I was associated with, along with the help 

offered by many excellent research libraries associated with 

government agencies, learning institutions, and organizations. 

In addition, contact with many associates I worked with during 

these 50 years not only rekindled my memory, but we became 

reacquainted as friends again. Without all this help I could not 

have completed this book. It is with gratitude that I acknowledge the help that each provided. I tried hard to make sure all 

are listed but if some were inadvertently left out, I heartily apologize and blame it on these senior moments that are appearing 

more often. After all, I am 85 years old at this writing. 

Gen Paul Kauttu, USAF, retired, refreshed my memory on 

what occurred during my stint as a flight instructor at Randolph AFB and also provided me with some references on energy maneuvering. Col John France, USAF, retired, acquainted 

me with the present-day use of energy maneuvering. Thanks to 

Peter Torvick, AFIT Association of Graduates, for helping me 

remember my AFIT experiences; Col Harold N. Holt, USAF, retired, for the excellent discourse on F-84F introduction to operational use; John Williamson for his candid foreword and 

keeping me straight on the F-84 and other Republic programs; 

Rick DeMeis for the Republic XF-103 propulsion diagram; Bert 

Reime, Joe Dean, and Jack Evans for their Alpha Draco reminiscences; Gordon Cress, astronaut Tom Stafford, and John 

Weitekamp for their Mercury and Gemini reminiscences; Ron 

Naumer, Joe Bell, L. J. “Skip” Long, Bill Hirsch, Bill Rousseau, 

and John Hrenak for their help in resurrecting the BGRV and 

other McDonnell programs; Paul Landes, my harried Systems 

Engineering and Integration department head, for his thoughts 

during my time in his department; John Hodgkinson, Bill Moran, and McDonnell test pilot Joe Dobronski for helping me 

recall the flying qualities research we conducted; Clay Waldon, 

Rocky Flats project engineer, for recalling some lost details of 

the Giromill test program; and Col Chuck Scolatti, USAF, retired, for his thoughts on the Cyclogiro aircraft. Then there are 

those diligent librarians, archivists, or other titles who super-
xvi

ACKNOWLEDGMENTS

vise the storehouses of knowledge and are always helpful and 

accommodating of all requests for information. Among them 

are Lynn V. McDonald from the Cradle of Aviation Museum; 

Willis Benson from the Air Force Research Library; Mara Sprain 

from the National Wind Technology Library; Linda Hall from 

the Library of Science, Engineering, and Technology; Wes Henry 

from the Air Force Museum library; Larry Merritt from the McDonnell archives; and Archie DiFante from the Air Force Historical Research Agency. Without them history would be lost.

Thanks for all the help.

ROBERT V. BRULLE
xvii

Introduction

An insatiable fascination with aviation must have been ingrained by my earliest memory of being awed by a flimsy wood 

and canvas flying machine. Typical of many pilots and aeronautical engineers that grew up in the 1930s, I cultivated that 

dream by making balsa wood and paper model aircraft powered 

by a rubber-band motor. When the Graf Zeppelin flew overhead 

during the 1933 Chicago World’s Fair, I was the only one of the 

gang to be excited and climb on the garage roof to get a better 

look at it. I also will never forget when I heard the historic live 

radio broadcast (Chicago station WLS) of the fiery crash of the 

Hindenburg at Lakehurst Naval Air Station, New Jersey, in May 

1936. During World War II my aviation dream was realized by 

becoming a pilot and officer in the US Army Air Force and completing 70 combat missions flying the P-47 Thunderbolt fighter 

from England, France, Belgium, and Germany. 

Those three years in the Army Air Force turned out to be the 

most exciting in my life and are documented in my book, Angels Zero. During that time period I knew that my life was destined to be spent in the aviation field, but in what capacity? 

Fortunately I had the aptitude to absorb the knowledge of the 

technical disciplines, so I chose an aviation path as a pilot, engineer, professor, inventor, and entrepreneur. Those professions allowed me to be associated with and witness many of the 

historic aviation and space achievements that occurred during 

this epoch of conquering the air and space. 

Phenomenal advances in the aeronautical disciplines occurred during this epoch. The aircraft operating envelope increased from 400 mph to 5,000 mph and hit 25,000 mph in a 

manned spacecraft on the way to the moon. Jet aircraft were 

continuously improved until they could climb vertically and 

perform breathtaking maneuvers. The new discipline of rocket 

propulsion led to the development of missiles, both big and 

small, that had incredible tracking and guidance capabilities. 

This in turn led to space exploration, with both manned and 

unmanned spacecraft that amazed the world by their technical 

achievements and discoveries. 
INTRODUCTION

xviii

Aircraft became extremely complicated and, with the addition of computer-driven flight controls, inherently unstable aircraft became flyable. Determining pilot flying qualities became 

quite difficult, which led to the building of large aircraft simulator complexes. Then there was the Cold War period, where both 

the United States and Soviet Union had large inventories of 

nuclear-armed intercontinental missiles aimed at each other’s 

cities. For every missile or warhead advancement by one, the 

other countered with a better one. In this manner each country 

stressed the technological and financial resources of the other 

in a deadly serious game played for our human survival. An 

inside look is provided into how we in industry contributed to 

this game. 

Aeronautical technology improvements also extended to 

flight control operations, with new aircraft navigation instruments, radio, and radar aids. For comparison with modern 

ground flight control systems, a flight using the old-style lowfrequency radio ranges in the New York area during a miserable 

winter day is detailed. Reading that makes one wonder how 

any of us survived. 

A lot of the aerospace technology progress was driven by world 

events, especially the Cold War and the moon landing competition with the Soviets. To relate to these events in concert with 

the discussion at hand, “Historical Notes” of background information are liberally sprinkled throughout the text.

It was a wonderful time to be an aerospace engineer, the 

days filled with adventure and excitement as we tackled the 

engineering problems. Hopefully, reading about the excitement 

of being in the forefront of technology advancement will motivate some young people to pursue a life of challenges in the 

aviation and space technology field.


Chapter 1

Aeronautical Engineering

“Well, fix it,” my boss said after viewing several pictures of 

the B-45C spring bungee that secured the landing-gear uplock hook. This was the first upgraded North American Aviation (NAA) B-45C four-engine jet bomber assembled in their 

Long Beach, California, plant. Something was obviously wrong 

with the mounting of the bungee pivot axis, as it did not rotate 

in the correct plane. Fixing this problem was my initiation into 

the aeronautical engineer brotherhood.

It was a descriptive geometry problem—the hook and bungee 

were defined in the landing gear reference axis but were 

mounted on a wing stringer defined in the wing reference axis; 

both axes were skewed and offset from each other. Investigating, I found that the original designer had neglected one last 

geometric rotation to obtain the true view of the spring bungee 

mechanism. A small wedge that aligned the spring bungee with 

the hook pivot axis riveted to a bracket fixed the problem. Thus, 

my first contribution as an engineer was successful and fulfilled an ambition fostered during my combat flying in P-47s 

during World War II (WWII).

 After the war, I took advantage of the GI Bill to attend college 

and study aeronautical engineering.1 I had seen firsthand what 

the power of aviation could do and wanted to be part of the design 

team that produced these aviation marvels. My goal in high school 

was to become a machinist, not considering college at all, so I had 

pursued a technical course. This consisted of wood, auto, and 

machine shop classes; mechanical drawing; and math classes, 

including algebra, plane geometry, solid geometry, and trigonometry. Additionally, I elected to take general science, physics, 

and chemistry classes because I enjoyed them. However, I got by 

with just enough English, history, and civics classes to graduate. 

I thus graduated from high school without the prerequisite courses 

to attend an accredited university. This limited my college choice 

to a technical school that offered an aeronautical engineering degree in two years, attending school three semesters each year. The 
AERONAUTICAL ENGINEERING



school was Aeronautical University, located on the 15th and 16th 

floors of an office building on Michigan Avenue, across from the 

art museum in downtown Chicago. The GI Bill took care of tuition 

and books plus $65.00 per month living expense, which I gave to 

my parents to cover room and board. A part-time job refurbishing 

sewage ejector pumps gave me enough money for courting my 

future wife, Miss Margaret (Margie) Roth. 

Even though Aeronautical University was a technical school, 

its courses were rigorous. Each semester lasted 16 weeks, and 

we carried 20–22 credit hours per semester, starting at 8:00 

a.m. About half the students dropped out during the first semester, and half of the remainder during the second. Those of 

us who remained were a serious, dedicated, and studious group 

that really wanted an education. 

We covered the basic engineering courses of mathematics, 

through analytical geometry and integral calculus; mechanics; 

thermodynamics; structures; drafting, including lofting; aerodynamics; and aircraft design. But because of the accelerated 

curriculum, many engineering classes were presented in an 

abbreviated fashion. Not having a thorough undergraduate 

engineering base haunted me for a long time. As schoolwork 

progressed, I found I was attracted to the aerodynamics-type 

courses, which are defined as the study of the motion of air and 

the forces acting on a body in relative motion to the air. The 

structures courses—determining the loads and stresses on 

components and structural members—were the easiest for me 

to master, but I did not like them. I could only hope that my 

employer would agree to let me work in aerodynamics.

Aerodynamics is divided into three main areas: subsonic, 

supersonic, and transonic—the transition range between the 

other two. Subsonic aerodynamics is the study of aircraft moving 

through the air at a velocity below the speed of sound, or at a 

Mach number less than 1.0. (Mach number is the ratio of the aircraft speed to the speed of sound, so Mach 1.0 refers to an aircraft 

flying at the sonic velocity.) Supersonic refers to flight at a velocity 

greater than the speed of sound, or at a Mach number greater 

than 1.0. Where they meet is a region labeled transonic flow. 

Transonic flow involves subsonic and supersonic flow at various 

points on the aircraft. When the aircraft is flying at a subsonic 

velocity, parts of its curved surfaces may experience a local super-


AERONAUTICAL ENGINEERING

sonic flow. This is especially true for the wing’s cambered upper 

surface that causes a local supersonic flow to form along a portion of the wing. When an aircraft first exceeds the speed of sound, 

parts of it can still be within a local subsonic flow. In each of these 

conditions, both a subsonic and supersonic flow are present, 

which makes it an extremely difficult analytical problem for the 

aerodynamics engineers. Arbitrarily, a Mach number between 0.8 

and 1.2 is considered to be transonic. 

A primary job for an aerodynamics engineer is to compute the 

drag of an aircraft moving through the air. For subsonic flight, 

there are three types of drag: friction, form, and induced.

Friction drag occurs when two surfaces rub together; for air 

(or any fluid) moving over a solid surface, it is governed by a 

parameter called the Reynolds number. Between the freestream flowing fluid and the solid surface is a thin transition 

layer called the boundary layer, where the velocity is zero at the 

surface and increases to the free-stream velocity. The momentum loss within the boundary layer is related to the friction 

drag—the thinner the boundary layer, the less the friction drag. 

The Reynolds number, through its viscous parameter, governs 

the thickness of the boundary layer; hence, the Reynolds number governs the amount of friction drag. 

Form drag, sometimes referred to as pressure drag, is the 

force needed to move the air around the body. Streamlining the 

body shape will reduce form drag.

Induced drag is a consequence of generating a lift force and 

is sometimes called drag due to lift. It is caused by the generation of the lifting vortex and is inversely proportional to the 

wing aspect ratio (the ratio of the wing span to the mean wing 

chord). More on this later.

At transonic and supersonic speeds another drag, called 

wave drag, manifests itself. It is related to the shock waves generated at supersonic speeds. Wave drag rises rapidly as an aircraft approaches supersonic speed and continues its rise at a 

slower rate after penetrating into the supersonic regime. Total 

drag is the sum of all these components. 

Many of us studying aeronautical engineering were excited 

when an American aircraft broke the sound barrier at Muroc 

Army Air Field in California (now Edwards AFB). Capt Chuck 

Yeager, flying the Bell XS-1 experimental rocket aircraft, exceeded 
AERONAUTICAL ENGINEERING

the speed of sound on 14 October 1947. I was especially excited 

by this event since I had just completed a term paper on air compressibility effects as an aircraft approaches the speed of sound 

and was well aware of the problems that must be overcome.

Finally, the schoolwork grind ceased on 30 January 1948 

when 79 of us were presented our bachelor of science degrees 

in aeronautical engineering in a ceremony in the Museum of 

Science and Industry auditorium. We were all glad school was 

over and ready to step into industry and start contributing to 

the advancement of aviation. I was also ready to start making 

some money so that a young lady named Margie Roth and I 

could get married. Unfortunately, the postwar aircraft industry 

was in a doldrums because the public wanted to concentrate 

on peaceful pursuits, forcing the Truman administration to institute a precipitous drawdown of the armed forces and supporting industries. One of the most expensive, the aircraft industry was hit hard, so jobs for new engineers were scarce. I 

found a position with North American Aviation in Inglewood, 

California, next to the Los Angeles airport, as a junior engineer 

in the landing gear group. Instead of aerodynamics, my workplace was a large drafting table among several hundred others 

in the main engineering building. For better or worse on 1

March 1948 we made California our home, and I was put to 

work correcting landing gear drawings of the production aircraft: the F-82, FJ-1, F-86, and B-45.2

The F-82 was a propeller–driven, twin-engine fighter that 

looked like two WWII P-51 Mustang fighters connected at the 

wings. It was at the end of its production run. The FJ1 was a 

straight-wing (nonswept) Navy jet fighter that was the forerunner of the F-86. The surprise entry of the German Me-262

swept-wing jet fighter late in WWII spurred the US Air Force 

and Navy to encourage several aircraft companies to quickly 

develop a competing jet aircraft. The first one developed was the 

Bell P-59, which was not really a combat-worthy aircraft and 

was relegated to training jet pilots. The first true American jet 

fighter was the Lockheed F-80, which first flew in 1945. A 

plethora of jet aircraft followed closely behind, including the 

NAA FJ1 Fury, Grumman F9F Panther, McDonnell FH1 Phantom, and the Republic F-84 Thunderjet. These were all straightwing aircraft ordered into production prior to acquiring the 
AERONAUTICAL ENGINEERING

swept-wing research of the Germans. About a year behind the 

others, the F-86 Sabre incorporated the swept-wing design. In 

fact, the F-86 was initially proposed as a slimmed-down, 

straight-wing FJ1, but when its performance proved no better 

than the aircraft already in production, it was quickly redesigned with a swept wing. This fortunate turn of events made 

the F-86 famous over the Korean skies battling the swept-wing 

Russian MiG-15s, which incorporated the German research.3

A swept wing essentially presents a thinner body to the air 

flow, because in transonic flow, the velocity perpendicular to 

the wing is the governing parameter for wave drag. The point 

where an aircraft’s wave drag starts to rise dramatically is denoted as the critical Mach number. For example, a 30-degree 

wing sweep-back will allow an aircraft to increase its critical 

Mach number about 15 percent. Unfortunately, swept wings 

also create a span-wise flow over the wing, causing the aircraft 

to have a vicious stall characteristic along with an increase in 

stability and control problems. Many early swept-wing aircraft 

had flat-plate wing fences (small, flat plates oriented parallel to 

the velocity) and other fixes to ameliorate the span-wise flow 

effect. Examples include the MiG-15 and the RF-84F. 

The B-45A was a four-engine jet bomber with straight wings. It 

was the first large jet bomber ordered into production, first flown in 

March 1947, and hence unable to employ the German research. 

About a year later, the Boeing B-47 adopted the swept-wing design. 

It went on to become the mainstay of the US bomber force for many 

years. While only 142 B-45s were produced, they blazed the trail 

for jet bomber combat operations during the Korean War.4

Once a basic aircraft design was completed, it continued to be 

modified to improve, simplify, or correct design flaws. The implementation for effecting a design change was an engineering order 

(EO). The EO specified the applicable drawing(s) and design groups 

affected and usually contained a sketch of the change. After approval by all the relevant groups, the EO was stapled to the affected drawing. In the landing gear group it was not unusual for a 

drawing to have a dozen or more outstanding EOs. Deciphering 

the present configuration with all the EO changes could be quite 

difficult. My job was to access the drawing vellums that had outstanding EOs against them and change the drawing to reflect the 

design change. The revised drawing was then printed and released 
AERONAUTICAL ENGINEERING

as the latest configuration. It was a tedious and unchallenging 

job, but it familiarized me with the landing gear systems, particularly those of the F-86 and B-45 aircraft.

Historical Note

In June 1948, the United States was jarred from its tranquility by the Soviet 

blockade of West Berlin. Berlin, itself divided into American, British, French, 

and Soviet sectors, was isolated within the Soviet zone of Germany (later called 

East Germany), which limited ground access to the city. This was the first of 

many major confrontations between the Western allies and the Soviets. I recall 

that many people felt we should nuke Moscow and settle the issue right then. 

Instead, a massive airlift of supplies was instituted to keep West Berlin functioning. The successful airlift finally caused the Soviets to lift the blockade on 12

May 1949. This blatantly aggressive act by the Soviets woke up America to a new 

belligerent and galvanized the public and the politicians to rebuild our armed 

forces. It also led 12 countries to form the North Atlantic Treaty Organization 

(NATO) to combat the spread of the communist Soviet Union (USSR) into the 

western sphere of influence.

Historical Note

We lived in south Los Angeles County and went by the Northrop Aircraft plant in 

Hawthorne quite often. It was always a novelty to see their propeller-driven B-35 

“flying-wing” bombers take off and fly around, missing a fuselage. One evening at 

a reunion of Aeronautical University graduates, several fellows from Northrop were 

discussing the flying wing stability concerns. They said that the pilots had to remain aware of their gas consumption and keep switching among the many tanks to 

keep the aircraft stable. The Air Force was evidently pleased with the program, since 

Northrop was given a contract to build a larger, jet-engine version of the flying wing, 

which became the YB-49. Unfortunately, propellers provided a dynamic stability increment that was lost when replaced by jet engines. After the fatal crash of a test 

YB-49 that killed the five crew members—including Capt Glen Edwards, for whom 

Edwards AFB is named—the program was canceled in 1949. Only after development 

of electronic stability augmentation did the flying-wing design become practical in 

the B-2 bomber.5

The landing gear group was located near the offices of the test 

pilots, and occasionally they would take a shortcut through our 

area. One of the landing gear group fellows was a friend of George 

Welch, famous for his exploits at Pearl Harbor on 7 December 

1941 and now flight-testing the F-86. He is portrayed in the 

movie Tora! Tora! Tora! and also mentioned in many books about 

the Japanese attack.6 Several times while cutting through our 
AERONAUTICAL ENGINEERING

shop, George would stop to talk to his friend. I was fortunate to 

be close by on one such occasion and was introduced to him. It 

was a real honor to talk to him for a few minutes, comparing 

combat conditions between the Pacific and European theaters. 

There is an ongoing controversy that George may really have 

been the first pilot to break the sound barrier in an F-86 prior to 

Chuck Yeager in the Bell XS-1.

7 George was later killed in an 

F-100 when he encountered a dynamic stability problem and 

crashed during a high-speed rolling pullout. More on this later. 

The YF-93, first touted as an upgrade to the F-86, was in the 

design stage, and I was assigned to the group to detail and 

stress analyze small parts that a designer outlined on the layout blueprint. The YF-93 was designed around a larger and 

more powerful Pratt & Whitney J-48 engine. A dominant feature of the YF-93 was its unique flush side engine inlets which, 

to me, seemed inadequate for the engine airflow required. Although it sported many common features with the F-86, its 

greater weight required a completely new landing gear—a dual 

main-wheel landing gear. Only two hand-built aircraft were 

made, and they were eventually turned over to the National 

Advisory Committee for Aeronautics (NACA) for testing. 8

Historical Note

NACA was a government-supported aeronautical research organization established 

after World War I. It grew into several large laboratories located around the country. 

One of the largest and earliest laboratories established was at Langley Field near 

Hampton, Virginia. Another was at Moffett Field in San Jose, California, and one that 

specialized in engine testing and analyses was at Cleveland, Ohio. These laboratories 

conducted all types of tests and theoretical analyses, with the results widely distributed in various technical publications. NACA was absorbed by the National Aeronautics and Space Administration (NASA) on 1 December 1958 when that agency was 

created by an executive order of Pres. Dwight D. Eisenhower. 

During the design process, all the aircraft parts are designed 

simultaneously, so coordination between all concerned is an absolute necessity. In the spring of 1949, a rush job to design a 

new training aircraft, the T-28, took center stage, presenting a 

good example of the aircraft design process at that time as applied to landing gear. 
AERONAUTICAL ENGINEERING

Design work was accomplished on large drafting tables and 

coordinated through personal contact. The group leader first established the landing gear reference axes, interface attachment 

points, and design loads from the preliminary design—a fairly 

complete design but based on experience and rules of thumb. A 

large layout of the landing gear assembly was completed, and a 

first cut of the arrangement and size was developed based on the 

design data. This entailed a lot of coordination with the wing 

design group so they knew where the landing gear loads would 

enter the wing structure and where the gear would retract. 

Similar concerns had to be addressed with the forward fuselage 

group for the nose gear. Even with best intentions, slipups did 

occur, like the day a cable was found routed through the middle 

of the nose gear bay. (This was on the first XAJ-1.)

While looking over the nose gear loads to be used during detail design, a peculiar item caught my eye. It was labeled nose 

gear spin-up force. My design leader explained that it was a 

snap forward force on the gear strut caused by the inertia of 

spinning up the wheel upon landing. He mentioned that many 

nose gears failed on landing because they had not been designed for this forward force. He said that in a movie he saw of 

a nose gear failure, the forward collapse was evident before the 

gear was swept backward by the crash. Further analysis on my 

part convinced me it existed. It also convinced me that I had a 

lot to learn, especially about dynamics.

Analyzing the loads through the landing gear structure during retraction, I was confronted by a complex series of equations that had to be solved for various gear retraction positions. 

Since they were repetitive calculations, my boss told me to let 

the computer group do the job. Entering the computer group 

room, I was confronted by a large number of people—mostly 

ladies with a sprinkling of older men—all operating mechanical 

calculators that performed the four basic calculations of addition, subtraction, multiplication, and division. The individuals 

doing the computations were referred to as computers; at that 

time a computer was a person rather than a machine. This was 

my first association with a computer group that specialized in 

performing tedious, repetitive calculations to supplement our 

paper, pencil, and slide rule analyses. 
AERONAUTICAL ENGINEERING

After a finalized layout of the gear assembly was completed, 

the component parts of the design were parceled out to the junior designers to complete the details. They determined the 

local loads, selected the materials, sized the parts structure, 

and drew them up, continuously monitored by the strength 

engineers. At the completion of the design, the drawing was 

released for manufacture. As this process was going on, the 

weights engineers were invariably complaining that the gear 

design was overweight. This led to a concerted weight-reduction 

effort by trimming edges, reducing structural sizes, or making 

a more efficient design. The T-28 was probably the first aircraft 

to liberally use magnesium and, for noncritical items, plastic 

castings for weight control. 

Historical Note

During this endeavor, on 2 March 1949, a B-29 named Lucky Lady II completed 

the first nonstop around-the-world flight. This feat showed the world, and especially the USSR, that the USAF had intercontinental range with aerial refueling. 

It also coincided with the birth of our first son, Andrew Robert.

The schedule called for completing the design in three months, 

which meant having all the drawings released for manufacture. 

The pace was hectic, and we put in 12-hour days. I was teamed 

with several others to complete the nose-gear design, which included the retraction mechanism, gear doors, and all landinggear cockpit controls. My assignment was the nose gear steering 

mechanism that was controlled with a separate hand knob located on the pilot’s right console. I thought steering should be 

done with the brakes, but a hand controller was the specification requirement, so that is what we designed.9

Historical Note

The T-28 made its first flight on 24 September 1949, and almost 2,000 T-28s sporting various size engines were produced. The T-28 was used as an intermediate aircraft between the T-6 and the T-33 jet trainer. It was also upgraded and made into 

a ground support aircraft used by many emerging nations. The reign of the T-28 

in training pilots was short; a few years later an all-jet pilot training syllabus was 

introduced with the Cessna T-37 basic training jet, the T-33 jet trainer, and the supersonic Northrop T-38 advanced trainer. 
AERONAUTICAL ENGINEERING

10

We completed the design on time, albeit with quite a few loose 

ends to be cleared up afterwards. I was then tasked to design 

and have built a breadboard prototype of the hydraulic nose 

gear steering system for a test in a Navion, NAA’s entry in the 

civilian aircraft market. It was just about ready for testing when 

I was transferred to the wind tunnel model group. My persistent requests to be transferred to the aerodynamics field finally 

brought some results. 

Historical Note

The expected postwar civilian boom for private aircraft did not materialize, and 

many aircraft companies that entered the civilian market lost out in their endeavor. The NAA Navion was a great aircraft, but it sold for $10,000, which was 

$2,000 below cost. After a year of losing money, NAA sold the Navion design and 

manufacturing rights to Ryan Aeronautical Corporation, which successfully built 

and marketed it as the Ryan Navion for many years.

Many subsonic wind tunnels were in use throughout the 

United States during the WWII time period, but there were no 

supersonic tunnels. There were several experimental supersonic jets, but nothing that could be construed as a bona fide 

supersonic aerodynamic testing facility. Spurred by the German research in transonic and supersonic aerodynamic flow 

that led to the swept-wing Me-262 and supersonic V-2 missile, 

a postwar surge of transonic and supersonic wind tunnel construction was undertaken.10 All the aircraft manufacturers, 

armed forces, NACA, the Naval Research Laboratory, and many 

universities commenced a crash program for building new wind 

tunnels. Everyone was eager to get to the forefront of this new 

aerodynamic technology. 

Contrary to popular belief, a wind tunnel does not duplicate 

the flight of the full-size aircraft. The data collected must be 

corrected and scaled to the full-size configuration. Corrections 

to the tunnel data include tunnel-wall constraining effect, 

model blockage, and flow deviations caused by the mounting 

and balance system. The measured data from the model must 

then be scaled to full size by accounting for the Reynolds number difference. Reynolds number is a parameter that accounts 

for the viscous nature of an airflow and is affected by the size 
11

AERONAUTICAL ENGINEERING

of the body, thus similar but different size bodies will experience 

different forces relative to their size. To reduce the magnitude 

of these corrections, larger and pressurized wind tunnels were 

constructed to more closely simulate the Reynolds number.

Supersonic tunnels create additional problems when shock 

waves formed around the test model propagate outward and reflect back from the tunnel walls. They may impinge on the model, 

invalidating the collected data. The closer the test is to Mach 1.0, 

the worse this problem becomes because the shock waves are 

nearly normal (90 degrees) to the flow velocity and reflect directly back on the model. At higher Mach numbers, the shock 

waves become more oblique and thus reflect off the tunnel 

walls at an angle. This leaves a rhomboid-shaped shock-wavefree area between the original and reflected shock waves. The 

model must be small enough to fit within that area and, as I 

found out during my short stint in model design, made the 

models resemble a clockworks.

Historical Note

Several years later, engineers developed a porous-wall test section. By creating 

suction through the wall, the shock waves were absorbed, preventing a reflection. 

Until then, getting meaningful data at or near Mach 1.0 was impossible.

A small blow-down supersonic wind tunnel patterned after 

the German Peenemunde 40 cm (16 in) square tunnel test section had just begun operation at NAA.11 This tunnel system 

consisted of a large pressure tank connected through a convergent/divergent wind tunnel channel to a large spherical evacuation tank. When both tanks were charged—one with pressure 

and the other a near vacuum—the valves were opened and a 

supersonic flow that lasted about 20–30 seconds was generated within the tunnel. Watching a supersonic test was very 

interesting. During the 20-second test run, the string-mounted 

model was pitched through a complete angle-of-attack range 

while the test results were automatically recorded.

A convergent/divergent tunnel is required to create a supersonic Mach number. The Mach number in the convergent tunnel 

section starts subsonic and gradually increases to reach Mach 

1.0 at the throat. (The throat is where the convergent and di-
AERONAUTICAL ENGINEERING

12

vergent sections of the tunnel meet and is the smallest crosssection area of the tunnel.) The air flow is then expanded in the 

divergent section, increasing the Mach number until the design 

Mach number is reached. As air expands, the temperature decreases. The greater the expansion, the colder the air flow becomes, finally freezing the water vapor in the air. Hence, the air 

used in a supersonic tunnel must be extremely dry to prevent 

water vapor from freezing, which would invalidate the test results. (At very high Mach numbers, 5.0 or greater, the air is 

expanded and cooled to the point that the nitrogen in the air 

freezes. This problem is discussed later.) 

From the above discussion it should be apparent that wind 

tunnels have many stumbling blocks to acquiring usable data, 

are very expensive to build and run, and use a lot of manpower for 

data analyses. Fortunately, over the years the tunnel data acquisition and analyses were refined so that highly reliable qualitative 

results could be obtained. Without wind tunnels it would have 

been impossible to reach the level of aeronautical sophistication 

required to design those wonderful flying machines.

Historical Note

The mathematical equations describing the flow over a body and accounting for 

the viscous and dynamic properties of air are known as the Navier-Stokes equations and were formulated over a century ago.12 However, the complexity of the 

nonlinear partial differential equations defied solution except for very simplified situations. With the advent of supercomputers, these equations can now 

be solved for the air flow over an entire aircraft. It is a horrendous program that 

involves the simultaneous solution of the equations at hundreds of thousands of 

grid points defining the aircraft. The pressures, temperatures, and flow properties 

are directly computed, skipping entirely the expensive wind tunnel testing. These 

computational fluid dynamics programs have led to the gradual decline in wind 

tunnel testing and, in fact, many wind tunnels, both subsonic and supersonic, 

have been dismantled.13 It is interesting to note however, that small, low-cost, 

exploratory-type wind tunnels are now being used for investigating conceptual 

ideas and trade studies.14

With the armed forces building up again, I received a telegram from the Air Force stating that because of my engineering 

degree, I was eligible for recall to active duty. If I accepted, I 

would become an atomic weapons arming expert. This was the 

best of both worlds—obtain a highly technical armed forces oc-
13

AERONAUTICAL ENGINEERING

cupation specialty and keep flying. At the time, the atomic 

bombs were bulky and heavy and could only be carried in large 

bombers since the warhead required manual arming after takeoff, hence the arming specialist crew member. I accepted the 

challenge. It was a momentous decision on our part and, in 

hindsight, a fortunate turn of events. 

Notes

1. The so-called GI Bill (GI was the nickname for American soldiers, short 

for Government Issue) was an act of Congress titled, The Servicemen’s Readjustment Act of 1944. It entitled returning servicemen to free college tuition 

for up to four years, depending on length of service, and a living expense of 

$65.00 per month. More than two million servicemen took advantage of that 

opportunity.

2. In 1948 the USAF changed the designation of fighter aircraft from the 

outdated P for pursuit to F for fighter. The change in designation was natural 

for me except for the fighters that were used in WWII. Because the P-47, P-51, 

and P-38 were so ingrained in my mind, I never was able to effect that change 

for them.

3. Robert F. Dorr, F-86 Sabre (Osceola, WI: Motorbooks International, 

1993). This is an excellent text with many photographs of the F-86 during its 

development and operational life. 

4. Howard S. Myers Jr., “The RB-45C ‘Tornado,’” Air Force Museum Friends 

Journal 23, no. 3 (Fall 2000): 21–26. This article describes the operational 

use of the RB-45C reconnaissance version.

5. Charles Tucker and J. J. Quinn, “Flying Wings,” Flight Journal (October 

2003).

6. Gordon W. Prange, At Dawn We Slept—The Untold Story of Pearl Harbor

(New York: McGraw-Hill, 1981) presents a detailed account of George Welch 

on that fateful day. 

7. Al Blackburn, Aces Wild (Wilmington, DE: SR Books, 1998). Surfing the 

Web for “George Welch” results in many references to his being the first to fly 

supersonic.

8. Dorr, F-86 Sabre, 15, 16. 

9. Evidently the nose-wheel-steering hand controller did not survive the 

test phase. A student pilot that flew brand new T-28s in training in 1951

recalls that he used the rudder toe brakes for steering.

10. Peter P. Wegener, The Peenemünde Wind Tunnels (New Haven, CT: Yale 

University Press, 1996). This book is an eye-opener on just how close the 

Germans came to overwhelming us in the technical race during WWII. 

11. Ibid., 22–33. 

12. Many aerodynamic texts explain and show the derivation of these 

equations; for example, see A. M. Kuethe and J. D. Schetzer, Foundations of 

Aerodynamics (New York: John Wiley and Sons, 1950), appendix B, 336.
AERONAUTICAL ENGINEERING

14

13. Searching the Internet for Navier-Stokes equations results in a plethora of articles on their use. They are used in such diverse areas as aircraft 

and ship design, weather prediction, climate modeling, blood-flow analyses, 

and many other applications. 

14. Robert Howard, “Blowing in the Wind,” Boeing Frontiers, an employee 

magazine (August 2003), 29.
15

Chapter 2

Pilots and Education

The Air Force allowed us 30 days to get our affairs in order 

and report to Keesler AFB at Biloxi, Mississippi, on 22 August 

1949 to attend electronics school. This first course would last 

six months and then continue at Los Alamos, New Mexico, for 

another year. We decided that Marge and our new son would 

stay with her parents in Chicago while I went to Keesler and 

then plan on reuniting when ordered to Los Alamos. 

Historical Note 

I had just settled down to Air Force routine when the world was shocked by 

Pres. Harry S. Truman’s announcement that the Soviets had detonated an atomic 

bomb. This was years before anyone thought they could; the reason became apparent a few years later when a trusted scientist, Klaus Fuchs, was convicted of 

treason for passing the atomic bomb secrets to them. The damage was done; the 

United States and USSR were in a confrontation with awesome weapons capable 

of obliterating each other. The Cold War had started in earnest.

It was difficult to again acclimate to service life, but getting 

back into flying helped. Within a week I was cleared for flying, 

and my first flight was as a B-25 copilot on a hurricane evacuation flight to Nashville, Tennessee. Electronics school started a 

week later. The first two months were a review of basic electronics I had in college, so I was able to take time off to get in a 

great deal of flying and even become current and rated in the 

latest instrument-flying techniques. 

At Christmas time the remainder of our course, including Los 

Alamos, was canceled. Arming specialists were no longer needed, 

as automatic arming of the atomic weapons was perfected. After 

the holidays, for better or worse, I would be reassigned. While on 

Christmas leave, Marge and I decided to be a family again, so the 

three of us returned to Biloxi and settled in a dingy motel, hopefully for only a few weeks. A month later orders arrived to go to 

Randolph AFB at San Antonio, Texas, to be a basic flight instructor in a T-6 (formally designated AT-6) aircraft.
PILOTS AND EDUCATION

16

Randolph AFB, at the time dubbed “The West Point of the 

Air,” dates back to 1930. It is named after Capt William Randolph, who was killed when he crashed taking off from Gorman 

Field, Texas. Throughout its life, Randolph has been associated 

with the training of pilots and aircrew members. It is a beautiful air base with a picturesque administration building topped 

by a distinctive tower referred to as “the Taj Mahal.” It has been 

featured in many photographs and serves the purpose of housing the base water tank. The entire base is arranged in a circle 

between two rows of hangars and the two main runways, oriented in the NW-SE direction of the prevailing winds.1

A small duplex apartment about eight miles from Randolph 

and just outside Fort Sam Houston Army base became our 

home. Our neighbors were Capt Frank Swift, his wife Jean, and 

young son Frankie. He was a practicing pediatrician at Brooks 

Medical Center at Fort Sam Houston. We were close enough to 

the Post, as it was called, to hear the bugle calls broadcast over 

the base loudspeakers. 

Historical Note 

Fort Sam Houston dates back to the 1870s, and over the years, most of the country’s Army leaders served a tour of duty there. It has the distinction as the home 

of America’s first military airplane; in 1910, 1st Lt Benjamin Foulois brought a 

Wright Flyer to the post, learned how to fly by correspondence with the Wright 

brothers, and then flew several demonstration flights. This Army airplane number 1 is now displayed in the Air and Space Museum in Washington, DC.2 

The process of training pilots now is entirely different from my 

wartime flight training. During WWII we started in a 200-horsepower (hp) primary trainer (PT), which in my case was a Stearman 

PT-17 biplane. We soloed after about eight hours of instruction 

and accumulated 65 hours flying. We then went to a basic trainer 

(BT), in most cases a Vultee BT-13/15 with either a 425- or 450-

hp engine. The last step was the North American advanced 

trainer, the AT-6, with a 600-hp engine. We received our wings 

with a little over 200 hours flying time. Students now start flight 

training in a T-6, solo in about 20 hours, and accumulate 125 

hours of flying time. They then go to advanced training to master 
17

PILOTS AND EDUCATION

the NAA T-28 and the Lockheed T-33 jet before getting their 

wings with about 250 hours of pilot time.3 

In May 1950, after finishing a six-week flight instructor 

school, I was assigned to a new incoming class (Class 50F) and 

got four students, who all graduated six months later. There 

was no pause in the schedule between classes. The next week 

Class 51H checked in, the last T-6 training class at Randolph. 

I had four brand new students including one cadet named Paul 

Kauttu, whose career I kept track of for many years. 

Cadet Kauttu was a natural pilot and the first student in his 

class to solo. I was quite relaxed flying with him and taught him 

many additional maneuvers not included in the training curriculum, such as making a snap roll at the top of a loop and a squirrel 

cage, which is a series of four loops changing direction 90 degrees 

when inverted at the top of the loop. On the last ride I had with 

Paul we performed an outside loop, where the pilot pushes forward on the stick all the way around. During this maneuver the 

pilot is subjected to a negative g-force, meaning we would hang on 

our seat belts throughout the loop. The T-6 engine uses a carburetor float system that does not work under negative g’s, so the 

engine would quit, and our outside loop was done without power. 

We had to make two tries because, on the first one, the lap belt 

stretched lifting me off the seat so I could not reach full-forward 

stick; we made it on the second by using my foot on the stick to 

push it forward. I wonder if anyone else ever completed an outside 

loop in a standard-engine model T-6. I feel that I gave Paul a good 

start toward his very successful Air Force flying career.

Historical Note

Paul Kauttu was credited with the shoot-down of two MiG-15s while flying F-86s 

with the 16th Fighter Squadron in the Korean War. In 1962 he joined the famed 

USAF Thunderbirds acrobatic team and flew as slot pilot. He became Thunderbird leader from 1964 to 1966. All told he flew in 279 official demonstrations, 

including the 1963 and 1965 Paris Air Shows. In 1968 he went to Vietnam as 

commander of an F-4 Phantom II tactical fighter squadron and completed 111 

combat missions. Then, as deputy commander of an F-100 tactical fighter wing, 

he flew 110 more combat missions. After several other command positions, he 

was promoted to brigadier general and became vice commander of the Ninth Air 

Force at Shaw AFB, South Carolina. He has over 6,000 flying hours, all in jet 

fighters. General Kauttu retired in 1977 with 27 years of active flying service.4
PILOTS AND EDUCATION

18

On 22 June 1950, the Korean War began as the North Koreans swarmed into South Korea in a brutal attempt to subjugate 

and bring South Korea into the communist fold. President Truman, under a United Nations (UN) mandate, committed troops 

and air forces to help the South Koreans repel the invaders.

At first the Korean War did not affect us or our training schedule, but a few months later, Randolph was scheduled to become a 

B-29 crew retraining base. Within the next couple of months, the 

eastern runway and ramp were devoted to B-29 retraining of recalled pilots, but we continued pilot training on the western side.

An interesting interlude from teaching cadets arose when several of us were selected to check out a bunch of B-36 bomber 

pilots in a T-6. This bunch of pilots, mostly majors with a sprinkling of captains and lieutenant colonels, was there to get some 

landing practice. The past several years, they had acquired thousands of flying hours but only a few landings. It was sort of intimidating taking the controls from a lieutenant colonel because 

he was about to stall us for a landing 30 feet in the air. They were 

good sports about it and laughed as hard as we did at their antics trying to get that small, single-engine T-6 on the ground. For 

every try, they got in a half dozen landings as they bounced 

down the runway. We got them all checked out with no mishaps. 

By the end of the week their landings were almost passable.

Historical Note 

Early in WWII, when English Spitfires started to mix it up with the German Me109s over the Dunkirk evacuation area, the Germans noted that the English 

aircraft momentarily lost power during negative-g maneuvers. The English RollsRoyce engines used a float-type carburetor system, while the German DaimlerBenz engines used fuel injection. The German pilots used that knowledge to gain 

the upper hand in a dogfight by employing negative-g maneuvers. Rolls-Royce 

quickly corrected the deficiency.5

Historical Note 

The XC-99, a passenger/cargo version of the B-36 and the only one built, was 

stationed at Kelly Field southwest of the San Antonio area, about eight miles from 

home. The depot there was using the XC-99 to ferry high-priority material to other 

bases. Many mornings, usually just at dawn, the very distinctive deep-throated 

engine roar of that monster would awaken San Antonio as it took off for a mission. 

Many mornings when I heard it heading in our direction, I would get out of bed 
19

PILOTS AND EDUCATION

With cancellation of the atomic energy course, I reverted to a 

flying job. Although I liked flying, my ambition to be involved in 

aeronautical engineering was in limbo, so I investigated Air 

Force service school opportunities. The Air Force, like all the 

military forces, provides many educational opportunities to its 

officer and enlisted personnel to advance and improve their 

skills. Every military career track has several schools that cater 

to those wanting to pursue a particular profession. The military 

benefits greatly from having personnel that intimately know 

the workings and limitations of the machines required by a 

modern military force. My career track was in aeronautical engineering; the Air Force Institute of Technology (AFIT) at Wright 

Field (now Wright-Patterson AFB) in Dayton, Ohio, was the premier institution to advance that dream. 

The school offered a variety of undergraduate engineering 

courses and several postgraduate courses. I made a crosscountry trip to AFIT and talked to the registrar to determine the 

course for which I should apply. He reviewed my education 

background and recommended the postgraduate course in 

aeronautical engineering. I returned to Randolph elated and 

completed my application. My commanding officer sent it on 

with a great endorsement. 

Several months later a letter arrived saying that I was accepted for the new one-year graduate aeronautical engineering 

program. My orders would specify a report date to AFIT of 1 

August. It was a complete surprise being selected for the first 

graduate program at AFIT. I was also tinged with apprehension, as I knew my education limitations and wondered how I 

would be able keep up. AFIT also must have had some concerns, as they sent along a thick sheaf of problems to solve, 

many in math and engineering areas that I knew little or nothing about. 

and go outside just to watch a piece of history roar over the house, shaking up the 

entire neighborhood while clawing for altitude. However, it was just too expensive 

to maintain that one-of-a-kind flying marvel, and it was withdrawn from service. 

After it had deteriorated greatly while parked outside for many years at Kelly Field, 

the Air Force Museum accepted responsibility for it and began disassembling it for 

shipment to Wright-Patterson AFB for refurbishment and display.6
PILOTS AND EDUCATION

20

For readers not familiar with AFIT, the following is a short 

history excerpted from the 1954–55 Resident College Catalogue:

AFIT has a history dating back to 1919 when the Air School of Application was established within the Engineering Division at McCook 

Field at Dayton, Ohio for specialist training of selected officers. In 1920 

when the Army Air Service was created, it was renamed the Air Service 

Engineering School. The school provided technical education for senior 

officers holding command positions. By 1927 the engineering and test 

activities outgrew McCook Field and the entire operation was moved 

to a 4,500 acre plot of ground donated to the US Government by the 

citizens of Dayton. 

This new installation was named Wright Field in honor of Dayton’s 

celebrated sons, Orville and [Wilbur] Wright. The Air Service School 

now became the Air Corps Engineering School. Concurrent with 

their move the Engineering School expanded their program to include junior officers to prepare them to fill positions in research 

and design in the development of air power. By the beginning of 

WWII the school had graduated more than 200 officers including 

many of the WWII aviation leaders. 

In 1945 a high-level study of the Air Corps educational requirements 

found a general lack of educational attainment and the need for improving the competence of the corps. This study recommended that 

two programs be offered, one in engineering and the other in business 

administration and logistics. The courses were to be patterned after 

those offered in leading civilian institutions and should ultimately be 

conducted at the graduate level. The school was to take full advantage 

of the resources which existed in the Wright Field laboratories to round 

out the students with real-world situations and problems. This led to 

the establishment of the Army Air Force Institute of Technology (AAFIT) 

resident school at Wright Field in 1946. It was renamed AFIT when the 

Air Force became autonomous in 1947. 

At the time, AFIT was housed in Building 125, located on the 

hill across from the cafeteria. In back, another hangar-like 

building, 331T, housed the main engineering laboratory. The 

engineering laboratory contained a 13-inch test section, lowspeed wind tunnel, a water table, a very noisy supersonic jet 

facility, a hydraulic flow facility, and numerous other experimental devices. Several other laboratories and an auditorium 

were located with the classrooms on the second floor of Building 125. The first floor housed a well-stocked library, bookstore, and several more classrooms. Our professors were both 
21

PILOTS AND EDUCATION

civilian and military and had offices scattered on the first and 

second floors.

These were WWII temporary wooden buildings which have 

since been demolished and replaced by permanent structures, 

including a modern AFIT campus. Not only have the buildings 

been replaced, but the curriculum has been continually updated to reflect the technological advances that have taken 

place over the years. AFIT had an undergraduate school and 

was just starting a graduate school. Courses were offered in 

two main areas—engineering and business administration. 

Now AFIT is devoted to graduate studies in three areas—the 

Graduate School of Engineering and Management, the School 

of Systems and Logistics, and the Civil Engineering and Services School.7

Our graduate aero­nautical engineer class of 30 students, labeled GAE-52, was scheduled to graduate in late August 1952. 

The aeronautical engineering department was 

headed by Dr. Gunther R. 

Graetzer from the Prussian area of Germany. He 

received a Diplom-­Ingenieur

(PhD in engineering) from 

Munich Technical Institute in 1920. His assistant 

was Associate Professor 

Harold C. Larsen, who was 

a 1945 graduate of the 

AAF Engineering School 

and had a master of science (MS) degree in aeronautical engineering from 

California Institute of Technology. Both professors had 

a profound influence on 

my career and became lifelong friends.

The professors immediately jumped into class work. The first 

month was devoted to a review of undergraduate work to bring 

us all up to date. Unfortunately, most of the material presented 

Capt Robert V. Brulle at the Air Force Institute of Technology, 1951
PILOTS AND EDUCATION

22

was brand new to me. I had a terrible time keeping up, especially in thermodynamics and advanced calculus, and spent 

my entire day studying, most of the time in the library to be 

close to various references. I was not the only one having a 

rough time; within a few weeks half the class had transferred 

out. After two months, only nine of us were left. 

One month after moving to Dayton, our second son, Robert 

Joseph, was born at 0500 in the base hospital. I remember 

waiting for the birth while working on a take-home examination. After seeing Marge and the new baby, I grabbed an hour’s 

sleep and went to class for another test. My wife Marge, saddled 

with a new baby and a three-year-old, was a great help as she 

took charge of all the family work and did not complain about 

it. Over the weekend I would either go to campus to study or 

lock myself in the bedroom. It took every bit of my energy and 

capability to absorb the material. 

We went to school a full year, divided into four quarters, 

carrying 15 to 17 credit hours of difficult mathematicaltype courses each quarter. A sampling of course titles included: Foundations of Aerodynamics, Math Methods in Engineering, Advanced Engineering Math, Response of Physical 

Systems, Advanced Fluid Dynamics, Compressors and Turbines, Aircraft Stress Analysis, Complex Variables, Dynamic 

Stability and Control, Analytical Dynamics, and others. 

Gradually I acclimated, and class work became more routine, although it was a continual battle to learn and absorb 

all the material. 

The Air Force required that we participate in a sporting activity. Many of us did not volunteer for one, so it was a surprise when I was assigned to our class bowling team. I complained but to no avail. I was glad they enforced the edict 

because I thoroughly enjoyed the night out with the boys. We 

used a two-lane bowling alley in the Officers’ Club Dodge Memorial Gymnasium annex at Patterson Field. Since our class 

was small, we acquired several fellows from other classes. One 

was Jim Doolittle Jr., son of the famous American airman. 

Jim was a big guy and a good bowler even though he lofted the 

ball halfway up the alley. We used to kid him that his strikes 

were due to vibrating the pins down by lofting the ball. We 

would close out the evening with coffee and pie at the Patter-
23

PILOTS AND EDUCATION

son Field all-night cafeteria by Base Operations. I have to admit that the mandatory sport participation provided an excellent diversion from continuous study. 

Historical Note 

Maj Jim Doolittle, while commander of a fighter squadron at Bergstrom AFB, 

Austin, Texas, committed suicide in 1958. It was a tragic end for a fine man. In 

his autobiography, General Doolittle describes his anguish and grief on losing 

his son.8

An independent study of our choosing was required. I had 

witnessed several wind tunnel tests while employed as a model 

designer at NAA, and during every test the model vibrated. My 

study project was to record the vibrations of a wind tunnel 

model, then subtract the model’s natural vibration frequency 

to get the forcing function, and correlate the remainder with the 

wind tunnel fan properties. The results were inconclusive, as 

no significant correlation to any of the airflow parameters could 

be discerned, but my unique study and calculation approach 

earned me an A.9

Our main duty was going to school, but to stay on flying status we had to meet the Air Force Specification 60-2 flying requirements.10 The most difficult to fulfill was the actual weather 

instrument-flying requirement. Proficiency aircraft that we 

could use included the T-6, B-25, C-47, and C-45. When we 

were assigned an aircraft, we crisscrossed the country looking 

for some weather to meet our actual-instrument-flying requirement. Sometimes we performed an official service like delivering urgently needed material to NACA, located at Moffett Naval 

Air Station near San Jose, California; picking up some Secret 

material at Alamogordo AFB, New Mexico; or ferrying nurses 

home to Wright-Patterson AFB from Travis AFB, California. On 

many cross-country flights, we brought along our books so that 

while one pilot flew the other could study. We liked to take a 

C-47 since we could study, even at night, sitting at the lighted 

navigator’s crew station. For example, I completed a take-home 

exam during the night trip to Moffett. 
PILOTS AND EDUCATION

24

One of the most delightful flights was a B-25 cross-country 

to Long Beach, California, with classmate Capt Willard “Willy” 

Wilvert. Recall that in this period (the early 1950s), radar flight 

control was not yet developed, and most pilots flew under visual flight rules (VFR) direct whenever possible. This applied to 

both military and civilian flying, and even the airlines. Only 

when confronted with inclement weather would an instrument 

flight rules (IFR) flight plan be filed. VFR flying was essentially 

uncontrolled, which left the pilot a lot of leeway to select the 

routes and altitudes for the flight. It was still the era of seeand-avoid while flying.

It was August 1952 when Willy and I were assigned a B-25 for 

a weekend flight. On this flight to Long Beach, we brought along 

five young just-commissioned ROTC 2nd lieutenants. They just 

wanted to get in a flight, so we obliged with a flight through a 

monstrous afternoon thunderstorm, buzzed Boulder (now Hoover) 

Dam and Lake Mead, and flew from there up the Grand Canyon 

at the Colorado River level. We even took them to Juarez, a Mexican border town across the Rio Grande from El Paso, Texas, for a 

big steak dinner. There Willy tipped our vivacious and very attractive Mexican waitress to make a play for one of the young lieutenants. It was a good-natured joke that amused us all, even the 

young lieutenant who was the butt of the joke. It was a great flight 

that will be remembered by us all.11

I know we broke a few regulations, but it all worked out okay. 

Flying in the later years became more controlled and businesslike. You were required to stay on airways and regularly report 

your progress. That made it difficult, but not impossible, to get 

away with some buzzing or stunting. I understand the need for 

aircraft flight control but do look back nostalgically to a time 

when flying was freer.

Historical Note 

A few years later, on 30 June 1956, a United Airlines Douglas DC-7 and a TWA 

Lockheed L-1049C Super Constellation had a midair collision over the canyon as 

the pilots were circling to give their passengers a good look. All 70 people onboard 

the two aircraft were killed. That accident precipitated the practice of airliners 

routinely filing an IFR flight plan so they would be under ground control. About 

10 years later, the big curved-screen Cinerama, debuting its initial theater pre-
25

PILOTS AND EDUCATION

The nine graduating GAE-52 students were treated to a trip 

with Dr. Graetzer to Langley Field near Hampton, Virginia, and 

the Naval Ordnance Laboratory (NOL) near Silver Spring, Maryland. At Langley we visited the NACA facility and had a guided 

tour through the various wind tunnels. At NOL we met the husband-and-wife team of Ernst-Hans and Eva Winkler. They were 

both physicists who were employed at the German Peenemunde 

rocket facility, where they participated in the development of the 

V-2.12 Brought to the United States after the war, they were now 

running the 40 cm (16 in) blow-down supersonic wind tunnel 

brought over from Germany. This is the tunnel copied and installed at NAA while I was working there (see chap.1). It had the 

capability to achieve a Mach number of 4.4 and was used extensively to determine the V-2 tailfin size and shape for a stabilized 

supersonic final plunge to Earth. Late in the war, a modification 

of that tunnel achieved a Mach number of 8.8. The Winklers 

were attempting to reach Mach 10.0, which entailed solving a 

host of new problems in tunnel design. 

Recall that supersonic Mach numbers require a convergent/

divergent tunnel. The Mach number in the convergent tunnel 

section is increased to the throat, where the flow is at Mach 

1.0. The air flow is then expanded in the divergent section to 

the design Mach number in the test section. Expanding air decreases in temperature, possibly freezing any water vapor, so 

dry air must be used in the tunnel. Higher and higher test 

Mach numbers require a greater expansion and result in colder 

test air temperatures. At about Mach 5.0, the nitrogen in the 

air freezes (78 percent of air is nitrogen). To prevent the nitrogen from freezing, very hot air is used. In addition to using 

heated air, the pressure tank must be charged with very high 

pressure. To reach Mach 10.0, the tank pressure must be at 

least 42,500 times the test section pressure—a daunting tunnel design challenge. (Later I describe a hypersonic tunnel that 

was used in Projects Mercury and Gemini to reach Mach 27.)

sentation, showed a view from a camera mounted in the nose of a B-25 skimming 

the ground toward the Grand Canyon overlook. As the B-25 flew over the rim, the 

pilot banked the aircraft and dived into the canyon. The Cinerama camera view 

was spectacular and brought back memories of this flight.
PILOTS AND EDUCATION

26

When the Germans achieved Mach 8.8 in 1944, they saw the air 

fogging caused by the freezing nitrogen. They realized then that 

very hot air must be used, as frozen nitrogen invalidates any qualitative test results. These high supersonic Mach numbers are thus 

relegated to another new branch of aerodynamics labeled hyper-­

sonic. Arbitrarily, Mach 5.0 and above is defined as hypersonic.

Just before our graduation, Dwight D. Eisenhower was nominated for president on the Republican ticket. This was the first 

political convention televised, and it was an enlightening experience to view the process. The roll call of the delegates was 

conducted during the day while we were in school. (The political 

parties did not yet grasp the public relations impact of television. Later, the critical roll call vote was conducted in the 

evening.) Over the radio, we heard the vote count as “Mr. Republican,” Robert A. Taft, battled it out with Eisenhower. When 

the count was over, neither candidate had a majority. One state 

that had initially voted for a favorite son then requested to 

change its vote to Eisenhower. That evening we were glued to 

the TV set as the convention continued. For better or worse, 

television changed our view of the political process in America 

and had a large impact on the voting process from then on.

Finally the big day, 26 August 1952, arrived when we graduated from AFIT. An elaborate ceremony was arranged at the 

Patterson Field Officers’ Club with Maj Gen John De F. Baker, 

deputy commanding general of Air University, presenting our 

certificates. Since the AFIT program was not accredited, we were 

issued a certificate stating we had completed the course of study 

of (in my case) graduate aeronautical engineering. The Air Force 

accepted that as an equivalent master of science (MS) degree. 

Historical Note 

In 1955, based in part on the courses we just completed, the AFIT program was awarded 

accreditation by the Engineering Council for Professional Development (ECPD), now 

known as the Accreditation Board for Engineering and Technology (ABET), the primary 

education accreditation board for all technical education programs.

As a surprise, each of our wives was presented a “Distaff Diploma” since she had, “endured the prescribed tortures, suffered a thousand and one nights in the presence of genius at 
27

PILOTS AND EDUCATION

work, walked the last mile of academic agony with her espoused, and has in general completed that curriculum required 

for graduation with the degree UW (USAFIT Wife).” My studying 

paid off; I was exactly in the middle of the graduate aeronautical engineering class—fifth of nine graduates—with a grade 

point average of 3.06 out of 4.0. I had completed one of the 

hardest working years of my life. 

After graduation we all went on with our own careers and 

lost touch with each other. Over the years I would hear about 

or meet a former classmate, but there was no lasting companionship between us. One I did meet again was Joe Steele, our 

Coast Guard classmate. He worked his way up in the Coast 

Guard; when I met him again he was a rear admiral in charge 

of the St. Louis District.

Several graduates from other AFIT classes and I were assigned to the Wright Air Development Center (WADC), which 

contains all the technical facilities at Wright Field. Many opportunities thus beckoned, but I was not sure which avenue to 

pursue. I was torn between going to the WADC aircraft laboratory—the center for Air Force aerodynamics research—or becoming a weapon system project officer in the new aircraft procurement program just being initiated. I decided to become a 

project officer.

Notes

1. A history of Randolph AFB, including a photo of the “Taj Mahal,” is 

available at http://www.randolph.af.mil/home. 

2. Roger G. Miller, “ ‘Kept alive by the postman’ the Wright Brothers and 

1st Lt. Benjamin D. Foulois at Fort Sam Houston in 1910,” Air Power History

(Winter 2002), 32–45, provides an interesting account on how Lieutenant 

Foulois accomplished that feat.

3. Robert V. Brulle, Angels Zero: P-47 Close Air Support in Europe (Washington, DC: Smithsonian Institution Press, 2000), chaps. 1 and 2, provides a 

WWII pilot training syllabus. 

4. Official USAF biography, http://www.af.mil/bios/bio.asp?bioID=5998. 

The World Wide Web lists a half dozen sites on General Kauttu’s career. For 

example, http://afhra.maxwell.af.mil/avc/avc.asp/ provides access to his 

aerial victories flying F-86s in Korea.

5. Donald L. Caldwell, JG 26—Top Guns of the Luftwaffe (New York: Ballentine Books, 1991), 23.
PILOTS AND EDUCATION

28

6. Lt Col George A. Larson, USAF, retired, “XC-99—First of the Transport 

Giants,” Air Force Museum Friends Journal 25, no. 2 (Summer 2002): 29–33, 

provides an excellent summary of the XC-99 with pictures and specifications.

7. AFIT Web site, http://www.afit.edu/about/what_is_afit.cfm.

8. Gen James H. “Jimmy” Doolittle with Carroll V. Glines, I Could Never Be 

So Lucky Again (New York: Bantam Books, 1991), 482–85.

9. Robert V. Brulle, Preliminary Investigations on Wind Tunnel Model Vi-­

brations, AFIT Report GAE-52-1 (Washington, DC: AFIT, 1952). 

10. At that time, Air Force Specification 60-2 required pilots to fly at least 

120 hours per year apportioned between visual, instrument under the hood, 

actual weather instrument, and night flying. 

11. Robert V. Brulle, “Wild flight up the canyon,” Air Classics 34, no. 9

(September 1998): 44–49.

12. Wegener, Peenemünde Wind Tunnels, 27.
29

Chapter 3

Aircraft Procurement

When we received our orders to report to the Wright Air Development Center, I learned that the WADC commander, Maj 

Gen Al Boyd, would interview us for the positions desired, and 

I did not want that. About three weeks prior, I had cut him out 

of a landing approach to Wright Field. Both of us were cleared 

number one to land by the tower; however, I was on the local 

Wright Field frequency and General Boyd was on the crosscountry frequency, so neither of us heard the tower clear the 

other as number one. A severe dressing-down in his office was 

followed by a more humble “be more alert” admonishment, 

once the whole story unfolded. I was not anxious to again make 

his acquaintance.

Historical Note

Col Al Boyd set a flight speed record of 623.3 mph in a P-80 in June 1947 at Muroc AFB, California.

Fortunately the interview went pretty well. I am sure he recognized me but he did not mention or even acknowledge our 

previous encounter. The main point he stressed to the four of 

us in the interview was that we were engineers and would be 

responsible for ensuring that the aircraft and materiel acquired 

by the Air Force met all specifications and was absolutely the 

best obtainable. If it did not do the job, we were not to approve 

it for purchase by the Air Materiel Command (AMC). He asked 

for our assignment preferences, and I obtained my choice of 

assignment to the Fighter Branch Weapon System Project Office, usually just referred to as System Project Office (SPO). 

Relieved to have completed that hurdle, I reported to Col William “Bill” Gilchrist, commander of the fighter branch, and was 

able to choose the Republic Aviation Corporation (RAC) SPO.1

Prior to 1950 the AMC, headquartered at Patterson Field, 

Ohio, was responsible for all facets of procuring new weapon 

systems, from research and development through procurement 
AIRCRAFT PROCUREMENT

30

and support for the operational commands. This time period 

saw a meteoric rise in weapon systems complexity and cost, 

straining the ability of the AMC to manage it efficiently. To 

streamline the operation, on 23 January 1950 the research 

and development area was separated into a new command, the 

Air Research and Development Command (ARDC), leaving the 

logistic area of procurement, supply, and maintenance to the 

AMC. In this manner the ARDC would qualitatively approve the 

aircraft and equipment prior to the AMC procuring it. In addition, the ARDC would be responsible for all the research to 

analyze and test new technologies and follow through to the 

development of a weapon system. The AMC would be the procuring agency for the system as it was approved by the ARDC. 

The venue for this process was the SPO. 

This new concept, it was hoped, would provide the Air Force 

with a superior product at a reasonable cost. Concurrent with 

the implementation of the weapon system concept, an industry 

prime contractor was selected to integrate the entire system. At 

the project level, the SPO dealt with the prime contractor to assure Air Force requirements were being met.

ARDC headquarters was established at Andrews AFB in Maryland. The WADC technical facilities at Wright Field, including 

the wind tunnels, engine test stands, gun range, structures, 

equipment, armament, and aircraft laboratories, all became a 

part of the ARDC. Besides the facilities at Wright Field, the ARDC 

acquired several other major Air Force components—the Air 

Proving Ground (APG) at Eglin AFB, Florida, and the Special 

Weapons Center (nuclear weapons) located at Albuquerque AFB, 

New Mexico. Other specialized government laboratories scattered around the country also became a part of the ARDC.

Colonel Gilchrist commanded the ARDC side of the fighter 

branch SPO and reported directly to General Boyd. His deputy 

was Lt Col Richard L. “Dick” Johnson, who I got to know quite 

well. A civil service employee, Gerry Kaufhold, was a deputy to 

Colonel Gilchrist and provided continuity as Air Force officers 

were reassigned. The fighter branch had a separate SPO for 

each aircraft manufacturer. At the time these included Republic, North American, McDonnell, Convair, Northrop, and Lockheed. The RAC SPO exercised control for all Republic-produced 

aircraft—the F-84E and G (straight-wing version), the F/RF-
31

AIRCRAFT PROCUREMENT

84F (swept-wing version), and the F-105, still in the design 

stage. An adjunct SPO for the F-84H, an experimental derivative of the F-84F with a gas-turbine engine driving a supersonic 

propeller, was located next door. The other fighter aircraft managed in an SPO at the time included the North American F-86 

and F-100, McDonnell F-101, Convair F-102, Northrop F-89, 

and Lockheed F-94 and F-104.

Historical Note

Dick Johnson set a flight speed record at Muroc Field (later renamed Edwards 

AFB) of 670.98 mph in an F-86 in September 1948.2

Two Republic experimental aircraft were not controlled by an 

SPO. The XF-91 was an F-84 fuselage mated with a set of inverse tapered swept wings; that is, the wing thickness and 

chord increased outboard, so the tip was larger than the root. 

This unorthodox wing platform was being tested to see if it 

would eliminate the span-wise air flow over swept wings, which 

tended to have a viscous stall. It also had a variable-incidence 

wing and a rocket motor.3 The other RAC experimental aircraft 

was the XF-103, a bomber-defense aircraft which used a hybrid turbojet/ramjet engine (described later). 

As mentioned, each SPO had both ARDC and AMC personnel. 

Having ARDC approve AMC purchases did not set well with 

some AMC personnel, especially the civil service veterans who 

previously had been in charge of the entire procurement process. This created friction between ARDC and AMC factions, 

and it took a while to integrate the SPO into a cohesive team. 

By the time I was assigned, some of the animosity between the 

factions had worn off, but an underlying feeling of acrimony 

still permeated the SPO.4

Maj Walt Waller and a secretary staffed the ARDC side of the 

Republic SPO. Lt Col W. B. Sellers, Capt George Slentz, and 

several civilians made up the corresponding group of AMC personnel. Major Waller was snowed with work, so he greeted me 

with a hardy handshake and a glad-you’re-here speech. At the 

present time, the F-84D and E were performing yeoman service 

in the ground support role in Korea. One nagging problem was 

that the main wing spars were developing cracks from contin-
AIRCRAFT PROCUREMENT

32

ued wing flexing during high-speed, low-altitude operations in 

the turbulent mountain air of Korea. Field splices were being 

installed but only temporarily alleviated the problem. A permanent solution was the revised F-84G, sporting a more robust 

steel-forged wing spar. It was just starting to come off the assembly line. The F-84F was essentially a new swept-wing aircraft with a new engine and many other features for use as 

both a tactical ground support and long-range bomber escort 

for the Strategic Air Command (SAC). The only reason it bore 

an F-84 designation was that Congress was not funding any 

new aircraft programs, so the subterfuge funding ploy was used 

by the Air Force to underwrite its procurement. This is considered in more detail later. 

Clearing up the backlog of unsatisfactory reports (UR) issued 

against the F-84D and E models was my first assignment. Anyone associated with an aircraft can submit a UR for any unsatRepublic Aircraft

RF-84F reconnaissance version. Note wing fences to prevent span-wise air flow 

over the wing which resulted in a viscous stall.
33

AIRCRAFT PROCUREMENT

isfactory situation encountered. A pilot may submit one on the 

handling qualities during a high-speed flight; a mechanic may 

submit one to point out a dangerous situation during an engine change or on a multitude of other squawks that can endanger a person or impair the flight mission. The SPO was the 

recipient of these URs, and in conjunction with the applicable 

laboratory, had to answer them all. It was a tedious but effective way to learn about the F-84 aircraft. 

A welcome respite occurred when Major Waller sent me to RAC 

to monitor a test to find the source and correct the annoying 

loud “cow moan” noise from the jet exhaust. Noise complaints 

from persons working in the vicinity of an F-84F engine run-up 

were too numerous to ignore. RAC set up a test to record the 

sound frequency and loudness and wanted Air Force representation there. Major Waller did not think anything could be done 

and that it was a waste of time but agreed to send me with the 

dynamics specialist from the aircraft laboratory to monitor the 

test. He also mentioned that it would be a good time to become 

acquainted with the RAC tech reps (technical representatives).

After checking in with the Air Force plant representative the 

next morning, we went to the RAC tech rep office. They provided the coordination and arranged for contacting the appropriate engineers or other persons. I met Murray Barekow, who 

headed the office, and three others—Bob Johnson, Jack Riley, 

and Jeff Meeker. Having a cup of coffee with them precipitated 

a get-acquainted session. I gave them a little background of my 

experience, and when I mentioned I was a P-47 pilot in Europe, 

they motioned for Bob Johnson to rejoin the session. It then 

dawned on me that he was the famous Bob Johnson, secondhighest-scoring ace, who shot down 27 German fighters flying 

the Republic P-47 Thunderbolt during the large air battles in 

1943–44. This led to a long and memorable friendship with Bob 

for almost 50 years.5

The cow moan sound test was inconclusive. The engineers recorded the sound spectrum at several discrete points around the 

maximum intensity point. Following the test our ears kept ringing 

for the whole day. Appraising the data showed no discernable 

frequency that could be tagged as the culprit. It was undoubtedly 

an organ-pipe effect due to the long air duct. The pilots and ground 
AIRCRAFT PROCUREMENT

34

crew would just have to get used to the noise. (Perhaps this is 

when ear guard use became mandatory around jets.) 

Getting the F/RF-84F to the operational commands became 

our number one priority. That story provides an excellent example 

of the weapon system procurement process at that time. Many 

critical weapon programs were being procured then, so I do not 

know if the F/RF-84F procurement was a unique case. I do know 

that it was a chaotic, frustrating period that deserves to be remembered as an example of how we met the Soviet challenge.6

The F-84F was a hastily designed and constructed sweptwing upgrade of the F-84E, which belatedly entered the competition for a penetration fighter to escort the SAC bombers. The 

competition, held in 1950, was between the Republic sweptwing F-84, the North American YF-93, the Lockheed XF-90, 

and the McDonnell XF-88. From these, the swept-wing F-84 

was selected, not only for the penetration fighter role but also 

for the main ground support role. The F-96 designation proposed by RAC was quickly quashed by the Air Force. It was 

imperative that the aircraft retain an F-84 designation because 

it was impossible to get funding for a new aircraft from the administration and Congress. These were the conditions under 

which the F-84F Thunderstreak and its companion, the RF-84F 

reconnaissance-version Thunderflash were born.

The F-84F swept-wing fighter evolved during a period of great 

change within the US defense establishment following the 

post–WWII yo-yo of demobilization then rebuilding as the Cold 

War intensified. Russia was building and testing nuclear bombs 

and had hoards of tanks poised to strike into Europe. When 

NATO was born in April 1949 to offset this threat, the United 

States agreed to supply military aircraft under a treaty called 

the Military Defense Assistance Program. The F-84F was the 

primary aircraft selected for this role because it had a large and 

varied weapons load as a ground support aircraft to neutralize 

Soviet armor. Since it also performed the air defense fighter 

role, it was a versatile multirole aircraft. The continued expansion of the Soviet military and its abrogation of WWII treaties 

and understandings created an urgency to procure the aircraft 

and get it into the operational inventory.

By the time all the dual-role requirements were integrated 

into the aircraft, the weight had increased, requiring a higher-
35

AIRCRAFT PROCUREMENT

thrust engine. The engine selected by the Air Force was the J-65, 

an Americanized version of the British Armstrong Siddeley 

Sapphire engine manufactured by the Wright Aeronautical Division of the Curtis-Wright Company. The airframe was enlarged to accommodate the larger engine air flow, expanding 

the circular air duct into an oval by adding a seven-inch section on each side. Since it was supposedly an F-84E derivative, 

the delivery schedule specified only the first two production 

aircraft for flight tests—the first for engine testing and the second for performance, stability, and control testing. Succeeding 

aircraft were allocated to the operational commands. As the 

first few units came off the production line, the Air Force policy 

of not declaring it a new aircraft became self-defeating when 

the problems multiplied for lack of an adequate test program.

The first production F-84F was made ready for flight even 

though a host of major problems remained. The worst was that 

the Wright J-65 engine was not flight-worthy and had not yet 

completed its required 150-hour test run. Finally, an acceptable engine allowed the first flight of a production F-84F on 23 

November 1952. 

Republic Aircraft

The first F-84F flight on 23 November 1952. Many modifications were needed 

before it became operational in 1954.
AIRCRAFT PROCUREMENT

36

Serious power plant problems soon surfaced that for quite 

some time limited the engines to 25 flight hours. One of the 

most serious was the rubbing of the aluminum compressor 

turbine blades on the housing at high temperatures. An interim fix was accomplished by shaving the turbine blades a 

small amount to increase the clearance, but the problem was 

not really fixed until steel turbine blade engines were produced. 

This and a host of other engine problems, along with unreliable 

operation, plagued the program for several years, creating a 

shortage of engines that compelled Republic to store completed 

aircraft outside awaiting engines. At one time RAC had 450 

completed aircraft waiting for engines or other retrofits. Storing 

these aircraft outside unprotected created unforeseen consequences later. The problem was further compounded by coordinating the changes at the second-source engine manufacturing 

facility at the Buick Motor Division of General Motors in Flint, 

Michigan. These problems were the purview of the Propulsion 

Laboratory; our SPO contribution was to provide the necessary 

directives to perform the required work and authorize several 

additional aircraft for engine testing.

 In addition to engine problems, flight control and stability 

problems surfaced. The initial batch of aircraft with a conventional elevator could barely control the compressibility pitch-up 

phenomenon at transonic speeds.7 A full moving tail (then called 

a “flying tail”) would be needed. An interim fix utilized the trim 

actuator, which moved the stabilizer in conjunction with the elevator to provide what was called a “poor man’s flying tail.” 

Transonic-speed aileron control was also inadequate; pilots 

reported having to hold almost full aileron to maintain level flight 

in the high–Mach number, high–dynamic pressure flight region. 

(Dynamic pressure is the impact pressure generated on a body 

moving through the air and is a direct function of the air density 

and velocity squared. Therefore, high-speed flight at low altitude 

generates a high dynamic pressure.) These problems arose because the F-84F expanded the flight envelope into the unexplored aerodynamic, structural dynamic, and flight control regions of high transonic speed at high dynamic pressure. Wind 

tunnel tests cannot duplicate the flight conditions, and analysis 

methods were not available, so the only way to get data was to 

build and flight-test an aircraft. Undoubtedly spoilers—small 
37

AIRCRAFT PROCUREMENT

flaps mounted on the upper wing surface that pivot up—would 

be needed to achieve an adequate roll control. Test pilots were 

displeased and vocally critical of those and other flight-control 

deficiencies. I learned this firsthand when I attended a test program conference at Edwards AFB Test Center, where Maj Chuck 

Yeager and his cohorts testing the F-84F cornered me with their 

concerns. My only retort was that we were aware of and working 

to solve the problems, but the Air Force and administration 

wanted these aircraft operational.

The limited lateral control dictated that the wing-rigging mismatch between the left and right wings be within 1/4 degree. 

This was difficult to achieve in production, so RAC considered 

matching the wings to pair equal tolerances together to minimize the wing-rigging mismatch. This was summarily rejected. 

Fortunately, RAC solved the manufacturing wing-rigging problem by making very thin shims that were used on assembly to 

correctly rig the wings; however, several test aircraft had the 

wings paired for minimum mismatch.

It was obvious that more than two aircraft were going to be 

required for testing. In fact, Major Waller and I stuck our necks 

out and signed the contract-change notification, over the advice of various ARDC laboratories, granting RAC a list of deviations to allow AMC to purchase the first 10 aircraft to get them 

into test. I recall that one of the most controversial deviations 

was that they could use Camlock access panel fasteners, which 

were not yet approved fasteners. I just could not understand 

such bureaucratic nit-picking holding up the entire program 

when we were trying to get a needed aircraft operational.

The Air Force selected the revolutionary Westinghouse E-9 autopilot for the F-84F. This autopilot employed new magnetic amplifiers instead of the failure-prone and high-energy-drain vacuum 

tubes (this was the pre–transistor era). As with any new device, 

problem after problem arose. The most annoying were a highaltitude longitudinal oscillation that precluded the use of a sextant 

to shoot navigational sights and the inability to maintain a coordinated turn. Fortunately, Republic also elected to flight-test a 

Lear F-5 autopilot and, because of the E-9 problems, recommended that it be used in the F-84F. The Air Force agreed with 

the recommendation but not until several hundred or so aircraft 

had been produced with the E-9 autopilot. They then had to de-
AIRCRAFT PROCUREMENT

38

termine how to cool the F-5, especially during the cook-off period 

when the aircraft was shut down and the vacuum tubes overheated. (Cook-off heating was caused by the hot tubes radiating 

heat because the cooling fans were shut off. In fact, all vacuumtube-driven electronics had that problem.)

A potentially serious problem was discovered by pilots testing 

the flying tail. Returning from a test flight in formation, the chase 

pilot noticed that the test aircraft’s flying tail was canted about 

10 degrees; however, as they slowed down the tail snapped back 

into place. After landing he could not convince the engineers 

that this happened. Photographs taken on the next flight proved 

his contention and brought a flurry of effort. 

It was found that the flying tail had three structurally stable 

points: horizontal and canted either 10 degrees clockwise or 

counterclockwise. Pilots could flip from one point to the other 

by yawing the aircraft left or right, or center it by easing in a 

yaw against the cant. The problem was traced to the flying tail 

actuator and pivot geometry arrangement—the actuator attachment was too close to the pivot axis. As with many engineering problems, structural dynamics solutions were not 

amenable to the analyses techniques available at the time. The 

solution—build, test, and fix it.

The fix was to move the actuator attachment point further away 

from the pivot. In addition to hardware changes, this required 

new analyses on control sensitivity, pilot-induced oscillation (PIO) 

susceptibility, and trim capability. (PIO is a phenomenon where 

the pilot-control pitch frequency is close to the aircraft pitching 

response, making the pilot susceptible to being 180 degrees out of 

sync with the aircraft pitching. This leads to a severe divergent 

oscillation that can destroy the aircraft in a few seconds and is 

most susceptible at high dynamic pressure flight.)

This whole control problem episode reached the highest levels, 

and several RAC top management personnel, including vice 

presidents Alexander Kartvelli and Lowery Brabham, were called 

on the carpet in General Boyd’s office to explain and outline the 

proposed solution. As secretary, I recorded the pertinent decisions and agreed-upon work effort. In essence it entailed a lot of 

rework, analyses and tests, and interim fixes to keep the aircraft 

flying. There was also the question of what to do with all the air-
39

AIRCRAFT PROCUREMENT

craft in production; they just waited with the others parked outside on Republic Field until the fix could be retrofitted. 

For its weight and external stores carried, the F-84F aircraft 

was grossly underpowered. The rated static thrust of the J-65 

was 7,220 pounds. Installed usable thrust was a lot less, about 

6,000 pounds on a standard day, and on a hot day it deteriorated to 5,200 pounds. This low thrust, combined with the 

heavy loads, gave the F-84F a sluggish takeoff and climb out. 

(It was given the unflattering title of “superhog” by the pilots, 

who had already labeled the straight-wing F-84s a hog.) This 

condition increased the possibility of pilots flying on what was 

called “the back side of the drag curve” and ending up at the 

minimum equilibrium airspeed point. At that point the pilot 

has two options for recovery—either reduce drag by dropping 

external stores or lower the nose to gain airspeed. At low altitude, close to the ground, lowering the nose to gain airspeed is 

impossible, so ejection is the final recourse. A detailed description of this phenomenon appears in figure 1.

Republic Aircraft

F-84F air refueling checkout viewed from the piston-engine KC-97 tanker boom 

operator’s station. Note that the F-84F pilot had to use half flaps to fly slowly 

enough to connect with the refueling boom.
Figure 1. Back side of drag curve explanation

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AIRCRAFT PROCUREMENT

One such crash at Eglin AFB required an all-night trip to 

participate in the accident investigation. Since it was a test 

flight, tracking movies allowed an accurate assessment of the 

flight. The pilot pulled the aircraft off the ground too soon, trading a few knots of airspeed for 50 feet of altitude and, while 

flying at the minimum airspeed point, found himself heading 

toward a rising ground covered with pine trees. He jettisoned 

his wing tanks to reduce drag and weight, but one tank momentarily hung up, snapping him into the ground. The flight 

safety board agreed the accident was the result of pilot error, 

with a faulty tank release system as a contributing cause. This 

flight condition was of primary concern to pilots during that 

era of limited-thrust jet engines, so those of us who flew in 

those days held the aircraft level immediately after liftoff to gain 

sufficient airspeed to prevent that situation.

Historical Note

The first time I rode in a jet transport in 1962, greatly improved jet engines were 

available. I recall the pilot pulling the nose up in a steep climb immediately after 

takeoff, alarming me as I held on waiting for the deadly stall. It took me quite a 

long time to feel comfortable with the steep climb-out of modern jet transports.

F-84F production continued throughout all these problems, 

with RAC implementing fixes as quickly as possible. Fixes had 

to be implemented not only at Republic but also at the secondsource General Motors F-84F production facility in Kansas 

City. Many discussions occurred and, in some cases, firm directives were issued as to when certain fixes were to be effective. When RAC tried to delay installation of the flying tail for 

another several hundred or so aircraft, production was ordered 

stopped until the flying tail could be implemented in production. The aircraft without a flying tail (the first 265 produced) 

were declared combat deficient and relegated to the training 

command instead of their intended commands. It was a firstorder dilemma. We knew the aircraft had deficiencies, but it 

was needed as a weapon to deter the Soviets. We had to compromise and hope we made the right decisions.

In the midst of the frantic effort to get the F-84F into operation, I had to take off a few days to help out at home. Both of 
AIRCRAFT PROCUREMENT

42

our boys were sick with the measles, and Marge decided that 

was a good time to go to the hospital for several days to have 

our third child, a baby girl we named Susan. Fortunately, 

grandma came down from Chicago to help out. Thank God for 

those wonderful grandmothers.

Air Force insistence on incorporating new developments into 

weapons and equipment exacerbated the problems. This was a 

period of rapid advancement in aeronautical technology, and 

each new breakthrough was explored for incorporation feasibility. 

Many enhanced the capability of the aircraft, but any change 

complicated our getting the aircraft to the using commands 

and usually degraded performance due to the weight increase. 

Here are a few examples: 

• Nuclear weapons’ weights and sizes had been drastically 

reduced, allowing them to be carried on fighter aircraft, so 

the Air Force directed that a series of F-84Fs be equipped 

with that capability. 

• The SAC penetration fighter aircraft required bright thunderstorm lights in the cockpit to prevent lightning from 

blinding the pilot. 

• A pulsating cushion to keep the pilots from stiffening up 

during long flights was considered. 

• Several aircraft were configured as test aircraft for supersonic propellers and designated as F-84Hs. 

• Tactical Air Command (TAC) wanted the SAC flying-boom 

air refueling receptacle replaced with the TAC probe-anddrogue system.

• All aircraft were to have rocket-assist takeoff provisions. 

Historical Note

Mentioning nuclear weapons and SAC reminded me of when I became acquainted with 

the low-altitude bombing system (LABS) maneuver. As nuclear weapons became light 

enough to be carried by fighter aircraft, a dilemma arose on how to drop them at a high 

speed and low altitude and get far enough away before the blast occurred. Major Waller 

was handling the nuclear weapons integration on the F-84. When he returned from his 

Eglin AFB briefing and orientation on the weapons’ operational use, he mentioned the 

LABS maneuver and explained how it worked. The fighter roars in at high speed to the 
43

AIRCRAFT PROCUREMENT

Even though the F-84F had many defects, the Soviet threat 

was serious enough for the Air Force to use the aircraft in its 

“as is” condition to counter the USSR colossus. Air Force personnel accepted the challenge and paid the price for the belated 

rearming action by the president and Congress. Americans 

desperately wanted peace, but found that détente with the Soviets was impossible except on their terms of capitulation. I 

received the following discourse from Col H. Norman Holt, commander of the first American fighter unit to receive the F-84Fs 

in Europe: 

My experience as the commander of the 81st Fighter Wing in the United 

Kingdom began in early 1955. We were advised that our wing, located 

at Bentwaters RAF Station, would be the first to receive the new F-84F 

aircraft in Europe. We studied the aircraft specifications and requirements for operating the planes carefully. Among the requirements was 

the need for beefed up runways to take the very high footprint pressure. 

Third Air Force had not anticipated this need, so an accelerated construction program had to be undertaken.

The method of transporting the aircraft to Europe was deck-loaded 

aboard pocket carriers. Prior to loading, the planes received a new plastic 

cocoon envelope designed to keep the sea water spray out of the airframes. When the aircraft were off-loaded at Marseilles, France, just the 

opposite proved to be the case. When the cocoons were peeled off, sea 

water poured out of the airframes! Not only did the cocoons fail to keep 

the sea water out, they actually held it in! It was not discovered until later 

the damage that this salt water caused. Switches, relays and electrical 

contacts were all corroded. The damage was beyond belief.

Further, the aircraft were dependent on LOX (liquid oxygen) for the pilots at high altitude. There was none in Europe at that time. With the 

pilots ready to fly the planes to England, we faced the task of finding a 

satisfactory flight profile to fly the distance to our base at 10,000 feet so 

we could fly without oxygen. We did so without incident.

Then things began to happen. Accident after accident occurred, eleven in 

all with four fatalities. Nine of the accidents proved to be caused by metarget at a height of 500 feet and when over the target initiates a pull-up into an Immelmann turn (a half loop and roll-out at the top). While the aircraft is heading upward, the pilot releases the weapon and completes the getaway Immelmann. The bomb 

arcs upward before plunging to the target, allowing enough time for the pilot to exit the 

danger area. Years later talking to some B-47 pilots I was flabbergasted when they 

mentioned practicing the LABS maneuver. That must have been some sight—a sixengine jet bomber doing a low-altitude Immelmann.
AIRCRAFT PROCUREMENT

44

chanical or electrical failure. The other two were suspect with no specific 

proof possible after investigation.

The culprit in all instances proved to be corrosion of the electrical components. Inspections showed that most of the cannon plugs (multi-pin 

male and female connections) had corroded to such an extent that electrical currents were leaping across the connecting wires at the bases of 

the plugs. The pins were so loose and un-insulated that most of them 

pulled out when the plugs were separated. As unsatisfactory as that 

was, we had to continue flying the aircraft.

Worse still, the closest depot for F-84F parts was Burtonwood Depot (near 

Liverpool), a base out of touch with what was going on. Because the 

F-84G (straight wing aircraft) was already obsolete, and with no prior 

alerting that the F-84F was a new swept wing aircraft about to be introduced into the theater, some bright officer decided that the F-84F parts 

must be history. The depot salvaged (scrapped or disposed of) them. The 

result was we were grounded with no parts for some time abrogating our 

NATO support mission. The depot was closed, and rightfully so, and we 

received all of our support direct by air from the states.

The aircraft sent to us were the F-84F-40RE type, and were not fitted 

with spoilers to augment roll control at high Mach number and dynamic pressure. During a high-speed formation pass over our home 

base, I experienced loss of roll control that threw a scare into me that I 

can still recall. Close to maximum Mach number I had to use full aileron to the left to maintain level flight. That meant that restricted performance had to be uppermost in a pilot’s mind, not the best mental condition for a fighter pilot in combat.

On my strong complaint and presenting the evidence on the decrepit 

state of the aircraft, all of the original aircraft were replaced with new 

ones, supposedly shipped a different way.

We lost four fine, experienced jet pilots because of defects in the F-84F 

aircraft we were assigned to fly. I attributed the losses to corrosion both 

from the long storage period on Republic Field, but worse still from the 

sea water corrosion caused by the defective preparation and method of 

transporting the airplanes.

Basic to the whole series of problems was the foolish subterfuge of designating the new F-84 as an “F” model. All aspects of that labeling were out 

of order. It was fundamentally dishonest, questionable for its political maneuvering, disruptive to the necessary test requirements and supply channels, and finally to be indicted for the gross loss of lives and dissipation of 

valuable resources.

It has often been said, “We make our own problems.” This may be one 

of the classic examples.
45

AIRCRAFT PROCUREMENT

This whole period was, in fact, a disheartening experience in my career. 

To face the wives of those officers who died in the four accidents was a 

serious negative for me. All I could say to them was, “We are all taking the 

same risks. It is the sort of life your husband chose to follow, with all of 

its risks. You can be proud of his courage, for he did not flinch when he 

had to perform.”

The companion RF-84F aircraft struggled through the same 

problems and, in addition, possessed several unique ones of its 

own. It was initially an unarmed reconnaissance aircraft, but it 

soon acquired four guns for defensive purposes. The viewfinder, 

a lens system that projected a visual downward view on a cockpit screen, took up so much of the instrument panel that finding 

room to place all the other instruments was an annoying problem. In addition, 24 RF-84Fs underwent a major modification to 

hook them to a B-36 to provide an extended reconnaissance capability. It was called FICON, an acronym for fighter conveyer. 

Bombers carrying their own fighter protection was an attractive concept considered over the years by many countries including the United States. Early experiments were carried out 

by the US Navy in the mid 1930s with the dirigibles Akron and

Macon as the carriers. During WWII, both Russia and Germany 

used a version of the fighter hooking principle to launch unmanned bombers against military targets. Further research 

Republic Aircraft

RF-84F nose view shows camera windows for vertical- and oblique-view cameras.
AIRCRAFT PROCUREMENT

46

and testing in the late 1940s and early 1950s resulted in the 

McDonnell XF-85 program that developed a small aircraft that 

could be stowed in a B-36 bomb bay.8

Another experimental fighter protection program managed by 

RAC was the coupling of two F-84E aircraft to a B-29 at the wing 

tips. This allowed the F-84 pilots to idle their engines and relax as 

the combined configuration flew on a mission. Strange as it seems, 

the drag of the coupled configuration was less than a clean B-29 by 

itself. This occurred because the F-84s acted like a wing extension 

that increased the configuration aspect ratio. This, in turn, decreased the wing vortex-induced drag as explained in appendix A. 

The F-84s would uncouple in the combat area, provide fighter 

cover for the bomber, and then recouple for the trip home. Several successful couplings were completed over several months 

of testing. Unfortunately, an F-84 autopilot malfunction during 

a coupled flight in April 1953 caused the F-84 to flip over and 

destroy all three aircraft with no survivors.9

About one year after I was assigned to the SPO, Maj Bob Leyrer 

took charge. This allowed Major Waller to devote his entire effort 

to the F-84F problems. I was relieved of my F-84F involvement 

but was tagged to handle the F-84G, just getting into production, and development of the RF-84F and FICON program. 

Historical Note

Major Leyrer was one of the unfortunate P-40 pilots sent to the Philippines just 

before the Japanese bombed Pearl Harbor. He was shipped over as a lieutenant 

directly out of flight school, arriving in late June 1941. He was assigned to the 

17th Pursuit Squadron, 24th Pursuit Group. He never got a chance to fly a combat mission and ended up as an infantryman in Bataan. He became a POW and 

survived the death march and a journey to Japan on a Japanese cargo ship 

known as a “hell ship.” He labored in a mine in Japan until finally liberated in 

September 1945. Occasionally he talked about his POW experience, and it was a 

grim story. He was very unforgiving for being abandoned in the Philippines and 

left to rot in that mine that claimed almost all of his fellow POWs.10

The FICON program began in early 1952 when the experimental 

swept-wing F-84E was configured with a fixed nose hook and a 23-

degree anhedral (drooped down) horizontal tail. The nose hook 

latched onto a retractable trapeze mounted in the forward bomb 

bay of a B-36. The tail anhedral let the F-84 be retracted far enough 
47

AIRCRAFT PROCUREMENT

into the bomb bay to allow the F-84 pilot to exit the aircraft. Feasibility tests proved the practicality of the FICON system. 

Since Republic was inundated with the urgent task of getting 

the F-84Fs to the operational commands, they contracted with 

Beech Aircraft in Wichita, Kansas, to modify the RF-84F to the 

FICON configuration, which was then designated RF-84K. P-47 

fighter ace Bob Johnson was the RAC technical representative 

monitoring the program, so on many trips with him to Wichita, 

he and I traded stories on our war experiences and expounded 

on the merits of that great Republic P-47 aircraft. Bob and I 

became good friends and visited each other over the years when 

we could until he died in 1998. 

A cocky stunt using the FICON system was contrived during 

the 1954 Dayton air show. The prototype FICON system was to 

be revealed during the show, with three passes over the crowd. 

The first pass was with the F-84 pulled into the bomb bay. The 

next pass was with the trapeze lowered and the F-84 engine 

operating. On the final pass the F-84 was to separate from the 

trapeze. The pilots of the B-36 and F-84 (I cannot remember 

their names) conspired to make the second pass, where the 

trapeze is lowered and the F-84 engine is running, with the six 

piston engines of the B-36 feathered. They calculated that the 

four jets of the B-36 plus the power from the F-84 were sufficient to keep the combined system flying. I surmise they had 

practiced this arrangement at altitude and were sure it would 

work. Their conspiracy was found out however and quashed. It 

would have been a spectacular display of airmanship. 

The FICON modification at Beech Aircraft Corporation went reasonably well. There were the usual problems of a new mechanical 

system but nothing very serious. The retractable hook jammed 

under some severe loading conditions and had to be modified. Also 

the rear latching lugs tended to jam, but again that was remedied. 

I attended the acceptance inspection of the first flight article in mid 

1954 but was not officially involved, as I had been transferred to 

AFIT as an instructor of aeronautical engineering.

My last trip to Wichita was a nostalgic trip in several respects. There were a half-dozen WADC engineers going to the 

inspection, so the SPO tried to get a C-47 for transportation. 

Instead they got a converted Boeing B-17 bomber with a large 

radome perched on the fuselage that was being used as a flying 
AIRCRAFT PROCUREMENT

48

antenna laboratory. We flew into Wichita airport and parked at 

the Boeing complex now involved in the B-47 jet bomber production. Many Boeing employees surrounded the B-17, nostalgically remembering their work in producing those venerable 

bombers. As we walked past them we could hear their comments on what part of the bomber they worked on. Several 

commented they were glad to see the old warhorse still performing a vital function. I think we livened up their day. The 

FICON inspection went well. While there Bob Johnson and I 

were invited to fly the new, improved model of their V-tail Beech 

Bonanza, which was quite enjoyable. In a way I was sorry to be 

leaving the SPO which, in hindsight, provided me with an invaluable experience. For the record, the FICON concept did become operational, and several aircraft flew reconnaissance missions over unfriendly territory, including China and the Soviet 

Union. I could not find any information on those missions.11

Many trips to RAC were necessary to coordinate various F-84F 

changes and finalize contract negotiations. We could take a 

commercial flight, ride the overnight sleeper train, or get an 

aircraft assigned and combine the trip with getting our compulsory monthly flying time. One memorable trip in a Beech 

C-45 utility aircraft during a miserable winter day in February 

1953 provides an excellent example of instrument flight techniques and tribulations using the low-frequency radio range 

navigation system. This flight is presented for posteriority as a 

gauge point for judging the improvement made in flight control 

procedures and equipment in subsequent years. 

While reading this narrative, be aware that this low-frequency, 

radio-range system, perfected in the early 1930s, was still the primary aerial navigation method for most aircraft. Newer systems 

were being implemented, but at this time, most military and civilian aircraft were not equipped to use them. Primitive as the system was, we performed cross-countries and made low approaches 

to airfields having ceilings as low as 800 feet and visibility of one 

mile. Ground-controlled approach (GCA) was available at most 

military bases. GCA employs a ground controller using a precision azimuth and elevation radar to guide aircraft to the runway. 

This allows an approach and landing with a minimum ceiling of 

500 feet. Several large military and commercial fields had an instrument landing system (ILS) installed; however, a separate re-
49

AIRCRAFT PROCUREMENT

ceiver and indicator were required in the aircraft. ILS utilizes a 

precision radio beam oriented along the runway centerline and 

the approach glide path. This beam is accessed by a receiver in 

the aircraft which then displays the height and azimuth correction to remain on the approach beam.

 The low-frequency radio ranges consisted of four quadrants 

that broadcast a Morse code “A” (dit-dah) and an “N” (dah-dit) 

in alternate quadrants as illustrated in figure 2. The “A” and 

“N” signals were broadcast so they overlapped one another; 

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AIRCRAFT PROCUREMENT

50

therefore, when both signals were received with equal strength, 

a steady hum was heard. This was the so-called beam depicted 

on the navigation charts. When one strayed from the beam, 

either the A or N signal became predominant, and a heading 

correction was applied to get back on the beam. The station 

identification was transmitted every 30 seconds, first in the N 

quadrant and then in the A.

There were many drawbacks to the low-frequency beam navigation system. It was easy to become confused regarding which 

leg of the beam we were on and whether we were inbound or 

outbound from the station. In mountainous areas the beams 

could be bent or split into multiple beams. Static could easily 

drown out the beam signal, and in thunderstorms they were 

useless, but that was all we had. 

Station locations and intersection points of different stations’ 

beams were usually designated IFR compulsory reporting 

points. Station passage was detected by a cone of silence that 

existed above the antenna. Beam intersection points were determined by establishing the heading along the beam centerline and then tuning in the crossing beam until the steady hum 

was heard. Beam intersections were given names such as Ambrose and Riis Park, both located over the Atlantic Ocean near 

Idlewild (now Kennedy) Airport. These are shown on the small 

section of a 1950s New York local aeronautical chart reproduced in figure 3. Radio marker beacons, the fan-shaped symbols on the beams, also mark a position on the beam. They 

were detected by a marker beacon light on the instrument panel 

that blinked the marker beacon code signal, such as “M” (dahdah) for Rockaway Park.

A position report was a curt, sequential chant that included 

aircraft identification, geographic position, time, altitude, type 

of flight plan (IFR or VFR), next reporting point, estimated time 

to next reporting point, and the reporting point after that. For 

example, assume an aircraft over the Harrisburg radio station 

with the next reporting point Allentown. The position report 

chant to the Harrisburg controller would go like this: “This is 

Air Force 315, over your station at 17 past the hour, 7,000 feet, 

IFR flight plan to Mitchel AFB, Allentown at 42, Ambrose.” The 

hour was not given since local time could change several times 

during a flight. Later we were ordered to use Greenwich Mean 
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Figure 3. New York radio range congestion
AIRCRAFT PROCUREMENT

52

Time, or Zulu time as it was called; therefore, the hour had no 

relationship to day or night.

The position report given to the Harrisburg communication 

station was transmitted to the regional flight control center. 

These centers, distributed around the country, handle all flights 

within their region’s airspace. When an aircraft exits a center’s 

airspace, control is passed to an adjacent center for continuation of the flight. At the control center, the flight report information is written on a plastic strip and slipped into a slot on a 

large board. The board displays the flight reports, categorized 

by the airways that cross the region. A flight controller studying the display can keep the aircraft separated in flight. It was 

a manpower-intensive way of doing the job, but it worked. By 

the time of this flight, however, it was overloaded and unable to 

handle the large increase in air travel. After this introduction to 

the low-frequency navigation system, here is an account of an 

actual flight, showing what we had to contend with.

It began with a phone call from the RAC Air Force plant representative stating that he was unwilling to sign off on the 

auto­pilot installation and requesting the SPO make the decision. Colonel Sellers from AMC and I were delegated to make 

a quick overnight trip and get it resolved. Then, as now, the 

New York City area was an extremely congested flying area 

that became a nightmare under instrument flying conditions.12 

The weather officer advised us that a front was approaching 

New York City and would be there when we reached the area; 

we would have to contend with rain and icing conditions as 

we penetrated the front around Pittsburgh. Our destination 

for the night was Mitchel AFB, located at Garden City, just 

east of New York City on Long Island. Mitchel Field was a favorite place to stay since it was close to RAC and featured a 

two-lobster dinner for $3.00 in the club. Our instrument flight 

plan used the Pittsburgh, Harrisburg, and Allentown radio 

range beams and then flew outbound along the ESE Allentown beam until we intercepted the SW Mitchel Field beam at 

the Ambrose checkpoint. (Ambrose checkpoint is about 15 miles 

south of Idlewild Airport at the intersection of the Newark and 

Mitchel Field radio range beams.) We then flew inbound on 

the Mitchel range and made an instrument approach. We re-
53

AIRCRAFT PROCUREMENT

quested a low altitude, just above the minimum flight altitudes, to minimize icing but were assigned 7,000 feet. 

 The C-45 is powered by two 450-hp engines, giving a cruising speed between 150 and 170 mph. We took off at 1500 and 

estimated our trip time as 3.5 hours, with 5.5 hours of fuel. 

Navigation radio aids on board included a VHF transmitter/

receiver with eight preset channels, a hand-tuned radio compass that could receive the broadcast and low-range frequencies, and a dedicated low-frequency receiver for the radio 

ranges. We also had a marker beacon receiver that operated a 

light on the instrument panel. Around Pittsburgh we penetrated the weather front and promptly picked up a light coating of ice. Updated New York weather reports remained constant; a 1,000-foot ceiling with a visibility of 2–3 miles in light 

rain. Flying was smooth, and there was no lightening around 

to impair low-frequency reception.

By the time we reached Harrisburg, the radio became extremely congested by pilots calling to report over a checkpoint 

and others trying to change their flight plans because New York 

weather was deteriorating. As we penetrated the New York area, 

it just became hopeless. Too many aircraft along with a limited 

number of radio channels created a chaotic condition. We were 

two position reports in arrears and getting close to the third 

when we suddenly came to a clear area between cloud layers. 

In the fading light we could see it was quite large so Colonel 

Sellers said, “We’re staying here—tell ground control we are 

circling in the clear and get clearance to go to our alternate 

[Olmsted AFB at Harrisburg, PA].” It took about 10 minutes 

before a ground controller finally cleared us to our alternate via 

east over the Atlantic Ocean and then south to Atlantic City 

and Philadelphia, hence to Olmsted. By this time our fuel was 

getting low and we were collecting quite a load of ice. The deicer 

boots on the leading edge of the wings were working, but we did 

not think they were doing any good and could not see outside 

because the iced-over windows reflected the light from the 

flashlight. After four hours and 40 minutes in the air, a safe 

instrument approach and landing at Olmsted AFB was a relief. 

After landing, the large load of ice we accumulated was melting, 

but it was going to take some time. We called it a day. The next 
AIRCRAFT PROCUREMENT

54

morning New York was still socked in so we returned to WrightPatterson AFB. It was a flight to remember.

In October 1953 the F-105 mock-up inspection was held at 

Republic Aviation. (A mock-up is a wood-and-metal replica of 

the airplane and looks quite realistic.) While examining the 

landing gear with the chief structural engineer, I was amazed 

when he mentioned that the massive forged gear strut is made 

from a very high-strength steel having a tensile stress of 240–

280 psi. Just six years previous, the steel we used for the North 

American B-45 strut was 180–220 psi, a phenomenal advance 

in steel-making technology in such a short time. 

Col Gabby Grabeski participated in the inspection as commander of Air Force Flight Safety, and I was introduced to him 

by Bob Johnson. Gabby was the highest-scoring American ace 

against the Germans in WWII with 28 confirmed victories, flying 

the P-47 and also became a jet ace in Korea with 6.5 victories 

flying F-86s. During dinner I listened with awe as Bob Johnson 

and Gabby Grabeski, two exemplary fighter pilots, recalled 

some of their exploits together in the 56th Fighter Group, flying 

P-47s. It was indeed a memorable moment and revived my regret that I did not have more opportunity to participate in airto-air battles during my combat tour.13 

Bob Johnson was able to get a few Air Force officers cleared to 

view the mock-up of the XF-103, a secret experimental bomberinterceptor aircraft being built to counter the threat of a Russian 

supersonic bomber. It sported a delta wingspan of 35 feet and 

had a fuselage 82 feet long, all constructed of titanium, one of 

the first uses of that exotic material. The pilot was provided with 

two flush side windows and a retractable periscope. The power 

plant used a standard turbojet engine with afterburner for takeoff and accelerated to near Mach 2. At that point splitter doors 

directed the engine airflow to the ramjet engine that accelerated 

the aircraft to Mach 3.5. It was a novel and experimental approach to aircraft design. Recently I obtained a copy of the engine 

flow diagram from Rick DeMeis and with his permission have 

reproduced it, with a silhouette view of the aircraft, in figure 4.14

The horizontal tail assembly and the majority of the fuselage titanium sections were completed before the contract was terminated in August 1957, primarily because the Soviets were not 

making headway on their supersonic bomber. 
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Figure 4. Republic XF-103 and power plant operation diagrams
AIRCRAFT PROCUREMENT

56

In late 1953 I had the opportunity to inspect a Soviet MiG15. The Air Force acquired this aircraft on 27 July 1953 when 

Lt No Kum-Sok, North Korean air force, defected and landed 

his aircraft in South Korea. The MiG-15 was disassembled and 

flown to Okinawa, where test pilot Tom Collins took it up for 

the first test flight. After several other flights, it was brought to 

Wright Field, where it was thoroughly examined. 

My first impression was that it looked quite conventional and 

aerodynamically clean. A closer inspection revealed that the 

Soviets used a lot of handwork to make the skin panels fit. My 

greatest surprise was that the hydraulic lines were welded together. I am sure that prevented hydraulic leaks that plagued 

our hydraulic fittings construction, but I could not think of 

how they got a line out of the way to perform other maintenance in the area. I spent an interesting hour seeing how our 

antagonists built their aircraft.

Historical Note

After the MiG-15 was thoroughly examined, it was test-flown by many test and 

active service pilots. In 1957 the United States offered to return the aircraft to its 

rightful owner, but no one claimed it. It was donated to the Air Force Museum 

where it now resides.15

A notice in the Wright Field employee newspaper that AFIT 

was looking for a professor in the aerodynamics department of 

the aeronautical engineering school caught my eye. It specified 

the education requirements and that perspective applicants 

were requested to get in contact with the department head, Dr. 

Gunther Graetzer, my former professor at AFIT. When I called 

on Dr. Graetzer, he encouraged me to submit an official application, which I did. Three weeks later he notified me that I was 

selected and the transfer paperwork was being processed. 

About a month later orders arrived to report to AFIT on 1 March 

1954. So began a pleasant three years, first as an instructor 

and, after one year, an assistant professor. 
57

AIRCRAFT PROCUREMENT

Notes

1. Joshua Stoff, The Thunder Factory, An Illustrated History of Republic Aviation Corporation (Osceola, WI: Motorbooks International Publishers and Wholesalers, 1990), provides an inside look at the activities within Republic Aviation 

Corporation from inception until it was incorporated with Fairchild-Hiller. 

2. In the spring of 1953 Dick Johnson resigned from the Air Force and 

went to work as the chief test pilot for Convair to test their YF-102. He made 

several flights but then crashed on takeoff and was severely injured. As I recall, his accident was due to a marginal thrust engine being further degraded 

by bleeding off too much air to run the auxiliary equipment. He made a full 

recovery and continued in-flight testing. 

3. Several pictures of the aircraft can be seen at the NASA Web site, www.dfrc

.nasa.gov/gallery/photo/XF-91.

4. An excellent treatise on the evolvement of the weapons system concept, 

as slanted to the procurement of the ballistic missile is presented in Stephen 

B. Johnson, “Bernard Schriever and the Scientific Vision,” Air Power History

(Spring 2002): 30–45.

5. Bob Johnson’s heroic exploits are narrated in his book about the 56th 

Fighter Group that shot down over 1,000 Nazi aircraft. Robert S. Johnson 

with Martin Caidin, Thunderbolt (New York: Ballantine Books, 1961). Several 

new editions are available. 

6. Kevin Keaveney, Republic F-84/Swept Wing Variants, Aerofax Minigraph 

15 (London: Aerofax, 1987), presents a detailed history of the development 

and operational use of the F/RF-84F. It contains a lot of good photographs 

and lists serial numbers, block numbers, and aircraft assignments. Robert V. 

Brulle, “F-84F Struggle for Operational Capability,” Air Force Museum Friends 

Journal 18, no. 1 (Spring 1995): 21–25, presents a personal account of my 

involvement. 

7. WWII fighter aircraft experienced an uncontrollable vertical dive because of transonic flight air compressibility effects. This phenomenon was 

alleviated by the thinner wings of jet aircraft which achieved a higher speed, 

but now had to contend with a severe pitch up. See Robert V. Brulle, “Don’t 

Panic—It’s just a Compressibility Dive,” Air Power History (Spring 1996): 40–

53. 

8. An excellent article describing the history of coupling aircraft in flight is 

presented in William Hallstead, “Parasite Aircraft,” Aviation History (November 2001): 38. 

9. Stoff, Thunder Factory, 87–88. 

10. William H. Bartsch, Doomed at the Start—American Pursuit Pilots in 

the Philippines, 1941–1942 (College Station: Texas A & M University Press, 

1992). 

11. Keaveney, Republic F-84, 11.

12. Robert V. Brulle, “Instrument Flying Using the Low Frequency Radio 

Ranges,” Air Force Museum Friends Bulletin 11, no. 3 (Fall 1988): 42–45. 
AIRCRAFT PROCUREMENT

58

13. The exploits of Gabby as a fighter pilot are narrated in his book: Francis 

Grabeski as told to Carl Molesworth, Gabby, A Fighter Pilot’s Life (New York: 

Dell Books, 1991).

14. Richard A. DeMeis, “The Trisonic Titanium Republic,” Air Enthusiast 

7 (July–September 1978): 195–211. Another excellent XF-103 description 

and its intended operational role can be found in the book, Lloyd S. Jones, 

U.S. Fighters (Fallbrook, CA: Aero Publishers, Inc., 1975), 275–77. See also, 

Stoff, Thunder Factory, 117–22. 

15. See http://www.wpafb.af.mil/museum for more information on the 

aircraft. 
59

Chapter 4

Aeronautics

Somewhere I read or heard that if you want to understand a 

subject, teach it. Students will always bring up points that you 

had not thought about; thus, teaching a subject always adds to 

your knowledge of that subject. I was about to find out if that 

is true, and I was apprehensive—no, terrified is a better word—

as just a few years earlier I was attending AFIT as a student 

and was now returning as an instructor.

Dr. Graetzer gave me a fatherly type talk, explaining his decision to accept me on the faculty. He knew my education was 

weak in certain areas but also knew I was continuing my education toward a PhD, attending Ohio State University classes 

offered at Wright Field. I would begin teaching undergraduate 

courses and gradually be given the more advanced ones as my 

teaching confidence grew. He prophesied that by the end of 

three years (a normal tour of duty), I would be able to teach all 

aerodynamic courses offered. I was to work directly for Prof. 

Hal Larsen, a most enjoyable assignment that cemented a close, 

45-year professional relationship and friendship.1

Two months were allotted to get settled in and prepare for my 

first class. As expected it was a beginning aerodynamics class—

I looked at it more as an aerodynamics summary—to a bunch 

of engineering sciences–electronic option students who required a course in aerodynamics for graduation. It started with 

the definition of aerodynamics and its terms, and then went 

through the entire process of using aerodynamics to determine 

the performance of an aircraft. At the end of the class, they had 

a good understanding of aerodynamics; I was quite proud when 

they all passed the final examination. I had survived my introduction as a professor. From then on, teaching became more 

relaxed and enjoyable as I was assigned more difficult courses.

A Polish professor named Peter Bielkowicz was now an aerodynamics department faculty member, and we became good 

friends. His experiences during WWII were—well, just fascinating. He was a doctor of mathematics working in the Polish air-
AERONAUTICS

60

craft industry when Germany overran his country. He evaded 

capture and made his way to France only to be overrun again 

by the Germans. He escaped to Spain by crossing the Pyrenees 

Mountains on foot and then walked through Spain. Just as he 

was about to step onto British soil at Gibraltar, the Spanish 

police arrested him. After two years in a filthy Spanish prison, 

he was set free when the American and British forces threw the 

Germans out of Africa. He worked in the British aircraft industry a while and, a few years after the war, made his way to 

America. He was a brilliant man—he could speak, read, and 

write six languages and had a smattering knowledge of many 

others. Several other young professors and I enjoyed eating 

lunch with him as he taught us Russian to fulfill the technical 

language requirement for our PhDs. Peter liked the way I could 

pronounce the Russian words because of my ability to roll my 

tongue as I did with my native Flemish language.

He gave me permission to audit his class on missile ballistics, but I could not join in the class discussions. This class 

covered the ballistic flight solutions and various empirical solutions that had been developed.2 Peter also introduced orbital 

mechanics and familiarized us with Moulton’s great text on celestial mechanics.3 It was my first venture into the field of missile trajectories and orbits that would become a large part of 

my engineering work.

 At the end of my first year of teaching, I felt at ease in class and 

must have impressed Hal and Dr. Graetzer, since I was promoted 

to assistant professor and assigned to teach several graduate 

courses. Two of these, aircraft dynamics and theoretical aerodynamics, had a profound effect on my career and were instrumental in my later teaching them at St. Louis University and 

the University of Missouri. 

Aircraft dynamics describes an aircraft in flight using the 

six-degree-of-freedom (SDF) equations of motion. These are six 

nonlinear differential equations, one for each translation velocity 

and one for each rotary motion. These equations are nonlinear, 

meaning each of the velocity and rotational variables appears 

in one or more of the other equations, so it is impossible to obtain 

a simplified equation showing how any one variable changes with 

time. Not only are the equations of motion nonlinear, but the 

aerodynamic forces that govern the motion are also nonlinear.
61

AERONAUTICS

To obtain a solution, engineers used a simplification method 

that allowed the SDF equations to be separated into two sets of 

three equations each. One set described the aircraft longitudinal 

motions of pitch rate, forward velocity, and vertical velocity, 

while the other described the lateral motions of yaw rate, roll 

rate, and side velocity. However, this simplification was only 

valid for aircraft through the WWII era that had a wingspan 

longer than the fuselage, making the moment of inertia in roll 

and pitch roughly equal. Supersonic aircraft that were then being designed did not satisfy these criteria, so the designers were 

forced to use empirical data and rules-of-thumb for estimating 

the aircraft motions. The F-100 was the first of the supersonic 

fighters which had a thin, short-span wing and a quite long 

fuselage to accommodate the fuel, engine, and armaments. The 

empirical design value used for the F-100 was woefully wrong 

and killed a Pearl Harbor hero in a crash.4

On 12 October 1954 an F-100 crashed at Edwards AFB, killing North American test pilot George Welch. Fortunately, it was 

an instrumented aircraft, and even though the oscillograph recording film was exposed when the instrumentation package 

was demolished, technicians were able to decipher enough of 

the trace to deduce that the cause of the accident was a horrendous yaw angle that overstressed the vertical stabilizer, 

causing it to break off. Further analysis showed that the yaw 

angle was generated by inertia roll coupling during a highspeed rolling pull-up. This brought a flurry of work within the 

military, the NACA, and the aircraft manufacturing community 

to more clearly define and solve this vexing problem.5

A simplified explanation of roll coupling, which is actually a 

gyroscopic property, can be related to riding a bicycle. The rotation 

of the bicycle wheels, through their gyroscopic coupling, provides 

stability to the bike rider by creating a turn when the rider tends to 

fall over. This also allows hands-off steering by leaning (banking) 

into the turn direction. For an aircraft in a rolling pullout, the rapid 

rolling of the aircraft acts like the wheel of the bicycle. The pullout 

is analogous to banking the bicycle, which causes a turn in the 

direction of the banking. The turning generated is the yaw rate that 

builds up the yaw angle. For the F-100, the aerodynamic restoring 

force on the vertical tail was insufficient to prevent a large yaw 

angle from being created, which overstressed the tail.
AERONAUTICS

62

Complicating the scenario are the vagaries of supersonic 

aerodynamic flow and the flexibility of the aircraft structure, 

which were again uncovered by a fatal crash. A few years later, 

in September 1956, the swept-wing Bell X-2 experimental 

rocket aircraft was involved in a fatal crash at Edwards AFB. 

The pilot, Capt Milburn G. Apt, set a rocket aircraft speed record of 2,094 mph or Mach 3.2. Unfortunately, he then encountered inertia roll coupling stability problems, exacerbated 

by supersonic flight and structural flexibility, and crashed. 

This crash uncovered the supersonic aerodynamic effect on dynamic stability.6 Similar dynamic stability problems hounded 

the Douglas X-3 and Northrop X-4. The Douglas X-3 was a 

needle-nose-type aircraft built to investigate dynamic problems 

at sustained supersonic speeds. The tendency to diverge from 

the flight path as it approached high supersonic speeds prevented the aircraft from achieving most of its flight objectives. 

The Northrop X-4 was a semi-tailless aircraft that experienced 

longitudinal stability problems as it approached supersonic 

flight, which also abrogated most of its flight objectives. Supersonic flight and dynamic stability presented real obstacles to the 

engineers trying to advance the aeronautical state of the art. 

The WADC Aircraft Laboratory, the NACA, and the aircraft 

contractors all looked for solutions to the problem, some trying 

to approximate a solution using an analog computer, while others espoused the use of a digital computer. At the time, neither 

was powerful enough to perform the simultaneous machine 

integration of the six differential equations. Fortunately, progress was swift in computer technology, and within a couple of 

years, solutions to the full set of equations were routinely comHistorical Note

Inertia roll coupling remains a bothersome factor for pilots. A young man completing his training in the F-15 wrote that he had just completed a defensive ride 

where he was supposed to show proficiency in evading a simulated missile fired 

by his instructor pilot. In doing so he got a little too fast and did a ham-fisted 

rolling pullout that overstressed the aircraft because of the asymmetric maneuver 

and yaw generated by inertia roll coupling. He had to buy his crew chief a case of 

beer for fixing it and also had to buy a bottle of liquor for the squadron bar. More 

modern aircraft, F-18E/Fs and F-22s, have digital flight control systems that 

protect against these control inputs.
63

AERONAUTICS

puted, albeit with a long computer run-time per case. (I was 

later involved in programming the equations for the official Air 

Force SDF computer program. This is discussed later.)

At the time, both analog and digital computers depended on 

a large array of vacuum tubes, which were temperamental in 

operation. The analog used the tubes as amplifiers, while the 

digital used them as switches. The front of the analog computer 

had numerous plug-in sockets wired to the amplifiers, variableresister potentiometers, and other components. Programming 

was accomplished by connecting the various components with 

a profusion of wires leading from one socket to another, creating 

a nightmare of tangled wires. The output was an oscillograph 

pen recorder plotting a continuous-time record of the flight. 

When it was correctly set up, one could follow the output dynamics of an airplane in flight and how it responded to a disturbing function such as a wind gust hitting the airplane. The 

change in flight dynamic response due to changes in aerodynamic 

or physical characteristics could be investigated by adjusting 

one or several potentiometers. Configuration changes, such as 

making the tail larger, moving it further aft, increasing wing 

dihedral, or other airplane modifications were investigated in 

this manner.

The digital computer was a monstrous affair with several 

large cabinets full of heat-producing vacuum tubes located in 

an air-conditioned room with fans that circulated cool air over 

the tubes. Programs were written in machine language and 

read into the computer by punched cards. The tabular output 

was an electric printer or punched cards which then were read 

by a reader. Investigating airplane configuration changes necessitated a separate run on the computer for each configuration. At the time, we were very impressed that the computer 

was able to solve a simultaneous set of differential equations, 

even if a 30-second real-time run took about five minutes to 

complete. Little did we suspect the enormous progress that 

would occur in computer technology.

This was also the time when low-level wind shear was discovered. These are winds that can vary up to 180 degrees within a 

very small altitude range. The little-understood phenomenon 

usually occurs near thunderstorms and was blamed for several 

aircraft accidents. Capt Paul Dow, a new aeronautical engineering 
AERONAUTICS

64

graduate assistant instructor (he was completing his PhD from 

the University of Michigan), became intrigued with that phenomenon and performed a simplified analysis of the problem. 

The results were astonishing; they were opposite of what a pilot 

would expect to happen and verified exactly what several aircraft had experienced.

Suppose an aircraft is on final approach at an airspeed of 

100 mph flying into a headwind of 20 mph. Suddenly the pilot 

encounters a wind shear, changing the 20-mph headwind to a 

10-mph tailwind. Most pilots, including myself, guessed that 

this would cause us to land farther down the runway. That was 

not the case at all—the aircraft would either stall or land short. 

Figure 5 explains this unusual phenomenon. 

Historical Note

In spite of years of research and the placement of wind-shear sensors near airports, wind shear is still a very dangerous phenomenon. Quoted below is a short 

notice from the Aviation Weather Center in Kansas City, Missouri, on the hazards 

of wind shear. 

Low-level wind shear, perhaps more than other aviation weather hazards, is one 

of the more dangerous phenomena a pilot can encounter. Defined as a sudden 

change in wind direction and speed vertically and/or horizontally, below 2,000 

feet, low-level wind shear can quickly overcome a pilot’s ability to control an 

aircraft. Because of the low altitude and landing configuration, aircraft are flying 

slower and usually in busy airspace. Faced with sudden loss or gain in airspeed, 

pilots have little time on approach to react. For some the decisions made have 

resulted in tragic losses, such as those on Delta 191 in Dallas, Eastern 66 at 

JFK airport in New York, Pan Am 73 in Kenner, Louisiana, and others. Sometimes, no matter how well an aircrew handles the wind shear, nothing can be 

done to compensate for the terrific forces imposed on the airplane.

The 3 August 2005 crash of Air France Flight 358 at Pearson International Airport, Toronto, Canada, was to my observation, the classic consequence of a pilot 

encounter with wind shear. He was too fast and too far down the runway when he 

touched down.7

A graduate aircraft design course gave students the practical 

experience to go through the aerodynamic design of a futuristic 

supersonic fighter. Since all students were cleared for Secret, 

we could have them use the latest trends in aerodynamics and 

engine design. A fictitious specification requirement for a Mach 

2+ supersonic fighter with advanced engine criteria was in-
65

AERONAUTICS

ferred. The course consisted of a one-hour lecture on methods 

of design and two three-hour design periods per week. All major design topics were covered, including aerodynamics, stability 

and control, performance, and major systems analysis. Students 

also used the Air Force Handbook of Instructions for Aircraft 

Designers that spelled out such details as pilot visibility, landingattitude ground clearance, maintenance considerations, and a 

myriad of other details.8 

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AERONAUTICS

66

One method of reducing transonic and supersonic wave drag 

due to shock wave formation, discovered by NACA aerodynamic 

engineer Richard Whitcomb, was introduced in class.9 This 

principle, called Whitcomb’s area rule, was a method of reducing transonic and supersonic wave drag by assuring a smooth 

cross-sectional area distribution of the aircraft from nose to 

tail. An aircraft, minus the wing and tail surfaces, would exhibit a fairly smooth cross-sectional area distribution from nose 

to tail. Thus, to fit in the cross-sectional area of the wing and 

retain the smooth area distribution, the fuselage is narrowed in 

the vicinity of the wing. The wave-drag reduction from using 

this area blending was quite significant. At the time, it was 

called Coke-bottling, since it shaped the fuselage much like the 

classic Coca-Cola bottle.10

Historical Note

Practical applications of this principle were immediately introduced into aircraft 

design. One of the first aircraft that benefited was the Convair F-102, with a large 

delta wing that created a lot of wave drag. We joked that the F-102 proved every 

day that there was a sound barrier. By lengthening and Coke-bottling the fuselage and adding a tail end fairing to further smooth the cross-sectional area at the 

rear, the F-102 was metamorphosed into a very successful interceptor and then 

into the F-106.11

The student designs that evolved were varied and quite good. 

Comparing their designs with the Republic F-105, the basis for 

their design specification, we were surprised at how well their 

designed size and weights agreed.

High-speed Mach 2+ aircraft were just being introduced into 

the operational inventory. These high-performance aircraft 

could, when lightly loaded, climb vertically, presenting capabilities that invalidated the classical methods of computing an 

aircraft performance envelope. A new method of performance 

computation was introduced by Edward S. Rutowski from 

Douglas Aircraft Company in his paper, Energy Approach to the 

General Aircraft Performance Problem.

12 He replaced the rateof-climb performance parameter with the rate of change of total 

energy, which had greater meaning in the coming era of super-
67

AERONAUTICS

sonic fighters. Thus, total energy of an aircraft in flight—the sum 

of kinetic (velocity) and potential (altitude) energy—becomes the 

dictating tactical parameter. I convinced Dr. Graetzer of the importance of this concept and got his approval to design a new 

course on high-speed aircraft performance around it. A full 

class enrolled the first time the course was offered. 

Historical Note 

I had future astronauts Virgil I. “Gus” Grissom and L. Gordon Cooper in class. 

Both were completing bachelor of science degrees, graduating in 1956. I worked 

with them later during Projects Mercury and Gemini man-in-space programs.

The stratagem of this technique is illustrated in figure 6. 

These plots show the aircraft altitude/velocity capabilities (heavy 

line)—what is called a performance curve. The aircraft can 

maintain equilibrium flight anywhere within the boundary by 

adjusting the engine power. Superimposed are contours of constant total energy (thin diagonal lines) that are labeled TEn; the 

larger the sub-n, the greater the total energy. For example, an 

aircraft that is at zero velocity has only potential energy; likewise at zero altitude, the aircraft’s energy is all kinetic. In between it has components of both forms of energy.

The upper plot portrays a typical subsonic jet fighter performance envelope, such as the F-86 or F-84F. The lower plot is a 

typical 1950s supersonic fighter performance envelope such as 

the F-104 or F-105. Note that for the subsonic case, the maximum total energy point (labeled MAX TE) is very near the maximum altitude capability; while in the supersonic case, it is near 

the maximum velocity capability. Comparing the plots shows 

the difference between subsonic and supersonic performance 

capabilities and points out the greater maneuvering options 

possible with a supersonic fighter. Because the subsonic and 

supersonic performance envelopes used different scales to allow greater detail, both envelopes are plotted to the same scale 

in figure 7 for ease in comparing the two.

The constant total energy contours (TEn ) show how kinetic 

energy can be exchanged for potential energy or vice versa, assuming that maneuvering losses are ignored. The exchange of 
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Figure 6. Performance envelopes
69

AERONAUTICS

kinetic energy for potential energy allows an aircraft to maneuver quickly within the boundary and temporarily even fly outside of the equilibrium flight boundary by performing what is 

called a zoom-climb. A subsonic fighter flying at its maximum 

energy point can only zoom-climb outside its performance 

boundary by a small amount, while the supersonic aircraft can 

zoom-climb to very high altitudes. Diving the aircraft to very 

high speeds outside the boundary is usually not an option since 

temperature and structural limits are quickly exceeded, although some early swept-wing fighters could temporarily dive 

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AERONAUTICS

70

As mentioned, aircraft can maintain equilibrium flight anywhere within the boundaries plotted in figure 6. The subboundary 

lines labeled Cn represent contours of the excess energy available 

from the engine; the greater the sub-n value, the more excess energy available from the engine. That excess energy can be used to 

climb or increase the airspeed, or in general terms, increase the 

aircraft’s energy. At the boundary, the excess energy available is 

zero because it represents where maximum engine thrust is used, 

so the aircraft cannot further increase its energy. This type of performance plot lends itself to determining the flight path to perform various maneuvers. For example, the velocity/altitude path 

for minimum time to climb to maximum energy is shown by the 

dot-dot-dash line. This path is the loci of points along the maximum values of excess energy. To fly this path, the pilot applies 

maximum engine thrust and then controls the aircraft to fly along 

the velocity/altitude profile shown. This requires the pilot to climb 

almost vertically to about 35,000 feet (at the tropopause) then 

level off and accelerate. After reaching the maximum energy point, 

the pilot performs a zoom-climb by establishing a ballistic path 

and trades the kinetic energy for altitude. In actual practice, 

shortly after passing through the boundary, usually around 

80,000 feet, the engine can flame out, and the pilot coasts power 

off to a high altitude. The pilot restarts the engine(s) when the 

aircraft descends below 40,000 feet.

Historical Note

This capability of a “zoom-climb,” as it was called, was utilized for a short time during 

1954. Intelligence revealed that the Soviets had a new jet bomber called a Bison that 

could reach the United States. When it reached the United States, it would have used 

most of its fuel and be flying well above the ceiling of the F-89 and F-94 interceptors. 

An emergency zoom-climb interception technique was developed for the F-89 to 

achieve a firing pass for launching its lethal load of 104 (52 in each wing-tip pod) 

2.75-inch folding-fin unguided rockets at the intruder. Correctly timing the zoomclimb initiation was the key to the one chance of a successful interception.13

Historical Note 

Although these plots were made for a fictitious 1955 supersonic aircraft, the plots 

I saw for time-to-climb records set in 1962 for the F-4 and 1975 for the F-15 were 

strikingly similar to figure 6. 
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AERONAUTICS

For readers who may have become lost with the technical 

jargon in the previous discussion, the main point to remember 

is that a supersonic fighter aircraft, because of its greater performance envelope, has different rules of engagement in a dogfight than those of the classic WWII battles.

The pilots in class immediately recognized the energy approach concept capability in the age of supersonic flight. No 

longer would altitude be the sought-after advantage in air-toair combat, having been replaced by the possession of greater 

energy. Introduction in the classroom brought this promising 

concept into the working arena. A lot of work remained to bring 

it to a practical level by considering maneuvering losses and 

tactics, but this was a start.

In April 1962 an F-4 zoomed through an altitude of 30,000 meters (98,425 feet) 

in 371.43 seconds from a standing start. In February 1975, an F-15 zoomed 

through an altitude of 30,000 meters in 207.8 seconds from a standing start, 

almost cutting in half the F-4 record time. This feat was accomplished in a time 

span of 13 years; a tremendous advancement in aviation technology.

Historical Note 

It took a long time to develop the correct technique to utilize this concept in combat; theory may be fine but application is a different story. The first generation of 

supersonic aircraft developed in the late 1950s and early 1960s did not have sufficient engine thrust nor the aerodynamic sophistication to remain supersonic 

during maneuvering flight unless the maneuvers were performed very gently. 

Consequently, exchanging the aircraft’s total energy between kinetic and potential was inefficient due to the energy lost in maneuvering. I talked to several pilots 

who flew F-105s or F-4s in Vietnam, and they admitted that the MiG-17, their 

principal antagonist, could beat them in a dogfight. This occurred even though 

the MiG-17 was not a supersonic aircraft but could maneuver more efficiently.

Col John Boyd at Eglin AFB was the individual that finally 

closed the loop between theory and practice to bring the concept, now called energy maneuverability (EM), to a practical 

application. He essentially 

plotted the characteristics of maneuver performance of one aircraft 

against another at certain sectors of the performance envelope. Turning 

rate and g forces might be plotted at a certain altitude and speed. Boyd 

decided to show the U.S. aircraft in blue and the enemy in red, a fairly 
AERONAUTICS

72

standard approach, but where they overlapped, he used purple. The 

visual presentation made explicit in an instant what might take hours 

to explain in scientific detail. Simply stated, the larger area of purple on 

a vu-graph, the less advantage of one plane over the other. Ideally, what 

is wanted were graphs with large blue areas, small purple zones, and no 

red areas of superior maneuverability. What the U.S. aircraft often got 

were graphs with large red areas, small purple areas, and almost no 

blue areas of superiority.14

The Air Force learned its lesson—succeeding air superiority 

aircraft were designed to ensure efficient maneuvering. Later I 

worked at McDonnell-Douglas in St. Louis, Missouri. During 

the F-15 inception phase, I occasionally had lunch with the F-15 

aerodynamics engineers, who told me of their endeavors to explore every aerodynamic advantage to assure exceptional maneuverability. It obviously paid off; the F-15 became the best 

maneuvering fighter in the world.

A welcome semester off gave us time to visit my parents in 

Santa Ana, California. They had not yet seen our new daughter 

Susan, now two years old, and it would give the two boys a 

chance to be reacquainted with their grandparents. In addition 

it allowed me to set up a meeting with Dr. Clark B. Millikan at Cal 

Tech to see if he would accept me as a PhD student. My threeyear AFIT tour of duty was half over, and I was exploring the 

option to complete my PhD at Cal Tech under AFIT auspices. 

I met with Dr. Millikan on the appointed day. After grilling 

me for about 30 minutes, he said he would approve my application but I would have to complete several more math courses, 

which would probably extend my completion time to over a 

year. Elated, I met Marge for lunch. We unexpectedly met Hal 

Larsen on a campus walkway (he was there completing his 

PhD), and he joined us for lunch. He was delighted when I told 

him Dr. Millikan had provisionally accepted me as a candidate 

and suggested that I take the advanced math courses offered at 

Ohio State to build up my math knowledge. Back at AFIT I immediately implemented that suggestion. 

In addition to teaching and attending Ohio State classes, I 

was still required to maintain my flying proficiency. Fortunately, 

the T-33 single-jet, two-man trainer aircraft with the latest 

flight equipment had filtered down to the office-bound (sometimes called swivel-chair) proficiency pilots. It was a great ad-
73

AERONAUTICS

vance over the piston-engine aircraft we had been using. The 

T-33 had a VHF radio that sported about 100 voice channels 

instead of eight and a transponder with multiple frequencies 

for ground radar control use. There was also a receiver and 

indicator to use the new VHF omnidirectional radio beacons 

being installed along the major airways. (These were the forerunner to the VOR stations still used.) This allowed us to home 

on the station along any specified radial. Lastly was the old 

standby—a low-frequency, tunable radio that could be used as 

a radio compass to home on broadcast frequencies. It also allowed us to listen to radio programs on long cross-country flights. 

An encounter at 20,000 feet with two Navy aircraft flying 

from Lockbourne Field (now Rickenbacker International Airport) near Columbus, Ohio, vividly demonstrated the wing vortex principle. I cannot remember the type of Navy aircraft, but 

one was a tanker trailing the funnel-like refueling drogue. Another two-place aircraft was trying to connect by inserting a 

probe into the drogue. It must have been a student pilot because he made numerous missed approaches as I observed 

them from Columbus to Indianapolis. Just as he was about to 

connect each time, the drogue would rise slightly due to the 

leading edge up-wash from his aircraft wing, and he would miss 

because he was not correcting for the expected up-wash. (See 

appendix A.) 

A jet instrument letdown and approach procedure is also quite 

different from what I was accustomed to in piston-engine aircraft. Jets gulp a notorious amount of fuel at low altitude, so 

pilots always strive to fly at least 20,000 feet or higher and let 

down for landing as rapidly as possible. Upon intercepting the 

cone of silence above the radio range antenna at Wright-Patterson 

AFB, we initiated a rapid letdown at 160 knots under idle power 

with the speed brake and gear extended. This resulted in about 

a 30-degree dive as we followed a standardized course-and-altitude 

letdown profile. Once committed to the letdown, I counted down 

the altitude out loud to keep track of it. We were supposed to 

level out at about 7,000 feet, and with the altimeter unwinding 

quite fast it was easy to misread 7,000 feet for 17,000 feet. The 

altimeters in use at the time had three needles—a 100-foot 

needle which was the largest, a smaller 1,000-foot needle, and 

a quite small 10,000-foot needle that was easy to misread; be-
AERONAUTICS

74

sides it was periodically hidden by the other two. Several aircraft had crashed during rapid instrument-approach descents, 

and the probable cause was misreading the altitude. Shortly 

thereafter the altimeters sported what we called a “barber pole” 

of yellow and black hash marks. As the aircraft descended 

through 10,000 feet, the barber pole would appear indicating it 

was time to start leveling off. Once level-off began, GCA usually 

had the aircraft on radar and directed it to landing.

Historical Note 

When the first commercial jet aircraft came into service, pilots carried over the 

steep, fuel-saving approach descent. This radical maneuver upset many passengers who were not used to diving an aircraft. Some episodes of near hysteria 

convinced the airlines to opt for a gentler letdown.

During our annual flight physical, we were required to participate in an altitude chamber test to verify our altitude adeptness. About a dozen of us were crowded into a large tank with 

our oxygen masks, and the air was evacuated until a simulated 

altitude of about 45,000 feet was reached. To prevent anoxia 

above 35,000 feet, pressure breathing must be initiated. When 

pressure breathing, oxygen is supplied to the mask at a pressure greater than ambient to ensure enough oxygen is forced 

through the lung membrane and absorbed by the blood. It is 

very fatiguing because it works opposite to normal breathing. 

In normal breathing, relaxing expels air from the lungs; when 

relaxing during pressure breathing, air is forced into the lungs, 

and a great deal of effort is required to expel it. Pressure breathing is an emergency measure in event of an explosive decompression at high altitude. 

An explosive decompression is a harrowing experience. After 

we were jammed standing up into the small airlock, the air 

pressure was set at about 8,000 feet altitude. The main chamber air pressure was set at about 35,000 feet altitude, and then 

a diaphragm between them was blown apart, stabilizing the 

combined altitude at about 20,000 feet. It was a startling experience as suddenly the air was forcefully expelled from the 

lungs. The decompression created a heavy fog in the chamber 

that took a few minutes to clear. After the fog cleared, one of the 
75

AERONAUTICS

participants was found crumpled on the floor. The chamber 

was quickly opened and a standby flight surgeon took charge. 

Some time later we heard that the young man, in his early 30s, 

had died from hardening of the arteries (now called cardiovascular disease). 

By this time, I had amassed over 2,000 hours of Air Force 

flying time (plus 200 more civilian time). This allowed me to be 

rated as a senior pilot (signified by a star above the pilot wings 

shield) after I passed the rigorous green card instrument-rating 

check. A senior pilot has self-clearing authority and no flying 

limits in instrument weather. I had occasion to use my clearing 

authority only once when Paul Dow and I were taking a group 

of professors in a B-25 to a conference in Ottawa, Canada, and 

had to land for customs at Selfridge AFB, Michigan, during a 

below-instrument-minimums rainy, foggy day.

Landing at Ottawa we noticed a new planting of small pine 

trees alongside the runway and taxiways. In Operations we inquired why anyone would plant trees alongside the runway. 

The answer was that they are an ideal marker to show the snow 

plow drivers where the runway and taxiways are. They are inexpensive and pliable; if an aircraft runs into one, it bends 

without damaging the aircraft. When the trees get too big, they 

are easily replaced. A very ingenious, nontechnical solution. 

On another occasion Paul Dow and I were again together in a 

B-25 taking advantage of an inclement weather system covering 

the entire eastern United States to get in our required instrument flying time. We went to Boston, where Paul’s parents lived, 

to pick up a box of lobsters his parents brought to the airport. 

We made a standard instrument approach at Logan Airport and 

picked up the lobsters from his parents. For some long-forgotten 

reason, we could not get fuel there so we filed a flight plan to Otis 

AFB on Cape Cod to refuel. When we landed at Otis, we found 

ourselves dwarfed by a group of EC-121 early-warning aircraft 

that patrolled far out over the North Atlantic to protect against a 

surprise Soviet air attack. These aircraft, which belonged to the 

551st Airborne Early Warning and Control Wing, were Lockheed 

Super Constellations sporting a large radome on top of the fuselage. They had just recently been put into service flying 15- to 

20-hour missions. We looked over those unique aircraft but 

could not talk the crew chief into letting us look inside.15
AERONAUTICS

76

Lt Col Ed Rex, associate professor and acting head of the 

mechanical engineering department, asked if I would accompany him on a trip to Burlington, Vermont. He was to give a 

presentation on aeronautical engineering to a National Guard 

unit and wanted me to cover the aerodynamics part. I presented 

an aircraft design topic I was considering for a magazine article 

titled “Why Aircraft are Getting Bigger.” This was an era of rapid 

increase in aircraft size to accommodate the ever-increasing 

equipment, weapons, and tactical capabilities, making them 

very heavy and expensive. A lot of clamor arose within the public and congressional sectors to make smaller, less-expensive 

airplanes. Why this was happening led to my topic.

The first aircraft, the Wright Brothers’ Flyer, had the pilot, engine, fuel tank, instruments, and the entire framework—consisting of wood members connected by a crisscross of wires—open 

to the outside. The first inside compartment was an enclosure to 

protect the pilot from the elements. Enclosing the pilot also 

moved the instruments and controls inside. Gradually, the entire fuselage structure was enclosed, moving the gas tanks and 

other equipment inside. Stress-skin construction eliminated 

wing structural wires and struts, as all the structure was contained inside the wing. Finally, the engine was moved inside a 

cowling and made part of the fuselage. The landing gear was 

retracted to further minimize drag. In one bold stroke, the propeller and the mass of air used for propulsion were moved inside 

by the introduction of jet propulsion. Furthermore, the wings 

themselves were moving inside as they became more efficient 

and retractable flaps were developed. With everything moving 

inside, the aircraft had to get bigger. At that time, an atomicpowered airplane was being investigated, so even the refueling 

tanker aircraft would move inside. I spiced my presentation with 

artistic sketches which made it quite amusing. 

Historical Note 

Use of the EC-121 by both the Navy and the Air Force expanded worldwide and 

continued until the 1980s. At that time, the Air Force was also busy constructing 

so-called Texas Towers (because they resembled the oil-drilling rigs off the Texas 

Gulf Coast). These towers were constructed about 100 miles out in the Atlantic and 

housed sophisticated long-range early warning radar. Unfortunately, one tower collapsed during a nor’easter, so they were abandoned and dismantled in 1964.16
77

AERONAUTICS

An announcement was made at the compulsory monthly flight 

safety meeting for all flight personnel that the venerable aircraft 

beacon lines—a series of rotating beacon lights placed 10 miles 

apart along major airways—were being discontinued. This brought 

a collective groan from all of us pilots who were brought up with 

and acclimated to their use. We were losing a night navigation 

friend that had provided security and safety on long, dark, crosscountry night flights. The beacons had a red signal light that was 

visible from an aircraft along the airway centerline. Each light was 

coded to blink in Morse code the initial letter from one of 10 words 

in a ditty I still remember today: “When Undertaking Very Hard 

Routes Choose Directions By Good Methods.” The sequence repeated every 100 miles, so if you knew your position within 100 

miles, you could orient yourself by identifying the code. These 

were of course a low-altitude night navigation aid which was made 

obsolete by radio navigation and higher-altitude flights. It still felt 

like we were losing an old friend. 

Historical Note 

One great proponent for designing small aircraft was Douglas Aircraft Company 

designer Ed Heinemann. He led a design effort to produce a small, light attack 

bomber, which became the A-4D Skyhawk, referred to as “Heinemann’s hotrod.” 

In spite of its small size, it was a very successful aircraft. However, its space constraints limited its versatility and growth. Later versions housed more avionics 

equipment in a humped addition to the fuselage behind the cockpit.

Historical Note 

The atomic-powered aircraft was a serious project during the 1950s. It reached 

the point where a B-36H aircraft had a test reactor installed that was made critical during several test flights. Radiation measurements on the heavily shielded 

crew and in the vicinity of the test aircraft showed that it would pose no threat. 

An accident, on the other hand, could have released lethal amounts of radiation. 

The project was canceled in 1961.17

Historical Note 

Night flying in the early 1940s was a dark experience. Electrification of the countryside was in its infancy, and light pollution was only evident over large cities 
AERONAUTICS

78

In September 1956 I was notified through the informal grapevine that my application to attend Cal Tech was approved all 

the way to Air Force headquarters. There, however, a personnel 

officer found that I had not been in a flying job in six years and, 

if I wanted to remain on flying status, I had to go back into a 

flying assignment. In fact I was going to be assigned to an Air 

Defense Command F-86D fighter group. 

This did not appeal to me at all. My days as a fighter pilot 

tiger were over. I was more cautious and did not push the aircraft to its limits, which is a prerequisite for a good fighter pilot. 

My promotion to major was pending, which meant I would be 

slated for command of a fighter squadron, and I knew I could 

not lead effectively if I did not fly better than the young pilots 

under my command. Also having three children with another 

on the way made me want a more stable home life. Underlying 

this was the fact that I was a reserve officer and my five-year 

active duty commitment was completed, so my Air Force status 

was uncertain. The decision was made; I would leave active 

duty and pursue a civilian career but remain in the active reserve so I could receive retired pay when I reached age 60. My 

declining a regular commission while teaching at AFIT was now 

viewed as a wise choice. After interviewing several organizations, I accepted a position in missile aerodynamics at the McDonnell Aircraft Corporation (MAC) in St. Louis, Missouri. I 

was relieved from active duty on Friday, 22 March 1957, just 

after Charles, our fourth child was born. I was leaving the Air 

Force with some trepidation. I had established myself in the Air 

Force technical field and felt comfortable and secure in the service. Now I had to start all over in the civilian workplace. Unfortunately, I never revived my ambition to finish my education, 

so I never completed my PhD.

and towns. When away from the cities, especially over the southern and western 

states, flying was in total darkness. The stars and the Milky Way were clear and 

bright, and one felt that they were only a short distance away. I can recall flying 

at night and not seeing any light on the ground for a half hour or more. Now there 

are only a few places over some western states where light pollution has not encroached on the night sky.
79

AERONAUTICS

Notes

1. Hal Larsen stayed with AFIT as a professor emeritus until retirement in 

1983. Even in retirement he was sought after as an engineering consultant 

by numerous organizations. I was devastated when his children notified me 

that he passed away in October 1998. 

2. These empirical solutions were surprisingly accurate. I realized this a 

few years later when I used an old-time empirical method to quickly estimate 

the impact point of a dummy missile dropped from 30,000 feet. Later, when 

a ballistic missile computer program was available, I redid the computations 

and found that the empirical solution was off by only 46 feet. 

3. Forest Moulton, Introduction to Celestial Mechanics (New York: MacMillan 

Books, 1914). Several newer editions are available.

4. The aircraft equations of motion and how they can be solved are presented in many aircraft stability texts. For example, see Courtland D. Perkins 

and Robert D. Hage, Airplane Performance, Stability and Control (New York: 

John Wiley and Sons, 1949); and Bernard Etkin, Dynamics of Flight: Stability 

and Control (New York: John Wiley and Sons, 1960). 

5. A great, but quite technical, dissertation on roll coupling, titled “Coupling 

Dynamics in Aircraft—A Historical Perspective,” is available on a NASA Web 

site, http://www.dfrc.nasa.gov. It details the stability coupling problems of the 

X-2, X-3, X-15, F-100, F-102, and space shuttle. The fatal accidents of George 

Welch in the F-100 and Capt Milburn G. Apt in the X-2 are covered as well. 

6. Ibid.

7. See http://www.awc-kc.noaa.gov.info/llws.html.

8. USAF, Handbook of Instructions for Aircraft Designers (HIAD), 9th edition 

(Dayton, OH: USAF Research and Development Command, 1953). This is a 

two-volume, loose-leaf book. 

9. Richard T. Whitcomb, A Study of the Zero-Lift Drag Rise Characteristics 

of Wing Body Combinations Near the Speed of Sound, NACA Research Memorandum RM-L52H08, 3 September 1952. See also Jim Quinn, “Hall of Fame 

Report—Richard Whitcomb Interview,” American Heritage of Invention and 

Technology 19, no. 2 (Fall 2003): 60–63.

10. One of the most pronounced Coke-bottled aircraft is the Northrop F-5 

or the trainer version T-38 Talon. 

11. For a more detailed explanation of how the area rule was implemented 

on the F-102, see http://www.fas.org/nuke/guide/usa/airdef/f-102.htm.

12. Edward S. Rutowski, Energy Approach to the General Aircraft Performance Problem, Institute of Aeronautical Science Aerodynamics Session, annual 

summer meeting, Los Angeles, CA, 15–17 July 1953. 

13. Several Web sites feature the Bison, for example, http://www.fas.org/

nuke/guide/russia/bomber/m-4.htm. See also Peter W. Merlin, “Fast, Cheap 

and Out of Control,” Air & Space Smithsonian (August/September 2005): 16, 

17, for an amusing article about two F-89s which had to fire rockets at an 

errant F-6F drone aircraft. They all missed the drone but caused several fires 

and terrified the people on the ground. 
AERONAUTICS

80

14. Grant T. Hammond, The Mind of War—John Boyd and American Security (Washington, DC: Smithsonian Institution Press, 2001). 

15. William J. Sifnas, “Warning Stars over the Atlantic,” Aviation History

(July 2002): 46–52, is an excellent article describing US Navy WV-2 (EC-121) 

missions from a base in Argentia, Newfoundland.

16. See http://www.dean-boys.com for several articles on the 551st Airborne Early Warning Wing at Otis AFB and the Texas Towers. 

17. For an interesting summary of the program, see http://www.atomic

engines.com. 
81

Chapter 5

Missiles

McDonnell Aircraft Corporation, called MAC, is located at 

Lambert Field, St. Louis Municipal Airport. It was founded 

by James S. McDonnell in 1939 and grew steadily. By the 

time I came to work there, it employed about 16,000 people 

and had annual sales of around $200 million. MAC designed 

and built its first fighter in 1943 for the US Army Air Force—

the XP-67 twin-engine bomber destroyer. This was followed 

by Navy jet fighters—the twinjet F1H Phantom and F2H Banshee and the single-jet F3H Demon—and then the twinjet 

F-101 Voodoo for the Air Force. When I joined MAC, both the 

F3H and F-101 were in production. The F4H (to be called the 

Phantom II) had recently made its first flight and was ready 

to start production. In addition to aircraft production, McDonnell was involved in the missile field with the development and manufacture of the GAM-72 Green Quail bomber 

decoy missile for the Air Force and the Navy’s surface-tosurface, ship-launched Talos missile. 

The missile aerodynamics chief, Harold Steinmetz, assigned 

me to project engineer Bill Rousseau, who headed up the aerodynamic effort on the GAM-72. This missile mimicked the 

characteristics and flight pattern of either a B-47 or B-52 

bomber in flight. A carriage of four missiles with wings folded 

was carried in the bomb bay. When approaching enemy territory, the missiles were launched on preprogrammed flight 

tracks. Radar enhancement made them resemble the signature of either a B-47 or B-52. Their flight characteristics also 

imitated an in-flight bomber, hopefully fooling and saturating 

Soviet air defenses long enough for the actual bombers to 

complete their mission. When lowered into the wind stream, 

the wings and stabilizers unfolded, the engine started, and 

the “bombers” were launched.1 By the time I came on board, 

the team was about halfway through the design phase. They 

had firmly defined the aerodynamic configuration and were 

finalizing the wing fold/unfold mechanism.
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My assignment was to compute the buffet loads on the GAM-72 

wings while unfolding during launch preparations. It was a 

very complex and challenging assignment since the environment underneath an open bomb bay creates an extremely turbulent flow. A wind tunnel test simulating those conditions was 

scheduled a few weeks later. The test involved a 0.075 scale 

model of the GAM-72, about the size of a small Subway sandwich, suspended under a model of a B-47 bomb bay. Various 

wing positions encountered during unfolding were inserted on 

the model and tested. Strain gauges recorded the wing buffet 

loads on a magnetic tape. 

This problem was somewhat similar to my AFIT thesis but 

was more involved and required familiarity with the mathematThe Boeing Company

The Green Quail B-52 decoy missile simulated the radar and infrared radiation 

signature and flight path characteristics of a full-size B-52. Either two or four 

were carried in the B-52 bomb bay and were launched on a preprogrammed 

flight path just before entering the enemy radar envelope. They were operational for many years.
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ics of power spectral density analysis. The analysis technique 

was developed by NACA, but understanding and applying it 

took several months of concentrated analysis to reduce all the 

recorded data and calculate a set of reasonable loads. As far as 

I know, no GAM-72 wing was ever lost during the long deployment period on B-52s.2 Although the GAM-72, known in the 

military as the Air Decoy Missile ADM-20, was designed for use 

in both the B-47 and B-52, only B-52s used it. The ADM-20 

was retired in the mid ’70s.3

The Boeing Company

A Green Quail decoy is deployed from a carriage lowered from a B-52 bomb 

bay, where the wings unfolded and the engine started.

In August 1957 McDonnell created a company project to design, build, and test an experimental long-range strategic missile—a hypersonic glider that could maneuver en route to the 

target. This was a hectic period within both the military and 

aerospace communities as the United States strived to develop 

an intercontinental ballistic missile (ICBM) to deter the Soviet 

Union. At the time, intermediate-range ballistic missiles (IRBM), 

having a range of about 1,500 miles, were being deployed to 

overseas bases where they could reach the Soviet Union. These 
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84

were the Thor, produced by Douglas, and the Jupiter, produced 

by Chrysler, for the Army’s Redstone Arsenal at Huntsville, Alabama. The race was on to develop a 5,000-mile-range missile that 

could be deployed within the United States. Two large aircraft 

corporations, Convair with its Atlas and Martin with its Titan, 

were well advanced in the study and manufacture of an ICBM. 

Several others, including Boeing, Douglas, Lockheed, and North 

American, were actively engaged in research and studies. Even 

the Navy had a missile development, which was being carried out 

in cooperation with Redstone Arsenal. McDonnell Aircraft, a relatively small newcomer, wanted to get into the game, and this new 

hypersonic glider concept offered a way of competing.4

Just after this new project began, the Soviets startled the 

world on 4 October 1957 by launching Sputnik, an artificial 

Earth satellite. We knew they were testing ballistic missiles but 

were surprised by their capability to orbit a satellite. The United 

States had stated its intent to orbit a satellite to study the nearEarth region of space during the International Geophysical Year 

(IGY) from July 1957 through December 1958.5 At that time, 

checkout of the Vanguard missile components was in progress 

at Cape Canaveral. This was a civilian IGY program administered by the Navy through the Naval Research Laboratory.

As news of the Soviet triumph spread, the magnitude of the 

achievement became apparent. The Soviets orbited a satellite 

that weighed 84 kg (184 lbs), while the first Vanguard weighed 

only 3.25 pounds. The Soviets used a military missile to launch 

their satellite, which meant they had a ballistic missile capable 

of reaching the United States from bases in the USSR. Only a 

month later, on 3 November 1957, a second Soviet satellite 

weighing a whopping 508 kg (1,118 lbs) was sent into orbit carrying a dog into space. The USSR not only had a ballistic missile that could reach the United States, but it also could carry 

a nuclear warhead! A further blow to US morale occurred when 

the first attempt to launch a Vanguard satellite blew up on the 

pad on 6 December 1958.

On 31 January 1958 the Army Ballistic Missile Agency at 

Huntsville, Alabama, launched a 14 kg (30 lb) satellite into orbit from Cape Canaveral, using a Redstone battlefield missile. 

This satellite, called Explorer 1, carried the first scientific instruments launched into space and transmitted back data on 
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the existence of a radiation belt of charged particles trapped in 

the earth’s magnetic field. This field was appropriately named 

the Van Allen radiation belt after the scientist who predicted it 

and built the instruments that were orbited in Explorer 1. Thus 

the United States scooped the Soviets in obtaining the first real 

data from space, but that fact was lost in the hubbub over the 

large Soviet satellites. For the record, several Vanguards and 

other Explorer satellites were successfully launched over the 

next year along with other more ambitious space projects that 

restored some of our credibility and faith in our endeavors.6

Historical Note

The realization that a radiation belt of charged particles encircled the earth immediately set off a flurry of discussions on whether that would preclude human spaceflight. To answer this question, many space probes were launched to map and determine the extent of this radiation belt, and the medical profession was spurred to 

research radiation effects in the human body. The problem was not solved, but an 

accommodation was found for low-Earth orbits and short stays in planetary space. 

The goal of mounting a manned Mars mission recently rekindled the research. An 

excellent article detailing the problems and postulating some novel solutions is 

found in Scientific American.

7

Orbiting satellites became a topic for news reporters and 

commentators around the country, many not even understanding what a satellite was or how it stayed in the sky. Some of the 

comments and explanations were just plain wrong and would 

have been amusing had they not been so pathetic. This was to 

be expected from the media, but what was not expected was 

the number of engineers that asked for an explanation of how 

a satellite stayed in orbit. At the time, most university engineering or physics curricula did not teach the elements of orbital mechanics. Fortunately, I had audited Peter Bielkowicz’s 

missile ballistics class, which covered the fundamentals of orbital mechanics, and was a member of the American Rocket 

Society. There were also many books available on rockets and 

space, the most interesting one by Willy Ley titled Rockets.

8

Long-range ballistic missiles armed with nuclear warheads 

were considered the ultimate offensive weapon, as there was no 

foreseeable defense against them. They had several drawbacks; 
MISSILES

86

the most serious, once launched there was no recall. How to 

protect against an unauthorized missile launch became a vexing problem; the system had to be foolproof yet allow the launch 

of a missile under emergency conditions. The United States 

fulfilled this requirement by using two launch consoles that 

required both to be manned to launch a missile—no one person could launch alone. The armed forces obviously selected 

only well-adjusted and responsible officers for that role and 

hoped that the Soviet Union also recognized the dilemma and 

set up a similar check-and-balance system to prevent a rogue 

officer from launching a missile. 

Once launched, a ballistic missile’s trajectory is defined, and 

there is no way to correct for launch anomalies without incurring a prohibitively large weight penalty. This is a particularly 

critical concern for long-range, air- and sea-launched missiles, 

because knowing the exact launch position is crucial to ensure 

the missile will impact the desired target. This was long before 

the global positioning system (GPS) was invented. Also at that 

time, the Earth’s pear-shaped geoid characteristics which affect the gravitational constant were unknown, as was the exact 

distance between New York and Moscow. All these unknowns 

gave a fairly large dispersion error to the missile. However, with 

a multimegaton warhead, just getting close to the target was 

enough to destroy it or at least make it untenable. 

NACA systematically studied many of the problems associated with developing a long-range missile—boost-phase optimization, including stage apportionment; warhead reentry characteristics; range optimization; and a host of others. An NACA 

report, “A Comparative Analysis of the Performance of LongRange Hypervelocity Vehicles,” showed the results of a study 

on the range efficiency for three types of hypervelocity missiles—the ballistic, the skip, and the glide—which are illustrated in figure 8.9

In the following discussion, missile and vehicle are used interchangeably. In general, I refer to ballistic missiles and skip or 

glide vehicles, the difference signifying that a ballistic missile is 

not controlled during flight, while the skip and glide vehicles 

are actively controlled. For skip and glide vehicles, this study is 

limited to cone-cylinder-type vehicles shaped like a pencil stub, 

or what is called a body of revolution. The lift of these vehicles is 
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quite small since they use only the body as a lifting surface, but 

they concurrently have very low drag, resulting in lift/drag ratios 

in the neighborhood of 4.0. The lift/drag ratio is the governing parameter for determining range and maneuvering characteristics.

A ballistic missile is aimed at the target and boosted to a high 

velocity. When the correct velocity vector is achieved, the rocket 

motor is cut off and the missile coasts along an elliptical (ballistic) path until it reenters the atmosphere to impact the target. A skip vehicle is similarly boosted to a high velocity but is 

targeted to coast in a ballistic path for only a short distance 

and then reenter the atmosphere at a shallow angle. The vehicle 

penetrates briefly into the atmosphere, and utilizing aerodynamic 

forces, is turned to exit the atmosphere for another ballistic 

segment. This skipping continues all the way to the target, 

trading kinetic energy for range, similar to skipping a flat stone 

over a pond. A glide vehicle is boosted to a high velocity into the 

upper reaches of the atmosphere. At booster cutoff, it is aerodynamically controlled to glide in the atmosphere, trading kinetic energy for range. Both the skip and glide vehicles can be 

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88

maneuvered en route to the target, not only to correct for launch 

anomalies but also to confuse enemy defenses.

The NACA study looked at the design and operational considerations for these three concepts. It concluded that the ballistic missile is the least efficient since it generally requires the 

highest boost velocity to attain a given range, but is the simplest because no active aerodynamic control system is needed. It 

does, however, require a heat shield capable of absorbing the 

massive amount of aerodynamic heat generated during its 

steep reentry. The skip vehicle is the most complicated since it 

requires two control systems—an aerodynamic control system 

during the atmospheric penetration and skip-out and control 

thrusters during its ballistic segment. The skip vehicle’s reentry 

heat loads are less severe than a ballistic missile’s, and it has 

an advantage of being cooled during the ballistic portion of the 

skip, but the air loads during a skip are very severe. The glide 

vehicle is highly efficient, but it must have an active aerodynamic 

control system throughout the flight. The heat loads are less 

severe than a ballistic missile but are imposed for a longer time, 

heating the inside of the vehicle so that interior heat shielding 

(insulation) or active cooling is needed. 

Historical Note 

In 1942 the Germans at the Peenemunde rocket facility conceived a glide vehicle 

derivative of the V-2 to bombard the United States. It was essentially a V-2 body 

with small wings. It never got beyond the conceptual phase.10

In the summer of 1957 the Air Force was exploring the feasibility of an air-launched ballistic missile called Bold Orion (later 

changed to Skybolt), and a request for proposal (RFP) was expected within the next year. McDonnell’s top management saw 

the Bold Orion program as a chance to break into the longrange missile business by proposing a long-range glide vehicle. 

That type of vehicle would solve the problem of correcting for 

launch anomalies of an air launch, provide recall or coursechanging capability, and be able to maneuver to confuse the 

enemy or skirt heavily defended areas. After confirming the 

NACA conclusions with an in-house study, McDonnell com-
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mitted to a three-vehicle proof-of-concept research program 

in October 1957. It acquired the program name of Alpha Draco. 

(At McDonnell we usually referred to it as the Model 122B, so 

out of habit I use both Model 122B and Alpha Draco to refer 

to the same vehicle.) It was up to us to prove the feasibility 

of this new concept.

Figure 9, extracted from NACA TN 4046, is a conceptual picture of a glide vehicle—a slender, streamlined vehicle with control flaps aft that keep it at an angle of attack for gliding and 

maneuvering in the atmosphere. The range of a glide vehicle is 

a direct function of its lift/drag ratio; therefore, it must have 

very low drag to achieve the required range. Analyses showed 

that the acceptable lift/drag ratio must be greater than 2.25. 

(For comparison, airplanes have lift/drag ratios of 15 or greater, 

and sailplanes double that amount.)

In addition to confirming the NACA conclusions, a study on 

the optimum glide configuration was initiated. Many engineers 

believed that adding small wings would greatly improve the 

lift/drag ratio, resulting in a greater range. To them it was inconceivable that a pencil could fly and maneuver. Many hours 

were spent performing studies on the tradeoff between a body 

of revolution with and without wings, including one having a 

cruciform wing arrangement that rolled during glide to even 

out the heating. At that time, aerodynamic wing heating at 

greater than Mach 5 presented a structural problem that could 

not be solved with available materials.11

$01*&%'30./"$" 5/ Copied from NACA TN 4046

Figure 9. NACA glide vehicle concept
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90

The selected 122B glide vehicle was a cone-cylinder body 

with a fineness ratio (vehicle length divided by diameter) of 10 

and a cruciform arrangement of four pivoting half cones for 

control. This arrangement was selected over the NACA fourflap control because of structural and aerodynamic heating 

constraints. The half-cone control surfaces generate more drag, 

which reduces the lift/drag ratio somewhat, but were easier to 

implement in the short development time allotted. Control in 

pitch and yaw was achieved by varying the deflection of diametrically opposite controls in pairs. Control in roll was achieved 

by differential deflection of opposing controls. A sketch of the 

Alpha Draco glide vehicle is shown in figure 10. 

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Boosting the glide vehicle to greater than Mach 5.0 in the 

outer regions of the atmosphere required two rocket motors. 

The first stage, or booster motor, was a Thiokol XM-20 used in 

the Hawk air defense missile program. It generated 44,600 

pounds of thrust and burned for 32 seconds. The first stage 

boost phase was unguided, so the booster was fitted with a 

cruciform arrangement of four aluminum fins on the aft end 

for stability during flight. The motor in the glide vehicle was a 

Thiokol XM-30 used in the Lockheed X-17 reentry research 

vehicle program. The nominal thrust of this motor was 12,200 

pounds, and it burned for 37 seconds. As finally configured, 

Alpha Draco was a two-stage, solid-rocket-motor missile as 

shown in figure 11.
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Figure 11. Alpha Draco configuration
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92

The 122B program was administered to allow the working 

personnel the freedom to do the job with a minimum of management interference or preparation of elaborate reports. We 

were given the end task of designing, building, and test-firing 

three missiles over 18 months to prove the concept. The peak 

number of people on the program never exceeded 200, including 75 engineers. The schedule was met; the first launch occurred 18 months later in February 1959.

My responsibility was to define the performance, stability 

and control characteristics, and range safety and meteorological aspects of the Cape Canaveral operations. Aerodynamic 

group leader Keith Glass had responsibility for the wind tunnel 

tests and obtaining the aerodynamic parameters. We both reported to project aerodynamic engineer Lamar Ramos.

Calculating the unguided first-stage trajectory and stability 

characteristics and the gliding flight performance required 

computer support. When I went to see what programs were 

available on the McDonnell IBM 704 digital computer, I was 

greeted with open arms by the programmers. At that time, computers were an enigma to most engineers, who neither knew 

nor understood their capabilities, so the programmers received 

very little work. My inquiry on possible programs yielded a 

point mass vehicle (a point having the mass of the vehicle) flying over a round Earth. That program was adapted for our glide 

performance calculations. I also found a six-degree-of-freedom 

flat Earth program that, with some modifications, allowed calculation of the missile dynamic characteristics during the unguided boost phase. Those two programs, along with additional 

modifications to perform specific tasks, formed the foundation 

for our performance computations during the 122B program. 

The guidance and control group, operating on a large analog 

computer, calculated the stability of the glide vehicle with the 

control system.

To gain some experience in running an extended wind tunnel 

test, I was tagged to run the launch configuration (the mated 

booster and glide vehicle assembly) test sketched in figure 11. 

The test was conducted in the Wright Field continuous-flow 10-

foot transonic tunnel covering a Mach number range of 0.8 to 

1.2. It was one of five tunnel tests scheduled to obtain firm 
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aerodynamic characteristics through a Mach number range 

from 0.8 to 8.08.12

During the test I was able to visit with Hal Larsen, my former 

boss at AFIT. Since I left a year and a half ago, the AFIT aerodynamics department had acquired the Wright Field five-foot, 

low-speed wind tunnel, and he proudly showed me his new 

acquisition. It was a closed-return tunnel, built in 1924, that 

could reach speeds of 260 mph. It was unique because it utilized the interior of the building for the return flow. The old 

wire-balance system was still in use and in good condition. The 

tunnel, constructed of laminated wood, harbored termites, but 

a determined eradication effort was in progress. The wind tunnel served the Air Force for over 35 years and was later used for 

instructing officers in testing techniques. As far as I know, it is 

still is in use.13

Because a glide vehicle stays within the upper reaches of the 

atmosphere while trading kinetic energy for range, aerodynamic 

The Boeing Company

Alpha Draco hypersonic glider. The four half-cone controls kept the glider at an 

angle of attack and rolling at 10 rpm to even the aerodynamic heating. A hole in 

the glider nose tip provided an aerodynamic total pressure tap used for altitude 

control. An imbedded Thiokol XM-30 rocket motor accelerated the glider to hypersonic velocity for gliding. 
MISSILES

94

heating causes the vehicle to become red hot and remain hot 

throughout the flight. Thus, it requires an external structure 

able to withstand the heat and an internal cooling system. A 

ballistic missile reenters the atmosphere in a short, fiery period, allowing a much simpler, ablative-type thermal protection. This is one of the drawbacks of a glide vehicle. To limit the 

effect of aerodynamic heating, the Alpha Draco vehicle was 

rolled slowly during glide at 10 rpm. This eliminated localized 

heating and thermal warping by distributing the absorbed heat 

evenly over the skin and structure. The internal systems were 

protected from heat transfer through the skin by a thick layer 

of insulation.

The vehicle body and conical control surfaces were made of 

321 stainless steel except for the nose caps and half-cone controls, which were made from silicone carbide. The vehicle carbide 

nose cap had a hole in it to measure the dynamic pressure, 

which was used as an input by the flight control system to 

maintain angle of attack during glide. A Minneapolis Honeywell 

test-model inertial platform donated to the Alpha Draco program kept the missile headed in a given direction and, with an 

associated roll resolver, assured proper control surface deflections to maintain angle of attack and roll rate. 

The missile launch used a modified Army Honest John battlefield missile launcher. Just prior to launch, it would be positioned in azimuth and elevation to counteract wind effects and 

assure the glide vehicle would arrive at a predetermined point 

in the sky when the booster thrust terminated and the booster 

dropped. At booster drop, t = 36 sec., the control system would 

be activated and a 10 rpm roll initiated. At second stage burnout, t = 90 sec., the glide vehicle would be at approximately 

Mach 5.5 near an altitude of 100,000 feet. After a short transition period, glide would be initiated, exchanging velocity for 

range. At t = 350 sec., with the vehicle at approximately Mach 

3 and 70,000 feet altitude, gliding flight would be terminated 

by neutralizing the controls, which would initiate a ballistic 

dive to impact. 

Figure 12 shows the altitude/range trajectory plot for an actual Alpha Draco launch, which followed very closely the nominal computed trajectory. The upper plot has range expressed 

in nautical miles and altitude in thousands of feet. This ex-
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pands the altitude scale so pertinent events can be noted. The 

lower plot shows the trajectory with a consistent nautical miles 

altitude and range scale. This emphasizes the truncation of a 

glide vehicle compared to a comparable-range ballistic missile, 

which would reach an altitude of over 60 nautical miles. This 

short-range, proof-of-concept demonstration glide vehicle can 

be plotted with consistent scales. The glide trajectory of a vehicle having a range of 5,000 miles cannot be plotted since the 







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Figure 12. Alpha Draco trajectory
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96

altitude would be the thickness of the line. A comparable 5,000-

mile-range ballistic missile would reach an altitude of about 

2,000 miles. 

McDonnell Aircraft had no prior experience firing missiles 

from Cape Canaveral and no idea how to proceed in that area. 

This led to some amusing incidents as we groped our way to 

firing the missiles. Some details of how Cape Canaveral operations were conducted are presented here to convey the spirit of 

the times. My complete article, “Alpha Draco—The Wingless 

Glider,” was published in the Air Force Museum Friends Journal.

14

Informal talks with Cape Canaveral personnel enlightened 

us to the fact that no support or preliminary planning could be 

committed by the government unless a contract existed. This 

led to a high-level trip to Cape Canaveral on 20 January 1958, 

headed by McDonnell Aircraft founder J. S. McDonnell, to brief 

Maj Gen D. N. Yates on the Model 122B flight-test vehicle and 

to collect information concerning testing techniques, facilities, 

and recommendations from his staff. One of the more forceful 

recommendations, made by a Colonel Worden, director of tests, 

was that failures are to be expected on early test missiles, and 

he felt that three test vehicles would be insufficient for demonstrating the objectives. He recommended that 10 to 20 be considered. Notwithstanding his strong recommendation, Mr. Mac 

(as J. S. McDonnell was called by his employees) stayed with 

three test vehicles on the continued assurances by the 122B 

personnel that they could do the job.

Not long after this, a research and development contract was 

negotiated that gave McDonnell a free hand in developing the 

boost-glide Model 122B and committed the Air Force to support 

the effort at Cape Canaveral. Soon two Air Force officers from 

Wright-Patterson AFB showed up unannounced at McDonnell 

and in effect said, “Now tell us what we have bought.” It was 

difficult to convince the Air Force that a wingless body could fly 

and maneuver, a mind-set that was never entirely dispelled, 

even when the program was successfully completed.

With a USAF support contract in place, operations at Cape 

Canaveral could commence. A prefab metal building, Hangar 

l366, previously used by Lockheed for its X-17 reentry research 

vehicle program, and Pad 10, previously used by North American 

for the canceled Navaho intercontinental ramjet cruise missile 
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program, were assigned to the 122B program. The hangar was 

located on Central Control Road near the row of ICBM launch 

pads, just far enough away that evacuation was not required for 

a launch. Consequently we had front-row seats to some spectacular launches of different missiles, such as the Lockheed Polaris, Boeing Bomarc, several research vehicles, the first launch of 

the Martin Titan, and one night launch of an Explorer satellite. On 

one Convair Atlas flight, the missile went straight up instead of 

curving over the Atlantic and was destroyed, raining debris all 

over our hangar area. Fortunately no one was injured.

The range safety personnel were located at Patrick AFB, about 

20 miles south of Cape Canaveral. On the initial briefing of the 

122B Alpha Draco missile, they were shown a trajectory plot and 

wanted to know how we could achieve the range by launching into 

such a low altitude (as opposed to a ballistic missile) and what 

caused the altitude truncation. They were stunned by the glide 

The Boeing Company

Cape Canaveral launch team, 16 February 1959 (author with tie standing on 

launcher)
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98

concept explanation and shook their heads in disbelief. When 

range safety personnel realized the 122B could maneuver in flight, 

they became quite concerned. They pointed out that we would 

have to provide them with estimates of maneuvering potential 

from all points along the nominal trajectory where the vehicle 

could conceivably reach a populated area in the event of a malfunction. They were also very concerned with possible trajectory 

deviations during the initial 36 seconds of unguided boost-phase 

flight. Their requirements were very strict and, from my point of 

view, would entail a lot of analyses. To ease their concern, the 

launch azimuth was changed from southeast along the established missile range to Eleuthera Island range station to a more 

easterly open-water direction, but they still wanted all the data.

One of their requirements was a computer printout of statistically maximum plus and minus deviation trajectories, which implies that 99.9 percent of all possible trajectories will lie within 

those confines. Computing these trajectories presented a dilemma because of the multitude of possible errors. It was easy to 

compute a deviation trajectory for a particular error and to get a 

statistical boundary by taking the square root of the sum of the 

squares of the individual errors, but I was stumped on how to 

statistically combine them for an actual trajectory computation. 

The range safety personnel had not encountered this problem 

before so could offer no help in formulating a solution.

This led to the development of a statistical analysis missile 

flight path dispersions computer program that utilized the ability 

of a computer to manipulate large groups of numbers in a reasonable time period. The range safety personnel were quite impressed with the technique, which led to MAC receiving an Air 

Force contract to develop an error and dispersion analysis program. The explanation is quite mathematical, so it is not included here; however, for anyone interested, it can be found in 

ASD TR 61-552.15

We also had to coordinate our weather requirements with the 

range meteorological office. The surface wind at the moment of 

launch for a non-guided, fin-stabilized missile has a large effect 

on the trajectory. As the missile leaves the launcher, the booster 

fins cause the missile to turn into the wind; that is, a crosswind from the left causes the launch vehicle to turn to the left, 

while a tailwind steepens the flight trajectory. That meant that 
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the launch elevation and azimuth had to be offset by the amount 

the launch vehicle turns due to the surface winds. As the vehicle gains speed and altitude, the wind effects decrease but 

again become significant around the tropopause, about 35,000 

feet, where wind shear can also cause problems.

A computer program was developed that integrated the wind 

effects to arrive at a so-called ballistic wind, which was then 

related to the launch-angle correction factor. To accurately apply this correction factor, an up-to-date altitude wind profile 

was required. This was one of the requests levied on the range 

meteorological office—an altitude wind profile to at least 35,000 

feet six hours prior to launch, along with a prognosis of surface 

wind speed and direction at launch time. During the countdown, updated wind profiles to 10,000 feet were requested, the 

latest within 30 minutes of launch. The high-altitude profile 

would ensure no large high-altitude wind shears existed that 

could upset the vehicle stability, and the low-altitude profile 

was used to align the launcher. Range safety specified that 

launch minimums were a cloud ceiling of 2,000 feet with a visibility of five miles. This was to give range safety personnel, scattered around the launch area, several seconds of visual observation during the critical launch period. 

All this coordination was accomplished through several trips 

to Cape Canaveral during the fall and winter of 1958–59 and 

during two weeks preparing for the first launch. Cape operations were a pleasant interlude of hard work tinged with the 

excitement of being at the forefront of missile technology. Cape 

Canaveral was a busy and bustling place with people coming 

and going at all hours of the day and night, seven days a week. 

The cape itself was mostly a wild, swampy area with an occasional large missile gantry seemingly placed in the middle of 

nowhere. The area accommodated a diverse assortment of wildlife; most prevalent were the thousands of rattlesnakes. They 

were everywhere, and we were cautioned to stay on the roads 

and never pick up a board or piece of equipment without first 

moving it with a stick. Civet cats, small relatives of the skunk 

but with two stripes on their backs, were also very prevalent. 

Actually they were quite cute, but we could occasionally smell 

the odor from one that had been disturbed, and any thought of 

cuddling them was put out of mind.
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As previously mentioned, I wrote an article for the Air Force 

Museum Friends Journal and during writing I contacted several 

of my former McDonnell team members for Alpha Draco stories. 

I am indebted to Joe Dean for this interesting reminiscence on 

how cape operations were conducted in those days.

At the cape we generally ate our noon lunches off of the mobile kitchen, 

informally known by the workers at the cape as the “roach coach.” It 

was not unusual to work late at night under portable flood lights with 

civet cats prowling around curling up close to the warm electrical equipment, rattlesnakes slithering over the warm roadways, and palmetto 

bugs flying around and getting into the test equipment. Many nights we 

closed up places like Ramon’s and Bernard’s Surf in Cocoa Beach for a 

late dinner, and afterwards rushed back to the pad to tie down things 

because a thunderstorm threatened.

It was mentioned by the Thiokol rocket motor representatives that if the 

rocket motors were kept warm, they would have a greater thrust and 

eliminate a potential for cracking the propellant insulation which could 

have catastrophic consequences. When a cold snap was predicted, several fellows were sent to Orlando to buy all the electric blankets they 

had money for, and for a week or so were used to keep the rocket motors 

warm until a tailor-made blanket was provided by MAC. The pad safety 

representative stipulated that a safety person must be standing by 

whenever the makeshift blankets were in use, so we all took two-hour 

turns to baby sit the missile all night long. The visiting McDonnell missile division director, Ben Bromberg, was even pressed into taking the 

midnight to 2:00 a.m. shift.

Missile launch required 27 people. At launch there were 11 

people in the blockhouse with four manning consoles; two in 

central control—me and the program manager, Jack Evans; one 

at telemetry receiving Tel-2; and the rest at the fallback area. 

Historical Note

Model 122B was the beginning of a successful missile launch career for pad technician Gunther Wendt. He was an engineer from Germany, a graduate of Beuth 

Engineering School, and worked at the Henschel Aircraft Company. He immigrated to the United States in 1949 and was hired by McDonnell. After helping 

launch the 122B, he became pad chief for the Mercury, Gemini, and Apollo programs, settling the astronauts into their capsules and buttoning them up for 

launch. Usually he was shown on TV helping the astronauts. Recently I talked to 

him and found he is busy writing books and is also a sought-after speaker on the 

US man-in-space program.
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In early 1959 three missiles were launched: the first on 16 

February, the second on 16 March, and the third on 27 April. 

The following is quoted from the flight summary reports by Bert 

Reime, the test conductor:

The S/N-1 Alpha Draco was launched successfully from Pad 10 of Cape 

Canaveral, Florida, at approximately 4:03 PM 16 February 1959 into a 

partly cloudy sky. It was launched on an azimuth of 106.9° true at an 

elevation of 74°33' corresponding to a ballistic wind having a tail wind 

component of 1.8 knots and a cross wind (from the left) component of 

11.7 knots. The anticipated flight path was 95° from true North. The 

glide vehicle impacted 224 nautical miles down range after 427 seconds 

of flight. Radar plots indicated that it flew very close to the nominal 

flight trajectory and terminated within 2 miles from the predicted impact point. 

When Bert said it was launched “into a partly cloudy sky,” he 

was slightly understating the situation; it was overcast at our 

launch-minimum cloud ceiling of 2,000 feet with scattered 

scud clouds at 1,800 feet. In addition there were rain showers 

in the area, and the Air Force meteorology officer, a captain 

whose name I have forgotten, was kept busy plotting them to 

warn us if any were heading our way. We were about 10 minutes from launch when he came over to me and whispered that 

the cloud ceiling was now 1,800 feet, and a rain shower was 

due to hit in 15 minutes. He was inclined to overlook the belowminimum cloud height but could not let us launch in a rain 

shower. Another hold could not be tolerated, and we had to either launch or scrub the mission. I talked it over with Jack 

Evans and we agreed not to warn the launch crew but to just 

let them continue hoping we would get off before the shower 

hit. The gamble worked, and the 122B roared off the launch 

pad and disappeared into the overcast just minutes before a 

heavy rainstorm hit the cape.

Launching the missile into a low cloud ceiling darkened by 

rain created a mystery about what was launched. The missile 

was visible for only 2.5 seconds before disappearing into the 

clouds. In fact at the central control observation balcony, about 

three miles from the launch pad, the rocket motor noise was 

heard only after the missile had entered the clouds. This led to 

some interesting speculation by columnists on what kind of 

missile was launched and for what purpose. Headlines in both 
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102

the Cape Canaveral and St. Louis papers stressed the secrecy 

and mystery of the launch. “Air Force Keeps Missile Secret,” 

read the headlines in a local paper, and the St. Louis paper had 

the story on page 1, which read, “Solid-Fueled Mystery Rocket 

Fired at Cape.” They only identified it as a McDonnell missile. 

This secrecy was maintained through the other launches; however, more information was released identifying it as a McDonnell 

rocket for the air-launched Bold Orion project. 

Alpha Draco launch. First-stage boost was provided by 

a Thiokol XM-20 rocket motor from a modified Honest 

John missile launcher. 

The Boeing Company
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Air Force personnel watching the large, real-time range safety 

tracking chart, shown in figure 13, wanted to know how the 

flight path could be so truncated from a ballistic flight. When 

told that the vehicle was gliding, they just shook their heads in 

disbelief. They also noted a cyclic radar transponder motion on 

the plot and asked if the missile were rolling. I nodded affirmatively and explained it was rolled to equalize the heating of the 

missile skin by air friction to prevent the missile from warping. 

As a matter of record, the stainless steel missile skin reached a 

temperature of 750° F—very close to the point where stainless 

steel loses it structural integrity. This first flight met all proposed objectives, even after the loss of one telemetry channel. 

The range safety elevation and azimuth plot of the initial 

flight path shown in figure 13 is copied from the large, foursquare-foot range safety tracking chart of the entire flight. The 

predicted boost and glide path shown is plotted from the data 

we supplied. The track labeled actual is the radar tracking data 

plotted in real time during the flight. The other lines on the 

chart are the range safety destruct criteria. If the actual flight 

path, either in elevation or azimuth, became tangent to any of 

the lines shown, the destruct command would be initiated because of the possibility it could impact in a populated area.

Note how close the actual path followed the predicted. The 

15-second break in the actual path at 108 seconds caused both 

Jack Evans and me to exclaim out loud, “What happened?!” 

The range safety officer alleviated our fears with a hand wave 

and mouthed “Okay.” He later explained that they lost a tracking radar and had to switch to a backup. It is interesting to 

note that the initial radar showed the actual path slightly higher 

and to the left of the predicted path, while the backup was below and to the right. Range safety said that was within their 

margin of error, and we were right on. 

The visiting missile division director, Ben Bromberg, was 

elated with the successful test and immediately appropriated 

the direct line to McDonnell to inform Mr. Mac. When I returned from Cape Canaveral, my associates told me about Mr. 

Mac’s exciting announcement over the company-wide public 

address system. Mr. Mac always started his announcements 

with, “This is Ole Mac calling all the team, this is Ole Mac calling all the team,” and then launched into his announcement. 
"$56"-

"$56"-

Figure 13. Alpha Draco range safety plot
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This time he prefaced his talk with, “This is Ole Mac calling all 

the team, this is a jubilant Ole Mac calling all the team with 

some exciting news from Cape Canaveral.” McDonnell was a 

small company with a family-type working atmosphere throughout. It was not unusual to see Mr. Mac wandering around, occasionally stopping to talk to employees. It was an excellent 

place to work, and almost everyone liked Mr. Mac and enjoyed 

his homey announcements. In the McDonnell annual report, 

Mr. Mac always reported his salary as equal to the wages of 10 

floor sweepers for a 48-hour work week.

Alpha Draco S/N-2 was launched one month later on 16 

March 1959 and was totally successful. It glided 212 nautical 

miles down range and impacted right at the predicted impact 

point. Six weeks later on 27 April, Alpha Draco S/N-3 was 

launched. Since all original objectives were met with the first 

two launches, this glide vehicle was to demonstrate the maneuvering capability by turning 20 degrees to the right during glide. 

Unfortunately, the range safety officer destroyed the vehicle 

just after second-stage ignition when it deviated from its flight 

path. Post-flight analysis showed that the roll axis resolver 

failed, causing the flight path departure.

There were the requisite post-launch parties at the Starlite 

Motel where we stayed; the first, by far, the most rambunctious. 

Everyone got thrown or pushed into the pool with some unforeseen consequences. This was prior to the general use of plastic 

charge cards, and cash was the usual payment method. We all 

had quite a bit in our wallets since we were on temporary duty, 

and we spread it out all over the small, shared motel rooms to 

dry. It was quite startling to wake up the next morning surrounded by hundreds of dollars drying all over the floor. 

The Alpha Draco program—or as it was officially known in 

the Air Force, DRACO 199D, or more commonly called, USAF 

Project 2120—merited three pages in the official history of the 

Air Force Missile Test Center.16 Alpha Draco was the first missile to fly in the atmosphere at a hypersonic velocity. It also 

demonstrated, beyond skeptics’ doubt, that the concept of 

aerodynamic body lift was feasible, could be controlled to fly at 

a hypersonic velocity, and should be exploited. Several years 

later, manned wingless lifting body vehicles demonstrated the 

ability to maneuver and land. Those vehicles, the Martin X-24, 
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Northrop/NASA M2-F3, and Northrop HL-10, provided flight 

techniques used for the space shuttle, especially in performing 

the high-speed approach and power-off landing.17 In fact, the 

aerodynamic trend is to now blend the body and wing together 

to achieve much greater efficiency than having a separate fuselage and wing.18

McDonnell expended a concerted effort on a proposal using 

the Alpha Draco concept for the Minuteman missile system, 

but it was just too new and not a completely proven concept. 

Our Model 122 research projects remained in work but at a 

reduced level. One tangible effect of our effort was that the 

English lexicon was increased by the acronym BGRV, for boost 

glide reentry vehicle, which was the Air Force–acceptable generic name for our glide concept. One of the research projects 

that finally garnered a contract and made it to the flight phase 

was the Model 122E BGRV. It was launched at Vandenberg 

AFB, California, using an Atlas booster and glided several thousand miles making a turn around Johnson Island on its way to 

Wake Island. This is covered later. 

McDonnell was preparing an Asset program proposal for testing hardware for the Air Force X-20 Dynasoar (acronym for dynamic soaring) man-in-space project. I was drafted to run a 

parametric launch trajectory study on the computer, and one 

launch put the vehicle in orbit. The computer just kept computing and computing as the vehicle orbited the Earth and never 

reached its programmed stop conditions of a downward flight 

path. When I picked up the computer runs, I was presented with 

a four-inch stack of useless paper. My embarrassing oversight 

led to more stringent control over computer-run submissions to 

assure the computations were stopped after a reasonable run 

time. We had a lot to learn to efficiently use the computer.

The X-20 Dynasoar was an Air Force space-plane project to 

quickly get a blue-suiter (Air Force personnel) into orbit via a 

hypersonic long-range glider that could also perform orbital 

missions. It was initiated in conceptual form in the early 1950s 

and became a formal project in 1957, with Boeing as the prime 

contractor. An immense amount of research and development 

was conducted over the years, and a group of Air Force astronauts went into training for possible flights in the 1964–65 

time frame. In December 1963, a month before the first test of 
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its gliding characteristics in a drop from a B-52, the project was 

canceled. The research, development, and piloting techniques, 

especially the reentry and landing procedures, were later applied to the space shuttle. Six of the Air Force astronauts elected 

to transfer to the NASA manned space program.19

Asset is a hypersonic lifting-body glide vehicle having a flat 

bottom with stubby wings and resembling the Dynasoar configuration. Fortunately, the Asset contract was continued even 

after the Air Force canceled the Dynasoar program, since the 

test objectives were applicable to many other space reentry 

programs. However, its purpose was changed to be an aerothermodynamic-structural test vehicle for materials tests at orbital reentry velocities. McDonnell won the Asset contract and 

in 1964 successfully launched six Asset vehicles from Cape 

Canaveral using a Thor Delta IRBM as a booster. They glided 

through the atmosphere the length of the Atlantic Missile Range 

and were recovered by parachute near Ascension Island. Hightemperature materials tested included a tungsten nose cap, 

molybdenum panels, and a liquid-cooled double-wall panel. 

One Asset vehicle had a variable center-of-gravity system that 

used compressed nitrogen to move a small amount of mercury 

between a forward and aft tank to vary the flight angle of attack. Another had a small flap to investigate heat loads during 

cycling. The tests returned a wealth of data on heat-tolerant 

exotic materials that aided many other programs.20

Bold headlines greeted us on an early May 1960 morning, 

proclaiming the shoot-down of an American spy plane by the 

Soviets. Apparently, a high-flying Lockheed U-2 was brought 

down by a Russian missile in the Sverdlovsk area, and the pilot, Francis Gary Powers, was captured. It was the major topic 

of conversation at work. When we checked where Sverdlovsk is 

located, we were dumbfounded; it is in the center of the USSR 

on the Eastern slopes of the Ural Mountains. We assumed that 

the shoot-down was in the border areas, where the Soviets continually complained of spying from American RB-47s. The U-2 

incident caused a major confrontation between the USSR and 

the United States that dragged on for several years. The Soviets 

threatened to execute Powers but only sentenced him to prison 

and hard labor for 10 years. He was released in trade for Soviet 

spy Rudolph Abel in February 1962.21
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A Soviet version of the Gary Powers incident was published by 

Sergei Khrushchev, the son of Premier Nikita Khrushchev, in the 

September 2000 American Heritage magazine.22 In it the Soviets 

mentioned an aircraft maneuver they called “exit into the dynamic 

ceiling,” what we called a zoom climb. Recall the Air Force planned 

to use that in 1954 to counter the threat of the Soviet Bison jet 

bomber (see chap. 4). Several attempts were made by MiG-19 pilots to shoot down a U-2 and, during Powers’ flight, a Russian 

Historical Note 

Recently I met several retired CIA and FBI agents, and the stories of their adventures during the Cold War are most fascinating. One of the CIA agents was the 

person who interrogated Gary Powers after his release from Russia. With his consent, here are some excerpts from the Gary Powers debriefing story as he told me. 

(His name is omitted to protect his privacy.) 

Powers was not told that a previous U-2 pilot reported seeing a surface-to-air 

missile (SAM) reach his altitude in the distance. As Powers was approaching the 

Sverdlovsk area at 74,000 feet, a SAM exploded off his right wing, blowing off 

several pieces of the wing. Shortly thereafter the right wing crumpled and separated from the aircraft. The aircraft went into a fluttering, spinning, tail-first descent. The centrifugal force of the spinning aircraft prevented him from using the 

ejection seat because he was out of the correct position and would have amputated his legs. He tried to get out over the front of the aircraft, however, his pressure suit hose kept him tied to the aircraft, and he could not reach the disconnect. In hindsight, this probably saved his life because if he had disconnected his 

oxygen hose at high altitude, he would have died. This thought did not occur to 

him even when describing it. He finally broke the suit hose and was tossed out 

over the nose. His parachute opened immediately on pulling the rip chord, which 

meant he was below the 13,000-foot barometric parachute opening setting. 

A poisoned needle screwed into a silver dollar was put into Powers’ left sleeve 

pocket—just in case he needed help. When he was floating down in his parachute, he thought about the silver dollar and realized it would be the first trophy 

they would find. He screwed out the needle (it was capped) and threw away the 

silver dollar. He kept the needle since it could be a weapon, but the Soviets found 

the needle when he was searched. They treated Powers well, and he maintained 

a cool head when interrogated by twisting the facts to protect sensitive information. For example, to protect the capability of the U-2, he did not give his correct 

flight altitude when shot down, telling the Russians he was at 68,000 feet when 

actually he was at 74,000 feet.

My contact said the CIA bugged the bed that Barbara (his wife) and Gary used 

that night to see if Powers would reveal any other information, but nothing more 

was heard, as they were “too busy.” I convinced the CIA agent to look at several 

Web sites on the Powers incident. His comments were mostly hearty guffaws or 

“that’s a lot of BS.” 
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pilot managed to reach the U-2’s altitude and vicinity but was unable to find the spy plane during his zoom-climb.23 

One other interesting aeronautical event: the supersonic 

Convair B-58 Hustler bomber was now in service and conducting supersonic training flights crisscrossing the United States. 

Thus, we were periodically subjected to window-rattling sonic 

booms. One day while talking to some neighbors outside, I noticed a fast-moving condensation trail of a B-58 overhead. I 

called their attention to it and pointed along the flight path at 

a 30-degree angle from the horizon and said that when it 

reaches that point we will hear the sonic boom. Sure enough, 

we heard the boom-boom when the aircraft was right where I 

pointed. They were surprised I could do that, but I knew the 

B-58 flies at Mach 2.0 and thus sheds a shock wave inclined at 

a 30-degree angle.24 Later, after many complaints and even 

some damaged homes, supersonic flights were banned in the 

United States except in certain designated rural locations. 

More and more engineers were beginning to appreciate the value 

of computers in solving mathematical problems, even though we 

had very little understanding of how they worked. In my own case 

I was going to be enlightened by firsthand knowledge. 

Notes

1. The Air Force Museum at Wright-Patterson AFB, Dayton, Ohio, has a 

GAM-72 on display. Information is available on the Web at http://www.wpafb

.af.mil/museum. 

2. Wilber B. Huston and T. H. Skopinski, Measurement and Analysis of 

Wing and Tail Buffeting Loads on a Fighter Airplane, NACA Report 1219, 1955; 

and Harry Press and Bernard Mazelsky, A Study of the Application of PowerSpectral Methods of Generalized Harmonic Analysis to Gust Loads on Airplanes, NACA Report 1172, 1954. 

3. MAC Report 5573, GAM-72 Buffet Analysis of the Series VIII High Speed 

Wind Tunnel Tests of the 0.075-Scale Model Wing Hinge Moment Model in the 

Presence of the B-47E Airplane; and Supplement Report, MAC Report 6403, 

GAM-72 Buffet Analysis Summary, 9 October 1958. 

4. Harry G. Stine, ICBM (New York: Orion Books, 1991), presents a history 

of ballistic missile development from the earliest times through the German, 

Soviet, and American ICBM development. 

5. An excellent summary of the IGY results is available from the Encyclopedia 

Britannica at http://www.britannica.com/seo/i/international-geophysical-year. 
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110

6. Tom D. Crouch, Aiming for the Stars—The Dreamers and Doers of the 

Space Age (Washington, DC: Smithsonian Institution Press, 1999). This is an 

excellent reference and summary of exploring the space age from the earliest 

times to the present. Another excellent text is William E. Burrows, This New 

Ocean—The Story of the First Space Age (New York: Random House, 1998). 

7. Eugene N. Parker, “Shielding Space Travelers,” Scientific American 294, 

no. 3 (March 2006): 40–47.

8. Willy Ley, Rockets, Missiles, and Men in Space (New York: Viking Press, 

1968). Ley initially published this book titled, simply, Rockets in 1944, which 

was the edition I first read. Since then it has been expanded in content and 

detail to the 1968 edition listed. Of the many books on the subject, this classic is by far the most readable text available.

9. Alfred J. Eggers, H. Julian Allen, and Stanford E. Niece, A Comparative 

Analysis of the Performance of Long-Range Hypervelocity Vehicles, NACA 

Technical Note 4046 (Washington, DC: NACA, October 1957). (Superseded by 

NACA Technical Report 1382, 1958.) 

10. Stine, ICBM, 87–93; and Wegener, Peenemünde Wind Tunnels, 44. 

11. A winged hypersonic vehicle was periodically studied by NASA and 

industry engineers, and the problem was solved by the present-day space 

shuttle using graphite shingles as the heat-protection system. 

12. The high Mach number test of 8.08 was conducted in the NOL 40 cm 

wind tunnel the Winklers were modifying when my AFIT class GAE 52 toured 

the NOL at graduation. 

13. Wayne E. Moyer, “The Wind Tunnel Air Force,” Air Force Museum 

Friends Journal 23, no. 3 (Fall 2000): 34–35. 

14. Robert V. Brulle, “Alpha Draco—The Wingless Glider,” Air Force Museum 

Friends Journal 13, no. 3 (Fall 1990): 30–35. The publication of this article 

sparked a reunion of former team members still residing in St. Louis. An attractive, glossy brochure was published, summarizing the program and dedicated by 

John McDonnell, then the McDonnell CEO. In his statement, he recounted, “You 

were the pioneers of a McDonnell presence at Cape Canaveral and established a 

standard for Mercury, Gemini, and other programs that followed.” 

15. The aircraft laboratory at Wright Field later awarded McDonnell Aircraft a contract to develop a computer program to exploit the random-number 

trajectory technique. The full derivation of the technique is presented in a 

report by Robert C. Brown et al., Flight Path Error and Dispersion Analysis 

Generalized Computer Program, Part 1—Formulation, ASD Technical Report 

61-552 (Wright-Patterson AFB: Air Force Systems Command, October 1961). 

There are two other parts to the report, a user’s manual and a program listing. 

16. Air Force Missile Test Center History, 1 January to 30 June 1959, Patrick AFB, FL. Available from Air Force Historical Research Center, Maxwell 

AFB, AL 36112.

17. Milton O. Thompson and Curtis Peebles, Flying without Wings, (Washington, DC: Smithsonian Institution Press, 1999). 

18. Boeing provides a futuristic look at a blended-wing-body type of aircraft we will be flying in the foreseeable future at www.boeing.com/phantom/

bwb.html.
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19. Martin Caidin, Rendezvous in Space (New York: E. P. Dutton & Co., 

1962), 260–69. 

20. Mark Wade, Encyclopedia Astronautica at www.friends-partners.org/

mwade/craft/dynasoar.htm presents a brief summary of the program.

21. Additional information is available from the movie Francis Gary Powers: 

The True Story of the U-2 Spy Incident, 1976; and Francis Gary Powers and 

Curt Gentry, Operation Overflight: The U-2 Spy Pilot Tells His Story for the 

First Time (New York: Henry Holt and Company, Inc., 1970). For photos and 

U-2 specifications, see http://www.robins.af.mil/lr/aircraft.htm and http://

www.milnet.com/milnet/u-2htm.

22. Sergei Khrushchev, “The Day We Shot Down the U-2,” American Heritage (September 2000): 36–48.

23. The MiG-19, known as the Farmer, had a supersonic performance 

capability of about Mach 1.4, comparable to the F-100. This would allow a 

zoom climb to about 75,000 feet. James Bamford, Body of Secrets: Anatomy 

of the Ultra-Secret National Security Agency (New York: Doubleday, 2001), 

gives several other interesting anecdotes on the Francis Gary Powers shoot 

down. In fact this entire book is an exposé of secret electronic intercepts over 

the years which provides an inside look at intelligence gathering. It shows 

how those intercepts helped the United States keep an upper hand through 

the many Cold War confrontations.

24. The shock wave angle shed by a slender body is expressed as the angle 

whose sine is 1/Mach number. Thus, if the body is traveling at Mach 2.0, the 

shock wave sweeps back at an angle whose sine is 0.5. Looking that up in a 

trigonometric function table shows it to be 30 degrees.

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Chapter 6

Computer Programming

What are the uses for computers? What can they do? These 

were the kinds of questions engineers asked as they explored 

the mystery of computers. Surprisingly, many had no inclination to learn how to use them. Fortunately, the potential was so 

great that engineers were dragged into the computer age; some 

old-timers very reluctantly, but most were anxious to embrace 

this new technology. The computer’s capability to manipulate 

large groups of numbers made it feasible to solve the nonlinear 

differential equations that describe many natural processes by 

using a numerical integration routine. This was the key that 

opened the door to computer usefulness. 

The Air Force Flight Dynamics Laboratory (AFFDL) at Wright 

Field issued a proposal for writing the official Air Force version 

of a multipurpose computer program that solves the SDF equations of motion, and McDonnell won the contract. (Recall that 

we encountered these equations in chapter 4, discussing the 

crash of an F-100 due to inertia roll coupling.) 

The SDF equations are written in a right-handed, body-oriented, 

three-dimensional, orthogonal axis system, denoted as the x, y, 

and z axes. The x axis points forward, the y axis points to the 

right, and the z axis points down. (Right-handed means that 

right-hand or clockwise rotations around any axis would advance a screw in the positive direction of that axis.) A body axis 

system is used because the applied forces and moments—like 

thrust, lift, pitching moment, jet damping, and so forth—are referred to the body axis system. Since Newton’s law, force = mass 

X acceleration, applies to an inertial frame of reference, all of the 

body axis system terms must be transformed to the inertial 

frame of reference. For aircraft, satellites, or other bodies near 

the earth, a Cartesian Earth-centered axis system is used as the 

inertial frame of reference. For interplanetary trajectories, a Cartesian heliocentric (sun-centered) inertial system is used. 

Rather than use the usual aircraft definitions of angles of attack, yaw, and flight path to express the equations, all the 
COMPUTER PROGRAMMING

114

equations are expressed in a matrix format of direction cosines 

of the body axis system. What this means is that the angle of 

attack, expressed as the angle between the body x axis and the 

velocity vector, is now defined as the angle between the body x 

axis and the x component of the velocity. A similar definition 

exists for the yaw angle and flight-path angle. This approach is 

taken because matrix computation techniques make it easy to 

relate any one axis system to another and eliminate the possibility of a program block by encountering an undefined angle. 

For example, how does one define yaw angle at 90 degrees angle 

of attack? Thus, matrix operations allow computation of a tumbling body trajectory. (Later I describe using the SDF program 

to compute the trajectory of an ejecting astronaut from a malfunctioning tumbling booster rocket.)

In this time period, individual computer programs were available that solved parts of the SDF equations. In fact I regularly 

used a two-degree-of-freedom, x and z velocity, point-mass program. This established a missile trajectory without expending a 

lot of computer time. The next step was to use a three-degreeof-freedom program by including the pitching motion. This was 

adequate for establishing a realistic trajectory except for the 

initial launch phase, where stability and control considerations 

in all three axes predominated. A very rudimentary SDF program was available to check the launch stability. This was the 

current state of affairs as we prepared to write and assemble a 

comprehensive SDF program.

Three engineers and two computer programmers were assigned to assemble the SDF computer program. The engineers 

derived the equations and diagrammed flowcharts on how the 

program computations should proceed, and the programmers 

translated the flow diagrams into computer language. This was 

an all-inclusive program that had 10 SDF trajectory options, 

from computing a simple point-mass trajectory over a flat Earth 

to the six-degree-of-freedom dynamic trajectory over an oblate 

spheroid. Geophysical characteristics, such as size, shape, mass, 

and gravitational influence of different planets, along with a 

variety of atmospheres and wind effects, were all considered so 

the program could be used to calculate trajectories on different 

planets. Vehicle characteristics, including mass changes as fuel 

is used, spin effects, aeroelastic (structural bending and vibra-
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COMPUTER PROGRAMMING

tion) effects, rotating machinery gyroscopic forces, jet damping, and cross-coupling between various axes are all included. 

Aerodynamic forces and moments due to control movements, 

along with a guidance system having an inertial platform and 

autopilot with a real-time feedback, were all simulated. An interplanetary tie-in lets the program hand off to an interplanetary 

program using a heliocentric axis system or accept an input to 

continue an interplanetary trajectory to orbit or land on a 

planet. In short, SDF provides a versatile tool for computing a 

large variety of vehicle motions and trajectories.1

Accounting for rotating machinery in the stability and control of satellites was especially critical as vividly demonstrated 

in one of the early Explorers. The satellite was the upper-stage 

rocket motor that housed the instruments in the nose and was 

spin-stabilized in orbit. A small tape recorder was used to record the instrumentation data so it could be played back when 

over a station. What had not been considered were the reaction 

forces when starting and stopping the tape. These small forces 

were transmitted to the satellite, upsetting the stabilizing spin, 

and the satellite started to tumble, negating the instrument 

readings—an embarrassing oversight.

Due to the versatility of the program, the programmers decided to centralize control in an executive program. They further divided it into individual building blocks, where each SDF 

option is treated as a separate entity. Further, each individual 

subprogram and subroutine is a separate and complete entity. 

A subprogram is a calculation of parameters that are used by 

the other parts of the program. For example, a vehicle physical 

characteristics subprogram calculates and keeps track of the 

vehicle mass, center-of-gravity location, and moments of inertia 

for use in the equations of motion. A subroutine is a generalized computation, such as a square-root routine, an exponential routine, an integration routine, or an N-dimensional table 

lookup routine. Any time a subprogram or subroutine is required, the executive program directs the calculations to the 

correct location. Since they are stand-alone entities, each option, subprogram, and subroutine is individually written and 

checked out without having to employ the complete program. 

In addition, the programmers assembled a versatile new integration routine that speeded up the integration. It was called 
COMPUTER PROGRAMMING

116

the predictor-corrector technique and used a variable time step 

for integration. At every time step, a prediction of the next integrated value was made. If the actual integrated value was within 

a specified accuracy, the next integration time step was increased. 

Therefore, if an integrated function was relatively smooth, the 

integration proceeded rapidly with large time steps. Conversely, 

if the integrated function was ragged, the time step was small. 

Recall that computer time was precious in that era of large, 

slow, vacuum-tube mainframe computers, so any design that 

saved time was employed. 

We started checking out the program using an IBM-709 

vacuum-tube computer and completed the task on an IBM7090 transistorized computer. To give us greater computer access, we elected to check out the program during the normally 

slow nightshift. Unfortunately it was also the time that the 

technicians were busy installing the new IBM-7090 computer, 

so we had to work around their routing cables and moving 

computer cabinets around. They did keep one or the other computers operating so we could complete our work. 

During the program checkout, we engineers could not help 

but learn how to program a computer. By analyzing the computer printouts, we could narrow the error location to the section of the program that contained it. Then by following the 

program listing, we could usually spot the problem. The programming language used at that time was a machine language 

that specifically designated each step in the calculation. All 

numbers were stored in registers and were recalled as needed. 

For example, to compute the dynamic pressure 0.5 ρ V2 (ρ is 

the density and V the velocity) the following steps are required. 

(This was copied from the SDF program user’s manual). 

LDQ .5 Load the number 0.5

FMP RHOS Float and multiply by ρ (RHOS is its designated label) 

XCA Exchange registers to get back to the working one

FMP VA))F Float and multiply by V (VA))F is the velocity label)

XCA Exchange

FMP VA))F Float and multiply by V again

STO DYNPP Store dynamic pressure in the register labeled DYNPP
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By today’s standards it is a very cumbersome way to program, but then it was all we had. I used SDF many times and 

made many unique modifications to it for solving a host of 

problems. 

Historical Note 

The SDF program became the paramount computing tool for McDonnell and the 

Air Force and over the years, was compiled into more-modern programming languages. I remember when the McDonnell and Air Force versions were switched to a 

FORTRAN computer language. Before I retired from McDonnell, I used a COBOLlanguage version. The SDF program and its derivatives have performed yeoman 

service in industry and the military for computing the trajectories and body motions of aircraft, missiles, and space vehicles. A derivative of the program is probably still used. 

A pleasant reunion with two of my former AFIT students, 

now astronauts, Gordon Cooper and Gus Grissom, occurred 

during the mockup inspection of the Mercury spacecraft. After 

I congratulated them, they introduced me to several of the other 

astronauts and proudly explained how they were training to fly 

in orbit while showing me that small capsule. I was proud to 

have two of my former students chosen to participate in America’s 

man-in-space program. 

I accepted the additional job of teaching a graduate theoretical 

aerodynamics course at St. Louis University. This was an evening class primarily attended by McDonnell Aircraft engineers 

pursuing their MS degrees. I used the text, Foundations of Aerodynamics by A. M. Kuethe and J. D. Schetzer, which I had used 

at AFIT.2 After I completed the course, the department head, a 

Jesuit priest, asked me to teach the class on a regular basis. I 

liked the extra money but declined since my area of interest 

was gravitating into the dynamics field and that theoretical 

aerodynamics class required a lot of preparation time. Later I 

taught an advanced flight dynamics course in the mechanical 

engineering department of the University of Missouri-Rolla’s 

St. Louis Graduate Engineering Center as an adjunct associate 

professor for eight years. It was during this period that my oldest son, watching me prepare my lectures, stated what he 

wanted to do, become a professor. As it turned out, he and my 
COMPUTER PROGRAMMING

118

second son both became university professors, and my daughter became a teacher and is now a principal. I think she decided 

on that role when she supervised my class as a test proctor 

while I was on a trip. My youngest son spurned the teaching 

profession but did become a hard-hat commercial diver and an 

Abrams tank mechanic for the Army National Guard. 

Historical Note 

At this time, both the United States and the USSR were launching various types 

of satellites—moon probes, communication satellites, and explorations of the Van 

Allen radiation belts. Most of the US launches were televised; however a series of 

launches, dubbed the Discover satellites, were secretly launched by the Air Force 

from Vandenberg AFB, California. These reconnaissance satellites were lofted 

into a polar orbit so they traversed the entire Earth, and the data they gathered, 

photographs of Russian installations, was de-orbited in a recovery capsule. The 

data capsule was recovered by a Fairchild C-119 aircraft, which snagged the recovery parachute. The operational name of the program was Corona. Starting in 

February 1959, the Air Force launched one Discover after another, and the first 

12 tries failed for one reason or another. Finally, in August 1960, they successfully snagged a capsule and recovered the reconnaissance images from space. The 

system and its derivatives were operational for 12 years. (Francis Gary Powers’ 

flight over Russia was supposedly the last U-2 flight, since Corona was approaching operational capability. The administration wanted just one last flight when he 

was shot down.)3

McDonnell won another contract from the Flight Dynamics 

Laboratory to develop a program titled “Flight Path Error and 

Dispersion Analysis Generalized Computer Program,” or EDA 

for short. This contract was awarded on the basis of the trajectory dispersion analysis McDonnell completed for the Cape Canaveral flight safety requirements during the Alpha Draco program. 

It is a versatile program to perform an error-and-dispersion 

analysis of the trajectory of a flight vehicle. Three alternate statistical methods are described for performing the analysis.4

Method 1 is the familiar square-root-of-the-sum-of-the-squares 

method for defining the standard deviation. This is the simplest 

of the options but also limits the output to only the mean and 

the standard deviation.

Method 2 first defines the trajectory influence functions of 

the dependent variables. For example, how much does a statis-
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tical value (like a 3σ value) of the motor-thrust variation change 

the velocity at the end of the trajectory? In this case, motor 

thrust variation is an independent variable, and the dependent 

variable is the velocity. (There are many independent and dependent variables, depending on the vehicle and trajectory.) 

The change of velocity for a given thrust variation is the influence function. Computing this for all independent and dependent variables gives a series of influence functions. Then, using 

a random number routine to select the values of the independent variables and applying the influence functions results in 

the dependent variables’ end condition. Computing this for a 

large number of cases produces a sample of dependent variables for a statistical analysis. The output calculates the mean, 

standard deviation, third moment, and fourth moment. Output 

analysis also allows the selection of a group of independent 

variables that can be used to compute an actual 3σ statistical 

value trajectory. This system was invented during the Alpha 

Draco program because, at that time, range safety wanted such 

a trajectory for the unguided first-stage launch. 

Method 3 calculates a number of trajectories with multiple 

random errors of the independent variables. The characteristics of the resulting cumulative frequency distribution are then 

examined to evaluate the population from which the sample was 

drawn. This method is the most comprehensive but can require 

a great number of trajectory computations. 

The program is also constructed so that the required data 

input can be automatically input by the SDF program. The 

mathematical details are quite complex and are not presented 

here. Those interested in the details should consult part I of the 

referenced report. Throughout my career I used both SDF and 

EDA quite often with good results. 

Historical Note 

An ominous warning crept into our daily lives when the festering Berlin issue 

erupted and precipitated another crisis with the Soviets. This became personalized 

when several McDonnell engineers I worked with were recalled to active duty. They 

were Missouri Air National Guard pilots whose unit was federalized. They and their 

F-84F aircraft were flown to Europe to bolster the US military presence. It was during this protracted crisis that construction of the Berlin Wall was begun.
COMPUTER PROGRAMMING

120

We now turn to the exciting field of manned spaceflight. It 

was a high-priority program filled with new and challenging 

problems that had never before been encountered. We were 

breaking new ground in the aeronautical engineering profession, and in the end, left an engineering legacy that will be remembered for many years. In hindsight, this portion of my career was the most fruitful and rewarding.

Notes

1. Robert C. Brown, Robert V. Brulle, and Gerald D. Giffin, Six-Degree-ofFreedom Flight-Path Study Generalized Computer Program, Part I—Problem 

Formulation, WADD Technical Report 60-781 (Wright-Patterson AFB, OH: 

Aeronautical Systems Division, May 1961); and Frederick W. Seubert and 

Newell E. Usher, Six-Degree-of-Freedom Flight-Path Study Generalized Computer Program, Part II—User’s Manual, WADD Technical Report 60-781 

(Wright-Patterson AFB, OH: Aeronautical Systems Division, May 1961). Part 

I is an excellent reference source that explains the derivation of the SDF 

equations of motion. An updated user’s manual was published specifically for 

use by the personnel and the computer facility at Wright-Patterson AFB, SixDegree-of-Freedom Flight-Path Study Generalized Computer Program, (SDFCP) 

User’s Manual, AFFDL-TR-75-1 (Wright-Patterson AFB, OH: Aeronautical 

Systems Division, July 1975). 

2. A. M. Kuethe and J. D. Schetzer, Foundations of Aerodynamics (New 

York: John Wiley and Sons, 1950). 

3. Dwayne A. Day, John M. Logsdon, and Brian Latell, eds., Eye in the Sky: 

The Story of the Corona Spy Satellites (Washington, DC: Smithsonian Institution Press, 1998). 

4. Robert C. Brown, Flight Path Error and Dispersion Analysis Generalized 

Computer Program, Part 1—Formulation, ASD Technical Report 61-552 

(Wright-Patterson AFB, OH: Air Force Systems Command, October 1961).
121

Chapter 7

Spacefarers

Can humans survive in space, and if you put them in space, 

what can they do? What technical problems must be solved to 

accomplish this feat? What can be accomplished in space that 

would benefit mankind? These and a host of other questions 

confounded the aerospace community as it attempted to exploit this new horizon of spaceflight. The ability to send artificial 

satellites whirling around the earth was no longer in doubt, but 

human survival in that environment was an unanswered question that both the Soviets and Americans were exploring. Orbiting the world’s first artificial satellite and then a dog in space 

earned the Soviets worldwide respect and acceptance. They 

boasted that their scientists and engineers were the best in the 

world, and that American capitalism was a corrupt society. Their 

boasting was enhanced by the failure of several US satellite 

and missile launches broadcast on live TV. The Soviets’ closed 

society kept their failures from being viewed, but word leaked 

out that several had occurred. 

The Soviets’ boasts and world acclaim for their achievements 

were troubling to all Americans, and the public clamored for action. In quick succession, the National Space Act and NASA were 

created, along with the National Defense Education Act, to stimulate the teaching of math and science. America’s resolve was 

raised to a fever pitch when Pres. John F. Kennedy addressed a 

joint session of Congress on 25 May 1961 and uttered the words, 

“I believe this nation should commit itself to achieving the goal, 

before this decade is out, of landing a man on the Moon and returning him safely to the Earth.” US superiority in space was 

thereby established as a goal and heartily accepted by the American people and government. The American public again had a 

national challenge and went to work as they had in WWII.

This era saw an intense effort to obtain information on the 

moon, so both the United States and the USSR launched a series of unmanned moon probes. The first US launches were 

called Ranger and were designed to transmit photographs as 
SPACEFARERS

122

they approached a crash landing on the moon. The first Ranger

was launched in August 1961, but the first success did not occur until Ranger 7 in July 1964. It was disheartening to witness six failures in a row. Fortunately, Rangers 7, 8, and 9

were unqualified successes and showed the moon’s surface to 

be pockmarked by craters. Finding a smooth spot to land a 

manned module was going to be a problem.1

The second series of probes were the Surveyor soft-lander 

spacecraft. They also had a few failures but successfully completed the program by safely landing five of seven spacecraft 

sent to the moon. The photographs they returned were spectacular and provided the site information for a manned landing. They also sampled the lunar soil and showed that it could 

support a manned lunar lander.2

The Soviets launched a series of Luna moon probes beginning in 1958, long before the United States had the capability 

to match their effort. That first probe had the distinction of first 

vehicle to reach Earth escape velocity. The first Luna impact on 

the moon occurred in September 1959, and shortly thereafter, 

another Luna obtained photographs of the back side of the 

moon. Rumors persisted of failed Soviet launches, but their 

program was so veiled in secrecy that no outsiders really knew 

what was happening. It was a very heartbreaking time for the 

US space program. No matter, the United States kept to its 

planned and open program for all the world to see.3

This was the status vis-à-vis the US and USSR space programs as we raced to the moon. I recall we were stunned and 

dismayed by the sudden emergence of the USSR as a major 

player in space exploration. I guess we should have expected it 

since they developed their own atomic and hydrogen bombs, 

but we wondered where they got the scientific talent to accomplish those feats. I do know we were resolute in our determination to beat them to the moon.

During those exciting days, various engineering organization 

meetings featured speakers who presented information and pictures of the latest triumphs. I recall when movies of the first Ranger

probe impacting on the moon were shown at an Institute of Aeronautical Science (IAS) meeting. The auditorium was filled to overflowing, waiting to see what the moon surface was like. The short 

movie was a series of still photographs projected in sequence, simu-
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SPACEFARERS

lating the real-time final plunge to the moon. It was enthralling to 

watch, as smaller and smaller craters came into view. The entire 

landscape was filled with craters. I did not know what to expect, 

but finding out that close-up pictures looked the same as what we 

saw through a telescope was sort of disappointing. 

This chapter summarizes the Mercury and Gemini projects, 

illustrating the technological evolution required to accomplish 

the early space program missions and relating the excitement 

and dedication we felt at that time. This information relies 

heavily on several NASA reports.4

McDonnell had studied the concept of a blunt-body, ballistic 

reentry capsule in the mid-1950s and had a spacecraft concept 

and engineering team ready when the NASA proposal for development of the Mercury spacecraft arrived. This prior effort paid 

off when, in January 1959, MAC was awarded the Mercury oneman spacecraft contract. I was quite surprised when I saw the 

notice of MAC winning the contract on our bulletin board at 

Cape Canaveral while there for the checkout and launch of the 

122B Alpha Draco missile. I was not aware, nor had I heard any 

rumors, that MAC was involved in man-in-space research. 

I joined the Mercury program shortly after President Kennedy’s 

profound speech establishing a moon landing as a top US objective. By that time the Mercury design effort was essentially 

complete, but the team was in the throes of designing a followup two-man space capsule. It was called Mercury Mark-II, but 

when the official NASA go-ahead was signed in December 1961, 

it acquired the apt name of Gemini. The main objectives of Project Gemini, as noted in the McDonnell Aircraft Corporation 

1963 annual report were (1) to evaluate astronaut performance 

in space for periods of a week or more, (2) to develop and demonstrate rendezvous and docking techniques in orbit, (3) to 

demonstrate controlled reentry and landing, and (4) to utilize 

the two-seat capacity of the spacecraft for astronaut training.

The Mercury aerodynamics group was led by project engineer 

John Weitekamp. After introducing me to the rest of the aerodynamics people, he outlined my task as head of the aerodynamics 

performance group. We would compute the trajectories and orbits 

and develop the escape and abort methods during boost phase. 

This included the aerodynamic analysis of the ejection seats the 

astronauts would use to escape from the spacecraft during the 
The Boeing Company

A two-man Gemini space capsule is shown with the two white adapters 

attached. The upper retro adapter houses the retro-rockets; the lower 

equipment adapter houses the spacecraft power fuel cells and the expendables—oxygen, water, and maneuvering fuel. Both are jettisoned 

prior to reentry.
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boost phase and reentry. Wilson McGough was in charge of the 

aerodynamics calculations and wind tunnel testing group.

Historical Note

Wilson McGough was a pilot on the first flight of B-17s to fly to England via the 

northern route during WWII. On 27 June 1942, flying from Goose Bay, Labrador, to 

BW-1 in Greenland, they encountered bad weather and could not locate BW-1. They 

made a belly landing in their B-17E (bureau number 41-9032, named My Gal Sal) on 

the Greenland ice cap. It was a harrowing experience, but they were rescued after 10 

days by the famous arctic explorer Bernt Balchen. In 1964, the aircraft was discovered still sitting on the ice cap. Life magazine found and interviewed the surviving 

crew members, including Wilson, and photographed him posing with a Gemini 

spacecraft. “The Saga of My Gal Sal” was published in Life’s 20 November 1964 issue. 

(I still have a copy of that issue.) In 1995 My Gal Sal was recovered by salvager Gary 

Larkins. Recently, Robert J. Ready bought the remains and is restoring it for display 

at Blue Ash airport in Cincinnati as an Ultimate Sacrifice Memorial.5

Historical Note

The main proponent of ejection seats was James A. Chamberlin, chief of the engineering division of NASA’s Space Task Group. In July 1996 at the Gemini memorial dedication in Titusville, Florida, I met Jim Rose, head of the Mercury and 

Gemini mission planning group we worked with during Project Gemini. When 

asked how NASA arrived at the credibility of using ejection seats, he told me this 

story. Chamberlin told him to get an estimate of the fireball buildup and size of 

exploding Atlas and Titan missile boosters. Jim said he reviewed dozens of Air 

Force films and painstakingly measured the fireball size of the exploding boosters. This first quantitative fireball data was the basis for proposing ejection seats, 

since the Titan, used as the booster for Gemini spacecraft, used a propellant that 

produced a deflagration instead of explosion in the event of a failure.

When I learned that ejection seats were proposed as the escape system for the Gemini spacecraft, I was flabbergasted. It 

was unimaginable that an ejection seat could safely propel an 

astronaut away from an exploding booster. Mercury used an escape rocket mounted on a tower that pulled the spacecraft away 

in an emergency, and I assumed the Gemini escape would be 

similar. This heavy tower/rocket system, however, compromised 

the ability of the Titan II to launch Gemini, and ejection seats 

offered a lighter, simpler system.6 Skeptical or not, the task was 

already under way, so I was admonished to find a way to make 

it work. It was the most challenging assignment in my career. 
SPACEFARERS

126

By the time I came to the program, a Mercury spacecraft 

called Freedom 7 with astronaut Alan B. Shepard on board had 

performed a 250-mile, suborbital ballistic flight launched on a 

Redstone booster on 5 May 1961, which provided the backdrop 

for President Kennedy’s declaration on going to the moon. Unfortunately, the Soviets orbited Yuri Gagarin in their large Vostok

spacecraft the previous month, again eclipsing the United States 

by launching the first human into space. 

The Mercury spacecraft was a small, one-man, conical-shaped 

vehicle that stood 9.5 feet high and had a six-foot-diameter 

base heat shield. It weighed 

4,200 pounds, including a 

1,200-pound escape-tower/

rocket-motor system. Designing and testing the Mercury system was a unique 

challenge which encountered unique engineering 

problems. The most crucial 

were man-rating the Convair Atlas booster and providing an escape system to 

ensure crew survival in any 

possible mishap.

The Atlas missile booster 

used a mixture of hydrocarbons (kerosene) as a fuel 

called RP-1, with liquid oxygen as the oxidizer. The resulting fireball and blast 

wave were spectacularly 

violent, as demonstrated by 

several Atlas boosters that 

malfunctioned during development. Mercury crewsurvival provisions consisted of an escape rocket 

mounted on a tower above 

the spacecraft. The escape 

rocket had three canted 

The Boeing Company

An Atlas rocket boosts Mercury into orbit. 

The white upper part of the booster is frost 

on the cold liquid oxygen (LOX) tank with 

particles breaking off due to noise and vibration. The escape tower is jettisoned as 

the rocket exits the dense atmosphere.
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SPACEFARERS

nozzles that directed the rocket exhaust away from the spacecraft. In 

a booster malfunction, the spacecraft would explosively separate from 

the booster, and the escape rocket 

would tow it a safe distance away for 

a normal parachute deployment and 

water landing. During a normal 

launch, the escape tower was jettisoned a few minutes into flight when 

the blast-wave danger had passed.

The Gemini spacecraft was only 

20 percent larger than Mercury and 

a tight fit for two persons. It was literally designed around Gus Grissom, 

the smallest of the astronauts. To fit 

in the larger ones, especially the tallest, Tom Stafford, the seat and hatch 

had to be extensively modified. 

Gemini was conically shaped like 

Mercury and stood 12.5 feet high 

with a base diameter of 7.5 feet. It 

had two conical sections, called 

adapters, attached to the base. One 

was the retro adapter and, as the 

name implies, housed the retrorockets. The other, the equipment 

adapter, housed the extended-orbit 

expendable supplies. These adapters 

tapered in size from the spacecraft’s 

heat shield diameter of 7.5 feet to 10 

feet, which mated to the Titan 

booster. Both adapters were jettisoned prior to reentry. The spacecraft launch weight was 8,400 

pounds.7 Major differences from 

Mercury were that Gemini had a 

maneuvering capability, an aerodynamic capability during reentry, and 

thrusters for in-orbit maneuvers.

The Boeing Company

The Mercury manned space 

capsule was equipped with a 

rocket motor on top of the escape tower. In the event of a 

booster rocket malfunction, the 

escape rocket would be fired to 

pull the capsule away to safety.
SPACEFARERS

128

Many schemes for putting a human on the moon were studied and hotly debated before one appeared reasonable from 

technical, cost, and safety standpoints. The simplest method 

would be a direct shot to the moon and back; however, analysis 

showed the hardware for this concept to be extremely large. It 

required landing a heavy crew capsule on the moon that carried a lot of weight required only for Earth reentry, along with 

the rocket to propel it back to Earth. Launching such a large 

object to the moon from Earth required an immense rocket. 

The main advantage was that it did not require development of 

a rendezvous-and-docking technique.

Another scheme involved assembling all the parts for a moon 

rocket in Earth orbit. Several smaller launch vehicles could 

send up the individual components and assemble them in orbit 

before blasting off for the moon. This scheme required rendezvous and docking and a lot of space walks, called extravehicular 

activity (EVA).

The scheme finally accepted was developed by Dr. John 

Houbolt, an independent engineer (outside of NASA’s Space 

Task Force). His plan was to launch the entire moon vehicle 

consisting of the command service module (CSM), which includes the command module Apollo; the lunar excursion module 

(LEM) that lands the astronauts on the moon; and the booster 

stack, the Saturn V. The crew of three astronauts travels to the 

moon in the CSM and establishes a moon orbit. Two astronauts then use the LEM to land on the moon. After completing 

their moon expedition, they return to lunar orbit and dock with 

the CSM containing the other member of the team. The LEM is 

then jettisoned, and the crew returns to Earth. This scheme 

required a rendezvous and several docking maneuvers. Gemini 

had to develop and prove those techniques and therefore was 

provided with an orbit maneuvering capability.8

Gemini was configured with two individual and separate control systems. One was the reentry control system (RCS), used 

only for reentry. The other was the orbital attitude and maneuvering system (OAMS). This system performed the normal orbit 

control functions, including separation of the spacecraft from 

the booster, attitude control, and all orbital maneuvers for rendezvous and docking. 
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SPACEFARERS

Besides its orbital maneuvering capability, Gemini could maneuver during reentry to land at a specific recovery point. This 

requirement arose when the Paraglider (see below) was proposed for landing on an airport runway. Aerodynamic maneuvering was accomplished by placing the center of gravity (c.g.) 

offset from the spacecraft centerline. This made the spacecraft 

heat shield fly at an angle of attack that provided lift during 

reentry, similar to water skiing. By rolling the capsule, the lift 

force could be oriented to provide a landing footprint around 

the target landing spot. The technique oriented the lift vector as 

soon as a reentry aerodynamic-drag g-force of 0.05 was felt. 

When a ballistic reentry prediction showed a target trajectory, 

the capsule was then slowly rolled. This rotated the lift vector, 

providing a corkscrewing ballistic trajectory flight path. The 

Gemini c.g. offset created a lift/drag ratio of 0.25, which provided a 30-mile crossrange and 270-mile downrange footprint. 

Apollo also used this system but established a c.g. offset which 

provided a lift/drag ratio of 0.5, twice that of Gemini.9

A modified Titan II ICBM rocket launched Gemini into orbit. 

The Titan II used a hypergolic (self-igniting) fuel called UDMH2, 

a blend of hydrazine and unsymmetrical dimethyl hydrazine, 

with nitrogen tetroxide as the oxidizer. The mixing of the fuel 

and oxidizer causes a rapid burning (deflagration) instead of an 

explosion and results in a less severe blast wave than encountered with the Atlas fuel. This rationalized the judgment that 

ejection seats were possible for crew escape, thus eliminating 

the weighty escape tower. 

Another proposal was an inflatable, controllable Rogallo wing, 

developed by North American Aviation, called a Paraglider. It 

would deploy after reentry and allow the astronauts to land the 

spacecraft at an airport using retractable skids. Ejection seats 

still provided a backup means of escape in the event of a malfunctioning Paraglider. Landing onshore is highly preferable 

because it eliminates the large and costly Navy support needed 

to recover the astronauts from a water landing. However, the 

Paraglider was dropped from consideration midway in the program due to development problems, and a Mercury-type parachute with a water landing was substituted.10

Getting an ejection seat away from the booster debris caused 

by an in-flight malfunction became the decisive argument be-
The Boeing Company

The hypergolic-fueled Titan II ballistic missile boosted Gemini to orbital 

velocity.
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SPACEFARERS

tween the ejection seat and tower advocates. It was assumed 

that the astronauts would eject a few seconds before a catastrophic booster malfunction, so the booster would explode above 

them. The debris pattern was postulated as a cylindrical envelope lying in the plane of the trajectory and was assumed to 

consist of debris of all sizes, shapes, and weights, with different 

rates of fall. Escape tower advocates saw no solution to getting 

the ejection seats away from the debris pattern raining down 

from the breakup.

The initial design had the Gemini astronauts inserted into 

orbit oriented the same as in Mercury, sitting upside down in 

the trajectory plane. This meant that if they ejected during 

launch phase, they would remain in the plane of the booster 

trajectory and within the falling debris field. (Actually the ejection seats were canted 12 degrees from the cockpit centerline—

24 degrees between the two seats—and therefore would have a 

small, insignificant, out-of-plane component when ejecting.) 

When I asked why not rotate the capsule 90 degrees so that the 

ejection would be out of the trajectory plane, the study engineer explained that the overriding objection to that proposal 

was that the astronauts would be inserted into orbit sitting 

sideways and would experience a side load, which is quite critical 

for humans. A boost-phase load factor analysis refuted his intuitive conclusion since the launch trajectory was very near a 

zero-g (ballistic) flight path. Thus, the astronauts would experience only the normal transverse (forward) booster acceleration.11 The astronauts agreed with this conclusion, so the solution to avoiding the booster debris was to simply turn Gemini 

90 degrees on the booster so that ejection would hurtle the astronauts away from the debris plane. This solution firmed the 

ejection seats as the booster escape mode and squelched all 

talk about using an escape tower.

During this time, the Mercury program continued with astronaut Gus Grissom making a suborbital flight on 21 July 1961 

in a spacecraft he called Liberty Bell 7. The flight was normal 

until splashdown. While Gus was waiting for the helicopter recovery team, the hatch inadvertently released and the spacecraft started to fill with water. He was able to exit the spacecraft, 

but because his air inlet hose was not closed, water entered his 

spacesuit almost swamping him. Another helicopter rescued 
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132

him just in time; however, the recovery team was unable to 

save the spacecraft as it sank in three miles of water. The two 

suborbital flights qualified all flight systems for orbital flight. 

Man-rating the Atlas booster was now the last hurdle before 

orbiting an astronaut. 

Historical Note 

A deep-sea salvage team led by salvage expert Curt Newport located and recovered Liberty Bell 7. They found it in 15,600 feet of water and successfully snared 

it and brought it to the surface on 20 July 1999. It was painstakingly disassembled and refurbished for eventual display in the Kansas Cosmosphere and Space 

Center in Hutchinson, Kansas. It is also displayed during tours at various museums throughout the country.

Historical Note 

The Mercury spacecraft was by necessity very small, and everything was packed 

inside the capsule. The various units were stacked on top of each other, so if a 

lower unit malfunctioned, the upper ones had to be removed to get at the malfunctioning one. Only one person could work inside the capsule, so any repair 

was exceedingly slow. At MAC, we became concerned by how many times the 

various units were removed and rechecked, feeling that they would reach their 

operating life just during checkouts.

On 29 November an Atlas boosted a Mercury spacecraft into 

orbit carrying a chimpanzee named Enos. A few glitches—the 

most troubling, a rise in cabin temperature and unexpected attitude-control jet firings—marred the flight and shortened the 

mission to two orbits, but Enos was recovered safe and sound. 

The next flight would be manned. 

To no one’s surprise, Lt Col John Glenn was selected to fly 

the first US orbital flight, scheduled for launch on 19 December 

1961. Hardware glitches in both the spacecraft and the Atlas 

booster caused several disappointing scrubs; first on 19 December, then on 27 January, and once more on 14 February, 

but that one was for weather. It seemed that we would never get 

Glenn’s Mercury–Atlas V off the ground. 
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Finally, John Glenn squeezed into a Mercury spacecraft he 

named Friendship 7 and accomplished the first US orbital flight 

on 20 February 1962. The flight was intently followed at MAC, 

not only via radio broadcasts, but also through a direct phone 

line from Cape Canaveral Mercury Control. Just after completion of the first orbit, John Weitekamp received a telephone 

call. When he hung up, he announced that an instrument indication showed that Glenn’s heat shield might be loose and he 

might have to reenter with the retropack attached. Mercury 

Control wanted to know if a stable reentry could be made with 

that configuration.

The heat shield that protects the spacecraft from the fiery 

reentry is locked to the base of the capsule. It is released after 

the parachute deploys, allowing it to drop a short distance to 

expose a rubber landing cushion/floatation bag. The retropack, 

housing the retro-rockets, is attached to the center of the heat 

shield with three metal straps which lead around the edge of 

the heat shield and fasten to the spacecraft structure. The retropack is normally jettisoned after retrofire by severing the straps. 

However, if the heat shield were in fact loose, jettisoning the 

retropack could release the heat shield, terminating the mission in a somber way. 

Weitekamp and Wilson McGough, who performed the Mercury 

wind-tunnel tests, immediately dug out the test reports. During the hot-shot tunnel testing of Mercury at Mach 22, one run 

had been completed with the retropack on and verified that the 

capsule was stable during reentry.12 The straps would burn off 

shortly after reentry began, but by then the air pressure would 

hold the heat shield in place. 

Of course, John Glenn made a safe reentry with the retropack on. His problems were not over, however, since he ran out 

of fuel for the control thrusters needed to maintain low-speed 

stability after reentry. He had experienced some control problems in orbit and also wasted precious fuel investigating some 

sparkles, which he called fireflies (they were residual fuel particles). Without stabilizing control, he experienced severe capsule oscillations at about 30,000 feet, so he deployed the drogue 

chute, not waiting for the automatic deployment set for 15,000 

feet. Fortunately, the drogue chute held together through the 
SPACEFARERS

134

severe opening shock from being deployed at that altitude, and 

he was safely recovered. 

Glenn’s flight lifted the spirits of all Americans distressed by 

the large Russian spaceflight lead from twice orbiting cosmonauts in their 10,000-pound Vostok spacecraft. The Soviets’ 

gloating over their accomplishments and their ridicule of our 

puny space efforts were especially galling. Unknown to us, they 

were also well along in development of their two-man Voskhod

spacecraft, but we plugged along with our spaceflight plan.

Four Mercury orbital missions were successfully completed: 

(1) John Glenn, 20 February 1962, three orbits; (2) Scott Carpenter, 24 May 1962, three orbits; (3) Wally Schirrah, 3 October 1962, six orbits; and (4) Gordon Cooper, 15–16 May 1963, 

22 orbits. Cooper still holds the record for the longest solo orbital flight of 34 hours, 20 minutes. It was a commendable finish for the Mercury program.13 

Historical Note

We were in the midst of the Gemini design when the Cuban missile crisis erupted 

on 16 October 1962. En route to work that morning, we saw a squadron of B-47s 

parked on an airport ramp that was normally crowded with TWA transport planes. 

Even more ominous, all the B-47s had several armed guards around them. They 

were undoubtedly armed with nuclear weapons and ready to take off on a moment’s notice. We had been glued to the TV listening to the latest developments, 

but the seriousness of the situation did not really hit home until we saw the dispersed B-47s parked so close to home. It was quite scary to realize how close we 

were to Armageddon.14

During the ejection seat design phase, crew safety was of 

paramount importance, but a realistic attitude pervaded both 

the corps of astronauts and the engineers that this new spaceflight discipline was dangerous and that casualties were bound 

to occur. Our philosophy was that we, as engineers, would do 

our best to provide a reasonable probability of crew survival in 

a catastrophic occurrence, but we could not guarantee safety 

under all conditions.

Weber Aircraft Company of Burbank, California, had been in 

the ejection seat business for 17 years and was generally regarded as the prime supplier of ejection seats in the United 

States. Therefore, they became the design, test, and manufactur-
135

SPACEFARERS

ing agency for the Gemini ejection seat systems for McDonnell.15

A unique contractual arrangement was enacted where, in effect, Weber would function as a division of MAC using MAC 

procedures and drawing format. A cost-plus-fixed-fee contract 

guaranteed Weber would recover all costs associated with the 

program and receive a specified fee. This permitted Weber to go 

ahead with development and testing on an expedited basis 

without having to get formal MAC approval for every change. 

Weber became a Gemini team member in April 1962, just after 

the first Mercury orbital flight of John Glenn. 

Preliminary hand calculations showed that the ejection seat 

had to provide an astronaut recovery capability from liftoff to 

Mach 3 at 70,000 feet. As more detailed analyses and tests 

were completed, the criteria were modified to account for the 

latest analyses results. We were creating a new engineering 

discipline of manned spaceflight and had to feel our way toward a successful design. There were very few design precedents 

that could guide us toward the correct decisions, so we continually refined the criteria and design to arrive at a satisfactory solution. The final criteria that were used to design the 

seat and operational procedures are outlined below. 

It was intuitively obvious that an off-the-pad ejection was going to be the design factor for the seat rocket motor. It had to 

propel an astronaut-and-seat combination (seat/man) about 

1,000 feet from the launch booster. (This was our initial guess, 

which was continuously refined.) During rocket burn, seat/man 

tumbling that reduced the range was bound to occur, so a short 

rocket-thrust time would be required to minimize tumbling. This 

meant a high acceleration to achieve the required range, but just 

how high an acceleration can a human body withstand?

The Gemini safe-ejection acceleration criteria we used were 

based on human tolerance acceleration limits as postulated by 

Dr. Mike Rickards of Weber Aircraft Corporation and are shown 

in figure 14. This shows the human tolerance of g-loads as a 

function of the time they are applied. (Note that time is plotted 

in a logarithmic scale.) It shows that the human body can withstand high accelerations if the application time is very short; 

for example, in the parallel positive (upward acceleration), a 

human body can withstand about 20 g-forces if the application 

time is only 0.1 second. It was understood that these accelera-
SPACEFARERS

136

tion limits were for human bodies restrained in perfectly contoured couches, and even then some injury was possible. The 

seat catapult and rocket-motor thrust were tailored to follow 

very closely the parallel-positive acceleration limit of figure 14. 

Designing the seat to the human body acceleration limits was 

a design gamble that bothered some medical doctors but was 

necessary to escape from an on-the-pad booster deflagration.16

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The thermodynamics group undertook the estimation of an 

off-the-pad deflagration fireball. By extrapolating data of hypergolic propellant reactions tested by the Naval Ordnance Laboratory, they concluded that a booster malfunction on the launch 

pad would result in a fireball 610 feet in diameter that lasted 

for 12 seconds.17 That is a large, spectacular fireball, but the 

deflagration blast wave is mild. No matter, it presented a horrendous challenge to design an ejection seat to safely escape 

that boiling ball of fire. 

A fireball that size required that the ejection seat rocket motor propel the astronaut 400 feet from the booster at 3.5 sec-
137

SPACEFARERS

onds after ejection initiation. That distance was required to 

prevent the deploying parachute from melting in the radiant 

heat of the fireball. Reaching those conclusions required many 

tests and analyses. For example, tests of astronaut reaction 

time and analysis of necessary abort cues were conducted to 

arrive at the warning time to safely get away. Various types of 

booster failures were analyzed so sensors could be developed to 

warn of the impending malfunction. Parachute material was 

subjected to heat tests to firmly define its melting point. All 

these analyses and tests finally established the requirements 

and led to the development of the largest rocket motor ever installed in an ejection seat. 

About 60 percent of our analyses was concentrated on developing a safe ejection from an off-the-pad abort, but the highaltitude abort—up to Mach 3 at 70,000 feet—also had to be 

considered. High-altitude, supersonic ejections require survival 

and life-support equipment for astronaut survival until safe 

touchdown. The astronaut must be encased in a pressure suit 

that withstands an aerodynamic heating pulse to 350° C (660° 

F) in a Mach 3.0 ejection. During a long freefall of about five 

minutes, oxygen and thermal protection must be provided to 

survive a subzero temperature of -57° C (-70° F). Those requirements were levied on the pressure suit provider.

Ejections at high altitude also require that the astronaut delay parachute deployment until denser atmosphere is reached, 

preferably below 15,000 feet. This is an absolute requirement; 

deploying a parachute at high altitude would, most likely, destroy the parachute and/or kill the astronaut due to the opening shock. If the astronaut survived the opening shock, there 

was the distinct possibility of freezing to death during the long, 

slow descent through subzero temperatures.

Even a freefall from high altitude is extremely dangerous. In 

1959 Capt Joseph W. Kittinger performed several high-altitude 

jumps from a balloon, ranging from 76,000 to 112,000 feet. 

The greatest hazard he encountered during the long freefall 

was getting into a back-first flat spin. This flat spin is violent 

enough to render the person unconscious, as Captain Kittinger 

experienced on one of his first jumps when his stabilization 

parachute tangled around his legs. Fortunately, the automatic 
SPACEFARERS

138

reserve parachute deployed correctly at 10,000 feet while he 

was still unconscious.18

To prevent a flat spin, astronauts must have a stabilization 

device that will keep them in an upright position throughout 

the long freefall. Captain Kittinger used a small stabilization 

parachute, but he started his freefall from zero velocity. A stabilization device would have to be developed for Gemini that 

Gordon Cress, Weber Aircraft

Each Gemini ejection seat was designed to escape from a malfunctioning booster from off-the-pad to Mach 3 at 70,000 feet.
139

SPACEFARERS

could be safely deployed at Mach 3.0, survive the opening shock, 

and withstand the aerodynamic heat pulse. The stabilizer selected 

was the Goodyear Ballute (contraction of balloon-parachute). 

The design and testing of that device is covered later.

It became apparent that designing an ejection seat with the 

capabilities outlined might be asking too much. The established 

criteria were formidable, and no one had ever considered designing an ejection seat anywhere near to these requirements. 

Pressure suit designers, already required to design for a hostile 

space environment, also had to account for the severe ejection 

environment. These conflicting requirements created insurmountable problems, and the designers were unable to meet 

their goal. Also some flight surgeons were extremely skeptical 

that a human body could withstand the ejection air loads and 

accelerations, even with a perfectly contoured hard seat, sturdy 

restraints, and the protection afforded by a spacesuit. The 

clincher was that the astronauts were very concerned about 

using the seats. 

A discussion of these concerns between NASA and the principal contractors led to the development of a “ride-it-out abort 

mode.” Ride-it-out denoted that during the high-altitude flight 

phase, the astronauts would remain in the spacecraft in the 

event of a booster malfunction. They would manually shut 

down the booster engines and remain attached to the booster, 

even if it broke up or burned, until it was safe to separate the 

spacecraft and land normally. The spacecraft provided excellent protection from an in-flight fireball, small debris, and the 

hostile environment and also relieved the concern about the 

spacesuit capabilities. 

Once the decision was made to keep the astronauts in the 

spacecraft and ride out the booster malfunction, a study was 

instituted to explore the ramifications of that directive. Considerations included: 

1. Determining where the booster would break when subjected to large air loads caused by an engine control malfunction. 

2. Developing a procedure for a single-engine malfunction. 

This malfunction causes a roll windup that might incapacitate the astronauts before they could react. 
SPACEFARERS

140

3. The astronauts stated that they would not abort on a single 

cue; therefore, define what cues would be available and 

how much time they allowed to achieve a safe abort. 

4. Explore modifications to the booster to enhance the safety 

of this abort scheme. 

This effort established that during launch the ejection seats 

were the primary mode of escape up to 45,000 feet. This was 

designated a Mode I abort. From 45,000 to 70,000 feet, the 

ride-it-out abort mode was primary and ejection seats secondary. This was designated a Mode II abort.19

To ensure the adequacy of the ejection seat system, SDF trajectories of all possible abort conditions were necessary. Aerodynamic forces and moments for trajectory calculations were 

obtained from a series of wind tunnel tests of the seat/man 

configuration from Mach 0.5 to 3.5 and over a complete range 

of angle of attack in all three axes. This was the first set of 

seat/man aerodynamic data collected over a complete range of 

tumbling attitudes and supersonic Mach numbers.20 The computed trajectories considered many variables such as initial 

ejection conditions of spacecraft altitude, velocity and rotational rates, seat/man weight, wind conditions, variations in the 

seat rocket/catapult thrust, seat/man c.g. location, and a host 

of others. The studies confirmed that getting away from the 

fireball in an off-the-pad ejection was indeed the critical condition for defining the seat catapult and rocket thrust values.

The seat design effort went forward in parallel with performing the analyses. A rocket/catapult (RoCat) manufactured by 

Rocket Power, Inc., of Mesa, Arizona, consisting of two distinct 

parts (the catapult and the rocket section), was mounted in the 

back along the vertical centerline of the seat. The catapult forced 

the seat, restrained on the rails by three sets of rail sliders, 

upward and off the guide rails. As the seat left the rails, the rocket 

was ignited, which propelled the seat away from the spacecraft. 

Catapult thrust, with the axis well to the rear of the seat/

man c.g., induced a forward tumbling motion to the seat/man 

as it left the rails. The rocket thrust axis was aimed to counteract that initial forward tumble yet not induce an appreciable 

backward tumble before the rocket burned out. The relationship between the rocket thrust axis to seat/man c.g. (referred 
141

SPACEFARERS

to as thrust eccentricity) was a very critical and sensitive parameter and required a detailed engineering analysis to arrive 

at the allowable pitch and lateral c.g. eccentricity window. 

Freefall stabilization was provided by the Goodyear Ballute—

essentially a drag balloon that was shaped like a top when inflated. The Ballute, made of nylon coated with aluminum for 

protection against the high-heat pulse of a supersonic ejection, 

had a diameter of 48 inches and a length of 54 inches. After the 

ejection seat rocket motor burned out, the astronaut would be 

separated from the seat and, if at high altitude, the Ballute would 

be deployed. Spring-loaded inlets allowed ram air to inflate the 

Ballute, stabilizing the astronaut during the long freefall.21

The Ballute system went through an extensive development 

and test program to become qualified. There were wind tunnel 

tests to measure the drag, stability, and deployment characteristics and structural qualification. Most of these tests were 

done in the 16-foot by 16-foot supersonic propulsion wind tunnel 

at the Arnold Engineering and Development Center, Tullahoma, 

Tennessee. There were freefall dummy drops from a C-130 aircraft at the Naval Parachute Facility at El Centro, California, 

and a long series of live jump tests from as high as 40,000 feet. 

Many problems arose that questioned the Ballute’s suitability 

for the task, but testing and redesign continued nonstop, almost to the day of the first Gemini flight in March 1965, and 

finally resulted in it being qualified. 

Designing the seat, like the spacecraft, was complicated by 

the severe weight constraints imposed by the Titan II booster 

capability. The seat structure was primarily aluminum with 

some titanium, steel, and nonmetallic components. Each astronaut sat on a molded fiberglass-and-aluminum, hard-surface, 

individually contoured seat covered with a fire-resistant cloth. 

Nestled within the hard-surface seat and contoured backboard 

were the parachute, emergency oxygen system, survival kit, 

and Ballute. Foot stirrups and arm guards provided support to 

protect the astronauts from striking the hatch sill and ensured 

they remained within the hatch opening envelope to prevent leg 

and arm flail injuries. 

The center-pull ejection-control D-ring remained folded down 

and out of the way in its compartment, and protected by a sliding cover except during a potential ejection scenario. Ejection 
Photo courtesy of Loral Defense Systems-Akron

Live jump tests confirmed that the Ballute (balloon/parachute) stabilizes the 

astronaut to prevent a debilitating backwards spin from high-altitude bailouts. 

Tests also confirmed the Ballute can absorb the 6000 F heat pulse at a Mach 3, 

70,000-ft. ejection.
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SPACEFARERS

was very simple; just pull either seat ejection D-ring to eject 

both seats automatically. An inertial reel automatically retracted the restraining straps, pulling the astronaut to the correct ejection posture, and the pyrotechnic sequencing system 

began by venting hot gas to the hatch actuators.22 The hatch 

actuators unlocked the spacecraft hatches and opened them. 

When the hatch was fully open, hot gas ignited the catapult, 

moving the seat up the rails. As the seat progressed up the 

rails, a lanyard was pulled to start the emergency oxygen system flowing, and another lanyard activated the pyrotechnic 

time delay to separate the astronaut from the seat. Separation 

was achieved by a pyrotechnic plunger that released the lap 

belt and backboard from the seat. It then pulled a strap located 

under and in back of the astronaut taut, separating the astronaut 

and his equipment from the seat structure. All these operations 

were accomplished in less than 1.5 seconds from ejection initiation as summarized in the ejection seat sequencing below. 

Time (secs.) Event

0.00 Pull D-ring

0.24 Hatch fully open

0.39 Ejection seat reaches end of track

0.72 Seat rocket burnout

1.46 Initiation of seat/man separation

The astronaut was now free from the seat, and the parachute 

deployment sequence started. Above 7,500 feet, the stabilizing 

Ballute was deployed and cut loose when descending through 

7,500 feet. At 5,700 feet the parachute deployment gun fired. 

After parachute deployment, the backboard and oxygen system 

were automatically discarded and the survival kit was released 

and suspended below the astronaut with a line to the parachute harness. If ejection were below 5,700 feet, parachute deployment would initiate 3.5 seconds after ejection initiation. 

Getting all these systems working correctly became a trying 

ordeal of test, revise, and test again. Several of our more demanding tasks to get to the operational seat system just described are narrated below. This offers the reader a feel for the 

magnitude of the Gemini program, since the seat was only one 

of dozens of major Gemini systems that had to be developed.
SPACEFARERS

144

Development tests of the completely assembled seat system 

began in July 1962 with pad ejection tests conducted from the 

150-foot tower at the Naval Weapons Center’s China Lake facility in California. In the first test of an off-the-pad abort condition, radiation from the extremely hot rocket exhaust gases destroyed the lower portion of the seat structure, and the test 

dummy did not separate from the seat. After installing a nonmetallic flame bucket liner and revising the seat/man separation system, the second test was more successful. The seat/

man separation worked correctly, but parachute deployment 

did not work because the spring-loaded pilot chute drag was 

not adequate to deploy the tightly packed parachute. A gundeployed parachute system that uses a projectile and lanyard 

fired from a gun to pull open the parachute was installed. 

Those first tests also revealed the extreme sensitivity of the 

rocket thrust c.g. eccentricity when the seat tumbled, preventing achievement of the required range. We immediately launched 

a determined analysis to define the allowable pitch and lateral 

c.g. eccentricity and were dismayed when the analysis showed 

the allowable eccentricity window gave us a c.g. tolerance of 

about ± 0.5 inch in both the lateral and pitch axes. This meant 

that each astronaut’s seat had to be ballasted to the required 

c.g. position. Additionally, a calculated change in c.g. caused 

by the body and organ slump in response to ejection accelerations had to be considered in the measurements. The calculations allowed the c.g. to be placed within the thrust eccentricity 

window during ejection. This assured that the loads, accelerations, and onset rates would be within the human limits and 

that the seat/man would be stable enough during rocket burn 

(about 0.5 seconds) to achieve the required range. 

The test program progressed with the seats ejected from a 

fixed open-door boilerplate spacecraft and then a functioninghatch boilerplate spacecraft. Fifteen off-the-pad ejection tests 

were completed. Concurrent with the design and test, computersimulated ejections defined the entire operating envelope. Predicted trajectories were also computed for the ejection tests to 

allow a comparison between predicted and test trajectories. Figure 15 presents such a comparison for an off-the-pad ejection. 

An amusing (sort of) incident occurred with astronauts Frank 

Borman and Jim Lovell as witnesses. There is a test axiom that 
145

SPACEFARERS

“The odds of having a major system malfunction at a test are 

directly proportional to the importance of the observers.” During 

this twin ejection test using a boilerplate spacecraft (a welded 

steel mockup), the systems were initiated as programmed. The 

left-hand seat egressed as designed, and the test dummy was 

successfully recovered by parachute down range. The right-hand 

seat was another story. 

Hot gases generated by pyrotechnic devices drive the hatch 

actuator. As the hot gases expand, they force the piston upward, 

unlatching the hatch and opening it. When the hatch is fully 

opened, the hot gas in the actuator is vented to ignite the catapult. The seat then moves up the rails and out of the capsule 

past the locked-open hatch. The right-hand hatch actuator 

suffered a malfunction of the O-ring around the piston. This 

leak allowed the hot gases to escape prematurely and ignite the 

catapult before the hatch was completely open. The seat smashed 

into the partially open hatch, jamming the headrest and the 

dummy’s helmet into the hatch structure, and then jammed 

itself on the seat rails. The rocket-catapult was then essentially 

in a locked-shut firing condition, which it could not withstand 

and exploded, incinerating the inside of the boilerplate space-

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Figure 15. Typical off-the-pad trajectories
SPACEFARERS

146

craft. Burned propellant permeated the whole area. The test 

dummy, in what was to be Lovell’s seat, was cocked to one side 

with its helmet all crushed and cracked. After looking at it for 

a while, Lovell looked over at Borman and said, “You wouldn’t be 

interested in trading seats, would you?” Borman stated that he 

was perfectly happy where he was assigned and would stick with 

it. This incident resulted in a hatch actuator redesign and the use 

of redundant O-rings to ensure safe operation in the future. 

All our work was interrupted when the company loudspeakers came to life with a radio announcer saying something about 

an assassination attempt. We could not make out at first what 

he was talking about, but then we heard President Kennedy 

mentioned. The president was shot and killed while on a trip to 

Dallas, Texas. It was Friday, 22 November 1963, a day that one 

will never forget, just like when Pearl Harbor was attacked. 

That stopped work for the day. We tried to continue, but our 

thoughts kept slipping back to why and who would do such a 

thing. The following days were filled with grief and tearful eyes 

as we watched the somber funeral procession of President Kennedy on TV. Regardless of what happened, our life went on, and 

the Gemini problems still needed solving. 

President Kennedy’s legacy was gaining momentum as the 

proposal for design of the Apollo CSM was released by NASA. 

McDonnell assembled a team and submitted what we hoped 

would be the winning proposal. However, it was not to be; North 

American won the contract. We had the experience; manpower; 

facilities, including clean-room assembly areas; and had established a harmonious relationship with NASA. I truly believe the 

decision was political, since several NASA people confided to 

me that they were disturbed by it. According to mission flight 

director Gene Kranz in his book, Failure Is Not an Option, and 

flight director Chris Kraft in his book, Flight—My Life in Mission 

Control, North American was a difficult, aloof, and arrogant 

contractor.23 More on this later. 

Back to the Gemini program. Besides the pad ejection tests, 

six ejection tests were conducted on the Supersonic Naval Ordnance Research Test Track facility at China Lake. These used an 

aerodynamically similar boilerplate Gemini spacecraft mounted 

on the rocket-powered test sled with functioning seats and hatches 

to qualify the entire system at high dynamic pressures.
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SPACEFARERS

The first sled test was a learning experience and proved the 

axiom “If something can go wrong, it will.” This test, conducted 

in November 1962, was just a drag run to gather aerodynamic 

data and verify the structural adequacy of the boilerplate spacecraft, sled, and pusher systems. We decided to install two Gemini 

seats with test dummies to validate the operation and function 

of the telemetry systems. After all, it was just a drag run and 

what could possibly happen? 

The test was programmed to achieve a maximum speed of 

over 1,000 feet per second (680 mph). Twelve Genie (air-to-air 

missile) rocket motors, configured in four rows of three motors, 

drove the sled. The last phase of the sequenced ignition fired the 

top-center motor. When this motor ignited, the pusher sled suffered a structural failure, and the Genie motor came loose and 

crashed headlong into the aft end of the boilerplate spacecraft. It 

easily penetrated the half-inch-steel simulated heat shield and 

went right into the spacecraft, where it completely incinerated 

everything inside. This test resulted in a redesign of the pusher 

sled, and no further incidents of this type were encountered. 

Sled testing in the high-dynamic-pressure region finally got 

under way in June 1963, with a dual ejection using a refurbished boilerplate Gemini, and was successfully completed in 

December 1964. It demonstrated the entire ejection sequence 

and confirmed the structural design under the most severe 

conditions for which the seat system was designed. Figure 16 

shows an artist’s rendering of an in-flight ejection, which may 

clarify some the preceding explanations.

Notwithstanding our enthusiasm and effort, the Soviets 

again beat us by orbiting a three-man spacecraft called Voskhod on 12 October 1964 and safely recovering it 24 hours 

later. We later learned that Voskhod was really a two-man 

spacecraft, but the Russians squeezed in a third person to 

exaggerate their accomplishment. They succeeded in temporarily discouraging us, but we plodded ahead, determined to 

beat them to the moon. As more particulars surfaced, we 

were heartened to learn that Voskhod did not have any orbital maneuvering capability and, thus, could not perform a 

rendezvous in space. Perfecting rendezvous and docking was 

a primary goal of the Gemini program, since a moon landing 

depended on that capability. 
SPACEFARERS

148

Ejection seat tests were completed with three ejections from 

the backseat of an F-106B aircraft. One was a static firing to 

confirm the compatibility of the Gemini ejection seat and the 

F-106B modification. The other two, conducted during January and February 1965, were full systems tests of productionconfigured units. One test verified seat ejection at 15,000 feet 

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Figure 16. Artist’s rendition of an in-flight ejection

Historical Note 

The bellicose Soviet premier Nikita Khrushchev, who pounded his shoe on the 

table at a United Nations meeting and almost plunged the world into a nuclear 

holocaust during the 1962 Cuban missile crisis, was ousted from power during 

this Voskhod flight. 
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SPACEFARERS

at Mach 0.72. The other ejected at 40,000 feet at a Mach number of 1.7. These tests successfully qualified the operation of 

the complete seat ejection system under flight conditions. The 

ejection seat escape system was one of three Gemini systems 

most difficult to qualify; the other two were the fuel cells for 

electric power generation and the OAMS thrusters. However, 

all systems finally yielded to the persistent engineering analysis, design, and tests to clear the Gemini system for flight.

Coordination and control of major systems and critical analysis areas were managed through a series of working groups. 

These consisted of representatives from McDonnell, NASA, the 

Air Force, and other major contractors. These working groups 

met regularly and firmed up the interface requirements and 

division-of-work effort; they also appraised and cross-checked 

each other’s analyses. They were an important cog in assuring 

Gordon Cress, Weber Aircraft

The final dual-seat high-speed qualification test qualified the Gemini ejection 

seat at the Naval Ordnance Research Test Track, China Lake, by testing it at the 

most severe conditions.
SPACEFARERS

150

we were all heading in the same direction and made everyone 

aware of each other’s problem areas. NASA chaired the groups 

and made the final decisions on how to proceed. Several NASA 

working groups within our aerodynamic purview included 

Aerodynamics, Abort, Trajectory and Orbits, and Rendezvous 

Guidance and Control. 

I had not given much thought to rendezvous techniques, and 

even though I was well acquainted with orbital dynamics, I was 

surprised by rendezvous implementation. The technique to 

rendezvous in space is exactly opposite from rendezvous in an 

aircraft. If behind the target in an aircraft, increase velocity to 

catch up, but reduce velocity to overtake the target in space, as 

explained below.

The orbital period (time required to complete one orbit) increases as the distance from the center of the earth is increased. 

A satellite in a low, 100-mile Earth orbit takes about 90 minutes to complete an orbit, while one at the moon’s distance 

takes 28 days. A vehicle in a higher-altitude orbit takes more 

time to complete an orbit even though it possesses a greater 

total energy. Thrusting toward a target ahead of the vehicle increases its energy, causing a rise in orbit altitude. Since it is 

now in a higher orbit, it takes longer to complete an orbit and 

drops further behind the target. Thrusting away from the target reduces total energy and orbit altitude, thus completing an 

orbit in a shorter time, catching the target. It is really more involved since the orbits are elliptical, not circular, but the implementation is the same. To close on a target, thrust away from 

it; to draw away from a target, thrust toward it.24

Docking is a precise rendezvous that could last several orbits. 

First, rendezvous maneuvering positions the spacecraft within 

the capture cone of the target vehicle. Docking is then accomplished with a steady, very slow closure rate—on the order of 

one foot per second (0.68 mph). For Gemini, the target vehicle 

was an unmanned Agena rocket fitted with a docking collar 

that latched to the Gemini nose. MAC constructed the docking 

simulator for astronaut training. It consisted of a Gemini mockup 

mounted on a carriage that could roll, pitch, yaw, and move 

laterally. The target vehicle Agena docking collar was mounted 

on another carriage that moved up, down, fore, and aft. Between 

them, all six degrees of motion were simulated. All motions were 
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SPACEFARERS

on air bearings that were almost friction-free, so that a small 

push started the carriage moving and it kept moving until a force 

was applied to stop it. The motion simulations were computerdriven to approximate the real event.

Watching the astronauts docking on TV makes it look simple, 

but it is a complicated and careful operation. I was invited to fly 

the simulator once and found it to be a tricky affair. The instructor made a run to show me how to do it and then let me 

try. Everything must be done very, very slowly and deliberately. 

I made five tries and never did get a clean, straight-in docking. 

Every application of a thrust pulse must be followed by an identical one in the opposite direction to stop the motion. Nowadays 

they have automatic docking and other aids, but everything 

was manual then. No wonder it took a lot of training.25

With the first Gemini launch date fast approaching, the check 

and cross-checking rapport we had cultivated averted a potential 

catastrophic occurrence. The NASA Flight Dynamics Group 

sent me their official launch and orbit computer printouts for 

the first manned Gemini mission (GT-3) with Gus Grissom and 

John Young on board. Since the retro rockets were not yet flight 

qualified, the mission had a very low-altitude orbit so the astronauts could de-orbit using their onboard OAMS thrusters in an 

emergency. Checking the orbit with our orbit lifetime charts, I 

found that it was very marginal and probably would not even 

complete one orbit. This was confirmed when we checked that 

specific launch and orbit via a computer run. 

Fortunately, I was scheduled to be at NASA’s new Manned 

Spacecraft Center (MSC) in Houston the next day for a premission conference to clear up outstanding items. The four of us 

from MAC entered the large conference room and were settled 

in the center with 50 NASA personnel arranged completely 

around us. Since this was a critical item, I departed from the 

printed agenda and stated that we did not agree with the GT-3 

orbit which, according to our calculations, was too low and 

would not even complete one orbit. This brought a flurry of paper shuffling as the Flight Dynamics and Trajectory and Orbits 

Groups thumbed through their computer runs. Comparing the 

data, we found the discrepancy. Reentry is accomplished with 

only the Gemini capsule, which presents a surface area for drag 

computations of 44 square feet. While in orbit, both adapter 
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sections are attached, and the drag surface area for orbit lifetime trajectory calculations is 78.5 square feet. NASA used the 

normal reentry reference area of 44 square feet for their orbit 

lifetime computations. Their Flight Dynamics Group was very 

grateful that we uncovered that mistake, which showed that 

our amicable working relationship had paid off. They also had to 

do some night work to recompute the trajectory and the entire 

orbit timeline, as the scheduled launch was just weeks away. 

Historical Note 

During the conference, we were bombarded by questions from the NASA attendees. Some were obviously trivial and were asked just so the person could get his 

name printed in the conference minutes. However, I noted one individual that 

asked some very deep, understanding questions that required carefully thoughtout answers. At lunch I asked some of the NASA people who was the individual 

asking those questions. It was obvious from their answer that they also thought 

very highly of him. It was Neil Armstrong, and I was introduced to him during the 

afternoon break. He clearly lived up to my initial appraisal. 

After two unmanned flights that qualified all flight systems, 

astronauts Gus Grissom and John W. Young blasted off on 23 

March 1965 and completed three orbits. Eight more manned 

flights were completed. (All Gemini flights are summarized 

later.) The ejection seats were never used. The closest they 

came to being used was on the Gemini VI launch with astronauts Wally Schirra and Tom Stafford on board. The countdown reached zero, and the Titan II engines and mission clock 

had started. Suddenly, the engines cut off, leaving the Gemini 

spacecraft in a precarious position on top of a hot booster. Everyone expected the seats to come blasting out of the spacecraft, 

but the astronauts showed great fortitude and held off ejecting, 

saving the mission. The minor problem with the fuel system 

was corrected (a dust cover had not been removed), and two 

days later the mission roared off the pad to perform the first 

rendezvous in space with the already orbiting Gemini VII with 

Frank Borman and Jim Lovell on board.

The seats were qualified, meaning all the systems would 

work, but no one could guarantee that the astronauts would 

come through the ejection unscathed. The primary reasons 

were (1) ejection created accelerations that were at the absolute 
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limits of human tolerance, (2) escape could be near an unpredictable fireball and in a hostile environment, and (3) there was 

always the possibility of the unknown. 

How did the astronauts feel about using the ejection seats to 

escape from a malfunctioning booster? I asked Tom Stafford 

that question when we met again at the Gemini reunion and 

Gemini Memorial groundbreaking in Titusville, Florida, in July 

1996. He replied, “We were concerned about them and didn’t 

want to use them except as a last resort.” I believe his answer 

exemplifies the sentiments of not only the astronauts but also 

the designers and builders of that unique abort system. 

Gordon Cress, Weber Aircraft

Each astronaut had an individually balanced seat to assure the 

combination center of gravity was correct to prevent tumbling.
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As previously mentioned, Mode I was an ejection-seat abort, 

and Mode II was a ride-it-out abort. There were two other abort 

modes above 70,000 feet. A Mode III abort was for a booster 

failure that precluded the spacecraft reaching orbit. This case 

resulted in a landing in the Atlantic Ocean or in Africa. For a 

water landing, the astronauts separated from the booster and 

made a normal water landing. If the landing were on land, they 

would separate from the booster and remain in the spacecraft 

until it descended to about 10,000 feet and then eject. A Mode 

IV abort occurred when the spacecraft was nearly in the correct 

orbit when the booster failed. In this case the astronauts would 

separate from the booster and then use their OAMS to thrust 

forward and achieve a one-orbit velocity. The mission would 

terminate with a normal reentry and water landing in the Atlantic Ocean.26

The following paragraphs provide a summary of manned 

Gemini flights: 

Gemini III (Called Molly Brown, after the “unsinkable Molly 

Brown” from Titanic fame, it was the only Gemini spacecraft 

given a name) was launched 23 March 1965 with astronauts 

Gus Grissom and John W. Young on board. It completed three 

orbits in 4 hours, 52 minutes, 31 seconds. This first flight was 

dedicated to the testing of all the systems.

Gemini IV was launched 3 June 1965 for a four-day mission 

with astronauts James A. McDivitt and Edward H. White II on 

board. After booster separation in orbit, McDivitt tried to close 

with the booster by thrusting toward it. To his surprise he 

found they were getting further behind and above the booster. 

This was practical proof that the orbital rendezvous technique 

worked opposite to an aircraft rendezvous. The highlight of the 

mission was a 20-minute spacewalk by Ed White that almost 

ended catastrophically. The hatch seal lost its elasticity when 

exposed to the harsh, cold space environment, and the crew 

had a very difficult time resealing and latching it.

Gemini V was launched 21 August 1965 with astronauts L. 

Gordon Cooper Jr. and Charles Conrad Jr. for a seven-plusday, 120-orbit mission. This was the first spacecraft configured 

with fuel cells for electric power generation. The guidance and 

navigation systems were thoroughly evaluated for future rendezvous missions. 
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Gemini VII was launched 4 December 1965 with Frank Borman 

and James A. Lovell Jr. as astronauts. It was a long-duration 

mission of nearly 14 days to determine whether humans could 

live in space that long. It was launched out of sequence because Gemini VI was scrubbed when the Agena target, used for 

rendezvous-and-docking practice, failed to reach orbit. It was 

then decided to use Gemini VII as the target, since its mission 

lasted long enough to get another Gemini launched.

Gemini VI was launched on the second attempt on 15 December 1965 with Walter M. Schirra Jr. and Thomas P. Stafford 

on board. It was a one-day mission to rendezvous with Gemini 

VII already in orbit. The spacecraft stayed together for over five 

hours, maneuvering around each other and practicing station 

keeping. Separation varied from one to 295 feet. The flight was 

nicknamed the Spirit of ’76.

The Boeing Company

Astronaut Ed White made the first US space walk.
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Gemini VIII was launched 16 March 1966 with Neil A. Armstrong and David R. Scott. The mission was to rendezvous and 

dock with an Agena target vehicle and then fire up the Agena 

engine to change the orbit inclination. Just after docking with 

the Agena, a malfunction caused an uncontrollable rolling of 

the docked spacecraft. When the crew undocked, the rolling 

increased to a point that the centrifugal g-forces were close to 

incapacitating the astronauts. Even under those trying conditions, they were able to diagnose the problem as a stuck-open 

OAMS roll jet thruster. They shut down the OAMS system and 

regained control using the RCS. Because they activated the 

The Boeing Company

Gemini VI and VII conducted the first rendezvous in space on 15 December 1965.
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RCS, they were forced to effect the first emergency landing of a 

manned US space mission, splashing down 500 miles east of 

Okinawa in the western Pacific Ocean. (There is only enough 

RCS fuel to effect a reentry.) The mission lasted only 10 hours, 

41 minutes, 26 seconds, but did accomplish the first docking 

with another space vehicle.

Gemini IX launched 3 June 1966 with astronauts Thomas P. 

Stafford and Eugene A. Cernan on board. It was a three-day 

mission to test three different types of rendezvous and have 

astronaut Cernan perform a two-hour EVA. They rendezvoused 

with a hurriedly assembled augmented target docking adapter 

(ATDA) because their Agena again failed to reach orbit. Unfortunately, the ATDA could not jettison the launch shroud, so 

docking was not accomplished. Cernan then performed a twohour EVA in which he experienced all kinds of problems. He 

became quite fatigued and his visor fogged over, forcing him to 

feel his way back into the Gemini capsule. The mission completed three different types of rendezvous, two hours of EVA, 

and 44 orbits.

Gemini X launched 18 July 1966 with John W. Young and 

Michael Collins on board. They were able to rendezvous and 

dock with an Agena target vehicle and used the Agena’s engine 

to modify their orbit. They also rendezvoused with the Gemini 

VIII Agena target vehicle left in orbit four months earlier. Collins 

had 49 minutes of EVA standing in the hatch and 39 minutes 

of EVA to retrieve an experiment from the Gemini VIII Agena 

stage. The mission completed 43 orbits in two days, 22 hours, 

46 minutes. It was the first use of the Agena target vehicle’s 

propulsion systems.

Gemini XI launched 12 September 1966 with Charles Conrad 

Jr. and Richard F. Gordon Jr. as astronauts. They rendezvoused 

and docked with the target Agena and used its propulsion to 

boost their orbit to a Gemini record altitude of 739.2 miles. 

Gordon made a 33-minute EVA and two-hour standup EVA. The 

mission completed 44 orbits in two days, 23 hours, 17 minutes. 

Gemini XII launched 11 November 1966 with James A. Lovell 

Jr. and Edwin E. “Buzz” Aldrin Jr. This was the final Gemini 

flight and lasted three days, 22 hours, 34 minutes. They rendezvoused and docked with a target Agena and kept station 

with it during an EVA. Buzz Aldrin set an EVA record of 5.5 
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hours for one spacewalk and two standup exercises. This flight 

proved Project Gemini had accomplished its mission of perfecting rendezvous and docking and EVAs in space.

Reflecting on those Gemini days brings back memories of the 

demanding pressure we were under to get the spacecraft into 

orbit, perfect space rendezvous and docking, and beat the Soviets to the moon. It may sound quixotic now, but we enjoyed 

every minute of our hectic work schedule. We felt patriotic and 

good about our work and enthusiastic about meeting President 

Kennedy’s challenge of putting a man on the moon in the decade of the ’60s. It was a great time to be involved in the aerospace industry. We were in the midst of the Cold War, where both 

sides had multiple missiles poised to obliterate each other’s cities. 

As survival insurance, antiballistic missile defenses were being 

deployed to protect major cities and missile launch complexes. 

This created a new challenge—how to penetrate protected targets. Thus, I moved on to a new research group developing missiles and tactics to penetrate Soviet defenses.

Notes

1. See http://nssdc.gsfc.nasa.gov/planetary/lunar/ranger.html. 

2. See http://www.friends-partners.org.mwade/project/surveyor.htm.

3. Ibid.

4. Loyd S. Swenson Jr. et al., This New Ocean: A History of Project Mercury,

NASA SP-4201, 1966, NTIS; Barton C. Hacker and James M. Grimwood, On 

the Shoulders of Titans: A History of Project Gemini, NASA SP-4203, 1977, 

GPO; James M. Grimwood, Barton C. Hacker, and Peter J. Vorzimmer, Project 

Gemini, Technology and Operations—A Chronology, NASA SP-4002, 1969, 

NTIS. NASA reports can be accessed on the Internet at http://www.hq.nasa

.gov/office/pao/History/SP-4 xxx/ch10-5.htm. 

5. See http://www.ultimatesacrifice.com/my_gal_sal_history.htm.

6. For amplification, see Donald K. “Deke” Slayton with Michael Cassutt, 

Deke!—U.S. Manned Space: From Mercury to the Shuttle (New York: Tom 

Doherty Associates, 1994), 84. 

7. Hacker and Grimwood, On the Shoulders of Titans, 220.

8. Public Broadcasting System (PBS), “To the Moon,” a NOVA television 

documentary on the gigantic effort required to put men on the moon. VHS 

cassettes are available from PBS at http://www.pbs.org.

9. Ed P. Bradley, senior engineer, Project Gemini, to Bill Blatz, Gemini 

engineering manager, memorandum, 11 November 1963. 
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10. Although the Rogallo wing was not used, its development led to the 

very popular hang gliders. A concise history is presented at the NASA Web 

site, http://step.jpl.nasa.gov/hg/History/INFO_Roots-of-Hang-Gliding.htm.

11. A zero-g flight path occurs when the vehicle’s flight path is curved only 

by the influence of gravity and is usually referred to as a ballistic flight path. 

NASA’s zero-g jet aircraft trainer and some modern roller coasters can simulate a zero-g flight path for a short period.

12. The hot-shot tunnel uses the discharge from a large capacitor bank to 

quickly heat a slug of compressed air to a very high temperature and pressure. That slug of air is then expanded to a vacuum chamber through a hypersonic tunnel section. Very high Mach numbers, up to about 27, can be 

achieved for a fraction of a second. It is interesting to view a run and see the 

Gemini-model heat shield glow red hot during the short run time. 

13. Crouch, Aiming for the Stars, 180. 

14. James Bamford’s Body of Secrets has a whole chapter on the Russian 

and Cuban electronic surveillance that reveals just how close we came to an 

all-out war. See chap. 5, “Eyes.” 

15. During my many meetings with Weber personnel, I became friends 

with the engineer who conducted the ejection seat tests, Gordon Cress. Years 

later we happened to become reacquainted and collaborated on an article 

recalling our experiences developing that system. A great deal of the present 

Gemini narration is copied from that published article: Robert V. Brulle and 

Gordon P. Cress, “Gemini Ejection Seat Development Challenge,” Air Power 

History, Winter 1997, 50–61. 

16. The plot was extracted from Michael A. Rickards, Analysis of High 

Speed Encapsulated Seat Crew Escape System for Zero Speed and Zero Altitude Capability, ASA-TDR-62-242. 

17. Naval Ordnance Laboratory (NOL) Report 3058, Blast and Shock Tables 

for Explosions in Air. For an analysis of how those values were determined, 

see Martin Report 224, Analysis of the Gemini Launch Vehicle Escape Environment, February 1964. For the thermodynamically inclined, the radiant energy 

output of the fireball is 1.14 X 1011 Joules (1.08 X 108 BTU).

18. These jumps were performed as part of a USAF aeromedical study on 

the human factors inherent in high-speed, high-altitude ejections called Project Excelsior. Captain Kittinger’s experiences were summarized in NASA Report SP-8, Proceedings of 2nd Conference on Peaceful Uses of Outer Space, 

May 8–12, 1962, Seattle, WA, Paper no. 19—Discussion of Project Excelsior, 

by Joseph W. Kittinger. 

19. William L. Garmon, conference report, subject: Program for Mode I-II 

“Ride It Out” Aborts, 28 July 1964. Also MAC, memo titled Mode I Abort Revision, 28 May 1964.

20. The results were published as Aerodynamic Characteristics of the 

Gemini Ejection Seat-Man Configuration, Aerodynamics Information Note no. 

50, MAC, October 1963. 

21. Ballutes were also used as a retardation device for high-speed, lowlevel bomb delivery. 
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160

22. A pyrotechnic time-delay device is essentially a powder train that 

takes a specified time to burn and then ignites the output charge. It is not 

unlike an old-time dynamite fuse. A pyrotechnic time-sequencing system is a 

series of pyrotechnic devices with built-in time delays that accomplish a series of time-related tasks.

23. Gene Kranz, Failure Is Not an Option (Thorndike, ME: G. K. Hall & Co., 

2000), 158; and Chris Kraft, Flight—My Life in Mission Control (New York: 

Plume Publishers, 2002), 251. 

24. The scenario described involves approaching the target from behind. 

If in front of the target, the same procedure is used; however in this case, 

when thrust is applied away from the target, the thrust increases energy, 

lengthening the orbit time, which allows the target to catch up.

25. For additional information on the mechanics of rendezvous and docking, consult Buzz Aldrin and Malcolm McConnell, Men from Earth (New York: 

Bantam Books, 1989). Aldrin wrote his PhD dissertation at MIT on performing that maneuver before he became an astronaut. The book is also an excellent overall text on the US space program. 

26. It is interesting to note that while listening to a space shuttle launch, 

I heard someone announce “Mode III,” indicating that the shuttle just entered 

its Mode III abort scheme. NASA still uses the abort mode notation instituted 

so long ago on the Gemini program.
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Chapter 8

Secret Missiles and Tactics

The aim of our research group was to look 10 years into the 

future—to analyze and postulate Soviet missile defenses—and 

then design missiles, penetration aids, and tactics for getting 

through those defenses. The work was highly classified, so I 

can only reveal a general outline of our research. We worked 

closely with the management consultant firm for the Air Force 

on missile systems, the Aerospace Corporation in San Bernardino, 

California. Our McDonnell effort was to develop an understanding of the problems, build a competent team able to respond to 

the military efforts in that area, and determine the direction 

the company should pursue.1 

Heavily involved in our research was the discipline of operations analysis (also referred to as operations research [OR]). 

Operations analysis uses the scientific method to analyze and 

predict the effects of systems and actions on an engagement 

scenario. In this application it involved defining the kinds of 

defenses an enemy would require to defeat our postulated missile offense concept and identify probable enemy costs and 

technological stress points that might occur. This could lead to 

policy decisions at the highest levels. 

Historical Note 

Operations analysis came of age during WWII as both sides employed the intelligentsia of their universities to analyze weapons and tactics. My first recollection 

of operations analysis was reading how the Royal Navy called on university scientists early in the war to analyze why they were not sinking German submarines. 

After investigating, the scientists recommended that the size of the depth charges 

be greatly increased and that they be set to detonate deeper. The sinking of German submarines dramatically increased. Another application involved the Royal 

Air Force nighttime bombing of German cities. The British wanted to pulverize 

and overwhelm the defense of a large German city (Cologne) with 1,000 bombings 

in 90 minutes. The scientists again applied a theoretical method of analysis to 

show how it could be done. When briefing the airmen who would fly a closely 

spaced raid in the night sky, the Boffins, as the military referred to the scientists, 

assured them that statistically, only two aircraft would be lost due to collisions. 

One airman then asked, “Which two of us will be involved?”2
SECRET MISSILES AND TACTICS

162

The Soviets were constructing a missile warning system along 

their northern border, the access route for ballistic missiles 

fired from the United States, and were deploying antiballistic 

missile (ABM) defenses around critical targets. Their warning 

net was similar to the US distant early warning (DEW) line also 

being constructed.3 Since the Soviet radar was looking for 

ICBMs to come over the North Pole region, our boss, Harold 

Stienmetz, theorized that a very long-range boost glide reentry 

vehicle could maneuver to penetrate the USSR from the south 

and thus outflank a northern defense line. This threat would 

require the Soviets to construct a separate radar net to acquire 

and defend against the BGRV from the south—a very costly 

investment in infrastructure and manpower, perhaps stressing 

the Soviet capabilities to the breaking point. A report submitted to the Air Force resulted in McDonnell receiving a research 

contract to build and launch several long-range BGRVs from 

Vandenberg AFB, California. This is discussed later. 

Historical Note 

The Soviets were indeed deploying a Galosh ABM system of long-range, nucleartipped missiles integrated with their radar warning net. They began deployment 

in 1962 and, by 1972, had ABMs installed at 64 sites around Moscow.4 

Another way to penetrate Soviet last-ditch defenses was to have 

a BGRV pull out of its dive and conduct a low-level run-in at 500 

feet for 25 miles to the target at Mach 10 using the terrain contour 

matching (TERCOM) navigation system. TERCOM uses a 3-D terrain map stored in the navigation computer memory. Using its 

radar as an altimeter, the missile can obtain a picture of the terrain contour and thus orient itself by comparing the observed 

contour to the stored one. This allows it to follow a predetermined 

course across the terrain to the target. It is very accurate and very 

hard to be led astray by radar jamming.5 The pullout and run-in 

environment is extremely severe, with the temperature at the nose 

reaching 5,000o C. Fortunately, the time period within the severe 

environment is quite short, only about one minute.

Maintaining the high-speed terminal flight required that the 

vehicle have a very high weight/drag ratio and/or employ a rocketmotor boost. Developing preliminary design sketches of slim, low-
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SECRET MISSILES AND TACTICS

drag heavy missiles and postulating the research requirements to 

produce those various concepts was a challenging and interesting 

project. The results of our analyses were periodically presented to 

Aerospace Corporation personnel, as they kept us apprised of the 

latest US endeavors in missile plans and technology and updated 

our intelligence of Soviet missile advances.

Historical Note 

On 11 August 1965, a routine traffic stop of a black motorist by white police officers sparked a six-day riot in the predominately black Watts area of Los Angeles. 

Stores were looted and burned, and many people were killed and hurt in the violence. This riot accelerated the civil rights movement and made many of us acutely 

aware of the plight of black people in America. 

Several of us were on a trip to Aerospace Corporation during the riot and stayed 

in a high-rise motel near the Los Angeles airport. From our motel window we 

could see the smoke from the Watts riot. It was quite frightening and threatening 

to realize that a riot of that proportion could occur in our country.6 

The initial conditions for the low-level run-in required that the 

BGRV terminate its glide and start its dive to the target at Mach 

10. The advertised glide range assumed the vehicle was gliding to 

a point where it reached Mach 5, but it now required Mach 10. 

This effectively reduced the flight range, negating its range advantage over a ballistic missile. Also, using a brute-force approach to 

penetrate Soviet defenses with a low-level run-in negated the maneuvering approach. Use of nuclear-armed ABM systems that 

created a strong X-ray pulse was a distinct possibility, so samples 

of our coated structure were tested against heavy X-ray pulses. 

The coating separated, which would destroy the missile. With all 

those negatives, the BGRV effort was terminated. 

The emphasis shifted to applying the BGRV maneuvering 

control concept to a low-level run-in of a ballistic missile carrying multiple independently targeted reentry vehicles (MIRV).7 

To meet the high weight/drag ratio requirement and survive 

the severe heating environment, heavy tungsten- or ceramiccovered structures were considered. Creating control surfaces 

to withstand the harsh environment was daunting, so we investigated a control system that used a shifting c.g. by transferring mercury between fore and aft tanks. This was a similar 

but improved system over that flight-tested on Asset (discussed 
SECRET MISSILES AND TACTICS

164

in chap. 5). All these studies were directed toward an upcoming 

RFP from Aerospace Corporation to parametrically study the lowlevel run-in maneuvering MIRV concept to identify the critical 

technology and development areas and determine the most 

promising approach. 

A tungsten missile would be heated to a white-hot temperature 

during the run-in. Out of curiosity, we computed the light intensity 

of the streaking missile and related it to the electric power needed 

to produce such a bright light. Calculations showed it was equal to 

a 500,000-watt lightbulb. At a management briefing of new technologies, I used the title, “Development of a 500,000-Watt Light 

Bulb.” Those who were dozing woke up, and everyone acquired a 

puzzled expression, but I had their attention. Actually, a missile 

streaking by at Mach 10 would be quite destructive even without 

detonating a warhead. The shock wave it created would, in fact, be 

a blast wave and demolish everything along its flight path. 

We received the contract to parametrically study the low-level 

run-in of a MIRV concept and began our trade studies and 

analyses to penetrate a heavily defended target. The favored 

concept was to launch a standard ICBM with a warhead composed of MIRVs and possibly some decoys. The MIRVs would 

be released some distance from the target and make a maneuvering reentry to their individual targets. The favored terminal 

maneuver was to have the MIRV pull out at 500 feet and run in 

for 10–20 miles to the target at a very high Mach number.

As we worked through the preliminary designs, operations 

analysis postulated defensive strategies and offered suggestions to increase the penetration capability. We then repeated 

the cycle, gradually investigating numerous concepts and ideas, 

to arrive at an optimized concept that would be feasible to build 

yet stress the enemy’s infrastructure. 

We also won a contract from Aerospace Corporation to investigate the effectiveness of using maneuvering decoys to accompany the MIRVs. The decoys would simulate the warhead missile’s 

trajectory, atmospheric penetration characteristics, maneuvering characteristics, infrared and radar return signatures, electronic and radiation emissions, and other characteristics that 

might be used to discriminate between a decoy and a warhead. 

It was quite a challenge to make a small decoy look and act like 

a warhead missile. We also analyzed the cost-effectiveness of 
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SECRET MISSILES AND TACTICS

including decoys with the warheads and how much they would 

enhance the capability of penetrating an ABM-protected area. 

The program was called MANDEC, for maneuvering decoys. It 

was highly classified, and I cannot comment on the results of 

the study. It was a very interesting eight-month program.8

At a Secret-level conference and briefing at the Advanced Research Projects Agency (ARPA) in Washington, DC, ARPA presented the research results on a Hi-Boost Experiment (HiBEX) 

missile for an ABM.9 The launch videos were spectacular as the 

missile accelerated at the phenomenal rate of over 400 g’s, exiting its silo within 1/4 second after engine ignition. In a real-time, 

distant camera shot, it looked like it was fired from a cannon. 

During a slow-motion tracking-camera shot, the audience 

chuckled as the cameraman had difficulty tracking the missile. 

ARPA conducted the research in conjunction with the Army for 

a last-ditch ABM missile designed to intercept an incoming reentry vehicle at less than 20,000 feet. At that altitude the incoming vehicle could be traveling about 10,000 feet/second, so 

a very fast reaction time was essential to insure interception.

One problem with such a high-acceleration missile was designing a gyroscopically controlled inertial guidance system able 

to work under those accelerations. Mechanical gyros were not 

practical because they took too long to spin up. ARPA thus developed the laser gyro, which essentially made the gyros and 

associated guidance system instantly available. (Laser gyroscopes are now commonly used in the military and many commercial applications.) A major design goal of a very rapid launch 

was thus achieved. Seven missiles were tested at White Sands 

Missile Range, New Mexico, during 1965.10

Historical Note 

Shortly thereafter, the United States developed and tested the Sprint and Nike-EX 

ABM systems employing nuclear warheads. The Sprint was a short-range, lastditch interceptor, more conservative than the HiBEX, since it accelerated at only 

100 g’s, but it still achieved a speed of Mach 10 in five seconds. It sported an 

ablative coating to dissipate the air-friction heat and was tested in the all-out 

configuration in the 1970s at Kwajalein Island, where it intercepted several ICBM 

reentry vehicles fired from Vandenberg AFB.11 The Nike-EX was a longer-range 

space interceptor. Together they were deployed as the Sentinel ABM system to 

protect the new Minuteman ICBM installations.
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166

We were located on the third floor in the new engineering facility, 

Building 106, adjoining the large, new factory building for the 

production of F-4 aircraft, Building 101. From our floor we could 

survey the construction of Building 105 that would also abut 

Building 101. The morning of 28 February 1966 was cold, foggy, 

and rainy. As we were finishing our morning cup of coffee, we 

were suddenly jarred with double muffled bangs, and someone 

yelled that they saw an aircraft crash into Building 101 about 150 

feet from us, just where the Building 105 corridor to 101 was being constructed. From our lofty view we could see the hole in the 

roof of 101 and part of the aircraft on the ground. The crash was 

a NASA T-38 flown by astronauts Elliot See and Charles Bassett. 

They were coming to McDonnell to inspect Gemini IX, their assigned spacecraft for an upcoming flight. Something caused them 

to crash as they made an approach to Lambert Field in the murky 

weather. No one was seriously hurt on the ground, but water from 

the severed utility pipes and sprinkler system drenched a large 

area. Ironically, they died only 100 feet from their potential spacecraft being outfitted in a clean room, vividly demonstrating the 

frail nature of life here on Earth. 

In a laboratory not far from where they crashed, a new vehicle was under construction. Designated the 122E Program 

by McDonnell, it was an intercontinental BGRV that advanced 

the hypersonic-flight state of the art into the practical realm. 

One of the vehicles ended up in the Space Flight Gallery at the 

Air Force Museum at Wright-Patterson AFB. There, squeezed in 

between more notable spacecraft, stands a slender, needlenose, conical vehicle pointing into the sky. A very short description on the plaque merely denotes it as a boost glide reentry vehicle that investigated hypersonic maneuvering in the 

atmosphere. It did a lot more than that and probably caused 

the Soviets some anxious moments as well when they found 

that we had indeed solved the horrendous problems of longrange, hypersonic, gliding flight in the atmosphere. 

The BGRV, or McDonnell 122E Program, objective was to develop and test a glide vehicle with a 5,000-mile glide range when 

launched by a modified Atlas-F missile booster. Three flying 122E 

missiles and one boilerplate were built. The boilerplate, an inert 

missile having the correct shape and weight, was for checking the 

Atlas missile’s ability to place the BGRV into its atmospheric glide-
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flight insertion point. It required the Atlas to maneuver quite drastically, close to its structural and temperature limits. 

The 122B Alpha Draco glide missile launched from Cape Canaveral, which started its glide at Mach 5.5, was constructed of 

stainless steel (see chap. 5). The 122E BGRV started its glide at 

a Mach number near 20 and maintained hypersonic flight for 

5,000 miles, which takes about 45 minutes. The design criteria 

to achieve these requirements challenged the designers and 

forced them to use exotic materials and innovative design.

The 122E was a very slender, biconic-shaped glide vehicle 

with a fineness ratio of 10, as shown in figure 17. The 1.0-inch-

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SECRET MISSILES AND TACTICS

168

diameter nose tip was cooled to prevent melting by a transpiration system that squirted water through a porous nose. The 

nose-tip pores were so fine that the transpiration water must 

be free from bacteria to prevent clogging—a very difficult 

achievement. The vehicle was made from coated columbium 

Cb-752 panels, a refractory (ceramic-type) metal that is hard to 

shape and requires electron-beam welding in an inert atmosphere. Oxidation at high temperatures was prevented by a 

very brittle and easily chipped coating, necessitating delicate 

handling of the panels. All 122E engineers sported large, yellow 

buttons that said, “Help Stamp Out Cb-752” to continually remind them of the fickle nature of that material. Water-gel blankets provided insulation to keep the internal temperature cool 

enough to operate the equipment during the flight. 

Control was provided by a 12-piece, segmented, variabletrim flare and small rocket thrusters mounted on a spherical 

aft end behind the flare. Individual control flaps, as depicted in 

the NACA glide vehicle concept in figure 9, could not withstand 

the severe heating, so the flare/thruster system was designed. 

The flare changed the vehicle trim angle of attack, and the 

thrusters provided angle-of-attack transient control. Like the 

122B Alpha Draco, the 122E was slowly rolled to provide uniform heat distribution. Guidance was provided by an inertial 

navigation system and digital computer. 

The first Atlas launch at Vandenberg AFB with a boilerplate 

missile was unexpectedly terminated about 30 seconds into 

the flight by a malfunction of the Atlas self-destruct system. 

The second flight test, using a flight article, placed the 122E 

into the correct insertion point. Unfortunately, when the 122E 

separated from the Atlas, a static-electric buildup between the 

122E and the Atlas created a spark that set off the command 

destruct system in the 122E. Launch number three, on 26 February 1966, was an outstanding success. It glided down the 

entire range, even making a turn over Johnson Island to its 

planned target point. The flight was terminated by a programmed self-destruct when it reached Mach 5 at 100,000 feet 

altitude, where it would have been commanded to dive to the 

target in operational use. With that success and no plans to 

produce such a weapon, the last 122E BGRV was put on display at Wright-Patterson.12
169

SECRET MISSILES AND TACTICS

Research conducted on penetrating Soviet air defenses helped 

US leaders understand the various scenarios and provided options for responding to the multiple threats to our American 

way of life. My small input gave me a good feeling of helping 

bring about a détente with the Soviet Union once both sides 

saw the futility of trying to get the upper hand.

McDonnell Aircraft Company was doing great producing the 

fabulous F-4 in record numbers for the Air Force, Navy, and 

Marines—the first aircraft flown by all three services. Versions 

of the F-4 were also exported to several US allies.

Historical Note 

The F-4 went through several designations before it settled on its final identity. 

Originally a Navy fighter, it was designated the F4H, in line with the Navy aircraft 

designation scheme at the time. The “F” signified a fighter aircraft. The “4” implied it was the fourth model aircraft in the Navy inventory from that manufacturer. (The other three McDonnell aircraft were the F1H Phantom, F2H Banshee, 

and F3H Demon.) The “H” was the MAC designator.13

When the Air Force purchased the F4H, it was designated the F-110, using the 

Air Force identification scheme of listing the type category consecutively—the “F” 

indicating a fighter and “110” indicating the 110th fighter type accepted by the 

Air Force. However, the aircraft had been flying under the Navy designation for so 

long before the Air Force acquired it that pilots and others were used to calling it 

an F4, and hardly anyone called it an F-110. 

The Navy was also aware that their aircraft designation scheme was outdated 

since companies were combining and/or going out of the aircraft business, so in 

conference with the Air Force they decided the time was ripe for unifying their 

designation schemes. They agreed to use the consecutive-type (Air Force) designator, but starting with the commonly used F-4. 

The large production of the F-4, along with other profitable 

programs, provided Mr. Mac with the funds to acquire the ailing Douglas Aircraft Company, giving McDonnell the coveted 

transport aircraft line he had always wanted. The combined 

company, chartered on 28 April 1967, was known as McDonnellDouglas Corporation (MDC). 

Not long after the merger, Mr. Mac attended a small, intimate 

meeting of McDonnell and Douglas executives in our secluded 

and secure conference room. During a break, he came out of 

the conference room and started to look around the area. When 

I noticed him looking puzzled, I asked if I could help. He said he 
SECRET MISSILES AND TACTICS

170

was looking for his son, John, who was located nearby. (John 

was working on a drafting board to learn the aircraft business 

from the ground up.) I pointed out where John was, and Mr. Mac 

went over, pulled up a drafting stool, and sat down. In a few moments he had a bunch of young engineers sitting around him in 

animated conversation. It was an extraordinary display of his 

humble nature and why we respected him so much.

An appalling accident at Cape Canaveral greatly affected all 

Americans and mortified those of us who worked on the manned 

space projects. An Apollo capsule fire on 27 January 1967 took 

the lives of astronauts Gus Grissom, Edward H. White, and 

Roger B. Chaffee. I worked with them during Gemini, and Grissom was also a personal friend from AFIT days. The tragedy 

affected many of us and put all America into mourning. We all 

felt that there would be fatalities in the space program, but to 

have them occur on the ground rather than in flight was incomprehensible.14

The aircraft and space programs were becoming very complex, as teaming arrangements of various organizations around 

the world were involved in the process. This worldwide participation taxed the capabilities of the procurement management 

systems in use at the time, so a new Systems Engineering management system was implemented by the military and NASA to 

track and control the entire process. The Air Force Manned 

Orbiting Laboratory (MOL) was one of the first systems procured under the auspices of this new management system and 

serves as the theme for the next chapter.

Notes

1. James A. Wirtz and Jeffrey A. Larsen, Rockets’ Red Glare (Cambridge, 

MA: Westview Press, 2001) is an excellent treatise on how ICBM missile deployment and missile defense systems interacted to finally bring on a détente 

between the United States and the Soviets.

2. A treatise on operations research and its early development is presented 

in Sir Solly Zuckerman’s book, Scientists and War, The Impact of Science on 

Military and Civil Affairs (London, UK: Scientific Book Club, 1966). Another 

book that details the development and operational use of several scientific 

projects is Wilfrid Eggleston, Scientists at War (Toronto: Oxford University 

Press, 1950). A textbook reference is Philip M. Morse and George F. Kimball, 

Methods of Operations Research (London, UK: Chapman and Hall, 1951). 
171

SECRET MISSILES AND TACTICS

Several later editions were published by MIT and John Wiley and Sons Publishers. A more recent text is Robin Neillands, The Bomber War—The Allied 

Air Offensive against Nazi Germany (New York: Overlook Press, 2001). A recent study on how RAF Bomber Command assessed and used the operations 

research data is presented in Randall Wakelam, “Boffins at Bomber Command: The Role of Operational Research in Decision Making,” Air Power History 52, no. 4 (Winter 2005): 16–23.

3. The DEW line consisted of a group of isolated radar stations arranged 

in an arc along the 70° N parallel in Canada. The DEW line was fully operational in 1957, and selected stations were still in use up to a few years ago. 

See Peter Grier, “A Line in the Ice,” Journal of the Air Force Association (February 2004): 64–69, for a good article on the DEW line construction and operational difficulties.

4. Wirtz and Larsen, Rockets’ Red Glare, 37. 

5. TERCOM guided the cruise missiles to their targets during Operation 

Desert Storm in 1991. 

6. Web site htpp://www.usc.edu/isd/archives/ethnicstudies/watts.html 

presents a long list of references on the riot and its aftermath.

7. A discussion and photograph of a MIRV bus used to propel independent 

reentry vehicles to various targets is available at htpp://www.gwu.edu/

~nsarchiv/nsa/NC.mirv.html.

8. The missile defense value of decoys is still an ongoing program as part 

of the Star Wars doctrine. Surfing the Internet reveals many sites where these 

aspects are discussed, including http://www.fas.org/spp/starwars/offdocs/

tmddsp and htpp://www.fas.org/ssp/bmd/guide/terminal. 

9. ARPA (now known as Defense Advanced Research Projects Agency, 

DARPA) is the central research and development organization for the Department of Defense (DOD). It manages and directs selected basic and applied 

research and development projects for the DOD and pursues research and 

technology where risk and payoff are both very high but success may provide 

dramatic advances for traditional military roles. See http://www.darpa.mil/

body/main.html. 

10. From http://www2.tpgi.com.au/users/mpainf/missiles/sprint.html.

11. Ibid. 

12. The Air Force Museum Web site, http://www.wpafb.af.mil/museum/

space_flight/sf15.htm, includes a picture and short description of their BGRV 

display. 

13. Some other common company designators were B for Boeing, D for 

Douglas, F for Grumman, J for North American, O for Lockheed, U for Chance 

Vought, Y for Consolidated, and M for Martin. 

14. Slayton, Deke! 188–90; and Kranz, Failure Is Not an Option, 191–207. 

173

Chapter 9

Space Projects

System engineering covers a broad range of program management techniques to ensure effective control of the design, 

production, operation, maintenance, modification, and eventual retirement of the system. It provides a management tool to 

facilitate procurement of reliable, complex systems within cost 

and time constraints. The system engineering procedures and 

methods were, at that time, vested in a series of large manuals 

published by the Air Force Systems Command, labeled 375—

System Engineering Manuals, and included:

375‐1 Configuration Management during the Acquisition Phase 

375‐3 System Program Office Manual 

375‐4 System Program Management Procedures 

375‐5 System Engineering Management Procedures Manual

375-6 Development Engineering 

The work at our level was vested mainly in the 375-5 System 

Engineering Management Procedures Manual.

The Air Force developed the Manned Orbiting Laboratory for 

the DOD’s manned spacecraft program. Douglas’ Huntington 

Beach Division received the contract to develop the spacecraft, 

which housed two Air Force aerospace research pilots for up to 

30 days’ duration. McDonnell received the contract to develop 

a modified Gemini, called Gemini B. It would fit on the MOL 

and payload stack boosted into polar orbit on a Titan 3M launch 

vehicle from Vandenberg AFB. Once in orbit the astronauts 

would move into the laboratory by removing a heat-shield plug 

and crawling through a tunnel to the laboratory. The Titan 3 

final booster stage, called the transtage, contained a hypergolicfueled rocket motor and would remain with the laboratory, thus 

allowing the astronauts a 1,000 ft./sec. orbital maneuvering 

capability. When the mission was complete, the astronauts 

would return to the Gemini B, lock the heat-shield plug, then 

separate from the laboratory and return to Earth.1
SPACE PROJECTS

174

The MOL project was managed under the new system engineering procedures by the Air Force Space Systems Division under Gen 

Bernard Schriever. With the Gemini B a part of the MOL,McDonnell 

was catapulted into the intricacies of these new procedures. Soon 

we were involved in implementing the process by ensuring all 

analyses, testing, and manufacturing were proceeding in unison 

toward the final product. This involved not only McDonnell but also 

our subcontractors. We also had to keep the customer apprised of 

the progress, making sure possible problem areas were identified 

and detailing the steps taken to correct the situation. 

Historical Note 

General Schriever was the driving force that got the Thor IRBM and the Atlas and 

Titan ICBMs operational years before most experts thought feasible. He helped 

reach parity with the Soviets’ missile capability, preventing Soviet dominance in 

space by overcoming their several years’ head start. 

Historical Note 

System engineering has come a long way from its rocky beginning during my 

tenure and is now a major course of study in universities around the world. Its 

functions have been subdivided into its major components, allowing specialization and even the procurement of a college degree in the different aspects of the 

program management area. It has evolved into a well-disciplined, powerful, management tool covering the entire span of a system from cradle to grave.

At the time, systems engineering was foreign to most engineers, 

and they had very little tolerance for writing reports or completing 

the paperwork documenting their results.2 When asked if there 

was anything they needed to expedite a test and get back on 

schedule, their answer was usually, “just go away.” After my euphoric introduction to the process, I became disillusioned and felt 

the same as the engineers—that system engineering, at that time, 

was a big waste of money and talented manpower. It is no wonder 

that when the Air Force wanted an urgent Secret project completed, they dispensed with all the paperwork requirements and 

told the contractor what they wanted and to get it built. The 

“Skunk Works” at Lockheed Aircraft is the best known of these 

Secret projects establishments due to their development of the 

U-2, SR-71 Blackbird, and the F-117 Stealth Fighter.
175

SPACE PROJECTS

The hole-in-the-heat-shield concept was tested by an unmanned flight of the recovered Gemini GT-2 test vehicle. (GT-2 

was initially used to qualify the Gemini reentry systems prior to 

the first manned Gemini flight.) During this second reentry 

test, the heat-shield plug satisfactorily melted shut, creating a 

structurally sound heat shield for reentry. The payload stack, 

consisting of the transtage, laboratory module, and Gemini, 

was almost 60 feet tall and 10 feet in diameter. This long stack, 

mounted on top of the booster, caused some concern that its 

length might create problematic aerodynamic and dynamic loads 

on a quite flexible structure. A test launch verified the adequacy 

of the system. Next on the schedule was an unmanned test of 

the complete MOL system set for a late-1970 launch. 

The MOL program was canceled in June 1969, primarily because both the Air Force and NASA were developing similar 

space laboratories and the duplication of effort was just too 

costly. The MOL cancellation spelled the end of the Air Force’s 

ambition to have its own spacemen; like it or not, NASA was in 

charge of the manned flight agenda. The MOL engineering and 

test effort was not completely wasted, as NASA used some of 

the results in its space laboratory project called SkyLab. Even 

some completed space hardware was transferred to NASA. The 

Air Force had a group of astronauts in training for the MOL 

missions, so the cancellation left these well-trained astronauts 

without a mission. Through an agreement between NASA and 

the Air Force, seven of the MOL astronauts were transferred to 

NASA’s spaceflight program. All seven flew multiple space missions, including some moon landings. 

During this space dominance competition with the Soviets, 

the media were filled with articles on spaceflight and missile 

technology, along with speculations on what that would mean to 

mankind. Space authors like Willy Ley, Arthur C. Clark, Chesley 

“Chesty” Bonesell (who proposed a large, rotating-wheel space 

station portrayed in the movie 2001: A Space Odyssey), and others were interviewed on TV. German rocket scientist Wernher 

von Braun presented a TV series explaining to the Disney 

Mouseketeers how rocket ships work. As the entire world 

watched, the United States and Soviet Union strived to become 

the dominant space superpower by launching various spacecraft, including a series of planetary and deep-space probes—the 
SPACE PROJECTS

176

US Pioneer and Mariner and the Russian Venera series.3 It was a 

great time to be an aeronautical engineer and was captured in a 

well-written book, This New Ocean by William E. Burrows.

4

Historical Note 

At one of our ARS meetings, someone stated that a study was in progress to design an atomic spaceship propelled by exploding atomic bombs behind it. I recall 

that most of us thought the idea was ridiculous; however, it turns out that a serious study of the project was carried out for several years. It was called Project 

Orion and is featured in a recent book. 5

Historical Note 

The United States had won the race to the moon; however, not by a large margin. We had heard news reports about the Soviets’ moon effort using a monstrous launch vehicle with a cluster of 30 rocket motors for the first stage. Their 

booster stack (the assembly of all booster stages) was half-again as large as the 

massive Saturn V booster for the US program. In early 1969, after the Apollo 8

circumlunar flight, newspaper articles quoting a reliable source reported that 

the USSR moon lander program was set back by the explosion of its launch vehicle. We now know that a complete moon launch vehicle exploded in January 

1969 and obliterated a launch complex at the Baikonur Cosmodrome in Kazakhstan. That doomed the Soviet moon landing program, although it was not officially canceled until a year later. 

The manned moon-landing program continued with Apollo 8

astronauts Frank Borman, Jim Lovell, and William Anders getting the okay for translunar injection for a circumlunar flight. 

It was hard to believe that finally men were really free from 

Earth’s gravity and on their way to the moon. On Christmas 

Eve of 1968, as the Apollo 8 astronauts orbited the moon, they 

beamed a special message to Earth, reading from the book of 

Genesis. It was indeed a great Christmas.

The following July marked the climax of the Apollo program, 

as astronauts Neil Armstrong, Ed “Buzz” Aldrin, and Mike Collins 

blasted off in Apollo 11 for the first landing on the moon. We were 

glued to the television watching and listening as Neil Armstrong 

and Buzz Aldrin prepared to exit the LEM and step onto the 

moon’s surface. As we watched the historic event of men walking (really I should say hopping) on the moon, we were all proud 

for accomplishing such a task. 
177

SPACE PROJECTS

The Saturn V launches and moon landings became somewhat routine occurrences, but Apollo 13 brought suspense and 

tension back into the venture. Astronauts Jim Lovell, Fred 

Haise, and Jack Swigert were about one-quarter of the way to 

the moon when an explosion occurred in the service module. 

(The service module housed their expendables, fuel cells, and 

maneuvering engine.) This created a grave emergency, and they 

had to use the LEM as a lifeboat as they looped around the 

moon and headed back to Earth. Through heroic endeavors by 

the crew and mission control, they survived the trip and were 

safely recovered. This epic demonstration of teamwork and engineering abilities is chronicled in several books and even dramatized in a movie.6 

Historical Note 

NASA’s SkyLab space station was the Douglas-built third stage of the Saturn S-IVB 

moon rocket converted into a space laboratory. SkyLab was launched after completion of the moon landing program by a Saturn V booster in May 1973. During 

launch it lost a solar panel and part of its shielding, forcing the astronauts to rig a 

large, gold-plated plastic sheet to keep the station cool. The lost solar array caused 

only inconvenience. Over the next year, three groups of astronauts, using an Apollo 

spacecraft, visited SkyLab, each staying a month or two. It was then abandoned 

and its orbit decayed until 1979 when it reentered and scattered its burnt and 

charred debris over the Pacific Ocean and Australian outback.7 

As the moon landing phase wound down, NASA embarked on 

a program to design a completely reusable spacecraft, called a 

space transportation system (STS), able to launch large heavy 

payloads into orbit and return via a conventional landing at the 

launch site. An RFP from NASA was expected in about two 

years. The STS was to become the workhorse for putting payloads into orbit, eliminating the separate launch vehicles. The 

Air Force planned to use the STS to launch its large reconnaissance payloads from Vandenberg AFB. 

To prepare MDC for the RFP, a corporation-wide study team 

was assembled under the direction of Vice President John Yardley 

and located at the McDonnell St. Louis engineering campus. 

NASA was promoting a system consisting of a reusable booster 

that would boost a reusable orbiter 40 percent of the way to 

orbit. The booster would release the orbiter, turn, and cruise 
SPACE PROJECTS

178

back to a landing at the launch site while the orbiter continued 

to orbit. At about this point in time, it was officially named a 

space shuttle.

The MDC shuttle team began working up a configuration 

with company funding; however, study contracts were given to 

several possible primary shuttle contractors. MDC received a 

12-month NASA phase B space shuttle contract on 19 June 

1970. The objective was to analyze and provide a preliminary 

design and cost analysis of a completely reusable, two-stage 

space shuttle. We went through several designs and settled on 

a booster and orbiter system as shown in figure 18. It was 

about the size of the present-day Boeing 747 that carries the 

shuttle back to the launch site, but weighed 4.6 million pounds. 

The booster had a swept wing near the base of the body and a 

small canard surface forward. Twelve rocket motors, generating 6.6 million pounds of thrust, propelled the system to a velocity of 10,000 ft./sec. at an altitude of 200,000 feet. At that 

point, the orbiter would be released and continue on its own to 

orbit. The booster would reenter the atmosphere and cruise 

back in a conventional airplane mode to the launch site, using 

10 pop-out jet engines.

The proposed orbiter was a faired delta-wing configuration 

with two rocket motors for orbit injection. The motors were ignited as the booster engines were shut down at separation. The 

orbiter then completed its mission, reentered, and glided to a 

landing at the launch site. Provisions were made for mounting 

four pop-out jet engines as a landing aid to accommodate polar 

orbits, which could require a substantial cruise capability to 

reach the landing area.

Preliminary cost analyses revealed that this completely reusable shuttle was prohibitively expensive—much greater than 

initially realized. This was because two spacecraft—the orbiter 

and the booster—required simultaneous development. This 

prompted NASA to shift the design emphasis from a completely 

reusable system to an interim design of an orbiter with an external, expendable fuel tank with two large, solid-propellant 

rocket motors. Design of the reusable booster would be delayed 

until after the interim orbiter was in service. This spread out 

the cost over a longer time, making it easier to sell to Congress. 
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SPACE PROJECTS

180

In April 1971, MDC was issued a one-year extension of its NASA 

contract to study this interim version. 

Various liquid and solid boosters and the type of burn—parallel 

or series—were parametrically studied. In a parallel burn, both 

the booster and orbiter engines are operating; in a series burn, 

the orbiter engines are ignited when the booster engines are 

shut down. The most cost-effective and, hence, the recommended system was a parallel burn with twin 156-inch solid 

rocket motor boosters attached to a large fuel tank. This was 

the system finally built.8

Finally, the long-awaited NASA space shuttle proposal was 

received. During preparation of our proposal, the combined 

team became disoriented and confused. We changed directions 

so many times, I was never sure of our configuration. The entire project was in turmoil, nerves were on edge, and everyone 

became quite tired. Someone provided some levity that helped 

alleviate the tension and calm our nerves, which were reaching a short fuse. The best method for recovering the spent 

solid booster rocket motors for refurbishment was a point of 

contention until almost the last moment. One of the McDonnell 

directors was reading a preliminary version of our proposal 

when he suddenly erupted with a loud guffaw, startling all in 

his vicinity with, “Buy that man a cigar, that’s the best idea 

yet.” He then read a sentence that said, “After the spent boosters have landed in the water, they will be recovered by 12 

pygmies paddling purple war canoes.” The laugh provided a 

tonic to keep us going.

It was a great disappointment, but to some of us no surprise when we found out we did not win the space shuttle 

contract. Had we won the program, I was slated to become 

the configuration manager. It would have been a great promotion into the management field that could have led to more 

responsible positions, but I was not looking forward to the 

paperwork itself. 

Losing the shuttle contract was a big blow to McDonnell. It 

sent a ripple of readjustments within the workforce as management coped with a surplus of 100 engineers and other workers. 

In addition to many reassignments, there were layoffs, resignations, and retirements. I accepted a position back in aerodynamics, where I really belonged.
181

SPACE PROJECTS

Notes

1. Web sites http://www.friends-partners.org/mwade/craft/mol.htm and 

http://www.friends-partners.org/mwade/craft/geminib.htm present a summary of the MOL and Gemini B projects. 

2. I recall a cartoon of a fellow sitting on the “john” with the caption, “The 

job isn’t complete until the paperwork is done.” It was a crude but pointed 

reminder that we had an obligation to keep management, and our customer, 

completely apprised on the status of the system we were developing. 

3. Web site http://www.solarviews.com/eng/craft2.htm presents a complete chronology of space exploration probes—17 pages.

4. William E. Burrows, This New Ocean (New York: Random House, Inc., 

1998). 

5. George Dyson, Project Orion: The True Story of the Atomic Spaceship

(New York: Henry Holt & Company, 2001). Discover magazine published an 

article on this rocket, with conceptual pictures, and listed several Web sites 

where additional information can be found. George Dyson, “The Grandest 

Rocket Ever,” Discover 26, no. 2 (February 2005): 50–53.

6. For example, Kranz, Failure Is Not an Option; Kraft, Flight— My Life in 

Mission Control; and the 1995 movie, Apollo 13, starring Tom Hanks as Jim 

Lovell and directed by Ron Howard.

7. Web sites http://science.nasa.gov/ssl/pad/solar/skylab.htm and 

www.pao.ksc.nasa.gov/kscpao/history/skylab/skylab.htm.

8. Space Shuttle System, Phase B Study Final Report, Completely Reusable 

System, MDC Report E0308, 30 June 1971; and Space Shuttle System, Phase 

B Study Final Report, Water Recoverable Booster, MDC Report E0558, 15 

March 1972. The McDonnell graphics art director was so impressed with the 

Completely Reusable System executive summary that he submitted it to the 

awards committee of the Society for Technical Communication. Several 

months later I received an Award of Merit in the technical reports category 

presented at their 1972 Boston meeting. John F. Yardley also used it in a 

presentation, AIAA Paper No. 71-804, “McDonnell Douglas Fully Reusable 

Shuttle,” at the AIAA Space Shuttle Systems meeting in Denver, Colorado, 

19–20 July 1971.

183

Chapter 10

Pilots and Airplanes

Losing the space shuttle contract caused me to reexamine my 

career. For the past eight years I had been in a middle-management 

position and, upon reflection, realized that I did not like managing people. I wanted to be actively immersed where the challenge was—doing the calculations and analyses myself, not 

passing on the work to others. Aerodynamics chief Chester 

“Chet” Miller asked me if I wanted to come back into aerodynamics and head up a small airplane flying qualities research 

group. After wandering around for eight years trying to find a 

niche in other areas, I returned to my first love in a real engineering position.

Shortly after I returned to aerodynamics, McDonnell instituted a technical specialist career track that allowed technical 

people to advance parallel with management. I was designated 

a senior technical specialist, equivalent to a project engineer, 

but I only had to supervise a small research group and could 

dispense with most paperwork.

The term flying qualities (sometimes called handling qualities) relates to how pilots like the feel and response of an aircraft. It is not unlike how a person likes the feel of an automobile 

while driving. Drivers want positive steering without too much 

free play, good cornering characteristics without any tendency 

to fishtail, no wandering at high speeds so they can drive relaxed, and so forth. Similar factors apply to flying an aircraft. 

For many years, flying qualities were measured in qualitative 

terms, where pilots expressed their personal feeling on how an 

aircraft flew. Since there was seldom consensus among pilots, 

the aerodynamic and flight-control engineers were left in a 

quandary on the acceptability of the aircraft control system. In 

the 1960s, a flying qualities pilot rating system evolved based 

on a quantitative standard measure through the publication of 

NASA-TN-D-5153 by George Cooper and Robert Harper.1 The 

flying-qualities scale has been known as the Cooper-Harper 

pilot rating ever since and is presented in figure 19. This scale 
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185

PILOTS AND AIRPLANES

defines three levels of flying qualities: Level 1 as “satisfactory,” 

Level 2 as “needing improvement,” and Level 3 as “controllable 

but unsatisfactory.” The three levels are further subdivided into 

three sublevels relating to a Cooper-Harper scale of 1 to 10. Pilots 

rated an aircraft following the guidelines in the chart. Note that a 

pilot rating of 10 means that the aircraft is uncontrollable. 

Over the years, a great deal of information on the desired aircraft response and motions due to air disturbance or pilot control application was collected, assembled, and classified in quantitative terms as the preferred flying qualities. This led to 

publication of Air Force Specification MIL-F-8785, Flying Qualities of Piloted Airplanes.

2 These flying qualities were based on the 

classical response of conventionally controlled aircraft; that is, 

WWII-types that allowed the SDF equations to be separated into 

two sets of three equations. With the introduction of hydraulicdriven controls, stability augmentation devices, fly-by-wire control, and other innovations, aircraft motions exhibited a greater 

complexity, or in engineering terms, the system order increased. 

These are therefore referred to as high-order control systems. 

Determining the flying qualities of these aircraft became more 

difficult and degenerated into more of an art than a science.

When pilots take the controls of an aircraft, they become part 

of the control system by closing the loop between what the aircraft is doing and what the pilot wants it to do. A human pilot 

exhibits mental and neuromuscular features that provide a limb 

motion response that must be compatible with the aircraft control system. Since a pilot’s response characteristics cannot be 

appreciably altered, the aircraft control system must be designed 

around the pilot. A pilot also wants aircraft controls to be relaxing, have a rapid response to control inputs, quickly damp out 

unwanted motions and, above all, be safe. To understand a flying qualities discussion and the Cooper-Harper pilot rating scale, 

it is necessary to define some routinely used expressions.

Pilot workload refers to the necessary attention toward flying 

the aircraft—the greater the attention required, the higher the 

workload. A corollary would be driving an automobile on a slick 

roadway, forcing the driver to use small, smooth steering corrections to prevent a spin. The driver cannot drive relaxed because 

the workload is high to maintain control on the slick surface.
PILOTS AND AIRPLANES

186

Pilot gain is related to the anticipation and quickness of required control applications. Thus, driving a sports car requires 

a higher gain because of its agility and maneuverability and is 

therefore a more mentally tiring task than driving a limousine, 

although it is probably more enjoyable.

Pilot compensation is the combined pilot workload and gain 

necessary to fly the aircraft.

Pilot rating is an individual qualitative assessment of the aircraft’s flight performance. No two pilots will agree on all the specific control response parameters that they like. For example, some 

pilots prefer a low value of stick force per g, while others like a high 

value. Stick force per g, abbreviated as Fs/g, is a parameter that 

relates how hard the pilot has to pull on the stick to achieve a 

specified load factor. For example, Fs/g = 5 implies that a fivepound pull will result in a one-g pull-up, a 10-pound pull will give 

two g’s, a 20-pound pull four g’s, and so forth. For some pilots, 

that is too low, causing them to overshoot their intended g-value. 

Therefore, they have a higher workload. Pilots who like a low Fs/g 

might rate it a 2, while pilots who prefer a higher Fs/g would consider it an annoying deficiency and give it a pilot rating of 4.

This presents a dilemma to the design engineer. As a compromise to the pilots who want a higher Fs/g, increasing that parameter as the g-loads increase may alleviate their objections yet 

provide the nimble pull-up response pilots want. For example, 

Fs/g = 5 for one g, 13 for two g’s, 20 for 3 g’s, and so forth. Compromises usually result in satisfying most but not all the pilots. 

Getting them to agree that the aircraft has Level 1 handling 

qualities (pilot ratings 1–3) usually results in a satisfactory design. Since there are a multitude of parameters to consider, the 

control design engineer obviously has an exasperating problem. 

The classical method of designing a new aircraft control system begins with an open-loop (without a pilot) analysis of the 

aircraft and control system. This analysis provides the aircraft 

response due to some perturbation of the environment without 

any pilot inputs and defines what is called the natural response 

characteristics of the aircraft. Engineers then vary the control 

and aerodynamic parameters until the aircraft exhibits a satisfactory response that experience shows is acceptable to pilots. 

For example, assume the aircraft suddenly experiences an 

airspeed decrease of 10 knots. The natural tendency of an air-
187

PILOTS AND AIRPLANES

craft should be to lower the nose to regain airspeed; however, it 

will probably regain the lost 10 knots and overshoot it, causing 

the nose to rise. The resulting dynamic oscillation may or may 

not damp out over time. This is the so-called longitudinal phugoid motion exhibited by aircraft having a conventional control 

system. It has been determined that the phugoid motion is usually not a problem for pilots; they accept a slight dynamic instability since the oscillation frequency is very low and easy to control. Other aircraft motions have also been analyzed to determine 

the characteristics liked or disliked by pilots. These characteristics are documented in the aforementioned MIL-F-8785.

Prior to the late 1950s, the next step was to build and flighttest the aircraft and fix problems as they arose. This was a long, 

expensive, and dangerous process (Recall the trials and tribulations with the stability and maneuverability problems of the F-84F 

described in chap. 3). Piloted simulations gradually replaced this 

dangerous approach, but that did not significantly reduce the 

development time since the trial-and-fix method still applied. 

Elaborate complexes with a large, dedicated computer to run the 

simulation were constructed to simulate the real system and 

environment. Most were fixed-base simulators, meaning they 

were fixed in place, and had a large dome display that rolled, 

pitched, and yawed, simulating the aircraft motion. More elaborate were the moving-base simulators. These had large hydraulic or pneumatic cylinders that simulated the motions of the aircraft cockpit. McDonnell constructed a large, moving-base 

simulator consisting of an aircraft cockpit mounted on a long 

arm that produced a large pitching motion. It was used to investigate the PIO susceptibility of an aircraft and control system. 

Pilots flying that simulator said it was like riding a bucking 

bronco and closely simulated the real thing. 

PIO is a divergent oscillation that becomes evident when the aircraft response frequency approaches the human pilot response 

characteristics. This makes the pilot’s control inputs susceptible to 

becoming out of phase with the aircraft response, creating a divergent oscillation. When PIO is encountered during a high-dynamicpressure flight (high speed at low altitude), PIO can result in a 

catastrophic situation within a few seconds. I saw a motion picture 

sequence filmed in May 1961 of an early F4H Navy aircraft making 

a high-speed, low-altitude pass during Operation Sageburner to 
PILOTS AND AIRPLANES

188

break the 3 km low-altitude speed record. The flight appears normal until suddenly the two engines are seen tearing through the 

bottom of the aircraft as it breaks up in a few seconds due to PIO. 

I was told that instrumentation recorded 20 g’s as the two engines 

tore loose.3 A pilot has two options, one of which must be implemented immediately upon recognizing PIO onset—either freezing 

or releasing the stick to open the control loop. Neither option appeals to a pilot skimming low over the ground at high speed. 

Historical Note 

Investigation of the Operation Sageburner accident pointed to the failure of the 

pitch damper mechanism. Consequently, an accelerated effort was begun to reduce the PIO tendency of the F4H/F-4. Both aerodynamic and control system 

changes were investigated. The change implemented was a control system lag 

linkage redesign that reduced control sensitivity. McDonnell also constructed the 

moving-base simulator mentioned earlier and used it to test and refine the designs of fighter aircraft control systems. During the investigation, a PIO pilot rating scale was formulated that allowed pilots to quantify PIO susceptibility. This 

scale is presented in figure 20. Of interest, a few months later, 28 August 1961, 

Lt Huntington Hardisty, pilot, and Lt Earl De Esch, radar intercept officer, broke 

the low-altitude speed record in a modified F4H with a blistering speed of 784.48 

knots (902.76 mph) at the White Sands Missile Range in New Mexico.

That was the realm I stepped into upon returning to aerodynamics. Chet Miller welcomed me back and outlined my job as 

head of a group of five people performing research on flying qualities. We were investigating many new and innovative aircraft with 

extra control surfaces or vectoring propulsion to allow unusual 

flight maneuvers, which would enhance combat capability. Sideways translation, wing-level turns, up-and-down translation, roll 

along a skewed axis, and fuselage pointing were some of the flight 

modes being considered. Aircraft configured to perform these unorthodox maneuvers were referred to as control-configured vehicles (CCV). At the moment, the effort was being supported by the 

company under the auspices of independent research and development (IRAD). Several flying qualities proposals were expected 

from the AFFDL at Wright Field, and Chet wanted us to win them. 

IRAD was conducted on engineering and scientific research 

subjects endorsed by the US government. A yearly briefing on 

research was presented to the appropriate agency, and if it saw 

tangible evidence that the findings might benefit future pro-
189

PILOTS AND AIRPLANES

grams, the government would pay a percentage of the cost incurred. The AFFDL personnel acted as referee for all Air Force 

flying qualities research. Other companies were researching 

and developing techniques on the same problems, so there was 

a lot of competition to come up with the best approach. 

IRAD was a good deal for all concerned. Aircraft companies 

were able to pursue promising advances in the state of the art, 

build up a good working knowledge, and have a portion of their 

research paid for by the government. The government benefited 

from several companies doing independent research because 

when it issued a proposal, it could compare responses and select the best approach. It was quite gratifying to receive a new 

proposal using your approach to the problem, which signified 

that the AFFDL people agreed it was a good way to go. 

We responded to a proposal to quantify the flying qualities of 

CCV aircraft. The flying qualities group had been studying this 

problem for some time and formulated an approach that depended on developing a mathematical model of a human pilot. 

Such a model would allow the entire aircraft and pilot configuFigure 20. PIO tendency rating scale

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PILOTS AND AIRPLANES

190

ration to be modeled on a computer and quickly get a first-cut 

quantitative analysis of many configurations. Presumably, those 

showing a favorable mathematical pilot rating would be good 

candidates for further study. Thus, the large matrix of possible 

aircraft and control configurations could be whittled down to a 

more manageable size, eliminating many hours of expensive 

simulation exercises tying up test pilots. It seemed like an impossible task, but we thought it could work. The uniqueness of 

our approach won, and we were issued a one-year contract to 

test the idea. The mathematical pilot was given the name McPilot, 

in deference to McDonnell as its birthplace.4

People who are interested in seeing what a mathematical pilot 

looks like are disappointed, because the McPilot equation looks 

so deceptively simple. I suspect they do not understand it as a 

transfer function form using the complex frequency Laplace 

transform S terms.5 For those who have the interest and mathematical inclination, appendix B shows the McPilot equation 

along with a discussion on how it is used to relate to a flying 

qualities pilot rating. The primary conclusion reached in our 

study was that the McPilot approach showed some promise but 

required a great deal more analysis to make it practical.

An analytical approach proposed by Systems Technology Inc., 

called an equivalent system approach, appeared to offer a great 

potential for utilizing the large storehouse of classical system flying qualities in the MIL-F-8785 specification. Systems Technology 

suggested that the gain and phase angle of a high-order-system 

frequency response of a stability parameter (such as load factor 

per unit of elevator deflection) be replaced with a best fit of a classical system response.6 This allowed the large accumulated knowledge of flying qualities to be applied to the complex system, albeit 

with some loss of authenticity since the classical system, which is 

a second-order system, would not perfectly fit a higher-order system. The key to this system is to define a cost function that expresses the goodness of the fit simultaneously for both the gain 

and phase angle over the critical pilot operating frequency range. 

The frequency range used was from 0.01 to 10 radians per second 

(0.0016 to 1.6 cycles per second).

John Hodgkinson, a flying qualities teammate, was a strong 

proponent of that equivalent systems approach and developed 

a computer program to perform a best-fit matching of the fre-
191

PILOTS AND AIRPLANES

quency response characteristics. Computer technology was improving rapidly; remote access to the mainframe computer was 

now possible through a portable teletype and printer system 

and a telephone receptacle. A trip to Wright Field was arranged 

to demonstrate our equivalent systems technique to the AFFDL 

personnel, and John brought along the portable teletype machine. It was the size and weight of a 28-inch suitcase and just 

barely portable. We gave a demonstration, keeping our fingers 

crossed that the noise of the telephone connection going through 

several long-distance switchboards did not affect our communication with the McDonnell computer. The demonstration was 

a great success and impressed the AFFDL personnel. We left 

them a copy of our computer program so they could program 

their own computer to perform the curve fitting. Over the next 

several months, John was in almost daily telephone contact 

with AFFDL personnel discussing the technique. 

The simplicity of the equivalent systems technique made it 

an attractive tool to cope with the unconventional aircraft 

flight controls and fly-by-wire computer control systems. It 

provided the system designers a ballpark area for which to 

aim. Hodgkinson and several others worked studiously to refine and perfect the technique, and in 1976 they introduced it 

to the general aviation community.7 Equivalent systems were 

used extensively, especially at McDonnell-Douglas, with fair 

but less-than-perfect success. 

Historical Note 

John Hodgkinson became a renowned expert in handling qualities research. Recently, he published a handling qualities textbook for the AIAA.8

As we investigated and experimented with various methods to 

predict flying qualities, and incidentally won several small contracts, it became apparent that no one method would ever suffice. 

Flying qualities are a fickle problem that contains a human element, and humans are notoriously diverse. Our best suggestion 

was to use several credible criteria so there would be a good chance 

that the aircraft would have acceptable flying qualities. Fortunately, 

simulators became very affordable and versatile, so they became 

the primary tool to derive acceptable flying qualities.
PILOTS AND AIRPLANES

192

The 1970s saw a surge in analyzing and testing the effectiveness, capabilities, and flying qualities of CCV-type aircraft to 

perform military missions. The AFFDL issued a proposal for a 

simulator study using the CCV direct-side-force capability 

(DSFC) to perform a dive-bombing task with nonguided bombs. 

The gains in bombing accuracy, pilot acceptability, and control 

characteristics were part of the study objectives. This was a 

substantial contract, and our proposal won.

In addition to me, another aerodynamicist, a control system 

engineer, a simulator programmer, a bombsight specialist, and 

several McDonnell and Air Force test pilots to fly the simulator 

were committed to the program. A vertical canard control surface must be mounted forward of the aircraft c.g. to generate 

an appreciable aerodynamic side force. Deflecting that forward 

canard in conjunction with the rudder generates the side force 

and resulting sideways motion. To implement our simulation 

study, we used the characteristics of the proposed McDonnell 

advanced fighter technology integration (AFTI) aircraft configuration, which has a chin-mounted aerodynamic canard as 

shown in figure 21.9 This conceptual aircraft incorporated the 

latest innovative aerodynamic and control system CCV techniques and was designed strictly as a CCV demonstrator aircraft to explore these unusual flight modes. Therefore, with the 

AFTI engineering manager’s permission, we borrowed the aircraft characteristics for our study. 

Historical Note 

Although several aircraft companies submitted AFTI proposals, the Air Force contracted to modify an F-15B and YF-16 as CCV demonstrators. The F-15B acquired a horizontal canard surface and multi-axis thrust-vectoring engine exhaust nozzles. It was designated the F-15 ACTIVE (advanced controls technology 

for integrated vehicles).10 The YF-16 had twin chin vertical-control canards 

mounted underneath the air duct and modified trailing-edge flaps that were used 

as flaperons (a combined flap/aileron). The aircraft was designated the F-16 

CCV.11 Both aircraft tested the CCV concepts extensively for several years, proving the utility of these flight modes. Conventional aircraft drivers may shake their 

heads in disbelief, but be assured, these flight modes do work. Whether they provide enough of an advantage over a conventional aircraft to warrant the complexity and cost is an ongoing debate. It should be noted that some of the CCV research techniques have been incorporated in the F-22 Raptor aircraft just entering 

operational use, including thrust-vectoring engine nozzles.
193

PILOTS AND AIRPLANES

The direct-side-force capability allowed the pilot to execute a 

turn more rapidly, make very precise heading changes with the 

wings level, and trim out crosswinds without rolling or changing 

the aircraft heading. For example, consider the steps a conventional aircraft requires to correct the heading. The pilot must roll 

into a bank angle, perform a coordinated turn, and roll back 

level—three steps. A DSFC-configured aircraft making a wingslevel turn (WLT) requires only one step. Likewise, before a pilot 

in a conventional aircraft can achieve a turn rate, the aircraft 

must roll into a bank angle. A DSFC aircraft starts turning as 

the roll is initiated and thus turns further in a given time than a 

conventional aircraft. A longitudinal CCV aircraft starts pulling 

a g-load before a conventional aircraft even starts to rotate. 

The WLT is just what it says—making a turn while holding 

the wings level. This is actually making a coordinated turn at 

one g, not just skidding the aircraft around. It is coordinated 

N

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Figure 21. AFTI configuration
PILOTS AND AIRPLANES

194

because the fuselage is aligned with the velocity vector (zero 

sideslip), but of course the pilot experiences a one-g side acceleration. It is also possible to trim the aircraft so that the 

fuselage is pointed in a specific direction while actually flying 

in a slightly different direction and also providing a lateral 

translation capability to the aircraft. Figure 22 illustrates these 

DSFC flight modes.

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Our simulation matrix contained 2,500 runs testing three DSFC 

modes; a WLT using the rudder pedals and two lateral translation modes, proportional and integral. A lateral translationproportional (LTP) control meant that the harder the pilot pushed 

the rudder control, the more lateral translation he would 
195

PILOTS AND AIRPLANES

achieve. A lateral translation-integral (LTI) control meant that 

the lateral translation keeps increasing as long as the rudder 

control is depressed. When the control is released, the aircraft 

stays in that attitude until an opposite control brings it back. 

The pilot was provided with an advanced heads-up display 

(HUD), which is projected on a see-through glass screen in the 

pilot’s forward view. It displayed the normal flight and specific 

DSFC parameters. Three different bombsights were tested: a fixed, 

depressed reticle bombsight (the most common one in use at 

the time), a modified fixed bombsight that was roll-stabilized, 

and a future impact point (FIP) computing bombsight. 

A fixed bombsight has the line-of-sight axis depressed from 

the flight axis because, when the bomb is released, it will curve 

down due to gravity. When a conventional aircraft does a coordinated roll, the bombsight reticle swings like a pendulum as 

the roll is initiated. This occurs because the reticle line-of-sight 

axis is not coincident with the roll axis and makes it impossible 

for the pilot to keep the reticle on the target during a roll. It is 

called the pendulum effect. At the time, this was the standard 

operational bombing system and provided the baseline for comparison with other sights as well as several CCV flight modes 

that eliminated the pendulum effect. 

Figure 23 shows the HUD display implemented for the FIP 

computerized bombing system. As the pilot selects different 

weapons or combat engagement scenarios, the HUD changes 

to accommodate the different parameters. Some parts of the 

HUD are universal and are almost always displayed. They are 

the airspeed in knots, heading in degrees, and altitude in feet 

(the left, upper, and right scales). In this example they show an 

airspeed of 500 knots, a heading of 070 degrees, and an altitude of 5,000 feet. It should be noted that the cursors are stationary and the scales move. 

The pitch ladder is also universal and, in the example, indicates the aircraft has a bank angle near zero and is in a 30-degree 

dive. The bombsight reticle (formerly called a pipper, from “predicted impact point”), is the aiming device for bombing. The 

range to the target, obtained from the radar, is displayed by a 

peripheral scale around the reticle circle. Out of the center of 

the reticle is the display of the velocity vector. The small circle 

at the end is the location of the aircraft velocity vector and 
PILOTS AND AIRPLANES

196

shows the aircraft is in a 30-degree dive. The diamond represents 

the ground target which, in the simulation, is superimposed 

over the closed-circuit-TV terrain map. This provides a realistic 

background view for pilot orientation.

The numerical values of dive angle, Mach number, and load 

factor are shown underneath the airspeed scale. It shows the 

aircraft is in a 1.5-g pull-up to keep the aiming reticle on the 

target. The estimated time to bomb release and the control mode 

are underneath the altitude scale. Note that this HUD display is 

shown for a FIP bombing mode using the WLT control mode.

The large cross is the displayed impact point (DIP), where the 

bomb would impact if it were released at that moment. Figure 

24 shows the relationships between the DIP cross line of sight, 

the reticle line of sight, and the aircraft trajectory. The pilot 

just has to keep the target centered inside the reticle, and as 

the DIP cross becomes coincident with the reticle, the bomb is 

automatically released.

 

 

 

  













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197

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One may wonder how the pilot can keep track of all the information displayed and also fly the aircraft. It requires a lot of 

training and complete familiarity with the display. The key is to 

never focus on a specific parameter, but to constantly scan the 

entire display. We had military pilots who flew the simulation 

perfectly after only a few minutes’ explanation of this new system. I tried it and flew all over the sky. I just did not have the 

touch anymore.

The McDonnell simulator complex consisted of several fixedbase, manned, air combat simulators. They were interconnected 

so that several pilots could fly against each other or against the 

computer. These simulators were in constant use, so the assigned time was all that was available. It was interesting that 

when we had McDonnell test pilots doing our simulation, we 

were scheduled from midnight to 0400; however, when we had 

active-duty Air Force pilots, primarily Eglin Field test pilots or 

555th (Triple Nickel) Fighter Squadron pilots, we were scheduled during the normal workday. 

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PILOTS AND AIRPLANES

198

and an altitude and range from the target so that a 90-degree, 

4-g turn to line up with the target was required. The target was 

displayed on the simulator dome ground scene, and the pilot 

rolled into a turn toward the target and let the nose drop to the 

required dive angle. A nominal tracking time of 12 seconds was 

available to acquire the target, track it, and drop the bomb. 

Tracking time was varied to determine if this parameter had 

any effect on the pilot’s opinion of the flying qualities or on the 

bombing accuracies. This relatively long tracking time was selected as a compromise between combat maneuver realism and 

providing sufficient time to feel out the aircraft flying qualities. 

(In combat, pilots strive to keep the time in the bomb run to 

only a few seconds, as they are very vulnerable during that 

time period.)

The results indicated that the DSFC wings-level turn mode 

was liked by the pilots and greatly improved their bombing accuracy over that of a conventional roll-to-turn aircraft. The reduced workload from just having to use a small amount of rudder to correct aiming errors over having to bank, turn, and 

relevel for a conventional aircraft was a major factor in their 

liking the DSFC wings-level turn. Some of the unconventional 

DSFC control modes to eliminate the pendulum effect were 

confusing for the pilots, making them uncomfortable flying the 

simulation. A complete program description and analysis of the 

simulation results are found in the references indicated.12

Being back in the vanguard of aeronautical research and 

contributing a small part toward keeping our Air Force supplied with the best aircraft in the world was most interesting 

and enjoyable. However, an intriguing flying machine concept 

that had fascinated me for years now comes to life. The next 

chapter turns back the clock to introduce the cyclogiro concept 

and the quest for understanding this fascinating system.

Notes

1. George E. Cooper and Robert P. Harper, The Use of Pilot Rating in the 

Evaluation of Aircraft Handling Qualities, NASA-TN-D-5151, April 1969. 

2. The final version was MIL-F-8785C (ASG), Flying Qualities of Piloted 

Airplanes (5 November 1980). It was then superseded by MIL Standard 1797, 
199

PILOTS AND AIRPLANES

which is still in use. This MIL Standard essentially says that the contractor 

and the government should agree on a set of flying qualities requirements. 

3. Joe Dobronski, A Sky Full of Challenges, The Autobiography of a McDonnell 

Douglas Test Pilot, 3rd ed. (Ballwin, MO: Aiglon Publishing, 1999), 86. 

4. R. V. Brulle and D. C. Anderson, Design Methods for Specifying Handling Qualities for Control Configured Vehicles, AFFDL-TR-73-142, Air Force 

Flight Dynamics Laboratory, Air Force Systems Command, Wright-Patterson 

AFB, Ohio, November 1973. 

5. Laplace transform provides an easy and versatile method of solving a timedomain differential equation. It is accomplished by transforming the timedomain equation into an S or frequency-domain equation. The solution is then 

obtained by solving the resulting algebraic equation and performing an inverse 

Laplace transformation to get back into the time-domain. Actually the last step 

is usually eliminated because one starts to think in the frequency-domain.

6. Stapleford, McRuer, and Hoh, Outsmarting MIL-F-8785B(ASG), The Military 

Flying Qualities Specification, System Technology Inc., TR-190-1, August 1971. 

7. John Hodgkinson, W. J. LaManna, and J. L. Heyde, “Handling Qualities 

of Aircraft with Stability and Control Augmentation Systems—A Fundamental 

Approach,” Journal of the Royal Aeronautical Society, February 1976. 

8. John Hodgkinson, Aircraft Handling Qualities (Aeronautical Institute of 

Aeronautics and Astronautics Education Series), 1999.

9. Don M. Scheller, Advanced Fighter Technology Integration (AFTI), AFFDLRT-75-86, pt. 4, vol. 5, September 1975. Thrust vectoring is also a CCV type 

of control and can accomplish the same types of tasks in addition to providing a vertical or short takeoff and landing capability. 

10. See http://www.dfrc.nasa.gov/gallery/photo/f-15active/html/ec

96-43780-1.html for a write-up and picture of the F-15 ACTIVE. Searching 

the Web for F-15 ACTIVE brings up a large number of sites. 

11. See http://home.att.net/~jbaugher4/f16_31.html and http://www

.crosswinds.net/~rayni/versions/f16_ccv.html for a write-up and picture of 

the F-16 CCV. 

12. Robert V. Brulle, William A. Moran, Richard G. Marsh, Direct Side 

Force Control Criteria for Dive Bombing, AFFDL-TR-76-78 (Wright-Patterson 

AFB, OH: Air Force Flight Dynamics Laboratory, Air Force Systems Command, 

September 1976); and Robert V. Brulle, Dive Bombing Simulation Results using 

Direct Side Force Control Modes, AIAA Paper 77-1118, presented at the AIAA Atmospheric Flight Mechanics Conference, Hollywood, Florida, 8–10 August 

1977. 

201

Chapter 11

Cyclogiro Aircraft

An old concept of a cyclogiro flying machine was introduced in 

Professor Graetzer’s helicopter engineering class at AFIT in 1952 

and has intrigued me ever since. This concept has been studied 

for years by many independent investigators, starting in 1828 

with an “Aerial Carriage” proposal by Sir William Congreve, the 

same Congreve whose rockets bursting in air inspired Francis 

Scott Key to compose our national anthem. Throughout the 

years various investigators proposed and built this type of flying 

machine with little success, primarily because there was no solution to the complex aerodynamic flow through the rotor. Hence, 

no satisfactory blade modulation motion could be devised.

In an aircraft application, the cyclogiro has two articulating, multi-bladed rotors, one on each side of the aircraft. As 

the rotor turns, the blades modulate (pitch or rock on their 

own axes with respect to the rotor) providing an aerodynamic 

force that can be oriented to provide a vertical takeoff and 

landing (VTOL) and/or a fore-and-aft capability. It also has 

the ability to achieve a high speed and an independent fuselage pitch attitude control. A major advantage of the cyclogiro 

over a conventional helicopter is that it can fly faster than the 

velocity of the rearward-moving rotor blade. In conventional 

helicopters, the rearward-moving blade loses lift because of 

reduced blade velocity. Cyclic pitch of the helicopter rotor 

blades (an angle-of-attack variation between the forward- and 

rearward-moving blades), increases the angle of attack on the 

rearward-traveling blade; however, as the helicopter’s forward 

velocity increases further, the rearward-moving blade eventually stalls, creating an unbalanced rotor lift and loss of stability. 

The cyclogiro can vary its blade pitch mode to allow the aircraft to go faster than the rearward-moving blade. A cyclogiro 

flight speed performance from hover to over 300 knots (345 

mph) is deemed possible. 

A cyclogiro has this capability because it uses two cycloidal 

modulating modes of motion—one when the blade rotational 
CYCLOGIRO AIRCRAFT

202

velocity is greater than the forward velocity and the other where 

the blade rotational velocity is less than the forward velocity. 

The idealistic (zero angle of attack) modulations are illustrated 

in figure 25, extracted from the US Army Material Laboratories 

Technical Report 69-13.1 Also shown is the basic cycloid motion, where the blade rotational velocity is equal to the forward 

velocity. In all cases, the rotor is rotating clockwise and moving 

toward the right. The blades arranged in a circle represent the 

blade orientation as it would look to an observer traveling with 

the rotor, while the cycloidal arrangement shows how the blades 

would look to a stationary observer seeing the rotor moving by. 

The blade rock-angle shown represents the momentary orientation at that point, as the blades are in a continual rocking 

motion throughout a blade orbit cycle.

The upper picture shows the curtate cycloid or low-pitch system blade modulation where the blade rotational velocity is 

greater than the forward motion. Since the rotational motion is 

greater than the forward velocity, the blades generally point 

tangentially along the orbit. This low-pitch system is used in an 

aircraft application from hover to where the retreating blade is 

near the forward flight speed. It is also used in the Giromill 

wind energy windmill and the Aquagiro water turbine concepts 

discussed later.

Pi-pitch modulation occurs when the rotational velocity is 

equal to the forward velocity. Note that the pi-pitch blades are 

symmetrical because they turn through 180 degrees during 

one cycle, so each blade edge will alternate being the leading 

edge. The blades modulate so the blade chord line always points 

toward a specific location or control point; in the case shown, 

this point is at the rotor top. Rotor force vector control is 

achieved by moving the control point. The pi-pitch system can 

be used for the same applications as the low-pitch system but 

is less efficient. The cycloidal propulsion pump, discussed below, uses this pi-pitch system. 

High-pitch blade modulation is used where the rotational velocity is less than the forward velocity. In this case the total 

velocity vector is generally oriented in a forward direction so 

the blades are always pointing in a forward direction throughout the blade orbit. Thus, the rotor can be flown faster than its 

rotational speed, and the blades contribute to the lift and sta-
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CYCLOGIRO AIRCRAFT

204

bility of the aircraft throughout the entire orbit. For an aircraft 

to achieve its full potential, the rotor must have combined lowand high-pitch blade modulation capabilities.

In actual practice, the blade modulations are more complicated than the idealistic ones just described because the blades 

must have an angle of attack added to the modulations to generate a force. Each blade must account for the flow field vortices 

from the other blades so that they can be oriented to the correct 

angle. For hover and low-speed flight, the blades experience an 

alternating positive and negative angle of attack during a rotor 

rotation, with the flipping occurring at diametrically opposed locations of the blade orbit. All these effects must be accounted for 

in a theoretical calculation of the cyclogiro rotor performance.

My first application of cycloidal motion was for a fluid pump. 

While a professor at AFIT in 1956, I received a small research 

grant to design, build, and test a cycloidal propulsion pump. My 

estimated analysis of the performance, using the existing blade 

element and momentum theory of a cyclogiro, showed that it 

could perform as a low-pressure, high-volume pump that might 

have an application as a tanker aircraft refueling pump. 

A model of the pump (fig. 26) was built and tested in the AFIT 

hydrodynamic flow laboratory using mineral oil as the working 

fluid. The pump performance was very disappointing, so it was 

apparent that the existing blade element and momentum cyclogiro theory was inadequate. Even with the poor performance, 

the Air Force showed enough interest that they patented it.2

The next application, years later, was a preliminary design of 

a cyclogiro aircraft shown in figure 27. This preliminary design 

was proposed as a proof-of-concept test to determine the practicality and operation of a cyclogiro aircraft; however, there still 

was no satisfactory cyclogiro performance theory available. 

AFIT professor Hal Larsen also became fascinated with the cyclogiro concept, so we decided to develop an accurate flow analysis and performance method. Perusing the literature, we were 

surprised at how many researchers and organizations had 

looked into the concept. Fortunately for us, the US Army Aviation Materiel Laboratories at Fort Eustis, Virginia, had recently 

published TR 69-13, which contained an excellent history of 

cyclogiro systems.
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During the 1920s and ’30s, University of Washington professor Frederick Kurt Kirsten laid the foundation for a theoretical 

analysis of the concept. He also performed several wind tunnel 

tests and designed a mechanism to perform the blade-rocking 

motion. TR 69-13 lists 17 Kirsten references.3 Kirsten’s analyses and test results were instrumental in persuading NACA 

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and the Army Air Corps to perform additional tests. In 1935, 

NACA Langley Field performed a wind tunnel test on a model 

cyclogiro rotor. During WWII, engineers at Wright Field did a 

preliminary design of a cyclogiro fighter.4

While perusing these references, Hal got the idea of representing the rotor and blades with a vortex system and then using the 

computer to integrate the induced velocity effects of the vortex 

system to obtain the flow through the rotor. Recall that every 

aerodynamically generated force produces a vortex having a 

strength that is proportional to the aerodynamic force produced. 

Thus, the lift force of a wing can be represented by a vortex system, the lift generated being proportional to the strength of the 

vortex. That is why large, heavy aircraft like the C-17 or Boeing 

747 generate very strong and dangerous vortices that can flip a 

lighter aircraft around and possibly even disable it. 

Historical Note

The danger of the wingtip vortex from a large, heavy aircraft was vividly demonstrated by an accident involving the XB-70 experimental Mach-3 bomber on 8 

June 1966. This aircraft weighed in the 500,000-pound class and thus generated 

a very strong vortex. During a photographic flight of four fighter aircraft in formation with the bomber, an F-104 moved too close to the XB-70, and its wingtip 

vortex flipped the F-104 onto the top of the bomber. The impact destroyed the F104 and tore off the twin vertical tails of the XB-70. Both aircraft crashed, but 

one bomber pilot was able to eject safely.5

A simple wing vortex, as shown in appendix A, can easily be 

visualized, but the vortex system of the rotating multiple wings 

(blades) of a cyclogiro is a complicated maze of vortices that 

swirl through the rotor and then trail back in the slipstream. 

The problem we faced was defining this cyclogiro vortex system. 

Since the discussion of the cyclogiro aerodynamics in terms 

of a vortex system is quite complicated, it is presented in appendix C. It is an interesting account of how we arrived at the 

theoretical cyclogiro vortex pattern and thus retains the details 

for posterity. It took us several years, working part-time on our 

own, to work up the idea and write the program. It should be 

noted that Hal did most of the work.

As soon as we felt confident the answers were right, we 

quickly computed the cyclogiro performance, assuming a per-
CYCLOGIRO AIRCRAFT

208

fect control system, and were amazed at how well the cyclogiro 

performed. We now had to design a method of control and also 

some way of driving the blades to achieve maximum efficiency. 

The computer runs showed that the blade modulation was so 

complex that no mechanical system could reproduce it. (The 

next chapter shows the blade modulation scheme for a cyclogiro windmill, which is relatively simple compared to what is 

needed for an aircraft.) The idea of using computer-driven individual actuators to meet the blade modulation requirements 

naturally followed. Additional program development and preliminary design of a cyclogiro aircraft control system provided 

sufficient data to prepare a set of viewgraphs to approach possible contacts for development help.

The viewgraph presentation was titled “Resurrection of an Old 

Concept Made Feasible by Modern Technology.” It pointed out 

that composite blade materials, electronic control systems, and 

robust electrical actuators to drive the blade modulations were 

all now available to make the cyclogiro a viable system. We made 

many presentations to McDonnell and other organizations, but 

the closest we came to getting any help was from the AF Flight 

Dynamics Laboratory at Wright Field. Col Chuck Scolatti, a former AFIT student who gave me a hard time in my first teaching 

class, was now head of the AFFDL, so Hal and I briefed him and 

Demetries Zonars, his civilian counterpart. They both listened 

attentively and asked several questions, but a few weeks later we 

were notified that the AFFDL was not interested. 

Several years later I met Chuck Scolatti and asked him why he 

did not approve a small contract to at least look at the feasibility 

of the cyclogiro aircraft. He said, “Because you didn’t ask for a 

small contract effort but wanted us to do the whole thing.” He 

then explained that the AFFDL responds to unsolicited proposals; 

it does not create them. In other words, Hal and I did not do our 

homework to find out the amount of discretionary funds he had 

available for small, unsolicited contracts. If we had approached 

him informally, he could have hinted at what he could afford, and 

we could have tailored our presentation to be within his cost constraints. Trying to do it all on our own, we missed that important 

fact and thus did not get a small exploratory analysis contract.

After several other negative contacts, I finally realized our 

sales pitch was pointless and, talking it over with Hal, decided 
209

CYCLOGIRO AIRCRAFT

to let it lay a while. He was not quite ready to just give up and 

said he was going to continue improving the cyclogiro program. 

He had some ideas to correct annoying deficiencies in obtaining a satisfactory solution convergence and to also make it 

easier to run. It was a good thing he did, because a few months 

later an opportunity arose that finally garnered a contract to 

study the cyclogiro concept.

Notes

1. Figure extracted from W. F. Foshag and G. D. Boehler, Review and Preliminary Evaluation of Lifting Horizontal-Axis Rotating-Wing Aeronautical Systems (HARWAS), USAAVLABS Technical Report 69-13, figure 88 (Fort Eustis, 

VA: US Army Aviation Materiel Laboratories, March 1969), 112. 

2. Capt Robert V. Brulle, USAF, Cycloidal Propulsion Pump, AFIT Technical 

Report 56-8, 1956; and Robert V. Brulle, Translational Propulsion Pump, US 

patent 2,896,545, July 1959.

3. Foshag and Boehler, HARWAS TR 69-13, 285–86.

4. John Wheatley and Ray Windler, Wind Tunnel Tests of a Cyclogiro Rotor, 

NACA Technical Note 528, May 1935; H. M. Heuver and R. E. Hage, Analytical 

Study of the Performance of a Cycloidal Propeller and Preliminary Survey of a 

Fighter-Type Design, Memorandum Report No. ENG-51/P706-84 (Wright 

Field, OH: AAF Materiel Center Command, Engineering Division, 1943); and 

H. M. Heuver, Cycloidal Rotor for Aircraft, US patent 2,580,428, 1 January 

1952. A good write-up on that accident can be found at http://www.xb-70

.com/wmaa/xb70/. 

5. I had a harrowing experience with aircraft vortices when on a vacation 

with the family flying a small twin-engine Piper Apache to visit Expo 67, the 

Montreal World Fair. It was an uneventful flight until we landed in Rochester, 

New York, to visit some friends and stay for the night. I was cleared for landing right after a four-engine Lockheed Electra turboprop transport aircraft 

had taken off. While leveling off for landing, we ran into the wingtip vortex of 

the Electra that caused the wing to dip alarmingly. I slammed on full power 

to recover and then landed further down the runway. Marge almost left me to 

take the kids back home on the train.
The Brulle family on their flying vacation to the Montreal World Fair, 1967
211

Chapter 12

Giromill Wind Power

A notice in the Commerce Business Daily reported that the 

National Science Foundation (NSF) was looking for innovative 

windmill designs and soliciting study proposals from companies 

and individuals.1 After verifying with Hal Larsen that our cyclogiro program would work for a rotor mounted on a vertical axis 

and used as a windmill, I approached McDonnell management 

to see if they would entertain submitting a proposal for a cyclogiro windmill I called the Giromill (from cyclogiro windmill). 

Historical Note 

The sudden interest in wind energy was sparked by the Arab oil embargo imposed 

on the United States for helping Israel during the Yom Kippur war in October 

1973. It caused an oil and gasoline shortage that resulted in hours of waiting in 

gas lines to fill up and a surge of research to find alternate energy sources.

After a lot of persuading and a separate marketing analysis 

to convince McDonnell management, I got the budget to write a 

proposal. A convincing argument was the public relations ploy 

of portraying McDonnell, a part of the military-industrial complex, as an innovator in the wind energy field. Hal consulted for 

a week to help get the cyclogiro performance program running 

on McDonnell computers. He was a guest in our home, and it 

was great to relax in the evenings and reminisce about our association since 1951. 

Momentum theory predicts the maximum efficiency of a windmill as 59.3 percent, or it achieves a power coefficient of 0.593. 

This is sometimes referred to as the Betz limit, named for the 

engineer who derived the result.2 (Efficiency expressed as a 

percentage is identical with power coefficient expressed as a 

decimal; both terms are used throughout the text.) This implies 

it is possible to only extract 59.3 percent of the available wind 

power within a stream tube through the windmill’s frontal area. 

This can be visualized by noting that to achieve 100 percent 

efficiency requires stopping the wind flow, which is a ridiculous 
GIROMILL WIND POWER

212

situation since a flow through the windmill must exist. (There 

are, however, ways to extract a greater amount of power with 

the use of a diffuser, sometimes called an augmenter, as described in the next chapter.) According to our computer runs, 

the Giromill achieved nearly 60 percent efficiency considering 

only the blades; that is, ignoring the drag of the blade support 

arms and other parasite drag. Achieving that value was gratifying and showed that the cyclogiro vortex theory program, as we 

now call it, was accurately portraying the real-world situation. 

Continuing our analyses, other revelations quickly followed. 

We found that increasing the number of blades or making them 

larger caused the rotor to turn slower. Contrary to popular belief, increasing the number of blades does not mean more power. 

A greater number of blades provides a greater torque, but the 

power output (which is torque times rpm) is less because blade 

interference reduces the efficiency. A speed-increaser gearbox 

is necessary to increase the relatively slow rotor rotation to a 

synchronous 1,800 rpm to run a generator. Since the speedincreaser gearbox is an expensive item, it appeared that a rapid 

rotor rotation was wanted. However, rapid rotation increases 

the centrifugal force the blades have to withstand, complicating their construction. Analyses of this sort led to the realization that many tradeoffs had to be considered in the study. 

Four months after we submitted our proposal, Lou Divone, 

wind energy director for the NSF, notified us that McDonnell was 

to receive a feasibility study contract. As the Giromill principal 

investigator, I was asked to deliver a paper on our study proposal 

at the next wind energy workshop to be held at the Mayflower 

Hotel in Washington, DC, in June 1975. I invited Hal Larsen to 

present the portion on development of the cyclogiro vortex theory 

computer program. Just after McDonnell was awarded the grant, 

the NSF was relieved from administrating the study, and responsibility was turned over to the just-formed Energy Research and 

Development Administration (ERDA). Lou Divone transferred to 

ERDA and was named director of the Wind Energy Division.

Over 500 people attended the three-day conference; I did not 

realize that wind energy had generated such a large group of 

adherents. The conference covered all aspects of wind energy, 

including wind speed surveys, wind speed yearly duration surveys, bird kill probabilities, topographical features that en-
213

GIROMILL WIND POWER

hance wind speeds, and many others. Presentations were made 

by representatives from operating windmill systems in the 

United States, Sweden, Germany, and Denmark. Other presentations featured innovative systems that contained several 

types of wind speed augmenters, a tornado-type wind energy 

system, an electro-fluid-dynamic wind generator, and others. 

Truthfully, I was overwhelmed.3

Our presentation was well received; many participants cornered us in side discussions requesting further details of the 

cyclogiro vortex system aerodynamics. Within a few years of 

our vortex theory publication, several wind energy researchers 

published analyses and developed programs using a similar 

approach.4 Hal Larsen resurrected the old aerodynamic vortex 

theory technique that revolutionized the vertical-axis windmill 

analysis by putting it on a solid analytical foundation. 

The study contract specified we analyze three systems having power outputs of 120, 500, and 1,500 kW in a 20-mph 

wind with a constant-speed rotor driving a synchronous generator. The rotor had to withstand a 60-mph wind gust while 

operating, which implied that shutdown should be about 40 mph, 

as wind gusts to 60 mph are quite common at that speed. 

(Shutdown means the windmill is stopped and the blades feathered to ride out the stormy conditions.) The non-operating storm 

survival requirement was a 120-mph wind, and structure components must have a design life of 50 years. 

McDonnell managers gave me a free rein in running the study 

program and were satisfied with a short briefing once a week. The 

ERDA required monthly progress reports but was satisfied with a 

short-and-broad treatment of the progress. A major milestone 

was a midterm report, which seemed to come up suddenly, but 

the 140-page report was assembled and published on time.5

Historical Note

An unimaginable event occurred in mid-July 1975. There was a space linkup 

between a Soviet-manned Soyuz and a US-manned Apollo spacecraft. This was 

the first joint US–USSR manned space mission and marked the first easing of 

tensions between the two superpowers. Both spacecraft were launched from their 

respective launch sites on 15 July and docked two days later in space. After two 

days of joined flight, they separated and both landed safely.6 
GIROMILL WIND POWER

214

In lieu of a final report I was scheduled to present our results 

in a comprehensive article at the vertical-axis wind turbine technology workshop being arranged at Sandia Laboratories in Albuquerque, New Mexico.7 Sandia would present its results on developing the Darrieus rotor, and I would present the Giromill. 

The referenced article is a comprehensive analysis of the Giromill and is recommended reading to those wanting to increase 

their technical knowledge of that device.8 An artist’s rendition of 

a 120-kW Giromill designed during our study is shown in figure 

28. It was the first Giromill design based on a detailed engineering analysis sufficient to perform a viable cost analysis. 

That completed the work on that contract, but we received a 

contract for a wind tunnel test program follow-on study. The 

model shop designed and built a three-bladed Giromill rotor 

having a diameter of seven feet, a blade span (height) of five 

feet, and a blade chord of 8.4 inches. The blades were modulated by a pushrod recessed within the lower blade support 

arm and connected to a bell crank that rotated about the blade 

pivot point. The blade rock angle modulation profile was obtained by a cam and cam follower connected to the pushrod. A 

numerically controlled milling machine cut the various cams 

from coordinates computed by the cyclogiro vortex theory program. Typical cam variations are shown in figure 29 for a wind 

velocity range of 12 to 60 mph. The inset defines the various 

terms. The test conditions were achieved by varying the tunnel 

wind speed and adjusting the rotor rpm with an electric motor/generator that could either drive the rotor or absorb rotor 

power in a light bank. A torque meter measured the rotor torque 

and, together with the rpm, provided the rotor power.

Before we presented the results of the wind tunnel test, a correction to the vortex theory that Hal and I had completely overlooked was pointed out by Prof. Robert E. Wilson from Oregon 

State University in Corvallis, Oregon. This correction is applicable to all vertical-axis windmills, but I cannot recall it being mentioned in any previous literature. The correction arises because 

the blade aerodynamic characteristics were defined assuming a 

quasi steady-state condition; while in reality, the blades are in a 

continuous rotational motion because of the rotor rotation. Also, 

the Giromill blades themselves have an oscillating rocking motion that must be added to the normal rotating motion. 
Figure 28. Artist’s rendition of 120-kW Giromill
GIROMILL WIND POWER

216

A rotating blade will generate additional forces and moments 

similar to those generated by a pitching aircraft. For an aircraft, 

these are referred to as the dynamic derivatives and create an 

increment of lift, drag, and pitching moment. This can be visualized by following a particle of air as it journeys around the airfoil. 

Under steady-state conditions, the airfoil shape determines the 

path the particle will take as it journeys from the leading edge to 

the trailing edge. If, however, the airfoil is pitching, the path of 

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edge at a different spatial point than a nonrotating blade. The 

change in the particle’s spatial location between the steady-state 

and rotating blade must be accompanied by a force. That force 

and moment were neglected in the vortex theory.

The Boeing Company

Giromill wind tunnel test results validated that the aerodynamic vortex theory, 

a horrendous program involving millions of integrations, was correct. At the 

time, it took 15 minutes for a main frame IBM 704/709 computer to compute one 

angle-of-attack performance curve.
GIROMILL WIND POWER

218

The mathematics is quite involved, but we derived a simplified dynamic correction to the rotor power coefficient that depended on the rotor and blade dimensions and the rotor rpm. 

The correction is significant when the rotor blades are large 

and the wind speed is low. With our wind tunnel model that 

had relatively large blades, the power coefficient correction for 

some conditions was as high as 12 percent. However, for a fullsize Giromill, the correction is negligible. 

Figure 30 shows that the vortex theory computed power coefficient is in close agreement with the test results. One may be 

concerned that the power coefficient is low, but this was for a 

small model where the Reynolds number is small. Scaling these 

results to the Reynolds number for a full-scale Giromill shows 

that the maximum power coefficient is 0.54.9

The ERDA formed a new wind energy division for building 

and testing of 40-kW medium units and 2–10-kW small utilitytype systems. This new wind energy division was managed for 

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the ERDA by Rockwell International–Energy Systems Group at 

a test site established at the Rocky Flats Atomic Energy plant 

in Golden, Colorado. Lou Divone strongly recommended we 

contact them and see about bidding for one of the two 40-kW 

units to be tested.

It was another hard sell to McDonnell management, but they 

gave approval to bid with the stipulation that we not get involved in the manufacture and sale of the Giromill. That meant 

we had to find a team member who would be responsible for 

the design of the structural steel fixed tower, provide a place 

and facility to erect and test the Giromill, and be able to manufacture and market the product. After contacting several interested companies, we selected Valley Industries, Inc., basically 

a steel fabrication company headquartered in St. Louis, Missouri. They had experience in structural steel tower design and 

also owned Aermotor, producers of the ubiquitous farm windmills that dotted the American prairies. Aermotor was still producing these old farm water-pumping windmills in a plant located in Conway, Arkansas.

Historical Note 

This is a good place to break and mention one of America’s great spaceflight 

achievements—the saga of a couple of Voyagers. Two Voyager deep-space probes 

were launched in August and September 1977. Both flew by and photographed 

the outer planets of Jupiter and Saturn. Then Voyager 1 was ejected upward from 

the ecliptic (the orbital plane of the planets around the sun) and out of the solar 

system. Voyager 2 continued on to photograph Uranus and Neptune and was 

then ejected downward from the ecliptic plane out of the solar system. The large 

velocities required to accomplish these trajectory maneuvers were obtained by 

using the outer planets to provide a gravity assist, or as popularly known, a 

“slingshot effect.” The slingshot effect transfers a small amount of the planets’ 

orbital velocity around the sun to the spacecraft. A NASA Web site has an excellent explanation of how that works.10 

Recently NASA announced that Voyager 1 had reached the heliopause boundary 

area, which is the outer limit of the sun’s magnetic field and outward flow of the 

solar wind, at 94 AU from the sun. (An AU, or astronomical unit, is the mean 

distance of the earth from the sun). Voyager 2 is 75 AU from the sun. For you Star 

Trek fans, Voyager 1 is 15 and Voyager 2 is 11 light hours from the earth at Warp 

one. Recall that in the future, one of these Voyagers will end up in an alien system 

and will be sent back with instructions to learn everything as V’ger, portrayed in 

Star Trek: The Motion Picture.

11 
GIROMILL WIND POWER

220

The two companies that won 40-kW wind power contacts 

were McDonnell to build a Giromill, and Grumman Aircraft 

Company to build a conventional three-bladed windmill. We 

were each notified of the award in August 1977; however, a 

protest was lodged by Piasecki Aircraft Corporation against the 

Grumman contract award. Piasecki contended that they had a 

better and lower-cost proposal, along with 40 years’ experience 

in design of rotors and should have won a contract. 

The Boeing Company

Valley Industries Giromill checkout. McDonnell teamed with Valley, a steel construction firm, to manufacture the steel tower and erect the Giromill. First turn 

and complete checkout was accomplished at their plant.

The litigation dragged on about a year, with the protest denied. Finally, a Giromill contract was negotiated with Rockwell 

for $1,536,451 plus a fixed fee. The contract specified we were 

to develop the Giromill technology to be cost competitive with 

other energy sources and demonstrate that it is technically 

practical. Two main phases were specified: Phase I—Design 

and Phase II—Manufacture and Test. Phase I covered nine 

months, and Phase II covered 15 months.
221

GIROMILL WIND POWER

John Anderson, a department head, was the Giromill program manager; project engineer Bert Birchfield supervised the 

design and structural strength analyses; and I became the 

project engineer for all the rest of the supporting technologies. 

Bill Duwe, a Valley engineer temporarily relocated at McDonnell, 

designed the fixed tower. 

Defining an optimized (low-cost) baseline design was the first 

task. This was accomplished through a series of trade studies 

of the major components to define their cost sensitivity with 

respect to the Giromill operating conditions. For example, the 

rpm increaser was sensitive to the rotor rpm. There was, however, a step cost increase between a two-stage and a threestage gear increaser. It was therefore beneficial to have a sufficient rotor rpm to allow a two-stage increaser to be used. This 

bounded the rotor rpm, which in turn defined the rotor solidity 

and the blade chord. Trade studies of this type were completed 

on all systems. The results then allowed definition of an optimum low-cost 40-kW Giromill configuration, which is shown in 

figure 31.12

Historical Note 

Just after starting the Giromill design, I left on a long-planned two-week vacation 

to Europe, flying on the supersonic British Aircraft Corporation–Aerospatiale 

Concorde from New York to London. Ever since I took my first aerodynamic class 

in 1946, I wanted to fly supersonically. I left the Air Force prior to checking out in 

F-86s, which could dive supersonically, and finally decided I had waited long 

enough. It was great; 3.5 hours after takeoff from New York, we landed in London. 

The flight was smooth all the way as we cruised at Mach 2.0, reaching a maximum velocity of 1,380 mph and an altitude of 57,000 feet. 

Historical Note 

Several of us took a break on 18 November 1978 to view the first flight of the F/A18, the most technologically advanced aircraft at the time. It sported a fully computerized digital fly-by-wire flight control system that kept the aircraft stable 

throughout the entire flight envelope. Twenty onboard computers made the aircraft a dream to fly and maintain. It was rewarding to watch a bit of aviation history unfold as test pilot Jack Krings took off for the first flight, accompanied by 

several Navy tanker aircraft (in case an emergency required it to remain airborne 

longer) and several chase planes. All went well.
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223

GIROMILL WIND POWER

Concurrent with the structural design, Tom Schmidt from the 

McDonnell-Douglas Electronics Company located in St. Charles, 

Missouri, designed and built the control system electronics, 

and Bob Udell from McDonnell-Douglas Electronics Company 

in Grand Rapids, Michigan, designed and built the actuators. 

As the control system came together, the McDonnell patent department took an interest in the unique control system and 

patented it.13 One item that threatened to delay the whole project was samarium cobalt for making the permanent-magnet 

blade actuator motors. The cobalt came from Uganda, which 

was in civil war turmoil at the time. Fortunately, enough was 

acquired to make the actuator motors.

In late February 1980 all components were ready, and the 

Giromill erection was in progress at the Valley steel plant at 

Tallulah, Louisiana. I personally installed the blade actuators 

and checked them and the control system for proper operation. 

Steelworkers with a large crane then assembled the unit. It was 

exciting to see the Giromill take shape after working so long 

promoting the cyclogiro concept.14

Finally everything was ready, and on 3 March 1980, I pushed 

the start button to achieve first turn. Everything worked as 

designed as the rotor turned slowly in response to the blade 

rock angle program. Little by little I let the rpm increase to its 

design value of 33.5 rpm. The next month was spent conducting a thorough checkout and correcting the processor programming glitches and other annoying problems that appeared.

In April we passed Rockwell’s inspection and received permission to disassemble and ship the unit to Rocky Flats. Clay 

Waldon was assigned as project engineer to monitor the Giromill for Rockwell at Rocky Flats. First turn at Rocky Flats occurred on 3 July. When we started running the Giromill on a 

regular basis is when all the problems started to appear. Most 

were easy-to-fix glitches in the design, but one annoying problem—and hardest to fix because the components were located 

75 feet high at the end of the lower support arm—was the blade 

actuators. My record book is full of notes on the actuators not 

working. Bob Udell, designer and builder of the actuators, spent 

a week at Rocky Flats to refurbish all five (three operational 

plus two spare) actuators. Tom Schmidt, designer and builder 

of the controller, helped Bob Udell, then they both checked out 
GIROMILL WIND POWER

224

the entire control system. In addition to the technical problems, we went for days without any wind, so collecting data 

was a slow process.

The Boeing Company

The Department of Energy erected the Giromill at Rocky Flats Wind Energy Test 

Area. It was proven a very efficient wind turbine, but because of its many parts, 

was not cost competitive with a conventional propeller-type turbine.

This run-and-fix testing continued through the summer and 

fall. On 24 December 1980, a call from Clay Waldron notified 

us that the lightning pole had broken off and damaged a blade 

and support arm. He had it roped together and had made arrangements to remove the rotor and put it on the stub assembly 

tower. A follow-up call from Rocky Flats after Christmas told us 

the rotor on the stub tower was blown over because the frictiontype cement bolts anchoring the stub assembly tower had pulled 

loose. Early in the program, when we saw how Rockwell had 

the stub tower anchored, we sent them a letter stating that the 

friction-type concrete anchor bolt mounting was not satisfac-
225

GIROMILL WIND POWER

tory and requested the stub tower be reinforced with guy wires. 

(A McDonnell structure maxim was “Never depend on friction.”) 

This was not done, and the rotor suffered the consequences. 

The structures strength engineer and I were at Rocky Flats on 

30 December to assess the damage. We took a lot of photographs of the damaged parts and, in consultation with our 

manufacturing personnel, decided it could be repaired, so the 

rotor was shipped back to McDonnell.

The repaired system was reassembled, without a lightning 

rod, and on 24 April 1981, we again started the Giromill, but it 

started to turn backwards because the rotor potentiometer was 

mounted 180 degrees out of phase. And so it went all year. 

Sometimes a good run was obtained only to find that the recording instrumentation was lost. Rocky Flats is not a good 

place to test a windmill because the wind is very intermittent. 

We periodically went days with insufficient wind and had a 

spell of one month without being able to run at all. Then, just 

as suddenly, a storm can blow in giving good winds for a day 

but can also spawn very high winds. The Giromill survived a 

storm that recorded sustained winds of 116 mph with gusts to 

160 mph. Several test windmills at Rocky Flats suffered major 

damage, some light poles were lost, and a solar collector array 

was blown away. 

Sometimes we achieved several days of good running. During 

those running periods the generator would put out 50–60 kW 

at times, but it primarily stayed near the design value of 35–40 

kW. However, the actuators kept giving us problems, drawing a 

greater current than anticipated, which limited the life of the 

power transistors. Those high current spikes were finally determined to be due to oscillating airfoil aerodynamics. An oscillating airfoil can momentarily achieve greater lift than that obtained in the steady-state condition. This so-called dynamic lift 

allows a bumblebee to fly. It happens when an airfoil is oscillated to an angle of attack beyond stall. It takes time for the 

flow field to react to the stalled condition; thus momentarily, 

the airfoil has a greater lift than any steady-state value, causing the high current spike in the actuator electronics. With the 

blades continually flapping and passing through the vortices of 

the preceding blades, there was no doubt that we were experiencing a dynamic lift phenomenon. Little was known about os-
GIROMILL WIND POWER

226

cillating airfoil theory at the time, so there was not much we 

could do about changing the aerodynamics at this point. Our 

only recourse was to build new, more powerful actuators and, 

in hindsight, smooth the rock angle profiles more and accept 

the loss in efficiency. 

We provided a cost estimate to Rockwell for designing and 

building new actuators, but it was held in abeyance until all 

other electronic alternatives were tried. Nothing worked; we 

could not get more than a few weeks’ operation from an actuator. We acquired enough run time to define the Giromill performance as plotted in figure 32. These are one-meter-per-second 

binsed data (many data points within that test regime are statistically averaged) and are corrected to sea-level conditions.











































                













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227

GIROMILL WIND POWER

The data indicate that the performance is slightly lower than 

predicted, which can be related to increased rotor drag. The 

greatest rotor drag increase was due to the gaps between the 

blades and support arm fairing, which were caused by removing 

the gap-sealing blade wipers because they could not be accurately adjusted. I wanted a one-piece blade between the support 

arms, like our wind tunnel model, but was overruled by the designers and strength engineers who said it greatly increased the 

blade stress and resulted in a heavy blade. I only agreed to the 

change when they assured me they could provide the required 

sealing to eliminate the gap, but they could not. When I mentioned to Clay that those gaps caused a lot of drag, he spent a 

day using tape to make a temporary blade wiper. We only obtained a small amount of data before the tape peeled off, but the 

results showed a definite performance improvement. The fairing 

should also be more disk-shaped to cover the entire area of blade 

rotation and provide blade sealing for all blade rock angles. Also 

contributing to the drag were the gaps between the support arm 

and support arm blade fairing. Those gaps could have been 

sealed by caulk; however, that was impractical because the fairing had to be removed quite often to get to the blade actuators. 

Correcting these drag-producing features would improve the 

Giromill performance to better than predicted.

Although we showed an efficiency rating higher than conventional horizontal-axis windmills, it did not balance out the complexity between the Giromill and a conventional windmill. The 

blades and support arms were simple, easy-to-manufacture 

structures, but we had a lot of them (three blades, six support 

arms). Also our control system was much more complicated 

than a conventional windmill. In general, our advantages over 

a conventional windmill were not pronounced enough to continue the development. Thus, our Giromill effort was terminated in the summer of 1982. It was a great program, and I 

enjoyed every minute. It validated my faith that a cyclogiro system is workable and in the right application will do the job.15

Wind energy is touted as a renewable energy source and the 

salvation for our energy problems. However, after spending about 

six years in the wind energy field, I found myself doubting a lot 

of the hyped claims of the windmill advocates. The following 
GIROMILL WIND POWER

228

commentary is included to clear up some misconceptions of 

wind energy and present the problems as they really are.

Wind advocates visualize large windmill farms with whirling 

blades churning out large amounts of electrical power that is 

also free from earth-warming CO2 (carbon dioxide) emissions. 

The problem is, that scenario is valid only when the wind is 

blowing; not only blowing, but blowing within a narrow range 

of speeds defined as the running range. The wind speed must 

be at or above the design power threshold, usually about 20 

mph, and below the high-wind cutoff, usually around 40 mph. 

Within this running region, the design power output is a constant value. Below the design power threshold, the windmill 

will generate power, but at a greatly reduced rate since wind 

power is a function of wind speed cubed. Therefore, the power 

of a windmill at half the wind speed of its design value will generate only one-eighth (12.5 percent) of the design power. Under 

light wind conditions, it is better to shut down the windmill to 

prevent the wear and tear of running so inefficiently. Above the 

cutoff wind speed (storm), the blades are feathered and locked 

to ride out the storm. It is not economically feasible to design 

and build a windmill to run and produce power during an occasional storm.

True, there are places in the world where wind power can be 

efficiently and economically used, and wind farms at these 

places have contributed a small fraction of the world’s power 

needs. Also, some individual applications that can tolerate interruptions of power for short periods can employ wind energy. 

Pumping water, irrigating, or even the manufacture of hydrogen for use in fuel cells or engines are good prospects.16 Since 

wind energy is only available when the wind is blowing and I 

know of no accessible area where a windmill can be placed to 

produce power all the time, there will always have to be a base 

power plant available to provide power during those off times. 

That is why a windmill farm connected to a utility grid usually 

only gets paid for the cost of fuel the utility saves by using the 

energy produced by the wind farm. Since the utility cannot reliably count on the wind power to be available at all times, it 

cannot abrogate its commitment to making sure its base power 

plant is adequate to supply power to the entire area.
229

GIROMILL WIND POWER

The Giromill wind energy adventure was a gratifying and fun 

experience on my part and demonstrated that the cyclogiro 

concept is viable. For Hal Larsen and me, it proved that the 

vortex theory we developed does adequately represent the aerodynamic flow field through a cyclogiro.

In the early 1960s, McDonnell won a subcontract from General Dynamics (GD) to design and build the F-111 crew capsule. In an emergency, the capsule separates from the aircraft 

and deploys a parachute for recovery of the crew on water or 

land. The F-111 was going through an upgrade that increased 

the weight of the capsule and required installation of a larger 

separation rocket motor, so GD wanted a check on the separation trajectories using the new configuration. A very young engineer (I thought he was a high school kid) was computing the 

trajectories using a modified six-degree-of-freedom program 

that had been compiled into the COBAL language. The trajectories looked weird, and Chet did not think they were correct. 

The demise of the Giromill had occurred a few months before I 

could take my planned early retirement from McDonnell, so he 

asked me to confirm the trajectories.

The kid was a whiz with the computer, and I saw why Chet 

thought highly of him, but his aerodynamic explanation of why 

the revised trajectories could be so different from the previous 

ones was illogical. He became aloof and quite indignant when I 

started to check the data and follow the computation sequences 

checking the program listing. He was convinced that the program was correct since it had been automatically compiled into 

the COBAL language from an earlier, well-used, and verified SDF 

version, and that process was foolproof. Regardless, I continued the search with no help from the kid since he did not think 

that was part of his job. His utter disregard for assuring that 

the computed trajectories were correct was very troubling. 

It took a while, but a mistake that could not happen had happened. Two look-up tables of proximity aerodynamics (the aerodynamic flow field effect of one body on another) between the 

capsule and aircraft were not being used in the calculations. 

Something had gone drastically wrong during the automatic conversion into the COBAL language. This particular program was 

easily corrected, but the computing center had to do a lot of backtracking and checking of other converted programs and also had 
GIROMILL WIND POWER

230

to analyze the conversion program itself to find the error. The revised trajectories were transmitted to GD, along with an apology 

and explanation for the earlier erroneous transmittal. 

My association with the young engineer while resolving this 

problem was a disturbing experience, as he did not pay attention to basic engineering principles. He was an aerodynamics 

engineer, but his only analysis method seemed to be use of the 

computer. He had a misguided outlook that the computer cannot be wrong, and instead of using the computer for what it 

is—a computing tool—he thought it produced the answer by 

itself. He forgot that a computer will do only what a human 

programmed it to do, and a human is not infallible. 

I hoped that this experience with the new engineer was an 

isolated case, but the rash of space failures due to the ineptness 

of some engineer(s) leads me to believe that the problem is quite 

widespread. The NASA error of English/metric measurement 

confusion causing the destruction of the Mars climate orbiter is 

absolutely inexcusable. In my opinion, the blame for these errors is the academia that did not impress upon the students that 

a computer does not abrogate the application of basic engineering principles and common sense in problem solving.17 

That episode closed my 25-year McDonnell adventure. My overall feeling of the 25 years is that it was great, and I would not trade 

my experience for anyone else’s. I elected to take early retirement 

from McDonnell on my 60th birthday, 31 May 1983, and started 

to work full-time on developing the Aquagiro water turbine.

Notes

1. The Commerce Business Daily is a bulletin that lists government contract opportunities. 

2. A. Betz, Introduction to the Theory of Flow Machines, translation by B. G. 

Randall (Oxford, UK: Pergamon Press, 1966). 

3. Robert V. Brulle and Harold Larsen, “Giromill (Cyclogiro Windmill) Investigation for Generation of Electrical Power,” Proceedings of the Second Workshop on Wind Energy Conversion Systems, National Science Foundation Report NSF-RA-N-75-050 (Washington, DC: NSF, June 1975), 452–60. 

4. Robert E. Wilson, “Vortex Sheet Analysis of the Giromill,” ASME Journal 

of Fluids Engineering 100 (September 1978): 340–42. He replaced the vortex 

rings with a vortex sheet and was able to obtain an analytical solution to the 

performance. (A vortex sheet is defined as a line of infinitesimal vortex ele-
231

GIROMILL WIND POWER

ments placed side by side.) His solution clarified some of the peculiar flow 

effects we noted in our computer solutions, thus showing that our vortex 

rings representation was a good approximation. See also James H. Strickland, 

T. Smith, and K. Sun, Vortex Model of the Darrieus Turbine, SAND81-7017 

(Albuquerque, NM: Sandia National Laboratories, June 1981). The Darrieus 

rotor is a fixed-blade, vertical-axis rotor that has curved blades fixed to a 

central shaft and looks like an eggbeater. I recall getting a copy of their program, DART 2, and comparing it to our vortex theory program when run with 

fixed blades simulating the Darrieus mode. The results were very similar. 

5. Robert V. Brulle et al., Feasibility Investigation of the Giromill for Generation of Electrical Power, MDC Report A3734, 1 November 1975. 

6. NASA Web site http://history.nasa.gov/astp/.

7. Sandia Laboratories is a government facility that was initially a nuclear 

weapons development site. It diversified and at the time had a division devoted to wind and solar power.

8. Brulle et al., Feasibility Investigation, III, 39–60. 

9. Robert V. Brulle, “Giromill Wind Tunnel Test and Analysis,” Proceedings of the Third Biennial Conference and Workshop on Wind Energy Conversion Systems, Washington, DC, 19–21 September 1977, vol. 2, 775–81.

10. See http://www2.jpl.nasa.gov/basics/bsf4-1.htm.

11. NASA Web site http://voyager.jpl.nasa.gov/mission/interstellar.html 

has a description of the Voyager mission. 

12. Three Giromill reports were published for the Rockwell Energy Systems 

Group, Rocky Flats Plant: (1) John Anderson, R. Brulle, E. Birchfield, and W. 

Duwe, McDonnell 40 kW Giromill Wind System, Phase 1 Design and Analysis, 

Volume I—Executive Summary, Report RFP-3032/1; (2) Volume II—Technical 

Report, RFP-3032/2, August 1979; and (3) Robert Brulle, McDonnell 40 kW Giromill Wind System, Phase II, Fabrication and Test, Report RFP-3304, June 

1980. 

13. Robert V. Brulle, US patent, 4,410,806, Control System for a Vertical 

Axis Windmill, 18 October 1983. A similar technique would be applicable for 

a cyclogiro aircraft application. 

14. The Fabrication and Test Report, RFP-3304, contains a sequence of 

erection photographs, pages 17–25. 

15. In 1988 we took two of our grandsons to Disney World. In the energy 

exhibit at EPCOT, the Giromill was featured in a movie on wind energy. It was 

shot while the Giromill was running at Rocky Flats. I was quite proud and 

recall blurting to bystanders, “Hey! That’s my invention.” That movie was 

shown for many years.

16. A proposal to convert from petroleum to hydrogen power has many 

adherents, and serious study on how to accomplish this is in work. An excellent article expounding on its feasibility is presented in Lawrence D. Burns, 

J. Byron McCormick, and Christopher E. Borroni-Bird, “Vehicle of Change,” 

Scientific American (October 2002): 64–73. 

17. NASA Web site, http://mars.jpl.nasa.gov/msp98/news/mco990930.html 

reports the circumstances on how that mix-up occurred.

233

Chapter 13

Aquagiro Water Power

Throughout the Giromill program I tried unsuccessfully to convince the ERDA to investigate a cyclogiro water turbine. It would 

essentially be a Giromill rotor turned upside down and placed 

into the current of a river. I had become close friends with a 

strength engineer named Howard Clark, and we discussed the 

idea of designing and building a small cyclogiro water turbine that 

could be used in a flowing stream by campers or isolated cabins. 

He shared my enthusiasm, so on 11 December 1980 we formed a 

partnership to develop the unit we called an Aquagiro. 

We conducted a river current survey using a hand-built pitot 

tube mounted on a bamboo fishing pole with tubing running to 

a manometer that read the current. The Mississippi and Missouri 

Rivers had a current one bamboo-fishing-pole-length from the 

bank that varied from 2.7 to 4.5 ft./sec. (1.47 ft./sec. = 1.0 mph). 

In flood stages, the current was 5–6 ft./sec. Timing the debris 

motion indicated the current was obviously much greater in 

the middle of the turbulent rivers. Over time we found that the 

current at our test site on the Missouri River was relatively 

constant over a greater part of the year at 3.1–3.5 ft./sec. Since 

a river current is relatively steady in comparison to a wind 

speed, an Aquagiro needs only one blade-rocking motion, so a 

mechanical system with one cam similar to those used for the 

Giromill wind tunnel model is all that is needed. My wellequipped basement workshop for both wood and metal became 

our design, drafting, and shop area. We designed a cyclogiro 

water turbine rotor with a diameter of five feet and a blade span 

of 18 inches, and little by little built the parts, with Howard doing a lot of the handwork while I machined the parts. Fortunately, Hal Larsen at AFIT agreed to compute the rotor performance and define the rock-angle cam shape for us. 

The plan was to mount the unit between two canoes anchored 

in the river and measure the output from a direct current (DC) 

generator. Shopping for the speed increaser and generator led to 

a fortunate encounter with Bob Suttle, a salesman for Reliance 
AQUAGIRO WATER POWER

234

Electric, who had supplied the speed increaser and generator for 

the Giromill. He arranged for us to meet the owner of a steeldrawing business that he thought might be interested in the 

Aquagiro. A week later he introduced us to Lyle McNair, owner of 

Louis Cold Drawn, an obviously hard-working individual who got 

things done by being involved. After a tour of his plant, which included a fully equipped machine shop, and an explanation of his 

several steel-drawing machines, we explained our Aquagiro. He 

immediately showed an interest and offered to make the main 

driveshaft and also the blade shafts around which we would form 

the wooden blades. He also insisted we come to his house to view 

his ramped dock with a boat carriage that can be lowered onto the 

Missouri River. When Howard and I saw his place, we immediately recognized this was the ideal site to do our testing. Little did 

I know, but this test site and a drafting board set up in the corner 

of Lyle’s factory office was to become my workplace for six years. 

From that point on, Lyle turned into our patron and allowed us 

the use of his shop and even his employees to build and assemble 

the Aquagiro and then his boat ramp to test it. 

Brulle

Mod-1 test in the Missouri River of an 

Aquagiro mounted on a boat-cart ramp
235

AQUAGIRO WATER POWER

Although we achieved first turn of the Mod-1 Aquagiro on 20 

March 1982, our first real success occurred on 21 September 

1982 when we lit up three 60-watt light bulbs running in a 2.5 

to 3.1 ft./sec. river current. This was with a modified Aquagiro 

sporting three-foot blades (instead of 18 inches). Unfortunately, 

the lights lasted only a few minutes, as the rock-angle mechanism broke under the load. It was not a great deal of power but 

was good enough for Lyle to provide some champagne to toast 

our first tangible success. Within two weeks, we designed, built, 

and installed a sturdier rock-angle mechanism, and it ran 

great. To get a full-speed-range power curve, the unit was next 

mounted between two canoes and tow-tested behind Bill McNair’s (Lyle’s son) cabin cruiser on Lake of the Ozarks. The result showed we were very close to the computed power curve.

Lyle and his son Bill, who was a vice president of the plant, 

encouraged us to form a company, so on 25 October 1982 we 

Brulle

The Aquagiro was rigged between two canoes and tow-tested on Lake of 

the Ozarks to get a power curve over a range of water velocities since the 

Missouri River current is quite constant.
AQUAGIRO WATER POWER

236

incorporated as Sun Streams Technology, Inc., with me as 

president, Howard as treasurer, and Bill as secretary. We also 

agreed to design and build a Mod-2 Aquagiro, twice the size of 

the Mod-1, with a 10-foot-diameter rotor and six-foot blades 

and drive a synchronous generator connected to Lyle’s house 

power circuit. The blades and support arms were to be made 

from high-strength extruded aluminum. Because that system 

was too heavy for a boat ramp, it was mounted between two 

Styrofoam floats protected by a floating debris deflector.

Brulle

The large, float-mounted Mod-2 Aquagiro test proved impractical because of 

floating river debris snagging and fouling the system.
237

AQUAGIRO WATER POWER

By this time I had retired from McDonnell and was working 

full time on the Aquagiro in a small alcove in the office at St. 

Louis Cold Drawn. Watching the office staff doing their boring 

hand calculation of their profit margin on steel bars produced 

was quite irksome. Since small personal computers (PC) were 

now available, I mentioned to Lyle’s wife Nadine, who was the 

office manager, that I could set up a PC spreadsheet computation that would do all those calculations and print out the results. She needed no further encouragement; they purchased 

an IBM computer, monitor, printer, and a Lotus 1-2-3 spreadsheet program. Within a week the personnel were using the 

computer for those boring computations. I also wrote several 

BASIC language programs to print their steel stock inventory 

tickets, compute the factory workers’ piecework pay amounts, 

and perform other functions. Soon they had a dozen PCs and 

were sending their employees to school to learn to operate them.

Historical Note 

This era saw the introduction of the personal computer, with Apple and IBM becoming the dominant companies from a dozen or so that entered the business. 

The capability of computers then was much less than what a small, handheld 

calculator does now.

Lyle responded to my help by hiring a full-time employee to 

help build the Mod-2 and prepare the test site. After clearing 

the test site for easier access, a half-ton capacity crane was 

erected for assembling the unit. In late August 1983, the Mod2 was assembled and anchored in the Missouri River.

For the next two months we experienced the usual problems 

of getting a new system to work properly. In spite of the problems, several days of good data were collected, and we determined that our electrical apparent power output, measured by a 

voltmeter and ammeter, was 2.2–2.4 kVA in a river current between 3.5 and 4.0 ft./sec., very near the computed maximum 

power coefficient of 0.4 as shown in figure 33. Recall that the 

power coefficient has a maximum theoretical value of 0.593, so 

achieving a test value of 0.4 is deemed excellent for the smallsize unit. Real power read by a wattmeter was about 1.0 kW, 

showing we had a very low power factor of about 60 percent.1






















     









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The Mod-2 Aquagiro is producing 2.2 to 2.4 kVA in a river current between 3.5 and 4.0 ft./sec., as observed by Lyle McNair (left), owner of the 

Missouri River test site, and the author.

Figure 33. Aquagiro power coefficient
239

AQUAGIRO WATER POWER

With the Mod-2 running in the Missouri River, the biggest 

problem we faced was that debris started to collect between the 

anchor cables and the debris deflector. Bushes, large tree 

branches, and tree trunks all piled up in a big logjam. The debris deflector turned into a debris catcher. It took a lot of hand 

prying and pulling using a come-along (hand winch) to untangle the mess. The amount of debris that is swept down the Missouri River is unbelievable, even whole trees.

A proposal was prepared for the National Bureau of Standards (NBS) to evaluate the Aquagiro for US energy production 

and request a grant to help in its development. Six weeks later 

we received notice from the NBS that we were selected for a 

second-phase evaluation and to prepare a set of charts showing our thoughts on how much energy could be generated in 

the United States using Aquagiro systems. Since the Aquagiro 

was for individual use, the amount of power developed did not 

significantly impact the nation’s power needs, so our system 

was not given a further grant. They did, however, put us in 

touch with a person at the Agency for International Development (AID), African Bureau. They liked the concept because 

the unit could serve isolated communities as a source of power 

to run a community refrigerator and light each home. They 

mentioned that as much as 80 percent of the perishable food 

sent to those African communities spoiled because they lacked 

refrigeration. They encouraged us to develop a stand-alone system that would generate sufficient power for a large refrigerator 

and could be maintained by unskilled workers. When we had 

such a system, contact them again, but they had no means to 

help in the development. Somehow word got around because 

we received several letters from overseas missionary teams and 

from other countries expressing interest in the system.

Historical Note 

Burt Rutan built the Voyager aircraft to go around the world nonstop without 

refueling. It was a special-purpose aircraft; at takeoff, 90 percent of its gross 

weight was fuel. It was literally a flying gas tank. His brother Dick and copilot 

Jeana Yeager completed a nine-day, nonstop, around-the-world flight in Voyager 

in December 1986.
AQUAGIRO WATER POWER

240

By now the capability of personal computers had become 

sufficient that we converted the vortex theory program to run 

on an IBM PC. It took about 15 minutes of run time per case.2

With that computing capability, we embarked on a complete 

redesign of the Aquagiro. For the AID stand-alone, easy-tomaintain unit, we decided to use the small Mod-1 rotor and 

enclose it within a diffuser (or augmenter). The diffuser would 

protect the system from debris and locally increase the waterflow velocity, which increases the unit’s power output. In this 

manner a smaller unit should be able to generate the required 

power. We also designed it with a gin pole and winch to raise 

the unit and swing it to shore for maintenance. This also allows 

it to be pulled out during a flood when massive debris fields 

sweep downstream. 

Brulle

Augmented Aquagiro operating with the gin pole mounting arrangement to lift 

the unit out of the river and swing it ashore for maintenance and during flood 

stage when the river was filled with debris.
241

AQUAGIRO WATER POWER

A diffuser is shaped like a megaphone with the small end 

(inlet) facing into the current. The aft portion essentially opens 

a hole in the fluid, in this case water, increasing the amount 

flowing through the inlet to fill the void. The Aquagiro is placed 

near the inlet to take advantage of the increased velocity. It 

should be noted that diffusers are used in many flow applications. 

Hal Larsen consented to come to St. Louis to help in developing a performance calculation approach to compute the performance and rock angles for operating within the diffuser. He 

was very excited when he arrived, as he had used the long drive 

to formulate a vortex technique similar to that used for the rotor. The side walls of the diffuser are represented by a vortex 

sheet, which is a line of infinitesimal vortex elements placed 

side by side. The induced effect of these vortex sheets can be 

determined by using established aerodynamic theory. Again, 

the complex nature of the calculations dictates using an appendix to avoid cluttering the narrative with theoretical presentations. How to compute the blade-rock angles for an Aquagiro 

placed within a diffuser is explained in appendix D.

The design and building of the floating diffuser went well. For 

floatation, we mixed polyurethane, which was poured into the 

floatation spaces where it then foamed and set. It worked great, 

as it permeated the nooks and crannies and adhered to the 

aluminum skin, which made the unit very rigid. A revised Mod-1 

that used extruded aluminum blades and a new cam that accounted for the diffuser-induced velocities were fit into the diffuser. The electrical power output was connected to Lyle’s 

house power as we did with the Mod-2. By July 1985 we had 

the augmented Mod-1 in the river and for the next year tested 

and modified the unit. Figure 34 is a drawing of the final augmented Aquagiro that evolved from this effort, and Figure 35 

shows the predicted power output. 

The computer-program-predicted power output at a current 

of 3.5 ft./sec. is 1.56 kVA; however, we only achieved 1.3 kVA 

during our tests. Why were we not getting the predicted power? 

Talking over our problem with Hal, we decided to put a top on 

the diffuser and make sure the unit was fully submerged to 

create a completely underwater channel. This should reduce 

the surface rippling and splashing that absorb power. We also 

widened the inlet a small amount to increase the collection 
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Figure 34. Augmented Aquagiro
243

AQUAGIRO WATER POWER

area. When these modifications were completed, the power output was less, but the reason for the disappointing performance 

became apparent. With the top on, it was possible to see the 

rippling of the aluminum skin and hear the water-hammer effect of the blade support arms turning. There was insufficient 

space between the rotor and the diffuser top to ensure a smooth 

flow over the upper support arms. Undoubtedly the same interference was happening with the lower support arm and on the 

sides with the blades, all contributing to a power loss. This was 

a blow to my ego for forgetting such a basic aerodynamic principle. The only recourse was to redesign the diffuser.

I started the redesign; however, nature intervened, and I contracted asthma that severely limited my activity, including traveling. This setback came just as the new Department of Energy 

and the NBS showed a renewed interest and asked me to come 

to Washington to make a briefing. The Missouri Division of 

Community and Economic Development even sent two representatives to see the Aquagiro operation. Even a Chinese businessman in Beijing became interested in the Aquagiro, and we 

negotiated with him through a church mission that was working in China but broke off contact as he was unreasonable.3



































        





















30503108&3L8

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Figure 35. Augmented Aquagiro performance
AQUAGIRO WATER POWER

244

By this time my asthma became very debilitating, and I could 

not do anything strenuous. Nothing seemed to alleviate my 

breathing problems, and I became very susceptible to infections, 

so the Aquagiro effort languished. Howard took early retirement 

from McDonnell and took a position with an engineering jobshop and was sent to California to work for Douglas Aircraft. 

Bill was very busy with the St. Louis Cold Drawn expansion, so 

our Aquagiro effort dribbled to an end. It was very disappointing because we were getting a good handle on the problems and 

generating commercial and government interest. Reluctantly, 

Marge and I took our losses from the very interesting and enjoyable program and retired to Florida.

All the Aquagiro data is now in the custody of my environmental sciences professor son, Robert J. Brulle, at Drexel University in Philadelphia. He is promoting it as an individual unit 

Brulle

An augmented Aquagiro produced 1.5 kVA in a 2.4-mph current.
245

AQUAGIRO WATER POWER

to manufacture hydrogen for the coming hydrogen power era. I 

wish him luck. The unit itself and all our aluminum blades and 

other material were sold as scrap or buried in a large gully at 

Lyle’s home. Thus, my story comes to an end as I retired to 

Florida with a lot of other displaced northerners. 

Notes

1. Our low power-factor value was a result of running the generator at a 

fraction of its rated value where its efficiency is low. Power factor is a manifestation of alternating current and is related to how well the voltage and 

current (amps) are synchronized. At a power factor of 100 percent, both the 

current and voltage are in perfect sync; a power factor of zero occurs when 

they are 90 degrees out of phase and the energy sent out cannot perform any 

work. A wattmeter reads actual power, and that is the amount of electrical 

power you pay for as a homeowner. However, because of power factor, the 

electric company has to provide more energy, called apparent power, than is 

actually used. In commercial use, power factor is considered in the energy 

cost, and many manufacturers invest in banks of capacitors or other gimmicks to bring up the power factor so they can utilize all the energy they are 

paying for.

2. I recently ran a case on my 2004 computer, and it converged to a solution in about a second.

3. Two years later Howard notified me that our missionary friend negotiating for us in China was expelled and had arrived safely back in America. He 

told Howard that the Chinese businessman disappeared during the uprising 

and massacre at Tiananmen Square.

247

Appendix A 

Wing Vortex System

A vortex is a circular flow in which the circular velocity is 

inversely proportional to the radius. A vortex is created whenever a fluid dynamic force is generated, and the vortex strength 

is directly proportional to the strength of the generated force. 

The vortex generated by a wing is caused by the difference in 

pressure between the upper and lower wing surfaces. The airflow forms a vortex around the wing, called the bound vortex, 

and then streams off the wingtips, creating a trailing vortex that 

travels downstream as shown in the upper diagram of figure 

A-1. Every air particle within the neighborhood of the vortex 

system is affected, and will be deflected due to the vortex action. This deflection is defined as the induced effect and, at any 

point within the field, is the integrated effect of the entire vortex 

system. An air particle path is then determined by vectorally 

adding the free-stream velocity with the induced effect as shown 

in the lower diagram of figure A-1.

The calculations for a lifting wing vortex system were done 

many years ago and appear in most aerodynamics texts. The 

result shows that the vortex system causes air particles in front 

of the wing to go up (up-wash) and in back of the wing to go 

down (down-wash). The up-wash is only due to the bound vortex; however, the down-wash is caused by the bound and trailing vortices, making it relatively strong. The down-wash affects 

the stability of the aircraft since the tail operates within its influence and also causes an induced drag—sometimes referred 

to as drag due to lift. Fighter pilots will push the control stick 

forward to assume a temporary zero-g flight path to accelerate 

quicker. They call this unloading the aircraft and, without any 

lift, there is no vortex and therefore no induced drag. Drag due 

to lift is inversely proportional to the wing’s aspect ratio, which 

is the wingspan divided by the mean wing chord. Therefore, the 

higher the aspect ratio, the lower the drag due to lift. That is 

why sail planes have such long, narrow wings and why hooking 

the F-84s to the B-29 wingtips reduced the drag.
APPENDIX A

248

Aerodynamics tricks can be used to reduce the magnitude 

of the induced drag. The British WWII Spitfire fighter had an 

elliptical wing that resulted in a minimum induced drag, but 

of course the wing was difficult and expensive to produce. 

Wingtip end vanes (flat plates mounted at the wingtips), winglets (small specially contoured and canted wingtips), and even 

centerline-mounted wingtip fuel tanks, help in reducing the 

induced drag.

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Figure A-1. Wing vortex system effects
249

Appendix B 

McPilot 

The simplest and best results on relating a pilot rating with 

a McPilot equation were obtained with the simple transfer function shown in figure B-1.

Q F T

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The following is an approximate explanation of the terms relative to a human pilot:

Kp signifies the pilot gain, defined as the quickness 

and amount of control application needed.

e-τs

 refers to the neuromuscular time delay or the 

time for a signal to travel from the brain to the 

muscles. (τ was held constant at 0.2 seconds.)

T1S +1 lead term refers to the time ahead the pilot is anticipating the control inputs.

T2S +1 is the time the pilot takes to perform the control 

input.

Note that these are only relative explanations of what the terms 

imply since the human body and mind are infinitely more complicated than the McPilot equation. 

Figure B-1. McPilot math function
APPENDIX B

250

The procedure is to define an equation, called a pilot cost 

function, that contains the three pilot workload parameters of 

the gain (Kp), the lead (T1), and the lag (T2). The premise is that 

the lower these values, the better a pilot likes the handling 

qualities, so the technique was to find the lowest values of the 

workload parameters satisfying the cost function.

After all was said and done, it was concluded that the technique is more of an art than a science. Attempts to improve on 

and use the method were made for a few years, but it died a 

merciful death.
251

Appendix C 

Whirlpools

While Hal and I were perusing Prof. Frederick Kurt Kirsten’s 

reports on his cyclogiro aerodynamic theory, we found that he 

used constant induced velocities across and through the rotor. 

He based those on the momentum flux through the rotor, thus 

he was neglecting the non‐steady effects. To correct these deficien‐

cies, Hal proposed we describe a cyclogiro vortex theory model, 

similar to what Prandtl did for wing theory and Theodorsen did 

for propeller theory.1 These theories state that every aerodynamic, 

or more generalized hydrodynamic, force is accompanied by a 

vortex, and this vortex trails downstream as explained for a 

wing in appendix A.

A key point in Kirsten’s cyclogiro theory was that the blade 

must flip from a positive angle of attack to a negative angle of 

attack and vice versa, at the 90- and 270-degree points along 

the blade orbit as measured from the direction of the incoming 

wind velocity. That means that, at those points, the bound vor‐

tex also has to change its sign. Hal postulated that the vortex 

must be shed from the blade at those points because it has to 

change direction, and thus the shed vortex will travel down‐

stream with the wake.

Thus, the wake was modeled by an array of concentrated 

vortex rings generated by the blade‐flipping motion at the blade 

angle-of-attack reversal points. Simplified calculations showed 

that approximately 90 percent of the vorticity shed should be 

concentrated at these blade flip points, with the remainder 

spread across the wake in weak vortices shed by the changing 

blade velocity. The wake was therefore modeled by concentrating 

all vorticity at the blade flip points where they are shed as a free 

vortex ring. The resulting wake is illustrated in figure C-1. 

To interpret figure C-1, view it as two wagon wheels turning 

on an axle. Every time a point on the wagon wheel rim, which 

corresponds to a blade, goes through a blade flip point, a vortex 

ring is ejected, and a new ring started. When that point then 

comes to the opposed flip point, that ring is ejected, and the 
APPENDIX C

252

process repeats. Each blade goes through the same process, so 

there is a succession of vortex rings ejected as the rotor turns. 

The computer program we developed integrated all these vor‐

tices and determined the lift force. An iteration scheme then 

compared that to the flow momentum lift. The strength of the 

vorticity is adjusted, and the computations are redone until 

convergence is obtained. Fortunately Hal was given a small 

AFIT research grant allowing him the time and use of the Wright 

Field mainframe computer. The number of integrations can be 

very large depending on the density of the array points. Our 

first runs took over an hour; however, by experimenting, we got 

the runs down to about 15 minutes per case.

Figure C-2 shows the induced flow field of a cyclogiro rotor in 

hover. The length of the arrow signifies the flow velocity, and the 

angle shows the direction. Note that the flow converges on the 

capture area and passes down the stream tube formed by the 

wake vortex rings. This plot illustrates that down-wash velocities 

are nonuniform and vary directionally across the capture area.

A sample of the blade rock angle to give a constant alternating 

angle of attack around the blade orbit is shown in figure C-3. 

(Angles are exaggerated for clarity.) The inset further clarifies 

the definition of angle of attack and rock angle. Note the angles 

are positive when they are outward from the orbit circle. The 

arbitrary 10-degree blade flip region is where the angle of at‐

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APPENDIX C

254

tack changes sign. Figure C-4 shows the blade rock angle for a 

hovering cyclogiro for a 12-degree angle of attack. The vortextheory-derived rock angle is a radical departure from older 

theories that gave a sinusoidal-shaped blade rock angle, approxi‐

mating the angle-of-attack profile. These results explained why 

no cyclogiro aircraft was successful even though many experi‐

menters tried to build one.2 Hal and I were ecstatic; the compli‐

cated cyclogiro aircraft aerodynamic flow system was solved.

Notes

1. Ludwig Prandtl and Oskar G. Tietjens, Fundamentals of Hydro and 

Aeromechanics (New York: McGraw-Hill Book Company, 1934); and Theodore 

Theodorsen, Theory of Propellers (New York: McGraw-Hill Book Company, 

1948). 

2. W. F. Foshag and G. D. Boehler, HARWAS, Technical Report 69-13, 

shows pictures of the many cyclogiro aircraft that have been considered over 

the years.

Figure C-4. Hover blade rock angle

















   

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255

Appendix D 

Diffusers

From fluid flow theory, a wall can be represented by a vortex 

sheet consisting of an infinite number of infinitesimal vortex 

filaments placed side by side. The effect of a wall in the flow can 

then be calculated by computing the integrated effect of all the 

vortex filaments making up the wall. The induced velocities 

from the diffuser walls can then be combined into the present 

cyclogiro program. The nature of the problem is illustrated in 

figure D-1. 

Figure D-1. Augmented rotor vortex system

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APPENDIX D

256

Figure D-1 shows the diffuser walls as represented by a vortex sheet and the vortex rings of the rotor traveling downstream. 

The problem is to integrate the effect of all these vortices to determine the induced values around the blade orbit and then to 

get the rock angles to give a constant angle of attack. The nature of the problem is shown for one point P, and this has to be 

done throughout the blade orbit. It is a horrendous problem to 

solve this vortex mélange, so we broke the program into two 

parts—first computing the diffuser-wall-induced velocities and 

then inputting them in the cyclogiro performance program.

Getting the vortex-sheet-induced velocities was a straightforward calculation using established theory. The incremental 

vortex strength along the sheet is determined using potential 

flow equations coupled with the Kutta condition that the flow 

must leave at the diffuser trailing edge. The Biot-Savart law is 

used to integrate the effect of the rotor vortex rings and the side 

wall vortex sheets to get the induced effect at all points around 

the blade orbit. The Kutta condition and Biot-Savart law are 

discussed in many aerodynamic texts; see Kuethe and Schetzer, 

Foundations of Aerodynamics.
257

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265

advanced controls technology for integrated vehicles (ACTIVE), 12, 17, 56, 

78, 88, 119, 192

advanced fighter technology integration 

(AFTI), 192–93

Advanced Research Projects Agency 

(ARPA), 165

aerodynamics, 2–4, 10, 22, 26–27, 56, 

59–60, 64–65, 72, 76, 78, 81, 93, 117, 

123, 125, 150, 180, 183, 188, 207, 

213, 225–26, 229–30, 247–48, 256

aeronautical engineering, 1, 3–4, 19, 21, 

26–27, 47, 56, 63, 76, 120

Agency for International Development 

(AID), 77, 178, 239–40

air decoy missile (ADM), 81, 83

Air Force Flight Dynamics Laboratory 

(AFFDL), 113, 188–89, 191–92, 208

Air Force Institute of Technology 

(AFIT),19–21, 26–27, 47, 56, 59, 72, 

78, 82, 93, 117, 170, 201, 204, 208, 

233, 252

Air Materiel Command (AMC), 29–31, 

37, 52

Air Proving Ground, 30

Air Research and Development Command (ARDC), 30–31, 37

Aircraft, See individual designations, 

e.g., B-36

aircraft design, 2, 5, 7, 54, 64, 66, 76, 

204, 208

Alpha Draco (See also, Model 122B), 89–

91, 93–97, 100–102, 104–6, 118–19, 

123, 167–68

analog computer, 62–63, 92

analytical geometry, 2

antiballistic missile (ABM), 158, 162–63, 

165

Apollo, 100, 128–29, 146, 170, 176–77, 

213

Aquagiro, 202, 230, 233–44

astronaut, 114, 123, 125–26, 131–32, 

135–37, 141–44, 150, 153, 155, 157

astronomical unit (AU), 219

Atlantic Missile Range, 107

atomic-powered aircraft, 77

augmented target docking adapter 

(ATDA), 157

autopilot, 37, 46, 52, 115

B-25, 15, 23–25, 75

B-29, 9, 18, 46, 247

B-35 “flying wing,” 6, 262

B-36, 18, 45–47

B-45, 4, 6, 54

B-45A, 5

B-47, 5, 43, 48, 81–83

B-58, 109

ballistic missile, 83–84, 86–88, 94–97, 

130, 163

Ballute, 139, 141–43

basic trainer, 16

Bell XS-1, 3, 7

Berlin, 6, 119

boost glide reentry vehicle (BGRV), 106, 

162–63, 166–68

boundary layer, 3

Cape Canaveral, 84, 92, 96–97, 99, 101–3, 

105, 107, 118, 123, 133, 167, 170

center of gravity (c.g.), 129, 140–41, 

144, 153, 163, 192

Cold War, xviii, 15, 34, 108, 158

command service module (CSM), 128, 146

Congress, 32, 34, 43, 121, 178

constant total energy contours (TEn), 67

control configured vehicle (CCV), 188–89, 

192–93, 195

cyclogiro, 198, 201, 203–4, 206–9, 211–14, 

223, 227, 229, 233, 251–56

Department of Defense (DOD), 173

DEW (distant early warning) Line, 162

digital computer, 62–63, 92, 168

direct-side-force capability (DSFC), 192–

95, 198

displayed impact point (DIP), 196

Doolittle, Jim, 22–23

drafting, 2, 4, 8, 170, 233–34

Dynasoar, 106–7

EC-121, 75–76

Edwards AFB, 3, 6, 31, 37, 61–62

Eisenhower, Pres. Dwight D., 7

ejection, 39, 108, 123, 125, 129, 131, 

134–49, 152–53

energy maneuverability (EM), 71

Energy Research and Development Administration (ERDA), 212–13, 218–19, 

233

Index
INDEX

266

engineering order (EO), 5, 185

error and dispersion analysis (EDA), 98, 

118–19

escape tower, 125–27, 129, 131

Explorer, 84–85, 97, 125

explosive decompression, 74

extra-vehicular activity (EVA), 25, 128, 157

F-82, 4

F-84, See Thunderjet

F-86, 4–7, 31, 67

F-100, 7, 17, 31, 61, 113

FICON, 45–48

fighter conveyer, 45

fireball, 125–26, 136–37, 139–40, 153

FJ1 Fury, 4

flaperons, combined flap and aileron, 192

flying tail, 36, 38, 41

form drag, 3

friction drag, 3

Fs/g, See stick force per g

future impact point (FIP), 195–97

GAM-72 Green Quail, 81–83

Gemini, 25, 67, 100, 123–25, 127–31, 

134–35, 138, 141, 143, 146–58, 166, 

170, 173–75

General Dynamics, 229

General Motors, 36, 41

g-force, 17, 129

GI Bill, 1–2

Giromill, 202, 211–12, 214–15, 217–27, 

229, 233–34

Glenn, John, 132–35

global positioning system (GPS), 86

Green Quail (GAM-72), 81–83

Grissom, Gus, 67, 117, 127, 131, 151–52, 

154, 170

ground-controlled approach (GCA), 48, 74

Grumman F9F Panther, 4

heads-up display (HUD), 195–96

heat shield, 88, 126–27, 129, 133, 147, 

175

heliocentric axis system, 115

Hi–Boost Experiment (HiBEX), 165

independent research and development 

(IRAD), 188–89

induced drag, 3, 247–48

in-flight ejection, 147–48

Institute of Aeronautical Science, 122

instrument flight rules (IFR), 24, 50

instrument landing system (ILS), 48–49

integral calculus, 2

intercontinental ballistic missile (ICBM), 

83–84, 97, 129, 164–65

intermediate-range ballistic missiles 

(IRBM), 83, 107, 174

International Geophysical Year (IGY), 84

interplanetary trajectory, 113, 115

Kennedy, Pres. John F., 121

Khrushchev, 108, 148

Korean War, 5, 17–18

lateral translation-integral (LTI), 195

lateral translation-proportional (LTP), 194

Liberty Bell 7, 131–32

lift/drag ratio, 87, 89–90, 129

liquid oxygen (LOX), 43, 126

Lockbourne Field, 73

Los Alamos, 15

low-altitude bombing system (LABS), 

42–43

low-Earth orbit, 85

low-frequency radio ranges, xviii, 49, 53

Luna, 122

lunar excursion module (LEM), 128, 

176–77

Mach number, 2–3, 5, 11–12, 25, 36, 

44, 92–93, 149, 164, 167, 196

maneuvering decoys (MANDEC), 164–65

Manned Orbiting Laboratory (MOL), 

170, 173–75

Manned Spacecraft Center, Houston 

(MSC), 151

mathematics, 2, 59, 218

McDonnell Aircraft Corporation (MAC), 

78, 81, 96, 98, 100, 103, 105, 123, 

132–33, 135, 150–51, 169–70

McDonnell FH1 Phantom, 4

McDonnell, 4, 30–31, 34, 46, 78, 81, 

83–84, 88–89, 92, 96, 100, 102–3, 

105–7, 113, 117–19, 123, 135, 146, 

149, 161–62, 166, 169, 173–74, 177, 

180, 183, 187–88, 190–92, 197, 208, 

211–13, 219–21, 223, 225, 229–30, 

237, 244

McDonnell-Douglas Corporation (MDC), 

169, 177–78, 180

mechanics, 2, 60, 85

Mercury, 25, 67, 100, 107, 117, 123, 

125–27, 131–35, 163

MiG-15, 5, 56

MiG-17, 71
INDEX

267

MIRV, 163–64

Minuteman missile, 106

Mitchel AFB, 50, 52

Model 122B (See also, Alpha Draco), 89, 

96, 100

multiple independently targeted reentry 

vehicles (MIRV), 163–64

NASA, 7, 106–7, 121, 123, 125, 128, 

139, 146, 149–52, 166, 170, 175, 

177–78, 180, 219, 230

National Advisory Committee for Aeronautics (NACA), 7, 10, 23, 25, 61–62, 

66, 83, 86, 88–90, 168, 206–7

National Aeronautics and Space Administration, See NASA

National Bureau of Standards (NBS), 

239, 243

National Science Foundation (NSF), 

211–12

Naval Ordnance Laboratory, 25, 136

Navy, 4, 45, 73, 76, 81, 84, 129, 161, 

169, 187, 221

North American Aviation (NAA), 1, 4, 

10–11, 17, 23, 25, 129

North Atlantic Treaty Organization 

(NATO), 6, 34, 44

off-the-pad ejection, 135, 137, 140, 144

operations research, 161

orbital attitude and maneuvering system (OAMS), 128, 149, 151, 154, 156

P-47, xvii, 33, 47, 54

P-51 Mustang, 4

Paraglider, 129

Peenemunde, 11, 25, 88

personal computers, 237–38, 240

pilot-induced oscillation (PIO), 38, 187–89

Powers, Francis Gary, 107, 118

Pratt & Whitney, 7

primary trainer, 16

Project Gemini, 123, 125, 158

Randolph AFB, 15–16

Ranger, 121–22

reconnaissance, 32, 45, 48, 118, 177

Redstone Arsenal, 84

reentry control system (RCS), 128, 156–

57

Republic Aviation Corporation (RAC), 

29–31, 33–34, 36–38, 41, 46–48, 52

Republic F-84 Thunderjet, 4

Republic P-47 Thunderbolt, See P-47

request for proposal (RFP), 88, 164, 177

retropack, 133

Reynolds number, 3, 10–11, 218

RoCat rocket/catapult, 140, 145

Rogallo wing, 129

roll coupling, 61–62, 113

Rolls-Royce, 18

Sabre, See F-86

Saturn V, 128, 176–77

Shepard, Alan B., 126

six-degree-of-freedom equations of motion (SDF), 60–61, 63, 113–17, 119, 

140, 185, 229

Skyhawk (A-4D), 77

Soviet Union (See also, USSR), xviii, 6, 

48, 83, 86, 169, 175

space transportation system (STS), 177

Sputnik, 84

Stearman, 16

stick force per g (Fs/g), 186

Strategic Air Command (SAC), 32, 34, 42

structures, 2, 21, 30, 163, 225, 227

subsonic, 2–3, 10–12, 67, 69

supersonic, 2–3, 9–12, 20, 25–26, 31, 

42, 54, 61–62, 64, 66–67, 69–71, 

109, 137, 140–41, 146, 221

surface-to-air missile (SAM), 16, 108

Surveyor, 122

System Project Office (SPO), 29–31, 33, 

36, 46–48, 52

T-28, 7, 9, 17

T-33, 9, 17, 72–73

T-37, 9

Tactical Air Command (TAC), 42

tech rep, technical representative, 33, 47

TEn, 67

thermodynamics, 2, 22, 136

Thunderflash (RF-84F), 34

Thunderjet (F-84), 4

Thunderstreak (F-84F), 34

trajectory, 86, 92, 94–95, 97–98, 101, 

106, 114–15, 118–19, 129, 131, 140, 

150–52, 164, 196, 219

transonic, 2–3, 5, 10, 36, 66, 92

U-2, 107–9, 118, 174

United Nations (UN), 18, 148

unsatisfactory reports (UR), 32

USSR (See also, Soviet Union), 6, 9, 15, 

43, 84, 107, 118, 121–22, 162, 176, 

213
INDEX

268

Van Allen radiation belt, 85

Vandenberg AFB, 106, 118, 162, 165, 

168, 173, 177

Vanguard, 84, 198

vertical takeoff and landing (VTOL), 201

visual flight rules (VFR), 24, 50

Vultee, 16

Welch, George, 6, 61

wind shear, 63–64, 99

wind tunnel, 10–12, 20, 23, 25, 36, 82, 

92–93, 125, 133, 140–41, 206–7, 

214, 217–18, 227, 233

wings-level turn (WLT), 193–94, 196, 198

World War II (WWII), xvii, 1, 4, 10, 16, 

18, 20–21, 34, 45, 54, 59, 61, 71, 

121, 125, 161, 207, 248

Wright Air Development Center (WADC), 

27, 29–30, 47, 62

YB-49, 6

Yeager, Chuck, 3, 7, 37

YF-93, 7, 34

zoom-climb, 69–70, 109
Engineering the Space Age

A Rocket Scientist Remembers

Air University Press Team

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Jerry L. Gantt

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