Mach 3+

NASA/USAF

YF-12 Flight Research,

1969-1979

by Peter W. Merlin

Monographs in Aerospace History #25

NASA SP-2001-4525
i

NASA SP-2001-4525

 Mach 3+:

NASA/USAF

YF-12 Flight Research,

1969-1979

by

Peter W. Merlin

NASA History Division

Office of External Affairs

NASA Headquarters

Washington, DC 20546

Monographs in

Aerospace History

Number 25

2002
ii

 Library of Congress Cataloging-in-Publication Data

Merlin, Peter W., 1964-

 Mach 3+: NASA/USAF YF-12 flight research, 1969-1979 / by Peter W. Merlin.

 p.cm. -- (Monographs in aerospace history; no. 25) (NASA history series) (NASA SP

 2001-4525)

 Includes bibliogaphical references and index.

 1. Aerodynamics, Supersonic--Research--United States. 2. Aerodynamics,

Hypersonic--Research--United States. 3. United States. National Aeronautics and Space

Administration--Research. 4. United States. Air Force--Research. 5. SR-71 (Jet

reconnaissance plane) 6. Research aircraft--United States. I. Title II. Series, III. Series:

NASA History Series IV. NASA SP 4525.

TL571.M45 2002

629.132’305--dc2l

 2001044726

For sale by the Superintendent of Documents, U.S. Government Printing Office

Internet: bookstore.gpo.gov. Phone: (202) 512-1800. Fax: (202) 512-2250

Mail Stop SSOP, Washington, DC 20402-0001
iii

YF-12A on ramp, seen from above (NASA photo EC71-2679)

Back Cover Image:

YF-12C on ramp, seen from above (NASA photo E72-24985)

Front Cover Image:

YF-12 program personnel. Standing (left to right): Ray Young, Fitz Fulton, Don Mallick, and Vic

Horton. Kneeling: Frank Brown, MSgt. Cliff Fenwick, Larry Barnett, Ed Nice, Bud Franklin,

Carl Barnes, Joe Misplay, Charlie Grace, and Clayton Threewit. (NASA photo E72-24130)
iv

Preface...........................................................................................................................................vi

Chapter 1: YF-12 Design and Development .................................................................................1

Chapter 2: Joint USAF/NASA YF-12 Research ...........................................................................7

Chapter 3: Heating and Loads Research .....................................................................................12

Chapter 4: Propulsion Research ..................................................................................................16

Chapter 5: Landing Studies .........................................................................................................24

Chapter 6: A Flying Laboratory...................................................................................................30

Chapter 7: Lessons Learned ........................................................................................................43

Appendices ..................................................................................................................................49

Appendix 1: Flight Logs .......................................................................................................50

Appendix 2: Bibliography ....................................................................................................73

Appendix 3: Interview Transcripts, Gene Matranga and Berwin Kock ...............................87

Appendix 4: Don Mallick describes YF-12 flight operations...............................................99

Appendix 5: Don Mallick describes unstarts......................................................................105

Documents.................................................................................................................................107

Document 1: Letter, Eldon E. Kordes, [Flight Research Center] Chairman, YF-12 Struc-

 tural Dynamics Group, to L. Sternfield, Code RAS, NASA Headquarters, subj: NASA

Research and Development Program related to YF-12, 11 September 1969.....................108

Document 2: Memorandum of Understanding, USAF-NASA YF-12 Research and Development Program, 5 June 1969................................................................................................124

Document 3: NASA Management Instruction, USAF-NASA Agreement — Loan of the

YF-12A Aircraft, Serial Number 60-6935 .........................................................................129

 Document 4: Extract from YF-12A flight manual (declassified), concerning the air inlet

 system.................................................................................................................................136

Acronyms ..................................................................................................................................142

Index ..........................................................................................................................................143

About the Author .......................................................................................................................146

Monographs in Aerospace History ............................................................................................146

The NASA History Series .........................................................................................................147

Table of Contents
v
vi

Preface

During the 1950s, American aircraft designers emphasized configurations that flew increasingly high and fast,

a trend that continued for nearly two decades. Then, during the 1970s, efficiency, noise reduction, and fuel

economy also became important considerations, in part because military analysts no longer deemed speed and

altitude the paramount capabilities necessary to ensure national security.

Among the aircraft designs that transitioned from paper to hardware during the high-speed era, the Lockheed

Blackbirds hold a unique place. The A-12, YF-12A, M-21, D-21, and SR-71 variants outperformed all other

jet airplanes in terms of altitude and speed. To this day, they remain the only production aircraft capable of

sustained cruise in excess of Mach 3. Developed in utmost secrecy, they eventually became some of the

world’s most famous aircraft.

Conceived originally as spyplanes, several Blackbirds saw service with the National Aeronautics and Space

Administration (NASA) as research platforms. This monograph describes the first major NASA project

involving the Blackbirds. Conducted with the U.S. Air Force (USAF) as a partner, the NASA/USAF YF-12

research lasted 10 years, and produced a wealth of data on materials, structures, loads, heating, aerodynamics,

and performance for high-speed aircraft.

More than two decades after the program ended, no comprehensive history of the joint program has yet been

written. This monograph is an attempt to rectify that deficiency. Until recently, security restrictions prevented

the release of some information relative to the YF-12. Since then, numerous documents have been declassified, and program participants are free to speak about previously restricted aspects of the project. Unfortunately, some who contributed to the NASA/USAF YF-12 investigations have not outlived the blanket of

security that covered their work. Those who have must reach back more than 20 years to retrieve anecdotes

and historical details. In a sense, the oral history interviews in this monograph amount to a sort of salvage

archeology into the fading memories of the remaining YF-12 participants.

Over the years, numerous books and articles have been written about the Blackbirds, but few give more than a

brief description of the YF-12 and its role as a research aircraft. In this monograph, I briefly describe the

origins of the Blackbird family of aircraft and how NASA became involved with them. Each of the following

chapters then describes a facet of the NASA/USAF YF-12 research program in detail. This monograph would

not have been possible without access to numerous technical reports (some recently declassified), briefings,

and other source material from the NASA Dryden Historical Reference Collection, as well as the oral interviews that fleshed out the story and provided an insider’s view of the project.

Finally, this work rests on the kind assistance of a number of individuals: Dr. Dill Hunley, the DFRC Historian and his successor, Dr. Michael Gorn, both served as editors of the study. Archives Assistant Betty Love

provided invaluable aid in identifying individuals in the group photos. Berwin Kock, a Dryden project

manager and engineer; Don Mallick, a retired NASA research pilot; Gene Matranga, a former Dryden project

manager and engineer; Fitz Fulton, a retired NASA research pilot; Col. Joe Rogers (USAF, Ret.), a former

commander of the SR-71/F-12 Test Force; and Col. Hugh Slater (USAF, Ret.), a former commander of the

1129th Special Activities Squadron that flew the early Blackbird variants all provided valuable information

about the project. Under a tight schedule, Dryden X-Press editor Jay Levine outdid himself in designing the

page layout of this monograph. The many photos were printed by Kerrie Paton and scanned by Jay. Further,

both Steve Lighthill and Muriel Khachooni helped shepherd the monograph through the process of printing.

Peter W. Merlin

Edwards, California

January 2002
1

The family of aircraft known collectively

as the Lockheed “Blackbirds” includes

the A-12, YF-12, and SR-71. Designed by

Clarence L. “Kelly” Johnson under

Project OXCART, the A-12 resulted from

a series of designs for a successor to the

U-2 spyplane. The twelfth design in

Johnson’s series was a sleek aircraft built

almost entirely of titanium. With powerful turbo-ramjets, the A-12 was capable

of reaching a speed of Mach 3.29 and an

altitude of 90,000 feet.1

In August 1959, the Central Intelligence

Agency (CIA) approved funding for

construction of the A-12. In 1960 and

1961, Lockheed engineers conducted

tests of a scale model of the A-12 in the

NASA Ames Research Center’s 8x7-foot

Unitary Plan High-Speed Wind Tunnel at

Moffett Field, California.2 Tests included

various inlet designs, control of cowl

1

 “OXCART A-12 Aircraft Experience Data and Systems Reliability,” BYE-8725-68, formerly classified TOP SECRETOXCART, Central Intelligence Agency, Washington, D.C., 15 January 1968. Declassified 14 December 1998, p. 2.

NASA Dryden Historical Reference Collection.

2

 Jay Miller, Lockheed’s Skunk Works—The First Fifty Years (Arlington, Texas: Aerofax, Inc., 1993), p. 116.

3

 “Proposed High Speed Wind Tunnel Tests of an Inlet Model 204 in the 8x7 Unitary Plan Wind Tunnel of the NASA at

the Ames Research Center,” Lockheed Aircraft Company, Burbank, California: LAL 455-IIP by H. H. Shibata, 3 June

1960; LAL 455-IVP by Donald K. Hill, 7 December 1960; LAL 455-VIIP by Donald K. Hill, 1 August 1961. NASA

Dryden Historical Reference Collection.

Chapter 1:

YF-12

Design and

Development

Lockheed engineers tested a scale model of the A-12 (Lockheed

Model 204) in the 8’x7’ Unitary Plan Wind Tunnel at NASA

Ames Research Center on Moffett Field, California, in the early

1960s. Note the absence of the inlet spikes. (Lockheed photo)

In 1962, the NASA Ames wind tunnel simulated

speeds up to Mach 3.25 for a scale model of the

A-12 (with inlet spikes installed). The white coating

aided in flow visualization. (Lockheed photo)

bleed, design performance at Mach 3.2,

and off-design performance of an optimum configuration up to Mach 3.5.3

This marked the beginning of a long

relationship between NASA and the

Blackbirds.

As a reconnaissance platform, the A-12

was flown exclusively by the CIA. The

first airframe was delivered in February

1962. Test flights and operational missions continued until June 1968. The A12 pilots required full pressure suits,

enabling them to fly for extended periods

at Mach 3.2 and at operational altitudes

of 70,000 to 85,000 feet.

In March 1960, even before delivery of

the first A-12 prototype, Lockheed and

the U.S. Air Force (USAF) discussed

development of an interceptor version of

the A-12. Designed as the AF-12 under
2

project KEDLOCK, the interceptor

featured a Hughes ASG-18 pulse-Doppler

radar system and launch bays for three

AIM-47 missiles. A second crew position,

located just behind the cockpit, accommodated a Fire Control Officer (FCO) to

operate the missile launch system.

With the assistance of the CIA, the Air

Force entered an agreement with

Lockheed to build three prototypes,

now designated YF-12A, for testing.

On 7 August 1963, Lockheed test pilot

James D. Eastham piloted the maiden

flight of the YF-12A (USAF serial

number 60-6934). Two other YF-12A

aircraft were built: 60-6935 and

60-6936. Early testing of the YF-12A

occurred in secret throughout 1963 and

early 1964.

The public first became aware of the

aircraft on 29 February 1964, when

4

 Miller, Lockheed’s Skunk Works—The First Fifty Years, pp. 122–125. The President asked Kelly Johnson for advice

regarding a proposed public announcement of the Blackbird program. On 25 February 1964, Johnson wrote in his

personal log: “Plans going forward for surfacing of AF-12 program. I worked on the draft to be used by President

Johnson and proposed the terminology ‘A-11’ as it was the non-anti-radar-version.”

First of the Blackbirds to fly, the A-12

(code-named

OXCART) was

capable of speeds in

excess of Mach 3.

The Central Intelligence Agency (CIA)

operated the aircraft

exclusively from

1962 to 1968.

(Lockheed photo)

President Lyndon B. Johnson announced

its existence. By agreement with Kelly

Johnson, the President intentionally

misidentified the aircraft as an “A-11.”4

Now public knowledge, the YF-12A

flight-test program moved to Edwards

Air Force Base (AFB) northeast of Los

Angeles in the Mojave Desert. The Air

Force soon began testing the aircraft’s

weapons system and worked on solving

troublesome problems with transonic

acceleration and various subsystems. On 1

May 1965, the aircraft set several official

speed and altitude records, including a

closed course speed of 2,070.101 mph and

a sustained altitude of 80,257.65 feet.

Lockheed engineers faced unique challenges in designing and building the

YF-12. The aircraft’s flight profile

demanded structural materials able to

withstand prolonged exposure to high

temperatures from aerodynamic heating,
3

in some places exceeding 1,000 degrees

Fahrenheit (F). Fully 93 percent of the

vehicle’s structural weight consisted of

titanium alloys. Since all-titanium

construction had not yet become common, Lockheed engineers and technicians

pioneered new inspection, test, quality

control, and manufacturing techniques.

Moreover, large sections of the leading

and trailing edges, vertical stabilizers,

chines, and inlet spikes were made of

“plastic” laminates of phenyl silane,

silicone-asbestos, and fiberglass. These

materials—featured primarily on the

A-12 and SR-71 families—helped reduce

the aircraft’s radar signature. However,

the first A-12 and the YF-12A prototypes

employed titanium instead of the composite laminates.

The Blackbirds not only incorporated

some cutting-edge materials, but also

Lockheed test pilot

James D. Eastham

lands in the first of

three YF-12A

aircraft on its

maiden flight.

(Lockheed photo)

some novel design concepts. The

Lockheed team developed a monocoque

structure for the fuselage and nacelles,

and a multispar/multirib wing structure

with cordwise corrugations for stiffness.

The presence of fuselage side-fairings, or

chines, generated almost 20 percent of

the aircraft’s total lift. Acting as fixed

canards, they also produced a favorable

effect on trim drag. Additionally, vortices

from the chines improved directional

stability of the aircraft as angle of attack

increased. The chines also provided a

convenient housing for wires and plumbing on either side of the cylindrical

center-body fuel tanks.

Propulsion for the Blackbirds consisted

of two Pratt & Whitney JTD-11B-20

(J58) afterburning turbojet engines. Each

had nine compressor and two turbine

stages. A variable geometry inlet diffuser
4

and a complex bleed bypass system

allowed for high engine efficiency in the

Mach 2 to Mach 3.2 flight regime by

controlling the location of the

shockwave inside the inlet and allowing

air to bypass the turbine section and go

directly to the afterburner.

By contrast with some of its other, more

advanced concepts, the aircraft operated

with fairly conventional flight controls.

Control surfaces included inboard and

outboard elevons for pitch and roll and

two all-moving vertical fins for lateral

control. The vertical control surfaces

had to be large to counteract the effect

of severe yaw during an inlet unstart or

engine failure. (An unstart resulted

when the shock wave moved outside the

engine inlet).

In addition, inwardly canted fins minimized roll-yaw coupling with vertical

tail deflection, and further reduced radar

cross section. Internal control linkages

included a dual-redundant hydraulic

and mechanical system. Stability

augmentation was controlled by a

triple-redundant fail-operational

electronics system.5 Although the

Blackbird designers considered fly-bywire and adaptive flight controls, they

rejected them because of potential

unknown problems that might develop

in the extreme operational environment

of the aircraft. NASA researchers later

adopted an experimental digital control

system.

Because it operated in an environment

of high aerodynamic heating, the

Blackbird required a special lowvapor-pressure (high-flash-point) fuel,

designated JP-7, one so difficult to

ignite that a lit match thrown into a

puddle of it is extinguished.6 Consequently, a catalytic igniter called triethylborane (TEB) had to be injected

into the fuel for engine start and

afterburner ignition. Fuel for the

5

 Fail-operational is defined as the ability to control the aircraft after any single failure (in the electronics system in this

case).

6

 Author’s personal experience.

The large radome

(housing a Hughes

AN/ASG-18 radar)

sets the YF-12A, left,

apart from the

SR-71. Other

differences include

ventral fins on the

YF-12A’s centerline

and engine nacelles.

Additionally, the

leading and trailing

edges of the wings

and the chines of the

SR-71 are largely

comprised of

fiberglass-asbestos

laminates that

sandwiched a

silicone-filled

asbestos honeycomb.

(Lockheed photo

CC-471)
5

SR-71—pressurized and rendered inert

with nitrogen—was contained in six

integral tanks within the fuselage and

wing structure. (The A-12 and YF-12A

had no wing tanks). Although they

included 10,000 linear feet of sealant,

the tanks leaked a considerable amount

of fuel as a result of the provisions for

expansion and contraction of the tanks

with changes in temperature. According

to NASA project engineer Gene

Matranga, Lockheed designers faced a

difficult challenge with the sealant.

They needed to find one that would be

compatible with titanium, yet “remain

elastic enough to move with the expanding and contracting airframe,

which grows up to four inches in length

when hot, shudders through an unstart,

reaches temperatures over 600 ̊F and

bounces through turbulence and taxi

loads.”7

The A-12 fleet operated in secret until

June 1968. At that time, all of the A-12

aircraft ended their service lives and

went to Lockheed’s Palmdale facility

for storage. Their operational mission

had been assumed by the SR-71A,

operated by the Air Force. A planned

operational version of the YF-12A

interceptor, designated F-12B, failed to

materialize as Secretary of Defense

Robert McNamara ultimately cancelled

the program as a cost-cutting measure.

As a consequence, on 29 December

YF-12A (USAF

serial number 60-

6935), seen in flight

just east of Edwards

AFB, was the first

to join the NASA/

USAF research

program. The two

pointed objects on

the underside of the

engine nacelles are

camera pods.

(NASA photo

EC76-5086)

7

 Gene J. Matranga and William J. Fox, “YF-12A Development and Operational Experience”, unpublished paper

presented at the Supercruiser Conference, Wright-Patterson AFB, Ohio, 17-20 February 1976. NASA Dryden Historical

Reference Collection.
6

1967, the Air Force instructed Kelly

Johnson to terminate F-12B development. The YF-12A program ended on 1

February 1968, and the aircraft joined

the A-12s in storage. There they reThis cutaway

view illustrates

the complex

internal structure

of the YF-12A.

Design and

construction of a

mostly titanium

airframe posed

numerous

challenges for

Lockheed

engineers.

(NASA photo

E76-30059)

mained until NASA reached an agreement with the USAF for a joint research

program, beginning in 1969. Subsequent

events proved this partnership to be a

long and rewarding one.

Figure 1
7

Chapter 2:

Joint USAF/

NASA YF-12

Research

Within a year of the public debut of the

YF-12A, NASA expressed an interest in

using the aircraft as a research platform.

In an overview of active and proposed

research programs for 1965, planners at

the NASA Flight Research Center (FRC)

at Edwards AFB, California, wrote that

the YF-12A had “significant features of

the configuration and operation of the

aircraft that are of vital research interest,”

and which would complement research

being conducted with the XB-70, F-111,

and X-15.

NASA engineers regarded the YF-12A,

with its capacity to sustain Mach 3 cruise

speeds, as a potential source of data for

developing advanced supersonic and

hypersonic aircraft. Initially, the FRC

program consisted of analyzing results of

the USAF-Lockheed test program in

hopes of a better understanding of:

• High-altitude hypersonic handling qualities.

8

 “Project Programs-Part II,” briefing material from the center director’s monthly Projects Review meeting, NASA

Flight Research Center, Edwards, California, March 1965. NASA Dryden Historical Reference Collection.

9

 A note on serial numbers: Only three YF-12A aircraft were built by Lockheed; they include USAF serial numbers 60-

6934 through 60-6936. A-12 aircraft serial numbers include 60-6924 through 60-6933 and 60-6937 through 60-6939.

The M-21 variants were 60-6940 and 60-6941. The SR-71 series includes 61-7950 through 61-7981. The SR-71 serial

numbers have frequently been published erroneously with a “64” prefix, as in 64-17950. All official documentation

bears out the statements above. The best example is a complete list of SR-71 serial numbers in SR-71 Final Report–

Category II Flight Test Program, 1 July 1965 to 30 June 1967, Volume II, Appendix X, p. X-8, declassified on 5 February

1991. A copy of this report is available in the Air Force Flight Test Center History Office at Edwards AFB, California.

• Techniques to determine the structural

integrity of hypersonic aircraft in flight.

• Performance of hypersonic air-breathing

propulsion systems.

• The interrelationships between the

aerodynamics of air propulsion systems

and the aerodynamics of hypersonic

cruise configurations.8

In the beginning, NASA failed to obtain

any of the YF-12A or SR-71 aircraft for

flight research. The first attempt was a

request by NASA to R. L. Miller of

Lockheed, who in turn submitted a

proposal to the company’s Director of

Flight Test Larry M. Bohanan in June

1968. NASA engineers wanted to obtain

SR-71 inlet data by installing instrumentation in the number four SR-71A (USAF

serial 61-7953).

9

 Miller agreed to

include the NASA request as a separate

part of a larger proposal for instrumentaNASA engineers

analyzed propulsion,

as well as stability

and control data

obtained from the

number four SR-71A

in 1968 and 1969 as

it underwent USAF

Category II (performance) tests at

Edwards AFB,

California. (USAF

photo)
8

tion in the aircraft. But even though he

forwarded the proposal, Miller did not

support it. In the first paragraph of the

proposal he wrote: “It is probably not

advantageous from our standpoint to

allow NASA participation since it would

require increased maintenance and would

interfere with our development tests

which are required in support of the fleet.

In addition, the measurements would not

provide any known benefits to the SR-71

program.”10

Not surprisingly then, Lockheed turned

down NASA’s request. However, a

second opportunity presented itself when

two NASA representatives participated in

the USAF Category II tests of the

SR-71A. Engineers Gene Matranga and

Bill Schweikhard worked with Air Force

officials in analyzing propulsion, stability,

and control data from the tests conducted

in 1968 and 1969.11

Although these contacts did not yield an

SR-71 for NASA to use, the Air Force

finally agreed to make two YF-12A

aircraft available to NASA researchers. A

Memorandum of Understanding (MOU)

for a joint NASA/USAF research program, signed on 5 June 1969, agreed that

the Air Force would provide the airplanes,

personnel, ground support equipment, and

facilities. NASA, in turn, agreed to pay

the operational expenses for the program,

using funding that became available

following termination of the XB-70 and

X-15 programs.

The MOU outlined the general provisions

of a joint NASA/USAF YF-12 research

program, consisting of Phases I and II.

The USAF Phase I, conducted to explore

10 Memorandum from R. L. Miller to L. M. Bohanan regarding Proposed Instrumentation for 2004 Follow On Tests, 17

June 1968. NASA Dryden Historical Reference Collection.

11 Berwin Kock, “Overview of the NASA YF-12 Program,” presentation during NASA YF-12 Experiments Symposium

held at Hugh L. Dryden Flight Research Center, Edwards, California, 13 September 1978. NASA Dryden Historical

Reference Collection.

12 “Memorandum of Understanding, USAF-NASA Research and Development Program,” 5 June 1969. NASA Dryden

Historical Reference Collection.

the tactical performance and support

requirements of an advanced interceptor,

included tactical tests of command,

control, and communications; test intercepts of flying targets; and tests of the

ASG-18 fire control system. The program

also involved an examination of postattack escape maneuvers, a demonstration

of a semi-autonomous operational

concept for a Mach 3 interceptor, and an

assessment of the feasibility of a visual

identification maneuver against an SuperSonic Transport (SST)-type target. The

renewed interest of the USAF in Phase I

resulted from the recent introduction of

the high-performance MiG-25 into the

Soviet Air Force inventory. Although

Phase I centered on Air Force needs, the

MOU also accommodated the objectives

of the NASA investigations.12

The two partners announced the joint

program on 18 July 1969. Gene Matranga

headed up the NASA team, which spent

the first several months of the project

installing instrumentation in the YF-12A.

By December, engineers had placed strain

gauges and thermocouples in the wing

and fuselage to measure dynamic loads

and temperatures.

The NASA Phase II program began when

Paul F. Bikle, director of the NASA FRC,

signed an agreement on 31 March 1970

with the Air Force, loaning YF-12A (60-

6935) to NASA. This second round of

tests included research into propulsion

systems, aerothermoelasticity, and flightdynamics characteristics of supersonic

cruise aircraft.

NASA YF-12 research represented a

cooperative effort by researchers from
9

every NASA aeronautical center.

Engineers from Langley Research

Center in Hampton, Virginia, concentrated primarily on aerodynamics and

structures. Lewis Research Center (now

Glenn Research Center) in Cleveland,

Ohio, had an interest in propulsion

aspects. Engineers from Ames Research

Center focused on inlet dynamics and

the correlation between wind-tunnel and

flight data. Researchers at NASA FRC

organized these various interests into a

single, unified investigation.13 According to a program overview by NASA

FRC engineer Berwin Kock, “the

program also had unique, strong, and

continuing support from NASA Headquarters, and the USAF was an active

partner in the program, providing

logistics support and playing an active

13 Richard P. Hallion, On the Frontier: Flight Research at Dryden, 1946-1981 (Washington, D.C.: NASA SP-4303,

1984), p. 191.

14 Berwin Kock, “Overview of the NASA YF-12 Program.”

role in formulating technology experiments.”14

In spite of its earlier resistance to the

project, Lockheed Aircraft Company now

provided valuable technical support.

Privately, however, YF-12 designer Kelly

Johnson made some frank observations

about NASA and the YF-12 in his personal log:

The YF-12A

collected aerodynamic data with and

without the ventral

fin. NASA engineers determined

that removing the

fin did not seriously

affect aircraft

stability. The white

circles with crosses

served as photo

calibration marks

for ground-based

tracking cameras.

(NASA photo

EC71-2710)

Had a visit from the NASA test

organizations [which] discussed their

research to date. They haven’t come

up with anything that is new to us,

but it seems to be a good program for

them to keep up their technical

organizations. I am attaching a letter

from Gene Matranga indicating our

current relationship, which is excel-
10

15 Jay Miller, Lockheed’s Skunk Works–The First Fifty Years, p. 133.

Personnel associated

with YF-12 research

included: (standing,

left to right) William

R. “Ray” Young,

Fitzhugh L. Fulton,

Jr., Donald L.

Mallick, Victor W.

Horton, and (kneeling, left to right)

Harry R. Childs,

William P. Albrecht,

Bob Eaton, Jack

Mayesh, Gene J.

Matranga, William

Fox, and Joe D.

Watts. (NASA photo

EC72-2989)

lent. I have two objections to the

NASA program, the main one is

that they will probably publish

important data, which the Russians will be happy to receive as

they always are with NASA

reports. Secondly, they are

repeating so many things we

pioneered in and I gravely doubt

our people will be given any, or

sufficient, credit for solving the

problems first. We have continued to cooperate to the hilt with

NASA in spite of the above.15

NASA flight crew members for the

YF-12 aircraft included two pilots and

two flight-test engineers. The first

NASA crew to be checked out in the

YF-12A consisted of Fitzhugh L.

Fulton, Jr. (research pilot) and Victor

W. Horton (flight-test engineer). Fulton,

a former Air Force test pilot, joined

NASA in 1966. Prior to assignment to

the YF-12 program, he had served as

project pilot on the XB-70. Aerospace

engineer Vic Horton joined NASA in

1959 and became involved in the

paraglider and lifting-body programs.

He also served as launch panel operator

on the NB-52B mothership aircraft.

Fulton and Horton underwent a series

of three checkout flights in YF-12A

(60-6936) in March 1970. The following month, NASA FRC chief research

pilot Donald L. Mallick, a former

XB-70 project pilot, was checked out in

YF-12A (60-6935). At the end of April,
11

YF-12A (USAF

serial number

60-6936) joined

the program in

1970 as the

primary USAF test

aircraft. White

markings near the

nose commemorate world speed

and altitude

records achieved

by this aircraft on

1 May 1965.

(NASA photo

EC70-22047)

aerospace engineer William R. “Ray”

Young, associated previously with the

X-15, XB-70, Lunar Landing Research

Vehicle (LLRV), and F-111 research

programs, teamed with Mallick. With the

completion of this process, the experiments aboard the Mach 3 Blackbirds

could begin.
12

Chapter 3:

Heating and

Loads

Research

Originally, NASA researchers planned to

concentrate the YF-12 program on

propulsion technology, especially inlet

performance. Since the YF-12 featured a

mixed-compression inlet, engineers

planned to investigate drag, compressor

face distortion, unstart margins, control

parameters, air data requirements, and

bleed system effects.

But problems associated with hightemperature instrumentation delayed the

propulsion investigation. This postponement gave NASA engineers time to

develop a second initiative: a structures

research program involving thermal

stresses and aerodynamic loads. The

overall effort relied on wind-tunnel data,

analytical prediction, and flight research.

SR-71A (61-7954)

served as a stand-in

for the YF-12A

during construction

of heaters for the

structural loads

program. (NASA

photo E71-23783)

Detail of the rear

fuselage heater

assembly under

construction

around SR-71A

(61-7954). When

construction was

completed, a total

of 16,430 radiant

quartz lamps

enabled researchers to simulate

flight temperatures

over a 5,000-

square-foot area of

the aircraft’s

surface. (NASA

photo E71-23782)
13

16 Interview of Gene Matranga by Peter Merlin, Lancaster, California, 30 May 2000. See Appendix 4 for a transcript of

this interview. An original copy is in the NASA Dryden Historical Reference Collection.

Since supersonic aircraft undergo aerodynamic as well as thermal loads, the

NASA team planned a series of experiments at the FRC to measure the two

types, both combined and separately.

Technicians installed instrumentation in

the wing and fuselage of YF-12A (60-

6935). Strain gauges placed in several

locations measured aerodynamic loads. At

the same time, instruments on the left side

of the aircraft recorded skin temperatures.

The YF-12 possessed ideal qualities for

thermal research. Previous research

aircraft, such as the X-15, had experienced high temperatures, but only for

short periods of time. The YF-12, however, could sustain high-speed thermal

loads for relatively long periods during

cruise, enabling temperatures to stabilize.

As FRC project manager Gene Matranga

noted:

The forebody

heater assembly,

shown undergoing

tests prior to

installation around

the foreward

fuselage of the

YF-12A. (NASA

photo EC71-2788)

We recognized that it would take a

while to develop instrumentation for

the aircraft, and we decided to use

this time to investigate steady-state

heating effects on the aircraft

structure.

In all the X-15 work, everything

had been transient. The vehicle

went to high speed in a matter of

two to three minutes. It slowed

down in a matter of three to five

minutes. Everything was always

transient because the temperature

was always increasing or decreasing. The YF-12, on the other hand,

could stay at Mach 3 for 15 minutes. We could get steady-state

temperature data that would augment

the X-15 data immeasurably.16

After collecting flight research data over

most of the YF-12 performance envelope,

researchers compared it to data collected

during ground testing in the High Temperature Loads Laboratory (HTLL) at the

NASA FRC during 1972-73. The process

of comparison involved several steps.
14

17 Jerald M. Jenkins and Robert D. Quinn, “A Historical Perspective of the YF-12A Thermal Loads and Structures

Program,” NASA Dryden FRC, Edwards, California, NASA TM (Technical Memorandum) 104317, May 1996,

pp. 8-11. NASA Dryden Historical Reference Collection.

Radiant quartz lamp heaters were fitted around the exterior of

the YF-12A and inside the engine nacelles. Thermocouples on

the aircraft’s skin measured temperatures that simulated those

occurring in flight. (The Radiant Heater graphics, Figures 2A-1C,

came from NASA FRC Basic Research Review, 23 July 1973.)

Engine Nacelle Heater

Flight research data provided measurements of the combined effects of temperature and loads. Once this information

had been gathered, technicians put the

aircraft into the HTLL and heated the

entire structure to the same temperatures

that it had experienced in flight. By

measuring the strain outputs from temperature alone, NASA engineers could

then separate the thermal effects from the

flight data to obtain accurate measurement of aerodynamic loads.

In the HTLL, a radiant heater provided

the necessary heating for the ground

simulation. The apparatus consisted of

464 stainless steel reflector panels

configured to fit the contours of the

aircraft. A total of 16,430 radiant quartz

lamps enabled the YF-12 team at the FRC

to simulate flight temperatures over a

5,000-square-foot area of the aircraft’s

surface. The heater units covered five

areas: aft fuselage, mid-fuselage and

forward nacelles (right and left), and the

right and left halves of the forward

fuselage. Additionally, another heater fit

into the nacelle in place of an engine,

allowing researchers to simulate exact

three-dimensional engine temperatures

inside the nacelle. All of the heaters were

subdivided into numerous control zones,

each one in turn governed by a surface

thermocouple. A data acquisition and

control system, a test monitor system, and

a test data processing system fulfilled the

remaining simulation requirements.17 By

feeding the temperature profiles recorded

in flight into a computer, the quartz lamps

could generate the same profiles during

the ground tests.

To prepare the aircraft for the heating

research, technicians removed the

aircraft’s vertical tails, nose cone, and

inlet spikes, parts not considered relevant

to the temperature calibration of the

aircraft. They also detached the engines,

relying on the nacelle heater to simulate

Figure 2C

Figure 2B

Figure 2A
15

18 Ibid., p. 12.

19 Ibid., p. 13.

engine temperatures. To avoid accidental

explosion, FRC technicians also removed fuel-soaked insulation and

replaced it with dry material. They

flushed and dried the fuel tanks as well

and purged them with gaseous nitrogen

during the tests.18

Results of the heating experiments

showed that the predictions largely

agreed with the laboratory results. Data

obtained during flight, however, indicated temperatures as much as 20

degrees higher than anticipated because

of the differences in the process of heat

transfer. The rate of radiant heating is

lower than that for aerodynamic heating

in areas of higher structural mass.

Moreover, the dry fuel tanks used in the

ground tests also influenced the results.

In flight, the aircraft’s fuel acted as a

heat sink. Given the absence of fuel in

the aircraft during ground-based heating

tests, the fuel tank skin temperatures

exceeded those obtained in flight. The

simulation and flight measurements

converged as the flight- test aircraft

depleted its fuel supply. Once these

values converged, researchers established a correction for in-flight strain

gauge measurements.19

With the resultant data about aerodynamic heating at high speeds recorded, the

YF-12 team could turn to its initial interest,

propulsion research at high speeds.
16

Chapter 4:

Propulsion

Research

Using the YF-12, NASA researchers

hoped to establish a technology base for

the design of an efficient propulsion

system for supersonic cruise aircraft,

such as a Supersonic Transport (SST).

The main areas under investigation

included inlet design analysis, propulsion system steady-state and dynamic

performance, inlet engine control

systems, and airframe/propulsion

interactions. Engineers and scientists

from NASA Ames, NASA Langley,

NASA Lewis, and the NASA FRC all

contributed to the YF-12 propulsion

studies.

Since supersonic cruise aircraft required

a propulsion system capable of operating efficiently throughout a wide range

of flight conditions, designers needed to

20 Reynolds number, named after Osborne Reynolds, is a nondimensional parameter equal to the product of the velocity of an

object (an airplane in this case) passing through a fluid (air in this case), the density of the fluid and a representative length,

divided by the fluid’s viscosity. In shorthand, the Reynolds Number represents the inertial forces divided by the viscous

forces for the mass of air acted upon by the vehicle. Among other uses, it served to compare data from wind-tunnel models

with that from full-sized airplanes or components. The Reynolds number was not determined solely by the viscosity of the

air. The YF-12, for example, would have a much larger Reynolds number when flying through air at a given altitude,

location, and time than would a small model simply because of the difference in size and the amount of air displaced.

Furthermore, the Reynolds number would be much larger at the rear of a flight vehicle than at the front.

optimize the inlet system to match engine

requirements at varying speeds and

altitudes. NASA FRC engineer James A.

Albers described the research process

inherent in the YF-12 investigation:

Technicians

opened the hinged

nacelle to gain

access to the Pratt

& Whitney J58

engine for repair

or replacement.

Operating in

continuous

afterburner during

cruise, the engine

consumed over

11,000 pounds of

fuel per hour.

(NASA photo

E71-23809)

A first step in optimization of the

propulsion system is an analytical

study of the various inlet geometries

that match the engine requirements.

This is followed by wind tunnel

testing of scaled models prior to

flight testing. In general, conditions

in the wind tunnel do not exactly

duplicate flight conditions. With

scaled models, the Reynolds numbers20 and local flow field do not

always correspond to those in flight.

In addition, the geometry and the

instrumentation location and accu-
17

21 James A. Albers, “Status of the NASA YF-12 Propulsion Research Program,” NASA TM X-56039, March 1976, p. 1.

NASA Dryden Historical Reference Collection. The FRC became the NASA Dryden Flight Research Center in the

month and year this paper appeared, but Albers had been an FRC engineer when he wrote it.

A movable cone,

or spike,

transitioned

forward and aft to

control the

position of the

shock wave and

the Mach number

of airflow into the

J58 engine’s inlet.

Forward bypass

doors opened and

closed automatically to control

airflow depending

on pressures

measured inside

the ducts. (NASA

photo E79-36284)

racy of wind tunnel models are

difficult to match to those of the

flight hardware. Since the flight

hardware and its expected performance are determined from scaled

wind tunnel models, scaling

techniques that allow the extrapolation of subscale inlet data to

full-scale flight are necessary.21

Employing two Pratt & Whitney J58

engines, the YF-12’s propulsion system

included a mixed compression inlet in

which air entered at supersonic speeds

and slowed down to subsonic speeds

before reaching the engine. The air’s

velocity had to be reduced because no

existing engines could run on supersonic

flow. Several devices moderated airflow

into the engine. A movable cone, or

spike, in the inlet transitioned forward

and aft to control the position of the

shock wave and inlet Mach number.

Forward bypass doors opened and closed

to maintain the proper position of the

shock wave. The doors operated automatically as a function of pressures

measured in the ducts. Aft bypass doors,

operated by the pilot as a function of

Mach number and forward door position, controlled airflow at the engine

turbine face. Designers also devised a

system to bleed off low-energy boundary-layer air that formed along the

surface of the inlet spike. This practice

improved inlet efficiency by making the

entire main inlet flow passage available

to the high-energy, high-velocity

airflow.

A CIA report on the Project OXCART

A-12 aircraft (predecessor to the YF-12)

underscored the pivotal function of the

Blackbird’s inlet:

A supersonic inlet or air induction

system is designed to provide [the]

best possible aerodynamic perfor-
18

22 “OXCART A-12 Aircraft Experience Data and Systems Reliability,” p. 6. (See Chapter 1, footnote 1.)

23 Gene Matranga and William J. Fox, “YF-12A Development and Operational Experience,” unpublished paper presented at the Supercruiser Conference, Wright-Patterson AFB, Ohio, February 17-20, 1976, p. 3. NASA Dryden

Historical Reference Collection.

mance over a range of supersonic

Mach numbers with a stable and

steady flow of air to the engine.

However, due to constraints

imposed by supersonic aerodynamics, truly optimum performance

with an ideal shock pattern and an

inlet airflow exactly matched to the

engine airflow requirement can

only be provided at one flight

condition. Since the OXCART

aircraft must cruise for considerable periods of time at a Mach 3

speed, maximum possible range is

realized by providing this optimum

inlet performance at the Mach 3

cruise condition. The basic geometry and airflow characteristics of

the inlet are then varied to provide

a minimum compromise of

aerodynamic performance and

efficiency at lower flight speeds.

Some of this needed flexibility is

provided by varying the position of

the inlet spike. Since the airflow

which can be admitted by the inlet

YF-12 inlet

diagram showing

translating spike

and bypass doors

and louvers.

(Drawing taken

from NASA TM

X-56039)

During high-speed flight in the YF-12,

compression of air in the inlets generated

most of the vehicle’s thrust. The turbojet

continued to run, but the inlet provided 70

to 80 percent of the total motive force. A

significant percentage of the air entering

the inlet bypassed the engine through

ducts and traveled directly to the afterburner. At cruise Mach conditions, fuel

burned more advantageously in the

afterburner than in the main burner

section. Hence, engineers described the

powerplant as a turbo-ramjet.23

The shock waves presented a challenge to

the system. If designers failed to properly

Figure 3

is in excess of that which can be

accepted by the engine at other than

the design condition, this excess

airflow is dumped overboard

through a series of forward bypass

doors or passed down the nacelle

airflow passage around the engine

through a series of aft bypass

doors.22
19

Conceptual

schematic drawing

of an integrated

inlet and airflow

control system.

(Drawing taken

from NASA TM

X-56039)

Airflow into the

nacelles with the

forward bypass

doors open. Note

areas of separated and reverse

airflow. (Drawing taken from

NASA TM

X-56039)

match airflow to the inlet, the shock

wave would create drag. Normally the

shock wave would be expected to occur

slightly behind the inlet throat and

supersonic diffuser for stability. But in

this case, the spike and bypass doors

functioned together to retain the shock

wave inside the inlet. Sometimes,

however, large airflow disturbances or

improper inlet control system operation

caused the inlet to expel the shock wave.

This resulted in an inlet unstart, the

byproduct of insufficient pressure and air

for normal engine operation. This

sudden loss of thrust produced violent

yawing, pitching, and rolling of the

airplane. Pilots likened the phenomenon

to a train wreck. During the YF-12

research program, unscheduled unstarts

were common on any given mission. But

as a result of the NASA investigation,

spike schedule refinements (coordinating spike position to retain the shock

wave in the inlet), and hardware improvements rendered unstarts a rare

occurrence.24

24 Ibid., p.4.

Figure 5

Figure 4
20

25 Two types of engines were used in the SR-71 aircraft. The early type (referred to as the J-engine), also used in the

YF-12A, incorporated fixed compressor inlet guide vanes and had a maximum afterburner thrust rating of 32,500

pounds at sea-level standard-day conditions. An improved configuration (the K-engine) incorporated two-position

compressor inlet guide vanes. The vanes were automatically positioned axially below Mach 1.9 to provide increased

airflow and increased thrust rating. Above Mach 1.9, the vanes moved to a cambered position and the engine provided

thrust equivalent to the J-engine. The K-engine had a maximum afterburner thrust rating of 34,000 pounds at sea-level

standard-day conditions.

26 Metal spikes were originally built for the first three SR-71A aircraft and the two SR-71B trainers. This type of spike

assembly was also used on the YF-12A. A “plastic” spike was later incorporated into production aircraft to reduce the

vehicle’s radar cross-section. Both types of spike were primarily constructed of A-100AT titanium alloy. On early

models, the conical front section of the spike was comprised of a built-up, ring-skin assembly. On the improved units an

asbestos-fiberglass laminate “plastic” assembly replaced the metal cone.

27 Several years later, the improved (K-type) engines were installed in the YF-12A (60-6935). The first flight of 935

with the K-engines took place on 18 October 1974. No propulsion research was conducted with the K-engines.

28 “Project Activity Guide (Accomplishments),” dated 2 June 1971 and 17 June 1971, lists all three aircraft (935, 936,

and 937) indicating that 937 was not simply a replacement for 936, which crashed on 24 June 1971. NASA Dryden

Historical Reference Collection.

29 YF-12A (60-6936) Mishap Report, “History Of Flight,” AF Form 711, Part 11, 16 July 1971. Formerly classified

SECRET-Special Access Required-SENIOR CROWN Program. Declassified in 1996 per Freedom Of Information Act

request by author. Released 14 May 1998. NASA Dryden Historical Reference Collection.

At the same time, NASA did not give up

its earlier attempts to acquire an SR-71A

for Blackbird flight research. Such

efforts did not meet with enthusiasm in

Air Force circles. Some USAF officials

felt that the sensitive SR-71 technology

might not be protected properly in

civilian hands. Indeed, the Blackbirds

then in service had improved engines25

as well as inlet spikes26 less visible to

radar than those on earlier models. For

security reasons, the Air Force refused to

lend NASA an aircraft with either of

these advanced features.27

Air Force representatives did finally relent,

but with conditions. They agreed to loan

NASA the second SR-71A (61-7951), but

with the earlier model engines, ostensibly

to match the inlet behavior of the YF-12A.

Additionally, to hide the aircraft’s identity,

it entered NASA service as the YF-12C

and received tail number 06937. The tail

number followed in sequence with the

other two aircraft—06935 and 06936—

and bolstered the assertion that this was a

YF-12, and not an SR-71. The SR-71s’

tail numbers began at 17950. A classified

A-12, with tail number 06937, also

existed. Placed in storage at the

Lockheed facility in Palmdale, California, its existence remained unknown to

the public until 1982. (For purposes of

convenience, the YF-12C designation

will be used throughout the remainder of

this monograph). By May of 1971,

Lockheed technicians undertook an

inspection of the YF-12C in preparation

for its addition to the NASA research

program. They completed their work on

number 937 by the middle of June, and

prepared it to join 935 and 936.28

On 24 June 1971, the program suffered a

setback. Lt. Col. Ronald J. “Jack”

Layton piloted number 936 on its 62nd

flight of the joint program, and Maj.

Billy A. Curtis served as flight-test

engineer. After performing a handling

qualities evaluation the crew returned to

base. But on the way home, disaster

stuck. A fuel line in the right engine

failed, causing a fire. As Layton approached Edwards, hoping to make an

emergency landing, flames engulfed the

right side of the aircraft. The crew

ejected safely, but the YF-12A plunged

into the desert.29 The loss of 936 caused
21

delays in the YF-12 propulsion research

program. While the remaining YF-12A

continued to serve as a loads testbed, the

YF-12C arrived at NASA FRC on 16 July

1971. It did not begin propulsion research

flights, however, until 6 June 1972.

Propulsion research using the YF-12C

included airspeed calibrations, collection

of baseline data, and data collection at

numerous flight conditions. To gather

data on propulsion system performance,

research crews performed such tasks as

level accelerations and decelerations,

constant power turns, and airspeed lag

YF-12A (serial

number 60-6936)

served as the

primary USAF test

aircraft during the

joint program. It

was lost in a nonfatal accident during

an Air Force flight

on 24 June 1971.

(Lockheed photo

LA-4087)

calibration roller-coaster maneuvers. As

the crews operated the engine inlet

controls in manual and automatic modes,

instruments measured oscillations known

as phugoids.30 They also gathered data on

engine-bypass-door and inlet-spike

performance and established speedpower points. Finally, they performed

constant-speed climbs and descents at

specific knots estimated airspeed

(KEAS) or Mach number and constantpower turns.

For the early USAF tests, Lockheed had

equipped a YF-12A with a Honeywell

30 A phugoid occurs when an aircraft’s airspeed or pitch attitude is disturbed from its trimmed equilibrium condition.

During flight, the pilot trims the aircraft to a desired angle of attack (pitch attitude) which may then be disturbed by

additional pilot input or natural air turbulence. The airplane’s tendency to return to its trimmed attitude is so strong that

it generally returns too quickly and overshoots. The resultant oscillations tend to die out after a few cycles and the

aircraft returns to its trimmed condition. John S. Denker provides an excellent description of phugoids in See How It

Flies (1996), a book available on the World Wide Web at http://www.monmouth.com/~jsd/how/htm/

how.html#contents.
22

general-purpose computer called the

Central Airborne Performance Analyzer

(CAPA) Phase I to monitor the aircraft’s

Air Inlet Control System (AICS). The

unique inlet system on the YF-12 made it

vulnerable to high stresses, severe

environmental conditions, and possible

malfunctions. Because the AICS only

realized its full operational capabilities at

high supersonic speeds, malfunctions—

which tended to occur in this regime—

proved most difficult to detect. Such

malfunctions could not be discovered

during static ground tests. But the CAPA

provided a central system to continuously

monitor and analyze the performance of

the AICS during flight and transmitted

maintenance messages identifying the

faulty components.

Honeywell delivered an improved CAPA

Phase II to Lockheed in February 1973.

The new CAPA featured a specialpurpose computer with an instruction

repertoire specifically tailored to the task

of in-flight performance monitoring,

malfunction detection, and fault isolation. A second remote unit monitored

additional signals including fuel and

hydraulic systems and engine functions

for information purposes rather than fault

detection. Lockheed technicians installed

the CAPA Phase II prototype in a Functional Mock-Up (FMU), a ground-based

model containing all the operational

systems of a real YF-12 aircraft.

Lockheed delivered the CAPA unit to

NASA in March for installation in the

YF-12A. By 28 June, NASA technicians

had completed the integration of the

CAPA Phase II system. Between 12 July

1973 and 6 June 1974, the CAPA system

operated during 28 flights. Because of

the high reliability associated with AICS,

the CAPA made only one valid fault

detection/diagnostic in over 71 hours of

By May 1971,

Lockheed technicians were

inspecting the

number two

SR-71A (61-7951)

in preparation for

its addition to the

NASA research

program. It was

redesignated

“YF-12C” for

reasons of security

and painted in

NASA markings

with a different tail

number, 06937.

The YF-12C

arrived at the

NASA Dryden

FRC on 16 July

1971. (NASA

photo EC72-3149)
23

31 “Final Report for the CAPA/YF-12 Central Airborne Performance Analyzer, Phase II: The Study of In-Flight Real

Time Diagnostics,” Honeywell, Report W8340-FR, 8 November 1974, pp. 1-1 to 4-2.

operation. The remote unit, however,

detected failures in other systems,

revealed in later ground-based data

processing. If the maintenance software

for these systems had been installed into

the CAPA, technicians on the ground could

have detected the failures in real time.31

Once this software had been evaluated,

the YF-12 crews conducted a series of

tests between 19 November 1976 and 21

July 1977 to correlate specific windtunnel data points with flight-test data

points. To establish the match points

precisely, the pilot had to fly the aircraft

within 0.05 Mach number of the recorded wind-tunnel speed. The match

points provided flight-test inlet data and

verified the earlier wind-tunnel results.

Researchers also studied the phenomenon of unstarts by inducing them

intentionally and then restarting the

engine. NASA technicians installed an

inlet override system, called Inlet Recall,

to allow manual control of the inlet spike

and bypass doors. During a test of the

system, the autopilot controlled attitude

and altitude. The pilot slowly trimmed

the inlets to maximum performance, then

went beyond and induced the unstart

condition. As the aircraft underwent a

sudden, violent loss of altitude and

airspeed, the pilot initiated either an

automatic or manual restart procedure.

These important investigations were

complemented by another phase of

NASA Blackbird flight research, involving the landing characteristics of these

high-speed vehicles.
24

Chapter 5:

Landing

Studies

In another facet of YF-12 research, NASA

and Lockheed engineers investigated

Space Shuttle landing dynamics using the

YF-12C. Several flights, conducted in

April and June 1973, demonstrated

Shuttle-type flight characteristics during

low lift-to-drag (L/D) approaches.32

Specifically, the researchers needed data

for L/D ratios of two to three, the range

predicted for the Space Shuttle orbiter.

This necessitated operating the YF-12C in

a high-drag configuration, achieved by

reducing power to idle, moving the inlet

spikes forward, and opening the bypass

doors to the restart position. In addition,

the pilots needed to transfer fuel to

maintain a forward center-of-gravity and

to burn off fuel to allow descent at as light

a weight as possible (to avoid flying the

aircraft at maximum L/D). The descent

profile maximized engine negative thrustinlet drag and also allowed for the lowest

possible lift coefficient.

Three flights, including 26 approaches,

resulted in satisfactory pilot ratings for

all handling qualities. The flight crews

noticed no tendency toward pilot-induced

oscillation and suggested that the YF-12C

would serve as an acceptable model for

Space Shuttle landing characteristics.

In 1974, NASA engineers decided to use

the YF-12 aircraft in a somewhat different role: to study the landing dynamics of

a low-aspect-ratio33 supersonic aircraft.

The data would be used to validate the

Flexible Aircraft Takeoff and Landing

Analysis (FATOLA) computer program

developed by NASA Langley, one that

offered a six-degrees-of-freedom rigid

body simulation.34 Technicians from

32 Lift-to-drag ratio is the value of the total aerodynamic force acting on a body (such as an aircraft or wing) divided by

the retarding force that acts on that body as it moves through a gaseous fluid.

33 Aspect ratio is the ratio of the square of the span of an airfoil to the total area, or the ratio of its span to its mean chord.

34 Six-degrees-of-freedom refers to six axes of motion, in this case: up, down, left, right, backward, and forward.

Following takeoff,

the YF-12C takes

on JP-7 fuel from

a KC-135Q tanker.

In 1973, NASA

crews flew the

YF-12C to

simulate Space

Shuttle landing

approaches.

Satisfactory pilot

ratings suggested

that the aircraft

had acceptable

handling qualities

to serve as a model

for Shuttle landing

characteristics.

(NASA photo

EC72-3146)
25

35 “YF-12 Runway Response,” James M. McKay notebook. NASA Dryden Historical Reference Collection. The original

program, designed by NASA Langley for use with rigid bodies, was called Takeoff and Landing Analysis (TOLA). After

McDonnell Douglas Astronautics Corporation programmers modified it with a flexible-body option, it was renamed

Flexible Aircraft Takeoff and Landing Analysis (FATOLA). James M. McKay refers to it simply as TOLA throughout his

notes, but it is more properly called FATOLA as used for the YF-12.

36 Ibid.

McDonnell Douglas Astronautics Corporation programmed FATOLA with the

YF-12 structural mode data and computed the airplane response to taxi,

landing, and takeoff using a measured

runway profile.35

Up to this time, aircraft designers lacked

a solution to a complex problem affecting

transport aircraft. They could not predict

adequately the structural and control

problems resulting from landing gear and

airframe interactions. Runway irregulariNASA research

pilots flew the

YF-12A to study

landing dynamics

of low-aspect-ratio

supersonic aircraft.

The data validated

computer simulation methods

developed by

NASA Langley.

(NASA photo

EC76-5110)

ties routinely affected tire loads. Surface

roughness, ground contour elevations and

slopes, and airplane-to-ground axis

orientation all contributed inputs through

tire deflections and unsprung mass

excitations.36 The increased structural

flexibility and higher takeoff and landing

speeds of proposed Supersonic Transport

(SST) designs magnified the problem.

Since the YF-12 shared many structural

characteristics with SST designs, the

Blackbirds assumed a leading role in

the landing dynamics research program.
26

Planning for the landing study involved

much teamwork inside and outside of

NASA. Gene Matranga and Jim McKay

represented NASA’s Flight Research

Center. Bob McGehee and Huey Carden

were the primary researchers from

NASA Langley. Bill Fox and Gus

Dishman of Lockheed Advanced Development Projects provided additional

support, particularly regarding the

calibration of instrumentation. These

calibrations were completed by the end

of 1974 and on 31 January 1975 Jim

McKay submitted a Request for Project

Approval to measure YF-12 response to

runway roughness. McKay proposed

instrumenting the YF-12A to measure

ground loads and dynamic response

during landing, taxiing, and takeoff on

the Edwards AFB main runway.

The program coordinated the research

efforts of the NASA Langley Structures

and Dynamics Division in developing an

active landing-gear-control system for

proposed SST aircraft. NASA FRC

researchers obtained experimental

response data from flight tests to correlate with the response calculated using

the FATOLA program. The validated

FATOLA program defined the interactive

characteristics of active-control landing

gear systems with other aircraft characteristics and systems such as engine

thrust, ground effect37 and crosswind

aerodynamics, unsymmetrical touchdown conditions, airframe structural

elasticity, and antiskid braking.

During March 1975, Flight Research

Center technicians instrumented the

YF-12A with strain gauges and accelerometers for the two-phase program. The

first phase consisted of consecutive

takeoffs and landings in the low-speed

flight regime. The second phase included

high-speed flight to assess the effect of

37 Ground effect is an increase in the lift of an aircraft operating close to the ground caused by reaction between highvelocity downwash from its wing and the ground.

38 The air-load-stroke curve is a function of landing gear strut stroke and strut loads. The stroke (length of extension/

compression of the gear strut) is a function of maximum touchdown load, impact velocity, stroking efficiency, and tire

deflection.

elevated temperatures on landing gear

performance.

Prior to conducting ground-loads and

aircraft-response experiments, researchers created a runway profile for the

primary paved airstrip at Edwards AFB,

California, to better define flight-test

conditions. Capt. Thomas Black of the

USAF Civil Engineers at Tyndall AFB,

Florida, supervised the runway profile

measurements. A three-track profile

encompassing an area within 18 feet on

either side of the runway centerline was

then added to the FATOLA program.

The first data flight took place on 27

January 1976. Research pilot Fitz Fulton,

accompanied by test engineer Vic

Horton, conducted a low-speed taxi test

and made a number of touch-and-go

landings for high-speed taxi data. Don

Mallick and Ray Young made a second

flight eight days later. Two other flights

failed to gather data; the first due to foam

on the runway, and the second because of

an unsafe landing gear indication on the

YF-12A. Based upon the correlation of

the computer simulations and flight data,

researchers validated FATOLA as a

versatile analytical tool.

A second landing project took place in

1977. This research demonstrated a dualmode adaptive landing gear system to

reduce the dynamic response of an

airplane during ground taxi. An airplane’s

landing gear system absorbs the kinetic

energy associated with vertical velocities

at touchdown and generally produces

maximum efficiency at its maximum sink

rate. Designers accomplish this by

adjusting the combined shape of the static

air-load-stroke curve38 and the hydraulic

damping curve to provide a constant load

during a maximum-design sink-rate
27

The YF-12A

main landing

gear included

three nitrogenfilled 32-ply

tires. They were

coated with a

thin film of

aluminum to

reflect heat while

retracted. (NASA

photo E71-

22968)

landing. For a given kinetic-energy

absorption, this yields the shortest gear

stroke. Such a design resulted in the

lightest practical gear to absorb the

landing energy. An adaptive landing gear

system can also increase the lifespan of

an airframe by reducing vibration stress

incurred during taxi, takeoff, and landing.

Such an approach reduced total aircraft

weight but did not necessarily result in a

static air-load-stroke curve suitable for

isolation of runway roughness during

taxi. This particular condition had special

significance for large flexible aircraft

designs such as the YF-12. To remedy

the problem, Lockheed engineers

designed a dual-mode adaptive landing

gear system for the YF-12A. The

configuration included a strut with an

optimized air-load-stroke curve during

landing and an automatic switch-over

system to allow for a flatter air-loadstroke curve during taxi.

Lockheed engineers first proposed

testing a dual-mode landing gear system

in 1976 and installed the prototype

system in the YF-12A in January 1977.

Pilots then flew three series of test runs,
28

demonstrating three gear configurations.

Don Mallick and Ray Young led off with

two baseline landing gear stiffness tests

in February. Fitz Fulton and Vic Horton

then flew two tests with a large-volume

auxiliary air chamber added to the

system to modify the air-load-stroke

curve. Mallick and Young accomplished

the final two tests to demonstrate a

mixed-volume configuration. For each of

the three configurations tested, the crew

performed a series of eight taxi runs,

providing constant-speed taxi data at a

variety of airplane weights and velocities.

The study demonstrated the effectiveness

of a dual-mode adaptive landing gear

system in reducing the dynamic response

of an airplane during taxi. It also provided a database to aid in determining the

degree of correlation between analytically

predicted responses and actual test results

with a full-scale YF-12A. During the

tests, the system reduced dynamic response by 25 percent at the aircraft’s

center of gravity and as much as 45

percent at the cockpit. The research pilots

who flew the aircraft commented that the

“degree of ride improvement is quite

noticeable, particularly at the higher gross

weights.”39

A final YF-12 landing study took place in

March 1978. Dryden engineers scheduled

three Space Shuttle orbiter landingapproach simulation flights in the

YF-12A. The first occurred on 23 March

with Fitz Fulton and Vic Horton as the

crew. The last two flights took place on

39 Max A. Gamon, “Testing and Analysis of Dual-Mode Adaptive Landing Gear, Taxi Mode Test System for YF-12A,”

Lockheed (Burbank, California: NASA CR-144884, September 1979), pp. 1.

In 1978, a dualmode landing gear

study with the

YF-12A demonstrated reduced

dynamic response

during taxi, takeoff,

and landing

operations. The

prototype system

was installed in the

YF-12A in January

1977. (NASA photo

EC77-6992)
29

31 March. Einar Enevoldson flew with

Ray Young, and Bill Dana flew with Vic

Horton. The pilots felt that the aircraft

had exceptionally good control characteristics during Shuttle-type approaches,

which involved precise maneuvering

just prior to touchdown. They did not

experience any tendency toward overcontrol or pilot-induced oscillation

(PIO).

Researchers compared data collected

from the YF-12 flights with that accumulated by simulated Shuttle approaches flown in the F-8 Digital FlyBy-Wire (DFBW) aircraft and the

NC-131H Total In-Flight Simulator

(TIFS). These simulations paved the

way for approach and landing tests

using the Space Shuttle Enterprise,

which in turn furnished planners with

data for the first Space Shuttle Orbital

Flight Test (OFT-1). Air-launched from

a Boeing 747, Enterprise completed

five Approach and Landing Tests (ALT)

between 12 August and 26 October

1977. The final flight ended with a

dramatic PIO as the vehicle settled onto

the concrete runway. In a presentation at

NASA Dryden on 17 August 1978, Milt

Thompson summarized the results of

the various Shuttle landing simulation

test programs: “The landing characteristics of the orbiter are conditionally

acceptable for an OFT-1 Edwards

recovery but unacceptable for general

operational use.”40

Under contract to NASA Dryden, Gary

Teper, Richard DiMarco, and Irving

Ashkenas of Systems Technology,

Incorporated (STI), compared data from

the YF-12 Shuttle simulations and the

ALT tests. They found that the YF-12

pilots could correct the vehicle’s flight

path quickly and smoothly while

maintaining desired altitude. By contrast, orbiter pilots in the Enterprise

experienced significant oscillations in

attitude and altitude. The comparative

analysis of the two vehicles identified

such critical orbiter flight-control

characteristics as excessive time delay

in the attitude response to pilot control

inputs and degraded flight path response

to attitude changes associated with an

unfavorable orbiter pilot location in the

cockpit. The STI study determined that

moving the pilot location forward

improved the pilot’s ability to control

the vehicle’s sink rate and landing

performance.41

Even as the Blackbirds carried out these

varied landing tests, they also contributed to aeronautical knowledge in a

unique way—as platforms capable of

carrying out a wide range of experiments during long-duration Mach 3

flight.

40 Milton O. Thompson, “DFRC Orbiter Landing Investigation Team—Final Presentation,” briefing at NASA Dryden

Flight Research Center, Edwards, California, on 17 August 1978. NASA Dryden Historical Reference Collection.

41 Gary L. Teper, Richard J. DiMarco, and Irving L. Ashkenas, “Analysis of Shuttle Orbiter Approach and Landing

Conditions,” Systems Technology, Inc., Hawthorne, California, (Technical Report number TR-1137-1, January 1980),

pp. 17–26.
30

Chapter 6:

A Flying

Laboratory

The two remaining YF-12 aircraft served

NASA as flying laboratories, ideally

suited as testbeds for a wide range of

experiments: boundary-layer flow effects,

digital integrated controls, heat transfer,

and drag. Other experiments included the

evaluation of a maintenance monitoring

and recording system, measurement of

engine effluents for pollution studies,

noise suppression tests, sonic boom

effects, and testing of a series of structural

wing panels designed by NASA Langley

and fabricated by Lockheed.

Not every potential use of the YF-12

aircraft came to fruition. In 1971, NASA

requested a Lockheed Advanced Development Projects (ADP) study on the feasibility of launching a hypersonic drone

from the YF-12C. On 30 July 1971,

Lockheed’s Henry G. Combs and John R.

McMaster submitted the results of the

study, based on the design of NASA’s

proposed HT-4 subscale high-speed

transport model. After investigating

various drone locations (dorsal and

ventral), mounting and separation methods, and launch and landing options, the

two engineers offered their conclusions.

The launch of a dorsally mounted drone

could be realized, but only with certain

provisions.

42 Henry G. Combs and John R. McMaster, “Feasibility Study on Launching a NASA HT-4 Hypersonic Drone from a

Lockheed YF-12C Airplane,” Lockheed Report No. SP-177930, July 1971. NASA Dryden Historical Reference Collection.

Combs and McMaster proposed a series

of steps before attempting a drone launch.

Predicted aerodynamic and drag data

would have to be substantiated with an

adequate wind-tunnel program, including

the determination of an optimum drone

launch angle with respect to the carrier

aircraft. Certain areas of the YF-12C

structure required rework, such as hard

points, for mounting the drone. Modification of the fuel system would be required

to maintain the center-of-gravity. Also,

engineers had to determine operating

restrictions to avoid exceeding the

aircraft’s structural load limits.

The proposed HT-4, a model of a highspeed transport design, was scaled down

to a length of 600 inches. Powered by a

Pratt & Whitney RL-10 engine, it was

designed for launch at standard YF-12

cruise and altitude conditions.

Although the Lockheed ADP study

declared the concept technically feasible,

some individuals raised concerns. ADP

Senior Vice President Kelly Johnson

approved the report, but commented

cautiously: “This is a progress report

only. I want to talk to NASA about safety

aspects before concrete action is taken to

implement any construction.”42

In 1971, at the request of NASA

researchers, Lockheed submitted a

study on the feasibility of using the

YF-12C to launch a hypersonic

drone from a dorsal pylon. The

Lockheed evaluation incorporated

data derived from the then-classified M-21/D-21 project which

involved the launch of a dorsallymounted Mach 3 drone from an

early Blackbird variant. (NASA

photo E71-23563)
31

Johnson had reason for concern.

Lockheed ADP had already flown a

similar configuration, in utmost secrecy,

in 1966. Two A-12 type aircraft (designated M-21) had been built expressly as

launch aircraft for the secret D-21

reconnaissance drone. Captive flight

The M-21 variant

of the Blackbird

carried a D-21

drone on a dorsal

pylon. Captive

carry tests began in

December 1964 and

flight tests occurred

in 1966. In 1971,

NASA pursued the

idea of launching a

hypersonic test

vehicle in a similar

manner. (Lockheed

photo)

tests of the dorsally mounted D-21

began in December 1964. Numerous

difficulties relative to range and transonic acceleration plagued the M-21/

D-21 combination. The first launch took

place on 5 March 1966. Kelly Johnson

later reported that “mainly, we demonThe M-21 variant served as a mothership for D-21 drones. Following three successful launches, a fatal accident brought

an end to the M-21/D-21 program. NASA personnel were briefed on the D-21 program and initially decided to pursue a

similar HT-4 proposal in spite of the difficulties Lockheed had experienced with the D-21. (Lockheed photo)
32

43 Jay Miller, Lockheed’s Skunk Works—The First Fifty Years, pp. 137-138.

strated the launch technique, which is the

most dangerous maneuver . . . [on] any

airplane I have worked on.”

compressible turbulent-boundary-layer

parameters. Since these theories produced substantially different values, they

required additional data from flight and

wind-tunnel experiments. NASA researchers fitted the YF-12A with boundary-layer rakes to collect such data

during flight. Each rake consisted of an

aerodynamic vertical pylon with hollow

tubes arrayed on its leading edge. Each

tube collected measurements at a different point within the boundary-layer

region of airflow. Instruments also took

static pressure and skin surface measurements. In order to provide undisturbed

airflow over the lower fuselage, all

upstream protrusions and vents needed to

be removed or faired over.

The YF-12A also carried an aft-facing

step experiment to determine the drag

penalty caused by aft-facing surface

discontinuities in a thick boundary-layer

region. Such discontinuities caused drag

and shock-wave propagation at supersonic speeds. The experiment provided

designers with data for predicting the

drag associated with lap joints and

shingle structures on large aircraft at high

Mach numbers. A panel on the aft

An aft-facing step

experiment determined the drag

penalty caused by

aft-facing surface

discontinuities in a

thick boundary

layer region.

Vertical rakes

contained probes to

collect data

throughout the

boundary-layer.

(Figure taken from

NASA FRC Basic

Research Review,

20 October 1975)

Figure 6

Two more successful launches followed,

but the fourth flight substantiated

Johnson’s statement. Moments after

separation, the drone collided with the

mothership. Both vehicles were destroyed. Lockheed test pilot Bill Park

parachuted to safety, but his launch

officer, Ray Torick, drowned in the

Pacific Ocean. An investigation board

concluded that Mach 3 launches of

large vehicles from the Blackbird were

essentially unsafe.43 In light of this

tragedy, it is apparent why Johnson

voiced concern over the YF-12C/HT-4

proposal. Ultimately, the HT-4 project

never materialized, possibly as a result of

Lockheed’s experience with the D-21.

But the Blackbirds did notable work as

platforms for many other projects. In July

1973, following ground tests in the High

Temperature Loads Laboratory, YF-12A

(935) was instrumented for boundarylayer measurements along the lower

fuselage. Engineers typically use a

number of empirical theories to predict
33

fuselage created a small step over which

the airflow passed. It consisted of a ramp

region, a reference region, the step, a

recovery region, and two boundary-layer

rakes. Technicians installed pressure

orifices along the plane of the surfaces of

the reference and recovery regions and

the step face. The step height—from

0.125 to 0.500 inches—could be varied

Preston probes

consisted of rakes

with hollow tubes

to collect measurements from

multiple points

within the boundary-layer airflow.

This set of probes,

on the aft-facing

step experiment,

included a fixed

rake (left) and a

movable rake.

(NASA photo E73-

25764)

44 Basic Research Review for the NASA OAST Research Council: RTOP-761-74-01, Robert D. Quinn, August 1971, p.15;

RTOP-501-06-05, RTOP-501-06-08, RTOP-770-18-10, RTOP 501-06-05, Edwin J. Saltzmann, 7 August 1972 and 20

August 1974, pp. 9-10; RTOP-505-06-31, Sheryll Goecke Powers, 20 October 1975, p. 9.

between flights. The experiment produced data from incompressible speeds to

ones in excess of Mach 3 and for ratios of

boundary-layer momentum thickness to

step height from 1 to 5. The results had

applicability to the prediction of drag

penalties for aft-facing discontinuities

over a wide speed range for both the

forward and aft regions of large airplanes.44

NASA technicians

glued tufts to the

fuselage of the

YF-12A for

surface flow

visualization

studies related to

the aft-facing step

experiment.

(NASA photo

E76-31377)
34

In early November 1974, the YF-12A

underwent a Coldwall experiment to

study the effects of compressible

turbulent boundary-layer and heat

transfer coefficient at high speed.

Designed and supported by NASA

Langley, the apparatus consisted of a

13-foot-long stainless steel tube

mounted on a ventral pylon below the

forward fuselage. The tube, equipped

with thermocouples and pressure

sensors, required cooling by liquid

nitrogen and a covering with an

insulating material. Planners desired

the insulator to be pyrotechnically

removed at Mach 3, exposing the tube

to aerodynamic heating. Researchers

also conducted wind-tunnel tests of a

similar tube for comparison with data

obtained in flight in order to validate

ground research methods.

The Coldwall program suffered

numerous setbacks. An initial lowspeed functional check flight had to be

aborted early when the experiment’s

accelerometer malfunctioned. A

second attempt a week later ended the

same way. The third flight, on 27

February 1975, took a more dramatic

turn. On this day, the crew consisted of

Don Mallick and Ray Young. Mallick

climbed to 15,000 feet and advanced

the throttle until the aircraft was

traveling at 0.9 Mach number. At one

point, the test card called for an aileron

pulse with roll/yaw Stability Augmentation System (SAS) off. As Mallick

executed the maneuver, the ventral fin

tore off, damaging the right wing and

causing a fuel leak. The crew brought

the YF-12A back to Edwards for a safe

landing. An investigation determined

that several factors contributed to the

incident:

• Inadequate definition and

documentation of aircraft limits.

• Inadequate attention and

adherence to existing, published,

operating limits for the transonic

region.

• A less than conservative

approach in the flight qualification of the Coldwall heat transfer

experiment in that tests were

The YF-12A

climbs to altitude

with the Coldwall

heat transfer

experiment pod

mounted beneath

the fuselage. After

the aircraft

attained Mach 3,

the white insulation covering the

pod was pyrotechnically removed

to expose the

nitrogen-cooled

stainless steel tube

to aerodynamic

heating.

(NASA photo

EC75-4765)
35

45 “Report of Investigation,” memorandum from YF-12 Ventral Incident Investigation Board to Director of NASA Hugh

L. Dryden FRC, 25 April 1975, p. 5. NASA Dryden Historical Reference Collection.

conducted at known limit conditions with a new configuration.45

Test flights to demonstrate the structural

characteristics of the Coldwall fixture

resumed in July 1975. An operational

check of the insulation removal system

followed in August. Actual Coldwall data

flights did not begin until August 1976,

During a lowspeed functional

check flight of the

YF-12A with the

Coldwall experiment attached, the

aircraft’s ventral

fin tore off.

Although the right

wing was damaged, causing a

fuel leak, the

pilot, Don

Mallick, landed

safely at Edwards.

(NASA photo

E75-28266)

when a series of baseline “Hotwall”

flights occurred without the liquid

nitrogen coolant or insulation. The first

true Coldwall flight took place on 21

October 1976. The premature loss of the

insulation material prevented the collection of data on that flight, however. This

problem continued to plague the experiment through 2 June 1977. The first good

Don Mallick holds

the ventral fin from

the YF-12A. It

took searchers

nearly a week to

locate the fin north

of Red Rock

Canyon in the

Mojave Desert.

With Mallick are

several members

of a search party.

(NASA photo

E75-28414)
36

Coldwall data finally began to flow on

23 June when “the insulation removal

system was successfully operated at the

design test condition of Mach 3.0 and

72,500 feet.”46

The next Coldwall flight, on 21 July

1977, although less successful, was

certainly more dramatic. Insulation

material from the experiment became

ingested into the left engine of the

YF-12A, resulting in an unstart. The

right engine also unstarted. As the crew

worked to restart the engines, the

YF-12C chase aircraft also experienced

multiple unstarts. Despite these problems, both aircraft returned safely to

Edwards but remained grounded until

September for inspection and repair.

The last two Coldwall flights occurred

successfully on 30 September and 13

October. At the time, several theories

existed regarding the nature of turbulent

heat transfer, but they yielded conflict46 “Aeronautical Projects Update—June 1977,” memorandum from Director of Aeronautical Projects and Director of

Research to the Director of NASA Hugh L. Dryden Flight Research Center, 5 July 1977. NASA Dryden Historical

Reference Collection.

ing results when compared with windtunnel data. The competing schools of

thought were represented by Edward R.

van Driest’s equations for estimating

turbulent heat transfer, E. R. G.

Eckert’s reference enthalpy method,

and the Spalding-and-Chi method for

determining skin friction coefficients.

Researchers used the Coldwall experiment data to validate Van Driest’s

theory.

Following the Coldwall flights, Don

Mallick and Ray Young flew the

YF-12A for a lower-surface boundarylayer survey and handling-qualities

evaluation. Unfortunately, a malfunction

of the wake-visualization water-spray

system prevented them from obtaining

any subsonic wake vortex flow data.

The incident of the lost ventral fin in

February 1975 gave researchers an

opportunity to flight-test a new material.

Without insulation,

the stainless steel

tube of the

Coldwall experiment is exposed to

aerodynamic

heating during

high-speed flight.

Engineers compared data from

flight tests to

validate predictive

methods for

estimating turbulent

heat transfer.

(NASA photo

EC75-4777)
37

Technicians fitted a replacement ventral

fin, made of Lockalloy, on the damaged

YF-12A. Lockalloy, a metal alloy

developed by Lockheed, consisted of 62

percent beryllium and 38 percent

aluminum. Aircraft designers considered

it a promising material for constructing

high-temperature aircraft structures. The

Lockalloy fin flew for the first time on

16 January 1976. Envelope expansion

The YF-12C

served as a chase

aircraft for the

YF-12A during

Coldwall flights.

On one sortie, both

aircraft suffered

simultaneous

multiple engine

unstarts. After

landing safely at

Edwards AFB,

they were

grounded for

inspection and

repair. (NASA

photo EC75-4775)

flights continued through 20 May.

Flight crews gradually exposed the new

ventral fin to a variety of low-speed

and high-speed flight conditions,

eventually exceeding Mach 3. Loads

and pressure distribution data closely

agreed with predicted results.

The YF-12 also served as a testbed for

advanced structural panels. A number

Loss of the titanium

ventral fin in

February 1975

provided researchers

with an opportunity

to test a new

material. In January

1976, the YF-12A

flew with a ventral

fin made from a

Lockheed-designed

beryllium-aluminum

alloy called

Lockalloy. (NASA

photo EC76-5103)
38

of structural-configuration and material

concepts showed promise in terms of

reducing aircraft structural weight.

Initially, a weldbrazed-skin stringer panel

(one with stiffeners spot-welded in place)

underwent approximately 37 hours of

flight, including eight hours at Mach 3,

with no adverse effects. Then, in July

1974, an experimental titanium honeycomb panel replaced an existing integrally stiffened primary structural part of

47 Basic Research Review for the NASA OAST Research Council: RTOP-743-32-23, Alan L. Carter, 20 August 1974,

pp. 43-45.

the YF-12A upper wing surface, located

over the landing gear. Researchers also

undertook flights with a composite panel

of titanium honeycomb with a boron/

aluminum face sheet onboard. NASA

Langley Research Center initiated these

panel tests under the Supersonic Cruise

Aircraft Research (SCAR) program.

Each panel type underwent ground

testing by Lockheed before the actual

flight test.47

The YF-12 aircraft served as testbeds for advanced structural panels. NASA Langley sponsored these tests under the

Supersonic Cruise Aircraft Research (SCAR) program. (Figures 7A-7D are from the NASA FRC Basic Research

Review, 20 August 1974)

Figure 7A Figure 7B

Figure 7D Figure 7C
39

In 1977, a SCAR panel was fitted to the

YF-12C wing surface and flown regularly on a non-interference basis. Engineers assessed its structural integrity

after each flight.

In December 1977, several NASA

research pilots who had not yet participated in the YF-12 program had the

opportunity to fly the YF-12A. John

Manke, Bill Dana, and Tom McMurtry

flew familiarization flights with Vic

Horton. Gary Krier and Einar

Enevoldson made short hops with Ray

Young. As noted in Chapter 5, both Dana

and Enevoldson then made additional

flights as part of the Space Shuttle

approach simulation program in March

1978. After that, the aircraft was

grounded for installation of a shaker vane

system.

As early as 1970, Lockheed had proposed testing a Loads Alleviation and

Mode Suppression (LAMS) system on a

YF-12A and conducted a feasibility

study. The design involved the use of

small canards (or shaker vanes) on the

aircraft forebody to excite the airplane’s

Engineers studied

samples of structural materials from

the SCAR program

to assess their

structural integrity

with regard to

future aircraft

construction.

(NASA photo E75-

28611)

structural modes using controlled dynamic inputs at selected flight conditions.

Such a system enabled a pilot to use

feedback control techniques to suppress

the aircraft’s aeroelastic contributions to

local acceleration and to develop techniques to reduce aircraft damage from air

turbulence. The resulting flight-test data

could then be compared with calculated

aeroelastic response data and thus

validate analytical techniques. The

YF-12A design did not require LAMS

technology itself and was, in fact, not

well suited for evaluating rigid-body load

alleviation techniques such as direct lift

control. However, as a flexible aircraft it

could be used to evaluate suppression

techniques for aeroelastic modes. According to a study of LAMS for the

YF-12, “evaluation of mode suppression

techniques on the YF-12A could result in

eliminating most of the design risk

associated with LAMS technology and,

thus, lead to acceptance by airframe

manufacturers.”48

The YF-12 mode suppression effort

expanded LAMS research already begun

with the NASA/USAF XB-70 and the

48 Lester D. Edinger, Frederick L. Schenk, and Alan R. Curtis, “Study of Load Alleviation and Mode Suppression

System (LAMS) on the YF-12 Airplane” (Washington, D.C.: NASA CR-2158, December 1972), p. 2.
40

Air Force’s NB-52E Control Configured

Vehicle (CCV) testbed. A Lockheed

study in 1972 compared five candidate

LAMS systems for the YF-12, evaluating

each in terms of performance and

mechanization. The Lockheed engineers

concluded that a combination of small

shaker vanes near the cockpit and inputs

to the outboard elevons would provide

the most effective LAMS system for the

YF-12 aircraft.49

While the YF-12A remained in the

hangar, the YF-12C returned to service.

It had been unavailable since October

1977 in preparation for cooperative

controls (Co-Op) research. This program

focused on digital integrated control of the

aircraft’s inlets, autopilot, autothrottle, air

data system, and navigation system.

Preparations for the Co-Op project began

in early 1977, including tests of the

aircraft’s autothrottle system designed to

control Mach and altitude simultaneously. In March 1977, Gene Matranga

observed that “the system provided

precision of control significantly better

than that attainable by manual control at

Mach 3.0 and constitutes a virtual

technological breakthrough in flight path

control for supersonic cruise aircraft.”

By June, he felt that “sufficient data had

been obtained to verify the operational

characteristics of the system, and to

define control logic to be implemented

in the upcoming Co-Op Digital Control

Program.” By September, the NASA

team had acquired all the baseline

propulsion/airframe interaction data

necessary to prepare for the Co-Op

study.

As a result, a Cooperative Airframe/

Propulsion Control System (CAPCS)

digital computer went into the YF-12C.

This system incorporated the air data,

inlet, and autopilot systems into a single

49 Ibid., pp. 1-5.

Small canards,

called shaker or

exciter vanes, were

installed on the

YF-12A as part of a

load alleviation and

mode suppression

system (LAMS).

Engineers compared structural

mode data from

research flights

with computergenerated data to

validate analytical

models. (Drawing

from the NASA

DFRC Historical

Reference Collection)

Figure 8
41

computer to improve overall aircraft

flight control. Following installation of

the CAPCS, Don Mallick and Ray

Young took the aircraft up for a functional check flight on 26 May 1978.

Gene Matranga later reported that “all

flight objectives were satisfactorily

accomplished with air data calculations,

inlet control, and autopilot demonstrated.” The flight also verified the

basic logic flow and system architecture

for the CAPCS.

Nine more CAPCS flights followed.

Seven of them proved to be successful.

The final CAPCS flight, on 28 September 1978, aborted early due to an engine

bypass door failure that precluded

acquisition of Co-Op control data. It

turned out to be NASA’s last flight of

the YF-12C. On 27 October, the aircraft

returned to the Air Force after being

ferried to the Lockheed facility in

Palmdale. The YF-12C ended its NASA

career on a high note. The CAPCS

system exceeded the designers’ goals.

Flight path control precision improved

by a factor of 10. Additionally, aircraft

range increased by seven percent, and

inlet unstarts became almost unknown.

Ultimately, Lockheed installed the

system in the entire operational SR-71

fleet.50

In order to undertake research on the

structural design required for a future

supersonic transport aircraft, Jim

McKay of the NASA FRC Dynamic

Analysis Branch submitted a request for

shaker-vane project approval on 4

February 1975. With a view toward

future SST development, NASA engineers needed accurate structural design

calculations for flexible, low-aspectratio aircraft in the transonic flight

regime. A large body of static and quasistatic test data had been generated

during flight and ground YF-12 loads

research. Additionally, McKay pointed

out that the YF-12 team had “developed

one of the most complete finite element

[NASA] structural analysis

(NASTRAN) programs ever assembled

for an aircraft, along with a complete

static aeroelastic analysis program

(FLEXSTAB).”51

Software engineers at NASA Goddard

Space Flight Center in Greenbelt,

Maryland, originally designed the

NASTRAN program for space vehicles.

In its first major application to an

airplane, Alan Carter of NASA asked

Lockheed’s Al Curtis to create a

NASTRAN model to support YF-12

loads research. The FLEXSTAB program, developed by Boeing for the SST,

allowed researchers to assess the effect

of airframe flexibility on stability and

control characteristics of a supersonic

aircraft. Perry Polentz of NASA Ames

also sought out Curtis to model the

YF-12 using FLEXSTAB. Although

Curtis encountered some problems

adapting the program to the YF-12 wing

configuration, the extensive analytical

database set the stage for the proposed

flight research effort. Jim McKay

thought the resulting data would have

“direct application to low-aspect-ratio

vehicles with close dynamic coupling

between major components such as

fuselage and wing.” He also believed

that it would “provide data input to the

Langley Research Center landing loads/

response study in support of the work

on actively controlled landing gear.”52

Finally, in February 1978, Dryden

received funding from NASA Langley

50 “NASA YF-12 Cooperative Control Program,” briefing, 1983. NASA Dryden Historical Reference Collection.

51 James M. McKay, “Request for Project Approval to Measure the YF-12 Structural Response to Aerodynamic Shaker

Excitation and to Correlate with Analytical Results,” letter to Acting Director, NASA Flight Research Center, Edwards,

California, 4 February 1975. NASA Dryden Historical Reference Collection.

52 Ibid.
42

and the Air Force Flight Dynamics

Laboratory to support a structural

dynamics program with the remaining

YF-12A. Installation of the shaker vanes

began in April. The system consisted of

a set of oscillating canards attached by a

shaft to a driving unit in the nose of the

airplane. The shaker vanes supplied

controlled dynamic inputs to excite the

response of various structural modes at

53 Ibid.

selected flight conditions. On 22 November, the YF-12A made its first flight with

the new shaker vanes. Five more flights

had occurred by 15 March 1979. The

shaker-vane study provided flight data

on aeroelastic response, allowed comparison with calculated response data, and

thereby validated analytical techniques.53

With these last missions, the NASA YF-12

flight research program ended.

Shaker vanes were

installed on the

YF-12A for a

series of six flights

between November

1978 and March

1979. Data from

these flights were

compared with

data generated by

the NASA Structural Analysis

(NASTRAN)

computer program.

(NASA photo E78-

34738)
43

Chapter 7:

Lessons

Learned

During a 10-year period, the NASA

YF-12 research program produced a

wealth of data, derived from flight and

ground research, as well as from simulation and modeling. Collectively, these

investigations made important contributions to the advancement of aerodynamics and thermodynamics. Among other

achievements, the comparison of flight

data to wind-tunnel data and predictions

helped researchers develop more

accurate modeling techniques for

flexible, supersonic aircraft designs.

At the start of the undertaking, NASA

engineers and technicians faced a

difficulty inherent in this type of research. Because the high speeds of the

YF-12 generated sustained aerodynamic

heating, the YF-12 team needed to

devise data recording techniques suited

to these conditions. Indeed, NASA

project manager Gene Matranga noted

that instrumentation for the YF-12 was

“very inadequate to begin with, and it

cost a lot of money to develop new

instrumentation and make it work.”

54 Matranga interview.

Once they resolved this problem, a wide

vista of research opportunities became

possible.

To begin with, researchers compared

heating measurements in the High

Temperature Loads Laboratory to inflight heating. The results allowed them

to more accurately calibrate instrumentation for loads measurement on highspeed aircraft by separating thermal

loads from aerodynamic loads. They

also explored structural configurations

relative to the thermal environment,

studied the resulting thermal stresses,

and demonstrated how a thermal calibration of the aircraft eliminated contaminating heating effects from loads equations. Additionally, Matranga and his

colleagues discovered unexpected hot

spots and leakage of hot air into the

aircraft’s internal structure.54

The YF-12 aircraft likewise provided a

wide range of propulsion data on

variable cycle engine operation and

mixed-compression inlet operation. The

The YF-12A was

equipped with a

water spray nozzle

on the forward

fuselage for flow

visualization. The

system underwent

ground tests prior

to flight in 1976.

Note the Coldwall

pod attached on

the lower fuselage.

(NASA photo E76-

31090)
44

flight research demonstrated that an inlet

could be designed using small-scale

models and also showed that YF-12 inlet

dynamics had a profound effect on

stability and control. The dynamics

sometimes surprised the researchers. Air

from the forward bypass doors, for

instance, actually moved forward at least

12 inches before mixing with the

boundary layer. “This startled everybody,” said Gene Matranga. “We didn’t

realize there was so much separation just

ahead of the bypass area.” Ultimately,

NASA developed a computer control

system for the bypass doors to improve

efficiency. It increased aircraft range and

performance and eventually became

incorporated into the operational SR-71

fleet.55 Flight-test data also indicated

that during Mach 3 flight, air venting

55 Ibid.

56 Hallion, On The Frontier, pp. 195-196.

through the inlet bypass doors accounted

for half of the aircraft’s total drag.56 The

inlet control proved to be imprecise due

to sensor placement and inaccuracy,

making unstarts a frequent occurrence.

But NASA’s YF-12 research program

virtually eliminated unstarts through a

combination of inlet spike schedule

refinements and hardware improvements.

Wind-tunnel model data provided an

opportunity to validate scale and windtunnel effects against the flight data. It

also enabled engineers to determine more

precisely the placement of instruments in

the airplane inlet. Inlet-flow-systems

interactions studies helped researchers

define the inlet operating envelope and

yielded information about unstart/restart

boundaries. Engineers compared data

YF-12C and crew. Standing, left to right: unknown USAF officer, Airman Baker, Glenn Gemenhardt, Fitz Fulton,

Lorenzo “Larry” Barnett, Thomas C. McDonald, Ralph A. Merkner, Byron D. Gibbs, John W. Louett, James C.

Gordon, LeRoy P. Frost, John R. Rifenberry, Victor Horton, unknown, unknown USAF life support technician, LeRoy

J. Adelsbach, and Billy Furr. Kneeling: Charles A. Grace, Jr., and John M. Bruno.(NASA photo EC78-9975)
45

from the NASA Ames and NASA Lewis

wind tunnels to data obtained during

research flights to better evaluate scaling

and tunnel effects. NASA researchers

found that testing limitations prevented

the attainment of identical test conditions

in the mixed-compression inlet mode. To

solve this problem, FRC engineers James

D. Brownlow, Henry H. Arnaiz, and

James A. Albers developed a mathematical model from which comparisons could

be made using statistical techniques.57

During a series of landing studies, a

mixed-volume dual-mode gear system

reduced airplane dynamic response

during high-speed taxi. The test procedure called for taxiing at constant speed

on the same section of runway during

each run. In practice, however, the

airplane traversed slightly different

sections of runway from one test to the

next. Aircraft weight differed throughout

the test series due to fuel consumption.

Although the mix of aircraft weights and

velocities used did not represent any one

specific aircraft configuration, the results

encompassed a wide range of operational

conditions. Overall, the dual mode

system provided significant dynamic

response reductions, yielding a smoother

ride. Analytical results generated by a

digital computer program provided

excellent correlation with the flight-test

data at most areas, except the cockpit.

During handling-qualities investigations

made during the YF-12 program, researchers concentrated on characteristics

associated with longitudinal control

during high-speed supersonic cruise,

with possible application to the development of a supersonic passenger transport

aircraft. Part of the investigation involved altitude hold and Mach hold,

important because maximum range

performance depended in part on accurate control of altitude and Mach num57 They derived the model from wind-tunnel test data using a multiple regression technique which uses a least-squares

method to fit equations to the data. The least-squares method is a statistical technique of fitting a curve close to some

given points, which minimizes the sum of the squares of the deviations of the given points from the curve.

Life support

technician John R.

Rifenberry looks

on as Fitz Fulton

(left) and Vic

Horton, the last

NASA crew to fly

the YF-12A, pose

following their

flight on 31

October 1979.

(NASA photo

EC79-11907)
46

ber. In flight tests with a modified

altitude and autothrottle hold mode, the

YF-12C proved to be the most stable

aircraft platform thus far demonstrated at

Mach 3 speeds.

Flight research on the YF-12 also included certain propulsion and aerodynamics problems encountered during the

Blackbird’s operational life. During

flight at a constant power setting, for

instance, many aircraft experienced a

natural oscillation called a phugoid.

NASA research pilot Milton O. Thompson described the phugoid effect in the

YF-12.

Automatic engine inlet operation

can have a pronounced effect on

phugoid characteristics. In fact,

under certain conditions, the

automatic inlet operation can

couple with the autopilot system in

a manner to drive the phugoid

unstable. Another unanticipated

problem is the effect of engine

bypass air on stability and control

characteristics. At certain flight

conditions, engine bypass air being

ducted overboard can produce

rolling moments comparable to

that available with full aileron

deflection. Inlet unstarts are not

uncommon even under so-called

ideal steady state cruise conditions.

Atmospheric anomalies may be

responsible for some of these inlet

unstarts, since we have seen some

rather abrupt changes in outside air

temperature at these high speeds;

however, other unstarts are not

readily explained.58

The YF-12 team also employed the

aircraft as a platform to study human

factors in a high-altitude supersonic

cruise environment. Researchers first

identified sets of aircraft and physiological parameters most sensitive to pilot

workload. Next, they isolated and

quantified physical and nonphysical

workload effects. Finally, they gathered

and reduced flight data for comparison

with findings from a clinical study to

develop a pilot workload model from

which predictions could be made.

NASA engineers conducted extensive

studies of the boundary layer, using

instrumented rakes. They found significant discrepancies between wind-tunnel

model data and flight-test results. These

apparently resulted from surface

imperfections on the full-scale aircraft.

“There were lumps, and bumps, and

waves,” said Gene Matranga. “A wind

tunnel model was a nice, smooth, rigid

structure.” Although researchers

developed predictive methods to

compensate for these differences,

58 Letter from Milton O. Thompson to Walter C. Williams, 1 November 1976. NASA Dryden Historical Reference

Collection.

Cockpit of the

YF-12A. The

vertical strip

instrument to the left

of the large attitude

indicator (artificial

horizon) is the

airspeed indicator

(measuring in knots

and Mach number).

The altimeter is on

the right. (NASA

photo E71-22774)
47

according to Matranga “it requires

interpretation on the part of very skilled

people.”59

Another benefit of the YF-12 program

arose from the extreme altitude range at

which the aircraft flew. NASA engineers

Terry Larsen and Jack Ehernberger—

working in support of the SR-71 Category II tests—extensively documented

upper atmosphere physics. Such atmospheric modeling proved useful for later

designs of high-altitude research

aircraft. The YF-12 contributed valuable sonic-boom information and

showed that mild turbulence could exist

even at the highest altitudes at which

the aircraft cruised.60

Finally, NASA and USAF researchers

gained valuable information concerning

loads suppression and mode alleviation

for flexible aircraft using a nosemounted canard (shaker vane) system.

This apparatus allowed them to make

direct comparisons with calculated

aeroelastic response data and thereby

validate available analysis techniques.

Once the shaker vane study had been

completed, the NASA YF-12 research

program essentially ended. Research

pilots Stephen Ishmael and Michael

Swann each received a familiarization

flight in the YF-12A on 29 March 1979.

On 31 October, Fitz Fulton and Vic

Horton made the final NASA flight of

the aircraft and on 7 November 1979,

Col. James V. Sullivan and Col. Richard

Uppstrom ferried the aircraft to WrightPatterson AFB, Ohio, for permanent

display in the USAF Museum.

Thus, over its long lifespan, the NASA

YF-12 program made significant

contributions to high-speed aeronautical

research. Perhaps most importantly, it

left a legacy of structural, aerodynamics, propulsion, and atmosphericphysics data likely to serve as the basis

for future high-speed aircraft designs

and analytical model evaluation.

The YF-12C

(SR-71A) cockpit.

The altimeter and

airspeed indicators

have been merged

into the triple

display indicator,

below and to the

left of the attitude

indicator. (NASA

photo E72-25349)

59 Matranga interview.

60 Gene J. Matranga, “The Realities of Manned Supersonic and Hypersonic Flight—Lessons Learned,” presentation at

NASA Lewis Research Center’s Hypersonic Propulsion Symposium, August 1988. NASA Dryden Historical Reference

collection.
48

Air Force security police halt traffic for the arrival of the YF-12A at the USAF Museum at Wright-Patterson AFB,

Ohio, on 7 November 1979. The aircraft was piloted by Col. James V. Sullivan with USAF Museum director

Col. Richard Uppstrom in the back seat. (Lockheed photo)

End of an Era
49

Appendices
50

Appendix 1: Flight Logs

This section includes lists of the aircraft in the YF-12 program, crewmembers, and

flight logs for each aircraft.

Aircraft:

YF-12A (60-6935) – Second YF-12A built. Flew 146 times from 1969 to 1979. Retired to USAF

Museum at Wright-Patterson Air Force Base near Dayton, Ohio.

YF-12A (60-6936) – Third YF-12A built. Flew 62 times in 1970 and 1971. Destroyed in crash

near Boron, California.

SR-71A (61-7951) – Second SR-71A built. Aircraft was given fictitious “YF-12C” designation

and borrowed A-12 tail number 06937 during NASA research program. Flew 90 times from 1971

to 1978. Retired to Pima Air Museum at Tucson, Arizona.

Pilots:

Maj. William J. Campbell, USAF: YF-12A (935 and 936)

William H. Dana, NASA: YF-12A (935), one pilot familiarization flight, one research flight

Einar K. Enevoldson, NASA: YF-12A (935), one pilot familiarization flight, one research flight

Maj. Mervin L. Evenson, USAF: YF-12C, delivered aircraft to NASA FRC

Fitzhugh L. Fulton, NASA: YF-12A (935 and 936), YF-12C, USAF test pilot and FRC research

pilot

Stephen D. “Steve” Ishmael, NASA: YF-12A (935), one pilot familiarization flight

Lt. Col. Calvin F. “Cal” Jewett, USAF: YF-12C, piloted final flight of aircraft

Gary E. Krier, NASA – YF-12A (935), one pilot familiarization flight

Lt. Col. Ronald J. “Jack” Layton, USAF: YF-12A (935 and 936)

Donald L. Mallick, NASA: YF-12A (935 and 936), YF-12C, FRC research pilot

John A. Manke, NASA: YF-12A (935), one pilot familiarization flight

Thomas C. McMurtry, NASA: YF-12A (935), one pilot familiarization flight
51

Col. Joseph W. Rogers, USAF: YF-12A (935 and 936), Director of USAF SR-71/F-12 Test Force

Col. Hugh C. “Slip” Slater, USAF: YF-12A (935 and 936)

Col. James V. Sullivan, USAF: YF-12A, YF-12C, transferred 935 and 937 back to USAF

Michael R. Swann, NASA: YF-12A (935), one pilot familiarization flight

Fire Control Officers/Test Engineers/Observers:

Lorenzo C. “Larry” Barnett, NASA: YF-12A (935), one flight, FRC YF-12 crew chief

Maj. Billy A. Curtis, USAF: YF-12A (936)

Maj. William J. Frazier, USAF: YF-12C RSO, transfer to USAF and last flight of aircraft

Maj. Gary I. Heidelbaugh, USAF: YF-12A (935 and 936) FCO

Victor W. Horton, NASA: YF-12A (935 and 936), YF-12C, FRC test engineer

Maj. Charles J. McNeer: YF-12C RSO, delivered aircraft to NASA FRC

Col. Richard Uppstrom, USAF: YF-12A (935), Director of USAF Museum

Maj. Sammel M. Ursini, USAF: YF-12A (935 and 936) FCO

William R. “Ray” Young, NASA: YF-12A (935), YF-12C, FRC test engineer

YF-12A (935) Flight Log:

Flt. 001 / 11 DEC 69: Rogers/Heidelbaugh. USAF test.

Flt. 002 / 17 DEC 69: Campbell/Ursini. USAF test.

Flt. 003 / 06 JAN 70: Rogers/Ursini. USAF test.

Flt. 004 / 14 JAN 70: Campbell/Heidelbaugh. USAF test.

Flt. 005 / 19 JAN 70: Slater/Heidelbaugh. USAF test.

Flt. 006 / 21 JAN 70: Slater/Ursini. USAF test.

Flt. 007 / 27 JAN 70: Slater/Heidelbaugh. USAF test.
52

Flt. 008 / 11 FEB 70: Campbell/Ursini. USAF test. Ventral fin damaged in sideslip.

Flt. 009 / 26 MAR 70: Campbell/Horton. Functional check flight of data acquisition systems, to

clear aircraft to Mach 2.0 without a ventral fin, and to obtain cruise data (Mach 2.0). First flight

with a NASA test engineer.

Flt. 010 / 01 APR 70: Mallick/Ursini. Pilot check-out #1, and FCF for data acquisition systems.

First flight with a NASA pilot.

Flt. 011 / 08 APR 70: Mallick/Ursini. Pilot check-out #2, and to acquire stability and deflection

data.

Flt. 012 / 14 APR 70: Fulton/Horton. Deflection points, stability data, and phugoids (Stability

Augmentation System [SAS] off). Biomedical data flight.

Flt. 013 / 17 APR 70: Fulton/Horton. Deflection points, stability data, and SST flight control

design data. Biomedical data flight.

Flt. 014 / 28 APR 70: Mallick/Young. Deflection points, stability data, phugoids (Mach 2.0, SAS

off, auto inlets). Biomedical data flight.

Flt. 015 / 01 MAY 70: Fulton/Horton. Deflection points, pitch pulse with SAS off, stability data,

phugoids (Mach 0.8, Pitch SAS off). Biomedical data flight.

Flt. 016 / 07 MAY 70: Mallick/Young. Deflection points, stability pitch pulses, and SST flight

control design data. Phugoid (Mach 2.0) data and use of 935 as a supersonic target for YF-12A

(60-0936) not accomplished. Biomedical data flight.

Flt. 017 / 15 MAY 70: Fulton/Horton. Deflection points, stability pitch pulses, phugoid (Mach 1.5,

manual inlets), stability and control set (Mach 1.5). Biomedical data flight (pilot only).

Flt. 018 / 22 MAY 70: Mallick/Young. Deflection points, stability pitch pulses, and phugoid

(Mach 1.3, Mach trim on and off). Phugoid at Mach 1.5 not accomplished. Biomedical data flight.

Flt. 019 / 27 MAY 70: Fulton/Horton. Deflection points, stability pitch pulses, phugoid (Mach

2.0), level acceleration at 35,000 feet, and functional check of wing camera. Biomedical data

flight.

Flt. 020 / 02 JUN 70: Mallick/Young. Level accelerations in maximum afterburner at 10,000 and

20,000 feet, and functional check of wing camera. Level accelerations (25,000 to 35,000 feet),

deflection data during transonic acceleration, inlet tuft data (Mach 2.0), phugoid (Mach 2.0,

autopilot in altitude hold), and constant KEAS supersonic climb not accomplished. Biomedical

data flight.

Flt. 021 / 11 JUN 70: Fulton/Horton. Level acceleration in minimum afterburner (10,000 to

30,000 feet), deflection and tuft data during supersonic acceleration, SST handling qualities
53

evaluation at Mach 2.0, phugoids (Mach 2.0 in altitude hold and Mach hold), and served as radar

target for YF-12A (60-6936). Biomedical data flight. Control room conflict with HL-10 liftingbody flight.

Flt. 022 / 16 JUN 70: Fulton/Young. SST handling qualities evaluation repeated, constant Mach

climbs (M=0.7, 0.8, and 0.9), two phugoids at Mach 2.0 and 60,000 feet (Mach hold, altitude

hold, inlets manual), and served as radar target for YF-12A (936). Deflection data at Mach 0.8 not

accomplished. Biomedical data flight. Aircraft grounded for instrumentation changes.

Flt. 023 / 22 MAR 71: Mallick/Horton. Functional check flight with ventral fin on, instrumentation check, and ventral fin loads data during sideslip. Phugoids, deflection data, and temperature

time history profile not accomplished. Biomedical data flight.

Flt. 024 / 07 MAR 71: Fulton/Horton. Ventral fin off.

Flt. 025 / 16 APR 71: Mallick/Horton. Stability and control points (Mach 2.4 to 2.6), and lightweight PIO data. Deflection data and level deceleration not accomplished. Biomedical data flight.

Flt. 026 / 29 APR 71: Mallick/Young. Stability and control data (Mach 2.6 and 2.7). Loads and

deflection data not accomplished. Biomedical data flight.

Flt. 027 / 05 MAY 71: Fulton/Horton. Stability and control data (Mach 2.7 and 2.8), loads data

(Mach 1.3), tuft data, level deceleration, deflection data, and PIO test. Phugoid not accomplished

due to shortage of fuel. Biomedical data flight.

Flt. 028 / 23 JUN 71: Mallick/Young. Ventral fin on. Refueling practice, deflection data and

ventral tuft photos in the transonic region. Temperature profiles and loads data not accomplished.

Flight aborted early due to landing gear warning light.

Flt. 029 / 09 JUL 71: Fulton/Horton. Loads data, level deceleration, wing camera data, and SST

handling qualities evaluation (Mach 2.5). Deflection data not collected.

Flt. 030 / 13 JUL 71: Mallick/Young. Air Force intercepts, loads and deflection data, temperature

profiles to Mach 2.65, ventral fin tuft photos in the transonic region, wing camera data, and

bypass tests. Biomedical data flight.

Flt. 031 / 20 JUL 71: Mallick/Horton. Air Force intercepts, loads and deflection data, temperature

profiles to Mach 3.0, wing camera data, and SST handling qualities evaluation at cruise (Mach

3.2). Aborted mission early, prior to refueling, due to SAS malfunction. Biomedical data flight.

Flt. 032 / 27 JUL 71: Mallick/Horton. Air Force intercepts, loads and deflection data, temperature

profiles to Mach 2.8, and wing camera data. Unable to hook on to tanker due to pilot error with

SAS channel settings. Aborted second leg of the mission. Biomedical data flight.
54

Flt. 033 / 03 AUG 71: Layton/Young. Air Force intercepts, loads and deflection data, temperature

profiles, wing camera data, and level deceleration. Biomedical data for FCO only. Had to retract

landing gear manually. Three unstarts. Had to use manual restart twice.

Flt. 034 / 10 AUG 71: Fulton/Young. Air Force intercepts, temperature profiles, wing camera data,

and level deceleration. Loads and deflection data not collected. Biomedical data flight. Unable to

find tanker. Aborted second leg of mission.

Flt. 035 / 17 AUG 71: Fulton/Horton. Air Force intercepts, loads and deflection data, wing camera

data, temperature profiles, stability and control data, and level deceleration. Biomedical data flight.

Flt. 036 / 22 OCT 71: Mallick/Horton. Low-speed functional check flight (Mach 1.2), PIO tracking investigation, level accelerations, and loads data. Biomedical data flight.

Flt. 037 / 22 OCT 71: Fulton/Horton. Loads data. Handling qualities, phugoid, and level acceleration not accomplished. Biomedical data flight. Flight aborted early due to hydraulic system failure.

Flt. 038 / 29 OCT 71: Mallick/Horton. Loads data and level accelerations. Biomedical data flight.

Flt. 039 / 29 OCT 71: Fulton/Young. Level decelerations, loads data, and level acceleration. Highspeed functional check and airframe/propulsion interaction test not accomplished. Biomedical data

flight.

Flt. 040 / 02 NOV 71: Mallick/Horton. Loads data, temperature profile, and constant KEAS climb.

Handling qualities evaluation (autopilot Mach hold) not performed. Biomedical data flight.

Flt. 041 / 09 NOV 71: Fulton/Young. Loads data and temperature profile. Handling qualities

evaluation (autopilot Mach hold) not completed. Biomedical data flight.

Flt. 042 / 16 NOV 71: Mallick/Horton. Loads data, temperature profile, airframe/propulsion

interaction test, and handling qualities evaluation.

Flt. 043 / 23 NOV 71: Fulton/Horton. Loads data and simulated single-engine approach. Airframe/

propulsion interaction test not accomplished. Second leg of mission cancelled because tanker

aborted. Biomedical data flight.

Flt. 044 / 30 NOV 71: Mallick/Young. Loads data, handling qualities evaluation, airframe/propulsion interaction test, and level deceleration. Biomedical data flight.

Flt. 045 / 07 DEC 71: Fulton/Horton. Bypass tests, angle-of-attack lag tests, and wing camera data.

Handling qualities evaluation not performed. Biomedical data flight. Aircraft diverted to Palmdale

due to Edwards AFB runway closure.

Flt. 046 / 07 DEC 71: Fulton/Horton. Ferried aircraft from Palmdale to Edwards.

Flt. 047 / 14 DEC 71: Mallick/Young. Air Force intercepts, loads data, sideslips (rudder doublet),

and handling qualities evaluation. Biomedical data flight.
55

Flt. 048 / 21 DEC 71: Fulton/Horton. Handling qualities evaluation, loads data, level acceleration, airframe/propulsion interaction, longitudinal static stability, and low-speed phugoids. Stability and control test with auto inlets and manual inlets not attempted. Biomedical data flight.

Flt. 049 / 11 JAN 72: Mallick/Young. Loads data, longitudinal handling qualities, and lateraldirectional handling qualities. Airframe/propulsion interaction tests, inlet doublets, and phugoids

not accomplished. INS system failed and the right-hand (R/H) bypass door control knob fell off

the panel.

Flt. 050 / 18 JAN 72: Fulton/Horton. Bypass tests, pitch pulse to evaluate angle-of-attack lag, and

airframe/propulsion interaction test. Biomedical data flight. The airplane was unable to turn

tightly enough to avoid overflying Death Valley National Monument.

Flt. 051 / 26 JAN 72: Fulton/Horton. Loads data, level cruise (Mach 3.2). Biomedical data flight.

Flt. 052 / 26 JAN 72: Fulton/Horton. Loads data and airframe/propulsion interaction test. Biomedical data flight.

Flt. 053 / 23 FEB 72: Mallick/Young. Refueled near El Paso, Texas for maximum time at Mach

3.2 cruise speed.

Aircraft grounded for studies in the NASA FRC Loads Laboratory.

Flt. 054 / 12 JUL 73: Fulton/Horton. Low-speed functional check. Nose gear failed to extend

during test of emergency gear extension cycle. The remainder of the mission was aborted.

Flt. 055 / 26 JUL 73: Mallick/Young. Emergency gear extension functional check, autopilot

checks, and stabilized cruise points for boundary-layer and aft-facing step experiments.

Flt. 056 / 03 AUG 73: Fulton/Horton. High-speed functional check, boundary-layer and aft-facing

step experiments, and sideslip data.

Flt. 057 / 23 AUG 73: Fulton/Young. Boundary-layer and aft-facing step experiments, sideslip

data, and low L/D landing.

Flt. 058 / 06 SEP 73: Mallick/Horton. Stabilized points for the aft-facing step and boundary-layer

experiments.

Flt. 059 / 13 SEP 73: Fulton/Horton. SAS-off pitch pulses, boundary-layer and aft-facing step

experiments, and phugoids.

Flt. 060 / 11 OCT 73: Mallick/Barnett. Aft-facing step and boundary-layer data point (Mach 1.1)

and functional check of emergency landing gear extension system.
56

Flt. 061 / 11 OCT 73: Mallick/Young. Autopilot baseline checks in altitude hold mode (Mach 2.5

to 3.2) and boundary-layer data point (Mach 3.0). Phugoid not accomplished. Tanker cancelled

because it was needed to support a project with a higher priority (probably SR-71 coverage of the

Arab-Israeli war, which started on 6 October).

Flt. 062 / 23 OCT 73: Fulton/Horton. Steady-state sideslip (Mach 1.6), boundary-layer, and aftfacing step experiments.

Flt. 063 / 07 NOV 73: Mallick/Young. Boundary-layer and aft-facing step experiments (Mach 2.2

to 3.2) and phugoid (Mach 3.0, altitude hold).

Flt. 064 / 16 NOV 73: Fulton/Horton. Boundary-layer and aft-facing step experiments (Mach

0.89 to 2.5) and autopilot baseline data (Mach hold and altitude hold).

Flt. 065 / 03 DEC 73: Mallick/Young. Boundary-layer and aft-facing step experiments (Mach 2.5

to 3.0) and autopilot baseline data (Mach 3.0, Mach hold and altitude hold).

Flt. 066 / 13 DEC 73: Fulton/Horton. Boundary-layer and aft-facing step experiments (Mach 0.6

to 2.8) and effect of bypass airflow on the wing boundary-layer rake.

Flt. 067 / 11 JAN 74: Mallick/Young. Boundary-layer and aft-facing step experiments (Mach 0.8

to 3.2).

Flt. 068 / 17 JAN 74: Fulton/Horton. Boundary-layer and aft-facing step experiments (Mach 0.6

to 3.2).

Flt. 069 / 25 JAN 74: Mallick/Young. Boundary-layer and aft-facing step experiments (Mach 0.9

to 3.2).

Flt. 070 / 04 MAR 74: Fulton/Horton. Boundary-layer, aft-facing step, and boat-tail-drag data

(Mach 0.9 to 3.0), modified autopilot tests, and elevator pulses (Mach 3.0, auto inlets and manual

inlets).

Flt. 071 / 08 MAR 74: Mallick/Young. Boundary-layer, aft-facing step, and boat-tail-drag data

(Mach 0.8 to 2.5).

Flt. 072 / 15 MAR 74: Fulton/Horton. Boundary-layer, aft-facing step, and boat-tail-drag data

(Mach 1.0 to 3.2).

Flt. 073 / 21 MAR 74: Mallick/Young. Boundary-layer, aft-facing step, and boat-tail-drag data

(Mach 0.6 to 3.2), altitude-hold test in climb.

Flt. 074 / 28 MAR 74: Fulton/Horton. Boundary-layer, aft-facing step, boat tail drag data (Mach

0.9 to 3.0), constant “G” turns, and modified autopilot tests.

Flt. 075 / 18 APR 74: Mallick/Young. Boundary-layer, aft-facing step, and boat-tail-drag data
57

(Mach 0.6 to 3.0). Flight aborted early due to left-hand (L/H) engine oil pressure malfunction.

Flt. 076 / 02 MAY 74: Fulton/Horton. Boundary-layer, aft-facing step, and boat-tail-drag data

(Mach 0.9 to 3.2).

Flt. 077 / 09 MAY 74: Mallick/Young. Boundary-layer, aft-facing step, and boat-tail-drag data

(Mach 0.9 to 2.5).

Flt. 078 / 16 MAY 74: Fulton/Horton. Boundary-layer, aft-facing step, and boat-tail-drag data

(Mach 0.6 to 3.2), modified autopilot tests, and handling-qualities evaluation.

Flt. 079 / 23 MAY 74: Mallick/Young. Aborted early due to R/H generator malfunction shortly

after takeoff. Boundary-layer, aft-facing step, and boat-tail-drag data not collected.

Flt. 080 / 30 MAY 74: Mallick/Young. Boundary-layer, aft-facing step, and boat-tail-drag data

(Mach 2.0 to 3.2).

Flt. 081 / 06 JUN 74: Fulton/Horton. Boundary-layer, aft-facing step, and boat-tail-drag data

(Mach 0.6 to 3.0).

Flt. 082 / 11 SEP 74: Fulton/Horton. Low-speed functional check, aft-facing step, four-foot

flow field survey rake, and boat-tail-drag data (Mach 0.6 to 1.5).

Flt. 083 / 17 SEP 74: Fulton/Horton. Aft-facing step, four-foot flow field survey rake, and boattail-drag data.

Flt. 084 / 03 OCT 74: Fulton/Horton. Aft-facing step, four-foot flow field survey rake, and

boat-tail-drag data (Mach 0.6 to 1.2). Back-up flight profile flown due to crew environmental

system malfunction.

Flt. 085 / 18 OCT 74: Fulton/Horton. Functional check of the Type K engines, aft-facing step,

four-foot flow field survey rake, boat-tail-drag data (Mach 0.9 to 3.2), rudder doublet (Mach

3.0), and water dump.

Flt. 086 / 25 OCT 74: Fulton/Horton. Coldwall track and profile data, aft-facing step, four-foot

flow field survey rake, and boat-tail-drag data (Mach 1.05 to 2.0).

Flt. 087 / 01 NOV 74: Fulton/Horton. Coldwall track and profile data, aft-facing step, four-foot

flow field survey rake, and boat-tail-drag data (Mach 1.05 to 3.2).

Aircraft grounded for installation of Coldwall experiment.

Flt. 088 / 07 FEB 75: Fulton/Horton. Low-speed functional check flight with Coldwall experiment. Aborted early due to Coldwall accelerometer malfunction.
58

Flt. 089 / 14 FEB 75: Mallick/Young. Planned functional check flight of Coldwall experiment

was aborted due to Coldwall accelerometer malfunction. A subsonic back-up mission profile was

flown for stability and control data.

Flt. 090 / 27 FEB 75: Mallick/Young. Rudder doublets (Mach 0.8 to 3.0). Ventral fin separated

from aircraft during flight. Mission ended with emergency landing at Edwards AFB.

Aircraft grounded for repairs. No ventral fin until Flight 097.

Flt. 091 / 11 JUL 75: Fulton/Horton. Structural demonstration of the Coldwall experiment at

supersonic speed, structural demonstration of the flow field survey rake in place of the ventral

fin, ventral flow field data, and documentation of the stability of the aircraft with Coldwall and

camera pods on and the ventral fin off.

Flt. 092 / 24 JUL 75: Mallick/Young. Structural demonstration of Coldwall with an insulation

blanket installed, flow field data in the ventral region, documentation of aircraft stability, and

collection of scanivalve data prior to and following each use of afterburner.

Flt. 093 / 07 AUG 75: Fulton/Horton. Operational check of the Coldwall insulation removal

system at Mach 2.4. Both inlets ingested insulation material and unstarted.

Flt. 094 / 21 AUG 75: Fulton/Horton. Flow field survey of aircraft with Coldwall experiment

removed and camera pods on.

Flt. 095 / 28 AUG 75: Mallick/Young. Flow field survey and aircraft stability with Coldwall

experiment off and camera pods on.

Flt. 096 / 05 SEP 75: Fulton/Horton. Aircraft stability with Coldwall experiment off, ventral

survey rake and camera pods on. Pilot declared an emergency on landing approach due to unsafe

R/H landing gear indication. Landing was accomplished without incident.

Aircraft grounded for installation of Lockalloy (62Be-38Al) ventral fin.

Flt. 097 / 16 JAN 76: Mallick/Young. First flight with new Lockalloy ventral fin; rudder and

aileron pulses, and steady-state sideslips.

Flt. 098 / 27 JAN 76: Fulton/Horton. Touch-and-go landings for high-speed taxi data with

instrumented landing gear, low-speed taxi test.

Flt. 099 / 05 FEB 76: Mallick/Young. Touch-and-go landings for high-speed taxi data with

instrumented landing gear, runway roughness tests, and low-speed taxi test.

Flt. 100 / 12 FEB 76: Fulton/Horton. Envelope expansion and sideslip data with Lockalloy

ventral fin. Landing gear data was not obtained due to foam on the runway.

Flt. 101 / 04 MAR 76: Fulton/Young. Envelope expansion and sideslip data with Lockalloy ventral

fin, plus low L/D approach. Landing gear data was not obtained due to unsafe gear indication.
59

Flt. 102 / 23 MAR 76: Fulton/Horton. Envelope expansion and sideslip data with Lockalloy

ventral fin, push-over and pull-up maneuvers, and landing gear.

Flt. 103 / 02 APR 76: Fulton/Young. Envelope expansion and sideslip data with Lockalloy

ventral fin.

Flt. 104 / 12 APR 76: Fulton/Young. Ventral tufts (flow-field photos), low landing approach,

and landing gear data.

Flt. 105 / 13 MAY 76: Mallick/Young. Envelope expansion with Lockalloy ventral fin; landing

gear data.

Flt. 106 / 20 MAY 76: Fulton/Horton. Envelope expansion with Lockalloy ventral fin; landing

gear data.

Flt. 107 / 15 JUL 76: Mallick/Young. Stability and control data with Coldwall, camera pods,

and Lockalloy ventral fin on.

Flt. 108 / 22 JUL 76: Fulton/Horton. Stability and control data with Coldwall, camera pods, and

Lockalloy ventral fin on, Coldwall alignment flight data, and operational test of Coldwall rake

guard.

Flt. 109 / 10 AUG 76: Mallick/Young. Coldwall profile and Hotwall data.

Flt. 110 / 31 AUG 76: Fulton/Horton. Coldwall profile, Hotwall data, and landing flare data.

Flt. 111 / 13 SEP 76: Fulton/Horton. Coldwall skin-friction balance-cooling verification and

conical probe alignment data.

Flt. 112 / 28 SEP 76: Fulton/Horton. Coldwall profile, Hotwall data and skin friction data.

Flt. 113 / 21 OCT 76: Fulton/Horton. Coldwall data not obtained due to premature loss of

Coldwall experiment insulation.

Flt. 114 / 10 NOV 76: Fulton/Horton. Gust-vane calibration, handling-qualities evaluation,

vortex flow visualization photos, and autopilot altitude-hold tests.

Flt. 115 / 09 DEC 76: Mallick/Young. Coldwall profile, Hotwall data, and fuselage tuft photos

at subsonic speeds.

Flt. 116 / 03 MAR 77 : Fulton/Horton. Coldwall data not obtained due to premature loss of

Coldwall experiment insulation.

Flt. 117 / 02 JUN 77: Fulton/Horton. Vortex flow visualization photos. Coldwall data not obtained due to premature loss of Coldwall experiment insulation.
60

Flt. 118 / 23 JUN 77: Fulton/Horton. Vortex flow visualization photos and Coldwall data.

Flt. 119 / 21 JUL 77: Fulton/Horton. Coldwall data not obtained because Coldwall insulation

was ingested into the L/H engine inlet, causing an unstart that did not clear correctly. Aircraft

made an emergency landing at Edwards. The YF-12C chase aircraft simultaneously experienced

a high KEAS condition and compressor stalls. Aircraft grounded for overspeed and overload

inspection.

Flt. 120 / 30 SEP 77: Fulton/Horton. Coldwall data, U-2 intercept, and a fly-by of the NASA

Dryden Flight Research Center.

Flt. 121 / 13 OCT 77: Fulton/Horton. Coldwall data. Final Coldwall flight.

Flt. 122 / 18 NOV 77: Mallick/Young. Lower surface boundary-layer survey and handling

qualities evaluation. Subsonic wake vortex flow visualization data not obtained due to a malfunction of the wake visualization water-spray system.

Flt. 123 / 01 DEC 77: Manke/Horton. Pilot familiarization.

Flt. 124 / 01 DEC 77: Dana/Horton. Pilot familiarization.

Flt. 125 / 09 DEC 77: Krier/Young. Pilot familiarization.

Flt. 126 / 13 DEC 77: Enevoldson/Young. Pilot familiarization.

Flt. 127 / 14 DEC 77: McMurtry/Horton. Pilot familiarization.

Flt. 128 / 28 FEB 78: Mallick/Young. Dual-mode landing gear baseline stiffness tests.

Flt. 129 / 28 FEB 78: Mallick/Young. Dual-mode landing gear baseline stiffness tests.

Flt. 130 / 07 MAR 78: Fulton/Horton. Large volume landing gear stiffness tests.

Flt. 131 / 07 MAR 78: Fulton/Horton. Large volume landing gear stiffness tests.

Flt. 132 / 15 MAR 78: Mallick/Young. Mixed volume landing gear stiffness tests.

Flt. 134 / 23 MAR 78: Fulton/Horton. Space Shuttle approach simulations.

Flt. 135 / 31 MAR 78: Enevoldson/Young. Space Shuttle approach simulations.

Flt. 136 / 31 MAR 78: Dana/Horton. Space Shuttle approach simulations. Aircraft grounded for

installation of shaker vane system.
61

Flt. 137/ 22 NOV 78: Fulton/Horton. Shaker vane study.

Flt. 138/ 01 DEC 78: Fulton/Horton. Shaker vane study.

Flt. 139/ 24 JAN 79: Mallick/Young. Shaker vane study.

Flt. 140/ 16 FEB 79: Fulton/Horton. Shaker vane study.

Flt. 141/ 08 MAR 79: Mallick/Young. Shaker vane study.

Flt. 142/ 15 MAR 79: Fulton/Horton. Shaker vane study.

Flt. 143/ 29 MAR 79: Ishmael/Horton. Pilot familiarization.

Flt. 144/ 29 MAR 79: Swann/Young. Pilot familiarization.

Flt. 145/ 31 OCT 79: Fulton/Horton. Final NASA flight of 935.

Flt. 146/ 07 NOV 79: Sullivan/Uppstrom. Ferried aircraft to USAF Museum.

YF-12A (936) Flight Log:

Flt. 001 / 03 MAR 70: Slater/Heidelbaugh. USAF test.

Flt. 002 / 05 MAR 70: Fulton/Horton. Pilot check-out #1.

Flt. 003 / 09 MAR 70: Fulton/Horton. Pilot check-out #2.

Flt. 004 / 11 MAR 70: Fulton/Horton. Pilot check-out #3.

Flt. 005 / 24 MAR 70: Slater/Heidelbaugh. Aborted.

Flt. 006 / 31 MAR 70: Slater/Heidelbaugh. Intercepts and turn performance, FCF, fuel tank

sealant curing, radar tracked constant KEAS descent.

Flt. 007 / 10 APR 70: Mallick/Ursini. Final check-out (#3) flight for Mallick, fuel tank sealant

curing, air-data system calibration (constant KEAS climb and descent), radar intercepts, and

NASA Edwards and Ely radar tracking range determination.

Flt. 008 / 16 APR 70: Slater/Ursini. Supersonic controlled intercepts, constant KEAS accelerations, and subsonic controlled intercepts. Other objectives not met due to mechanical malfunctions.

Flt. 009 / 21 APR 70: Slater/Heidelbaugh. Radar intercepts. Other objectives not accomplished

due to mechanical malfunctions.
62

Flt. 010 / 24 APR 70: Slater/Heidelbaugh. Simulated supersonic target ID intercept, controlled

and autonomous intercepts. Air data system calibrations not performed. No research engineers at

the USAF radar site to advise expected inbound track for radar acquisition.

Flt. 011 / 30 APR 70: Slater/Ursini. Mission Control data link check. Other objectives not

accomplished due to apparent high fuel consumption.

Flt. 012 / 07 MAY 70: Slater/Heidelbaugh. Fuel consumption and CG check, pitch trim calibration, air data system calibration (350 KEAS descent), and simulated supersonic ID intercept.

Flt. 013 / 17 MAY 70: Rogers/Heidelbaugh. Armed Forces Day airshow fly-by at Edwards

AFB.

Flt. 014 / 26 MAY 70: Campbell/Ursini. Supersonic cruise altitude control at Mach numbers of

2.6, 2.8, and 3.0. Unable to attain maximum Mach number (3.2) due to fuel flow variations

between engines at high speed.

Flt. 015 / 05 JUN 70: Slater/ Heidelbaugh. Air data system calibration (400 KEAS descent).

Planned airborne early warning (AEW) and B-57 intercepts not accomplished due to not receiving tone for radar time correlation as called for on the flight cards.

Flt. 016 / 11 JUN 70: Slater/Ursini. Supersonic transport intercept geometry using YF-12A (60-

6935) as a target, air data calibration (450 KEAS acceleration). Biomedical data flight. Control

room conflict with HL-10 lifting-body flight.

Flt. 017 / 16 JUN 70: Slater/Heidelbaugh. Supersonic Transport ID intercept, and Air Force

documentary photos. Biomedical data flight.

Aircraft grounded for instrumentation changes.

Flt. 018 / 29 AUG 70: Campbell/Heidelbaugh. Functional check flight, and inlet instrumentation

shakedown. Biomedical data flight.

Flt. 019 / 05 SEP 70: Layton/Heidelbaugh. Pilot check-out #1. Fire control officer (FCO)

biomedical data flight.

Flt. 020 / 06 SEP 70: Layton/Heidelbaugh. Pilot check-out #2. FCO biomedical data flight.

Flt. 021 / 06 SEP 70: Layton/Heidelbaugh. Pilot check-out #3. FCO biomedical data flight.

Flt. 022 / 11 SEP 70: Layton/Heidelbaugh. Pilot check-out #4, aerial refueling, and radar cross

sections and intercepts. FCO biomedical data flight.

Flt. 023 / 12 SEP 70: Layton/Heidelbaugh. Final pilot check-out (#5). No biomedical data on

this flight.
63

Flt. 024 / 15 SEP 70: Layton/Heidelbaugh. F-106 autonomous intercept, B-57 controlled intercept, and turn performance. EC-121 radar intercept not accomplished. Biomedical data for pilot

only.

Flt. 025 / 17 SEP 70: Layton/Heidelbaugh. USAF test.

Flt. 026 / 06 OCT 70: Layton/Heidelbaugh. High-speed altitude control, and level deceleration

(cruise to minimum KEAS). Radar intercepts not accomplished.

Flt. 027 / 09 OCT 70: Layton/Heidelbaugh. Aborted.

Flt. 028 / 16 OCT 70: Layton/Heidelbaugh. Air data system calibration. Biomedical data flight.

Flt. 029 / 23 OCT 70: Layton/Heidelbaugh. F-106 and B-57 controlled intercepts. Biomedical

data flight.

Flt. 030 / 27 OCT 70: Layton/Heidelbaugh. Radar intercepts of B-57 and F-106, and turn performance. Biomedical data flight. Control room conflict with X-24A lifting-body flight.

Flt. 031 / 29 OCT 70: Layton/Heidelbaugh. F-106 supersonic target ID intercept, F-106 radar

intercepts, and lag stair step profile (Mach 3.0). Biomedical data flight. U-2 high-altitude intercept

not accomplished.

Flt. 032 / 03 NOV 70: Mallick/Heidelbaugh. Pilot recurrency, phugoids (Mach 3.0, auto inlets,

pitch autopilot off). Biomedical data flight. Radar intercepts not accomplished due to inoperative

radar.

Flt. 033 / 03 NOV 70: Layton/Heidelbaugh. U-2 and F-4 controlled radar intercepts, F-106

autonomous radar intercepts, phugoids (Mach 3.0), and lag stair step (Mach 2.5).

Flt. 034 / 17 NOV 70: Layton/Curtis. FCO check-out, U-2 and F-106 radar intercepts.

Flt. 035 / 20 NOV 70: Layton/Curtis. F-106 radar intercepts. Unable to perform B-57 radar

intercepts, phugoids, and level deceleration. Mission aborted early due to oil quantity problem.

Flt. 036 / 25 NOV 70: Campbell/Heidelbaugh. F-106 radar intercepts, cruise sideslip, and level

deceleration (cruise to minimum KEAS). B-57 and F-4 radar intercepts not accomplished. Control

room conflict with M2-F3 lifting-body flight.

Flt. 037 / 01 DEC 70: Layton/Heidelbaugh. F-106 and B-52 radar intercepts.

F-106 and F-4 radar intercepts not accomplished. NASA sideslip and lag stair step not accomplished. Environmental test antenna fell off prior to flight. Flight aborted early due to hydraulic

system failure.

Flt. 038 / 17 DEC 70: Layton/Curtis. Flight aborted early due to liquid nitrogen system failure.

No data.
64

Flt. 039 / 19 JAN 71: Layton/Curtis. Subsonic pulse code modulation (PCM) failed.

Flt. 040 / 22 JAN 71: Mallick/Heidelbaugh. Pilot recurrency, B-57 radar intercept, sideslip and roller

coaster maneuver (Mach 2.75 and 3.0). Biomedical data flight. Landing approaches not accomplished

due to precautionary emergency straight-in landing (low oil pressure in R/H engine). NASA PCM

failed.

Flt. 041 / 29 JAN 71: Layton/Curtis. Aborted early due to repeat of problems from Flt. 40. Biomedical data flight. No other data.

Flt. 042 / 02 FEB 71: Layton/Heidelbaugh. ECM target (B-57), F-106 conversion target, and

sideslip (Mach 2.75). Other objectives not accomplished due to engine malfunction (R/H oil

pressure fluctuation, shutdown). Biomedical data flight.

Flt. 043 / 10 FEB 71: Layton/Heidelbaugh. Functional check flight, sideslip (Mach 3.0), cruise

bleed and bypass manual inlet, and phugoid. Biomedical data flight. B-57 offset target, F-106

conversion target, and Mach 3.0 roller coaster not accomplished.

Flt. 044 / 18 FEB 71: Layton/Curtis. F-106 head-on and conversion target, bleed and bypass

manual inlet (Mach 3.0), and B-57 conversion target. Biomedical data flight. Other objectives not

accomplished. Roller coaster maneuver found to be impractical.

Flt. 045 / 23 FEB 71: Layton/Curtis. PCM system noise checks, F-106 maneuvering target, B-57

conversion target, phugoid (Mach 3.0, pitch autopilot off), manual forward bypass acceleration,

and modified roller coaster maneuver (Mach 3.0). F-106 conversion target not completed.

Flt. 046 / 02 MAR 71: Layton/Curtis. B-57 maneuvering and conversion target, modified roller

coaster (Mach 2.75 and 3.0), bypass manual inlet (Mach 2.75), pitch and yaw pulse (Mach 3.0),

and B-57 PCM target.

Flt. 047 / 05 MAR 71: Mallick/Heidelbaugh. Pilot proficiency check, pitch and yaw pulse (auto

and manual inlets, SAS off), and B-57 offset and conversion target. C-130 radar intercept not

completed.

Flt. 048 / 09 MAR 71: Layton/Heidelbaugh. B-57 conversion target, and handling qualities

altitude change. F-106 conversion target, C-130 head-on target, and level deceleration not accomplished. Flight aborted early due to low L/H engine oil pressure.

Flt. 049 / 18 MAR 71: Layton/Curtis. B-57 maneuvering target, and phugoid (autopilot, Mach

hold, Mach 3.0). F-105 frontal intercept, B-57 conversion target, and 400 KEAS descent not

accomplished. SPORT radar unable to acquire YF-12 during descent.

Flt. 050 / 23 MAR 71: Layton/Heidelbaugh. B-52 maneuvering target, F-106 head-on target, B-57

conversion target, altitude control handling qualities (Mach 3.0), level deceleration (cruise to

minimum KEAS), and 400 KEAS descent. C-130 head-on target not accomplished due to radar

malfunction.
65

Flt. 051 / 25 MAR 71: Layton/Curtis. B-52 maneuvering target, altitude change handling qualities, and phugoid (Mach 3.0, altitude hold). F-106 and C-130 head-on intercepts not accomplished. Phugoid terminated after one cycle due to excess speed.

Flt. 052 / 30 MAR 71: Layton/Heidelbaugh. F-106 and B-57 conversion targets, altitude-control

handling qualities (Mach 2.75), level deceleration (cruise to minimum KEAS), and 400 KEAS

descent. Radar tracking kept breaking lock. SPORT tracking radar unable to re-acquire YF-12 for

level deceleration. Severe turbulence at 47,500 feet. Heavy persistent contrails at 65,000 feet.

Flt. 053 / 13 APR 71: Layton/Curtis. USAF test.

Flt. 054 / 20 APR 71: Layton/Curtis. C-131 radar target (propeller signatures), F-106 and F-4E

frontal intercepts, and speed stability trim point (Mach 3.0). B-57 detection and tracking,

phugoid, and ventral lateral accelerations not accomplished.

Flt. 055 / 27 APR 71: Layton/Heidelbaugh. Speed stability trim point (Mach 3.0).

Flt. 056 / 06 MAY 71: Layton/Curtis. Speed stability trim point (Mach 3.0). Cruise roller coaster

maneuver not accomplished.

Flt. 057 / 13 MAY 71: Layton/Heidelbaugh. Transonic ventral acceleration and deceleration data,

and roller coaster maneuvers (Mach 3.0 and 3.2). Inlet control parameter data and Mach 2.75

roller coaster not accomplished.

Flt. 058 / 04 JUN 71: Layton/Curtis. Transonic ventral accelerations, inlet cruise data calibration,

and auto inlet parameters. NASA bypass door walk instrumentation data and manual inlet parameters not accomplished. Initial flight abort resulted in lakebed takeoff.

Flt. 059 / 10 JUN 71: Layton/Heidelbaugh. Throttle advance/inlet noise correlation, and intervalometer data quality.

Flt. 060 / 15 JUN 71: Layton/Curtis. Handling qualities intervalometer data. Steady state inlet

data (Mach 2.0) not accomplished.

Flt. 061 / 22 JUN 71: Layton/Heidelbaugh. Steady-state inlet data (Mach 2.0), and handling

qualities mission survey.

Flt. 062 / 24 JUN 71: Layton/Curtis. Handling qualities intervalometer. Fire in R/H engine

resulted in crash. Crew ejected safely.

YF-12C (937) Flight Log:

Flt. 001 / 16 JUL 71: Evenson/McNeer. Delivery to NASA FRC. Aircraft grounded for installation of NASA instrumentation.
66

Flt. 002 / 24 MAY 72: Fulton/Horton. First NASA flight of 937. Functional check flight, phugoid,

airspeed calibration, and stability and control pulses. Biomedical data flight.

Flt. 003 / 06 JUN 72: Mallick/Young. Airspeed calibration. Level acceleration and deceleration,

and constant KEAS climb. Biomedical data flight.

Flt. 004 / 14 JUN 72: Fulton/Horton. Airspeed calibration and propulsion. Level decelerations,

constant KEAS descent, roller coaster maneuvers, and sideslips. Biomedical data flight.

Flt. 005 / 21 JUN 72: Mallick/Young. Propulsion performance baseline data, and stability and

control data. Forward engine bypass tests, roller coaster maneuvers, sideslip, level deceleration,

constant KEAS descent, and phugoids. Biomedical data flight.

Flt. 006 / 18 JUL 72: Fulton/Young. Performance baseline and airspeed calibration data. Functional check of engine revolutions-per-minute trim and SAS recall, roller coaster maneuvers,

sideslip, engine bypass tests (Mach 2.5 to 3.2), level deceleration, and constant KEAS descent.

Biomedical data flight.

Flt. 007 / 26 JUL 72: Mallick/Young. Propulsion baseline data, stability and control (Mach 2.9,

manual and auto inlets), and phugoids. Biomedical data flight.

Flt. 008 / 01 AUG 72: Fulton/Horton. Served as target for Navy F-14 radar intercept, propulsion

performance (roller coaster maneuvers, sideslip, and bypass tests), and stability and control data.

Biomedical data flight.

Flt. 009 / 15 AUG 72: Mallick/Young. Airspeed lag calibration roller coaster maneuvers, and

stability and control interactions. Biomedical data flight.

Flt. 010 / 22 AUG 72: Fulton/Horton. Propulsion baseline data, stability and control data, and

phugoid. Biomedical data flight.

Flt. 011 / 29 AUG 72: Mallick/Young. Performance baseline data, airspeed calibration, and

phugoids. Biomedical data flight.

Aircraft grounded for installation of Inlet Recall system.

Flt. 012 / 15 NOV 72: Fulton/Horton. RPM trim test (Mach 3.0), functional test of Inlet Recall

(intentional unstart), bypass tests, and roller coaster maneuvers. Biomedical data flight.

Flt. 013 / 22 NOV 72: Mallick/Young. Phase II propulsion tests. Biomedical data flight.

Flt. 014 / 05 DEC 72: Fulton/Horton. Phase II propulsion tests. Biomedical data flight.

Flt. 015 / 12 DEC 72: Mallick/Young. Phase II propulsion tests. Biomedical data flight.

Flt. 016 / 11 JAN 73: Fulton/Horton. Phase II propulsion tests. Biomedical data flight.
67

Flt. 017 / 18 JAN 73: Mallick/Young. Performance tests. Level accelerations, speed-power

points, roller coaster maneuvers, constant KEAS climb and descent, and constant power turns.

Biomedical data flight.

Flt. 018 / 24 JAN 73: Fulton/Horton. Performance tests. Level accelerations, speed power points,

roller coaster maneuvers, constant KEAS climb and descent, and constant power turns. Biomedical data flight.

Flt. 019 / 01 FEB 73: Fulton/Young. Phase II propulsion tests. Biomedical data flight.

Flt. 020 / 08 FEB 73: Mallick/Horton. Propulsion and handling qualities tests. Biomedical data

flight.

Flt. 021 / 15 FEB 73: Fulton/Young. Performance tests. Constant KEAS climb, speed-power

points, roller coaster maneuvers, and constant 400 KEAS descent. Biomedical data flight.

Flt. 022 / 22 FEB 73: Mallick/Horton. Performance tests. Level accelerations, speed-power

points, roller coaster maneuvers, and constant 400 KEAS climb and descent. Biomedical data

flight.

Flt. 023 / 22 MAR 73: Fulton/Horton. Functional check flight and Phase II propulsion tests.

Biomedical data flight.

Flt. 024 / 05 APR 73: Mallick/Horton. Support U-2A (56-6692) target radiation intensity measurement tests, Phase II propulsion tests, and radar targeting for Navy F-14. Biomedical data

flight.

Flt. 025 / 12 APR 73: Fulton/Young. Phase II propulsion tests. Biomedical data flight.

Flt. 026 / 20 APR 73: Mallick/Young. Phase II propulsion tests, low L/D approach. Biomedical

data flight.

Flt. 027 / 26 APR 73: Fulton/Horton. Phase II propulsion tests, low L/D approach. Biomedical

data flight.

Flt. 028 / 02 MAY 73: Mallick/Young. No objectives completed. Aborted to Naval Air Station

(NAS) Fallon, Nevada, due to R/H spike failure and subsequent high fuel consumption. Biomedical data flight.

Flt. 029 / 03 MAY 73: Mallick/Young. Subsonic ferry flight from NAS Fallon, Nevada, to

Edwards AFB.

Flt. 030 / 10 MAY 73: Fulton/Horton. Phase II propulsion tests. Biomedical data flight.

Flt. 031 / 17 MAY 73: Mallick/Young. Phase II propulsion tests. Biomedical data flight.
68

Flt. 032 / 31 MAY 73: Fulton/Horton. Stability and control, handling qualities, and phugoids.

Biomedical data flight.

Flt. 033 / 08 JUN 73: Mallick/Young. Constant 450 KEAS climb, constant Mach climb (maximum KEAS to minimum KEAS), speed-power point (Mach 2.5), constant 450 KEAS descent,

and low L/D approach to lakebed. Biomedical data flight.

Aircraft grounded for 13 months.

Flt. 034 / 11 JUL 74: Fulton/Horton. Aircraft functional check flight, Data Acquisition System

check-out for Phase III propulsion test program. Biomedical data flight.

Flt. 035 / 26 JUL 74: Mallick/Young. Aircraft performance data. Level accelerations, constant

Mach climb, speed-power points, and roller coaster maneuvers. Biomedical data flight.

Flt. 036 / 13 SEP 74: Mallick/Young. Phase III propulsion tests. Fixed inlet study, inlet Reynolds

number tests, Mach 2.48 wind-tunnel match point, aft bypass frequency generator test, and angleof-attack tests (Mach 2.1). Biomedical data flight.

Flt. 037 / 25 SEP 74: Mallick/Young. Phase IIIa propulsion tests. Real-time match tests,

Reynolds number tests, aft bypass function generator test, and inlet angle-of-attack tests. Biomedical data flight.

Flt. 038 / 07 NOV 74: Fulton/Horton. Performance data. Level accelerations, constant KEAS

climb, constant Mach climb, level cruise, constant KEAS descent, and constant Mach descent.

Biomedical data flight.

Flt. 039 / 19 DEC 74: Mallick/Young. Low-speed functional check flight and inlet transducer lag

checks. Biomedical data flight.

Flt. 040 / 19 DEC 74: Mallick/Young. High-speed functional check flight and performance

modeling data. Constant Mach climbs, level accelerations, constant KEAS climb and descent,

and speed-power points. Biomedical data flight.

Flt. 041 / 17 JAN 75: Fulton/Horton. Performance modeling data and Turbine Inlet Gas Temperature (TIGT) system check. Biomedical data flight.

Flt. 042 / 24 JAN 75: Mallick/Horton. Performance modeling data and TIGT system check.

Biomedical data flight.

Flt. 043 / 24 APR 75: Fulton/Horton. Performance modeling data and TIGT system check.

Biomedical data flight.

Flt. 044 / 05 JUN 75: Mallick/Young. TIGT system check, TIGT control tests in climb and

descent, and phugoids (Mach 2.9, auto inlets and manual inlets). Aft bypass door generator data

not accomplished. Biomedical data flight.
69

Flt. 045 / 12 JUN 75: Fulton/Horton. TIGT system transient tests (Mach 3.0), TIGT control tests

during a standard climb profile, and spike tip data (Mach 1.6 to 3.2). Biomedical data flight.

Flt. 046 / 20 JUN 75: Mallick/Young. Performance modeling data and TIGT system check.

Biomedical data flight.

Flt. 047 / 26 JUN 75: Fulton/Horton. TIGT transient tests, TIGT control test during a standard

descent, and baseline co-op control data (Mach 3.0) Aft bypass function generator tests not

accomplished. Biomedical data flight.

Flt. 048 / 03 JUL 75: Mallick/Young. Propulsion data. Mach tests, spike tests, sideslip tests, and

angle-of-attack tests (Mach 2.8 to 3.2). Biomedical data flight.

Flt. 049 / 07 AUG 75: Mallick/Young. Chase for YF-12A (935) Coldwall flight, and spike tip

tests (Mach 2.1 to 3.2). Biomedical data flight

Flt. 050 / 14 AUG 75: Mallick/Young. Propulsion data. Mach tests, spike tests, sideslip tests,

and angle-of-attack tests (Mach 2.8 to 3.2). Biomedical data flight. Repeat of Flight 048 test

card. Sine/step generator functional check not accomplished.

Flt. 051 / 11 SEP 75: Mallick/Young. Propulsion data at Mach 3.2 (Mach test, spike test, sideslip test, Duct Pressure Ratio (DPR) test, and angle-of-attack) and TIGT tests. Aft bypass function generator tests (Mach 3.0, manual inlets and auto inlets) not accomplished. Biomedical data

flight.

Flt. 052 / 24 SEP 75: Fulton/Horton. TIGT tests, and stability and control data. Subsonic TIGT

transient tests, co-op control interaction tests, autopilot altitude hold tests, and sine/step function

generator test. Biomedical data flight.

Flt. 053 / 16 OCT 75: Mallick/Young. Engine compressor stall tests (engines did not stall at any

of the test conditions), aft bypass function generator tests (Mach 3.0), and phugoid. Interaction

test series not performed. At end of flight, cockpit air temperature was 110 degrees and there

was no suit cooling. Biomedical data flight.

Flt. 054 / 30 OCT 75: Fulton/Horton. Engine compressor stall tests, interactions data, and

autopilot tests. Biomedical data flight. Aircraft grounded for 11 months.

Flt. 055 / 16 SEP 76: Mallick/Young. Low-speed functional check flight (FCF) and boattail drag

study. High-speed FCF and inlet DPR test not accomplished. The airplane was limited to Mach

1.6 due to a pitch SAS problem. Biomedical data flight.

Flt. 056 / 30 SEP 76: Mallick/Young. High-speed FCF, boattail drag study, and autothrottle data

(DPR tests). Biomedical data flight.

Flt. 057 / 21 OCT 76: Mallick/Young. Chase for YF-12A (935) Coldwall flight and subsonic

boattail drag data. Dynamic inlet data (DPR tests) not accomplished due to power supply failure.

Biomedical data flight.
70

Flt. 058 / 09 NOV 76: Mallick/Horton. Propulsion DPR tests and handling qualities evaluation

with pitch SAS in recall. Biomedical data flight.

Flt. 059 / 19 NOV 76: Mallick/Young. Inlet wind-tunnel dynamic match point tests, boattail

drag data, and handling qualities evaluation. Biomedical data flight.

Flt. 060 / 02 DEC 76: Mallick/Young. Inlet wind-tunnel dynamic match point tests, inlet DPR

tests, inlet variation tests, boattail drag data, and handling qualities evaluation. Biomedical data

flight.

Flt. 061 / 03 MAR 77: Mallick/Young. Chase for YF-12A (935) Coldwall flight, inlet windtunnel dynamic match point tests, boattail drag data, and bypass door data. Biomedical data

flight.

Flt. 062 / 18 MAR 77: Fulton/Horton. Propulsion match point data (Mach 2.44) and autothrottle

tests (Mach 3.0). Biomedical data flight.

Flt. 063 / 24 MAR 77: Fulton/Young. Propulsion match points, autothrottle tests, and gust vane

experiment. Boattail drag data not accomplished. Biomedical data flight.

Flt. 064 / 01 APR 77: Mallick/Horton. Propulsion match points, sine/step function generator

data, and gust vane experiment. Autothrottle tests not accomplished. Biomedical data flight.

Flt. 065 / 12 MAY 77: Fulton/Horton. Autothrottle tests (Mach 2.8). Propulsion match points

and gust vane experiment not accomplished.

Flt. 066 / 19 MAY 77: Mallick/Young. Propulsion match points, autothrottle tests, and gust vane

experiment.

Flt. 067 / 26 MAY 77: Fulton/Horton. Autothrottle tests, propulsion match points, and gust vane

experiment.

Flt. 068 / 02 JUN 77: Mallick/Young. Chase for YF-12A (935) Coldwall flight and propulsion

match points. Autothrottle test not accomplished.

Flt. 069 / 15 JUN 77: Mallick/Young. Propulsion match points and autothrottle test.

Flt. 070 / 16 JUN 77: Fulton/Horton. Steady-state and dynamic interactions (Mach 2.8),

autothrotle tests, and handling qualities evaluation.

Flt. 071 / 23 JUN 77: Mallick/Young. Chase for YF-12A (935) Coldwall flight and boattail drag

data. Propulsion match points not accomplished.
71

Flt. 072 / 14 JUL 77: Fulton/Horton. Propulsion match points, autothrottle tests, and airframe/

propulsion dynamic interactions.

Flt. 073 / 21 JUL 77: Mallick/Young. Chase for YF-12A (935) Coldwall flight. Propulsion

match points, autothrottle tests, and interaction tests not accomplished due to high KEAS

condition and compressor stalls during chase mission. The YF-12A simultaneously experienced

inlet unstarts and compressor stalls.

Aircraft grounded for overspeed and overload inspection.

Flt. 074 / 08 SEP 77: Mallick/Young. Propulsion transients, sine/step generator, steady-state

interactions, and autothrottle test. Chase for YF-12A (935) Coldwall flight not completed

because YF-12A aborted takeoff due to nosewheel shimmy.

Flt. 075 / 16 SEP 77: Fulton/Horton. Airframe/propulsion interactions, propulsion transients,

and autothrottle tests. Aborted early due to SAS caution light.

Flt. 076 / 22 SEP 77: Mallick/Young. Airframe/propulsion interactions and propulsion transients.

Flt. 077 / 30 SEP 77: Mallick/Young. Chase for YF-12A (935) Coldwall flight, U-2 intercept,

and a fly-by of NASA Dryden Flight Research Center.

Flt. 078 / 13 OCT 77: Mallick/Young. Chase for YF-12A (935) Coldwall flight, airframe/

propulsion interactions, aft bypass door tests, afterburner transients, and autothrottle tests.

Aircraft grounded for co-op control program modifications.

Flt. 079 / 26 MAY 78: Mallick/Young. Functional check of Cooperative Airframe/Propulsion

Control System (CAPCS) digital computer system (Mach 1.8).

Flt. 080 / 16 JUN 78: Fulton/Horton. CAPCS digital computer system envelope expansion

(Mach 2.8).

Flt. 081 / 17 JUL 78: Mallick/Young. CAPCS digital computer system test not accomplished.

Aborted early due to air data transducer failure.

Flt. 082 / 03 AUG 78: Fulton/Horton. CAPCS digital computer system test.

Flt. 083 / 18 AUG 78: Mallick/Young. CAPCS digital computer system test.

Flt. 084 / 31 AUG 78: Fulton/Horton. CAPCS digital computer system test.

Flt. 085 / 07 SEP 78: Mallick/Young. CAPCS digital computer system test, co-op control test.

Flt. 086 / 13 SEP 78: Fulton/Horton. CAPCS digital computer system test, co-op control test.
72

Flt. 087 / 25 SEP 78: Fulton/Horton. CAPCS digital computer system test, co-op control test.

Flt. 088 / 28 SEP 78: Mallick/Young. CAPCS digital computer system test. Co-op control test

not accomplished. Aborted early due to R/H forward bypass door failure. Last NASA flight of

YF-12C.

Flt. 089 / 27 OCT 78: Sullivan/Frazier. Transferred aircraft to USAF, ferry flight to Lockheed

facility in Palmdale, California.

Flt. 090 / 22 DEC 78: Jewett/Frazier. Last flight. Aircraft placed in storage at Palmdale.

Sources: Richard P. Hallion, On The Frontier: Flight Research at Dryden, 1946-1981 (Washington, DC: NASA SP-4303, 1984), pp. 189-199; YF-12 Research Flight Reports in the NASA

DFRC Historical Reference Collection (donated by Richard E. Klein); YF-12 Flight Requests in

the NASA DFRC Historical Reference Collection; NASA FRC Daily Logs in the NASA DFRC

Flight Operations Office.
73

Appendix 2: Bibliography

The below list includes a number of books and technical papers describing the

development and operational history of the Blackbird family of aircraft. Many,

but not all, of these publications served as sources for this monograph. Two

invaluable bibliographies are Gene Matranga’s list of 91 technical reports and

papers related to the YF-12 research program and Fifty Years of Flight Research:

An Annotated Bibliography of Technical Publications of NASA Dryden Flight

Research Center, 1946-1996 by David F. Fisher (NASA TP-1999-206568).

Books:

Byrnes, Donn A. and Kenneth D. Hurley. Blackbird Rising: Birth of an Aviation Legend.

Los Lunas, New Mexico: Sage Mesa Publications, 1999.

Crickmore, Paul F. Lockheed SR-71 Blackbird. London, England: Osprey Publishing Ltd., 1986.

Crickmore, Paul F. Lockheed SR-71, The Secret Missions Exposed. London, England: Osprey

Aerospace, 1993.

Drendel, Lou. SR-71 Blackbird In Action. Carrollton, Texas: Squadron/Signal Publications,

1982.

Goodall, James. SR-71 Blackbird. Carrollton, Texas: Squadron/Signal Publications, 1995.

Hallion, Richard P. On The Frontier: Flight Research at Dryden, 1946-1981. Washington, DC:

NASA SP-4303, 1984.

Hallion, Richard P. Test Pilots: The Frontiersmen of Flight. Washington, DC: Smithsonian

Institution Press, 1988.

Jenkins, Dennis R. Lockheed SR-71/YF-12 Blackbirds. North Branch, Minnesota: Specialty

Press, 1997.

Kommisarov, D. S. and K. G. Udalov. SR-71 Aircraft. Moscow, Russia: Aviko Press, 1993.

Miller, Jay. Lockheed SR-71. Arlington, Texas: Aerofax, Inc., 1985.

Miller, Jay. Lockheed’s Skunk Works: The First Fifty Years. Arlington, TX: Aerofax, Inc., 1993.

Peebles, Curtis. Dark Eagles. Novato, CA: Presidio Press, 1995.

Studies In Intelligence. Langley, VA: Central Intelligence Agency, 1982. This volume contains

McIninch, Thomas P. (pseud. of John Parangosky), “The OXCART Story.”
74

Technical Papers:

Albers, James A. “Inlet Operating Flow Field of the YF-12 Aircraft and Effects of this Flow

Field on Inlet Performance.” NASA Lewis Research Center Inlet Workshop, 1977

Albers, James A. “Status of the YF-12 Propulsion Research Program.” NASA TM X-56039,

March 1976.

Albers, James A. and Frank V. Olinger. “YF-12 Research Program and Results.” NASA CP001. Proceedings of the SCAR Conference, 1976.

Anderson, D. L.; G. F. Conolly; F. M. Mauro; Paul J. Reukauf; and R. Marks

“YF-12 Cooperative Airframe/Propulsion Control System Program,” Vol. 1.

NASA CR-163099, November 1980.

Anderson, J. Thomas; Robert K. Martin; and Harry H. Shibata. “1/3 Scale Inlet Model Test

Results,” Vols. I-III. NASA CR-114702 through CR-114704, 8 March 1974.

Arnaiz, Henry H.; James D. Brownlow; and James A. Albers. “A Comparison of Steady-State

Performance Among a Flight Inlet on a YF-12C Airplane and Two Wind-Tunnel Models Using

Statistical Techniques.” NASA CP-2054, Vol. 1. Proceedings of the YF-12 Experiments Symposium, August 1978

Bales, T. T.; E. L. Hoffman; L. Payne; and A. L. Carter. “Fabrication and Evaluation of Advanced Titanium and Composite Structural Panels.” NASA CP-001. Proceedings of the SCAR

Conference, 1976.

Bangert, L. H.; Frank W. Burcham, Jr.; and Karen G. Mackall. “YF-12 Inlet Suppression of

Compressor Noise – First Results.” AIAA Paper No. 80-0099, January 1980.

Bangert, L. H.; E. P. Feltz; L. A. Godby; and L. D. Miller. “Aerodynamic and Acoustic Behavior

of a YF-12 Inlet at Static Conditions.” NASA CR-163106, January 1981.

Bauer, Carol A.; Karen G. Mackall; Frederick Stoll; and Jeffrey W. Tremback. “Comparison of

Flight and Wind-Tunnel Model Instantaneous Distortion Data from a Mixed-Compression

Inlet.” NASA CP-2054, Vol. 1. Proceedings of the YF-12 Experiments Symposium, August 1978.

Bennett, Donald L. “Evaluation of a Hemispherical Head Flow Direction Sensor for Inlet Duct

Measurements.” NASA TM X-3232, May 1975.

Bentley, J. H.; S. M. Dent; and W. L. Kruse. “Final Report for the CAPA/YF-12 Central Airborne Performance Analyzer.” Honeywell Report W8340-FR.

Berry, Donald T. “A Summary of YF-12 Handling Qualities.” NASA CP-2054, Vol. 1. Proceedings of the YF-12 Experiments Symposium, August 1978.
75

Berry, Donald T. “Flight Experience with Longitudinal Long-Period Airframe/Propulsion

Interactions of a Mach 3 Cruise Vehicle.” AIAA Atmospheric Flight Mechanics Conference

Open Session, Palo Alto, California, 13 September 1972.

Berry, Donald T. and Glenn B. Gilyard. A Review of Supersonic Cruise Flight Path Control

Experience with the YF-12 Aircraft. NASA SP-416, 1976.

Berry, Donald T. and Glenn B. Gilyard. “Airframe/Propulsion System Interactions – An

Important Factor in Supersonic Aircraft Flight Control.” AIAA Paper No. 73-831, August

1973.

Berry, Donald T. and Glenn B. Gilyard. “Some Stability and Control Aspects of Airframe/

Propulsion System Interactions on the YF-12 Airplane.” ASME Paper No. 73-WA/Aero. 4,

November 1973.

Berry, Donald T.; Donald L. Mallick; and Glenn B. Gilyard. “Handling Qualities Aspects of

NASA YF-12 Flight Experience.” NASA CP-001. Proceedings of the SCAR Conference, 1976.

Berry, Donald T. and William G. Schweikhard. “Potential Benefits of Propulsion and Flight

Control Integration for Supersonic Cruise Vehicles.” NASA TM X-3409, August 1976.

Brilliant, Howard M. and Carol A. Bauer. “Comparison of Estimated with Measured Maximum Instantaneous Distortion Using Flight Data from an Axisymmetric Mixed Compression

Inlet.” AIAA Paper No. 77-876, July 1977.

Brilliant, Howard M.; Carol A. Bauer; and Robert A. Davis. “Predicted and Measured Maximum Instantaneous Distortion for Flight and Wind-Tunnel Model Data for Mixed-Compression Inlet.” NASA CP-2054, Vol. 1. Proceedings of the YF-12 Experiments Symposium, August

1978.

Brooks, William A., Jr. and Marvin B. Dow. “Service Evaluation of Aircraft Composite Structural Components.” NASA TM X-71994, October 1973.

Brown, Stuart C. “Computer Simulation of Aircraft Motions and Propulsion System Dynamics

for the YF-12 Aircraft at Supersonic Cruise Conditions.” NASA TM X-62245, August 1973.

Brownlow, James D.; Henry H. Arnaiz; and James A. Albers. “Mathematical Modeling of the

Performance of a YF-12C Mixed-Compression Inlet by Using Multiple Regression Techniques.” NASA CP-2054, Vol. 1. Proceedings of the YF-12 Experiments Symposium, August

1978.

Burcham, Frank W., Jr. and Donald R. Bellman. “A Flight Investigation of Steady State and

Dynamic Pressure Phenomena in the Air Inlets of Supersonic Aircraft.” NASA TM X-67495,

December 1971.
76

Burcham, Frank W., Jr.; Glenn B. Gilyard and Lawrence P. Myers. “Propulsion System-Flight

Control Integration and Optimization: Flight Evaluation and Technology Transition.” NASA TM4207, July 1990.

Burcham, Frank W., Jr.; Jon K. Holzman; and Paul J. Reukauf. “Preliminary Results of Flight

Tests of the Propulsion System of a YF-12 Airplane at Mach Numbers up to 3.0.” AIAA Paper

No. 73-1314, November 1973.

Burcham, Frank W., Jr.; Earl J. Montoya; and Phillip J. Lutschg. “Description of YF-12C Airplane, Propulsion System, and Instrumentation for Propulsion Research Flight Tests.”

NASA TM X-3099, September 1974.

Campbell, David H. “F-12 Inlet Development.” SAE Paper No. 740831, October 1974.

Campbell, David H. “F-12 Series Aircraft Propulsion System Performance and Development.”

AIAA Paper No. 73-821, August 1973

Campbell, David H. YF-12 Inlet Flight Test Experience. NASA SP-1655, 12 August 1970.

Campbell, David H. YF-12 Inlet Performance Data Package. NASA SP-1612, 4 May 1970.

Campbell, David H. YF-12 Inlet Performance Data Package. NASA SP-1635, 16 June 1970.

Cole, Gary L.; David S. Cwynar; and Lucille C. Geyser. “Wind-Tunnel Evaluation of the Response of a YF-12 Aircraft Flight Inlet to Internal Airflow Perturbations by Frequency-Response

Testing.” NASA TM X-3141, December 1974.

Cole, Gary L.; Miles O. Dustin; and George H. Neiner. “Wind-Tunnel Performance of a ThroatBypass Stability System for the YF-12 Inlet.” NASA CP-2054, Vol. 1. Proceedings of the YF-12

Experiments Symposium, August 1978.

Cole, Gary L.; George H. Neiner; and Miles O. Dustin. “Wind-Tunnel Evaluation of YF-12 Inlet

Response to Internal Airflow Disturbances With and Without Control.” NASA CP-2054, Vol. 1.

Proceedings of the YF-12 Experiments Symposium, August 1978.

Cole, Gary L.; Bobby W. Sanders; and George H. Neiner. “Wind-Tunnel Performance of a YF-12

Aircraft Flight Inlet Modified by various Stability Bypass Porous-Bleed Configurations.” NASA

TM-73801.

Combs, Henry G. and John R. McMaster. “Feasibility Study on Launching a NASA HT-4 Hypersonic Drone from a Lockheed YF-12C Airplane.” Lockheed report No. SP-1779, 30 July 1971.

Cooper, Paul A. and Richard R. Heldenfels. “NASA Research on Structure and Materials for

Supersonic Cruise Aircraft.” NASA TM X-72790.
77

Cubbison, Robert W. “Wind-Tunnel Performance of an Isolated, Full-Scale, YF-12 Aircraft Inlet

at Mach Numbers Above 2.1.” NASA TM X-3139, December 1974.

Cubbison, Robert W. and Bobby W. Sanders. “Comparison of the One-Third and Full-Scale

YF-12 Isolated Inlet Performance.” NASA CP-2054, Vol. 1. Proceedings of the YF-12 Experiments Symposium, August 1978.

Cubbison, Robert W. and Bobby W. Sanders. “Full-Scale YF-12 Inlet Calibration and Flow

System Interactions.” NASA CP-2054, Vol. 1. Proceedings of the YF-12 Experiments Symposium, August 1978.

DeAngelis, V. Michael. “A Historical Overview of High-Temperature Structural Testing at the

NASA Dryden Flight Research Facility.” Structural Testing Technology at High Temperature

Conference, Dayton, Ohio, November 1991.

DeAngelis, V. Michael and Karl F. Anderson. “Thermal-Structural Test Facilities at NASA

Dryden.” NASA TM-104249, August 1992.

DeMarco, D. M. “A Dynamic Pressure Generator for Checking Complete Pressure Sensing

Systems Installed on an Airplane.” NASA TM X-56026, September 1974.

Duba, R. J.; A. C. Haramis; R. F. Marks; Payme; R. C. Sessing, YF-12 Lockalloy Ventral Fin

Program: Design Analysis, fabrication, and Manufacturing of Aircraft Structures Using Aluminum and Beryllium Alloys for the YF-12 Aircraft. Vol. 1 (NASA CR-144971) and Vol. 2 (NASA

CR-144972), January 1976.

Dustin, Miles O.; Gary L. Cole; and George H. Neiner. “Continuous-Output Terminal-ShockPosition Sensor for Mixed-Compression Inlets Evaluated in Wind-Tunnel Tests of YF-12 Aircraft Inlet.” NASA TM X-3144, December 1974.

Dustin, Miles O. and George H. Neiner. “Evaluation by Step Response Tests of Prototype Relief

Valves Designed for YF-12 Inlet Stability Bleed System.” NASA TM X-3262.

Edinger, Lester D.; Alan R. Curtis; and Frederick L. Schenk. “YF-12A LAMS Feasibility

Study,” Vols. I through III, July 1970.

Edinger, Lester D.; Frederick L. Schenk; and Alan R. Curtis. “Study of Load Alleviation and

Mode Suppression (LAMS) on the YF-12A Airplane.” NASA CR-2158, December 1972.

Ehernberger, L. Jack. “High-Altitude Turbulence Encountered by the Supersonic YF-12A

Airplane. AMS Sixth Conference on Aerospace and Aeronautical Meteorology, El Paso, Texas,

November 1974.

Ehernberger, L. Jack. “High-Altitude Turbulence for Supersonic Cruise Vehicles.” NASA TM88285, May 1987.
78

Ehernberger, L. Jack. “High-Altitude Turbulence Investigation.” NASA Working Paper FWP-19,

August 1970.

Ehernberger, L. Jack. “The YF-12 Gust Velocity Measuring System.” NASA CP-2054, Vol. 1.

Proceedings of the YF-12 Experiments Symposium, August 1978.

Ehernberger, L. Jack and Betty J. Love. “High-Altitude Gust Acceleration Environment as Experienced by a Supersonic Airplane.” NASA TN D-7868, January 1975.

Falkner, Victor L.; Robert Clarke; and Frederick L. Schenk. “Cooperative Aircraft/Propulsion

Control System (CAPCS) for the YF-12A Aircraft.” NASA Flight Research Center Working Paper.

Farlow, N. H.; V. R. Watson; M. Lowenstein; K. L. Chan; H. Hoshizaki; R. J. Conti; and J. W.

Meyer. “Measurements of Supersonic Jet Aircraft Wakes in the Stratosphere.”

Fields, Roger A. “A Study of the Accuracy of a Flight Heating Simulation and its Effect on Load

Measurements.” NASA TN D-5741.

Fields, Roger A. “Flight Vehicle Thermal Testing With Infrared Lamps.” NASA TM-4336, January

1992.

Fisher, David F. “Boundary Layer, Skin Friction, and Boattail Pressure Measurements from the

YF-12 Airplane at Mach Numbers up to 3.” NASA CP-2054, Vol. 1. Proceedings of the YF-12

Experiments Symposium, August 1978.

Flight Research Center staff, “NASA YF-12 Flight Loads Program.” Proceedings from symposium

held at NASA Flight Research Center, Edwards, California. .NASA TM X-3061, 5-6 June 1974

Flight Research Center staff, “YF-12 Research Airplane Project Management Report.” NASA

FRC Working Paper.

Gamon, Max A. “Testing and Analysis of Dual-Mode Adaptive Landing Gear, Taxi Mode Test

System for YF-12A.” NASA CR-144884, September 1979.

Gilyard, Glenn B. “Determination of Propulsion-System-Induced Forces and Moments of a Mach

3 Cruise Aircraft.” NASA TN D-7647, April 1974.

Gilyard, Glenn B.; Donald T. Berry; and Daumants Belte. “Analysis of a Lateral-Directional

Airframe/Propulsion System Interaction.” NASA TM X-2829, 1973.

Gilyard, Glenn B. and John J. Burken. “Development and Flight Test Results of an Autothrottle

Control System at Mach 3 Cruise.” NASA TP-1621, July 1980.

Gilyard, Glenn B. and Daumants Belte. “Flight-Determined Lag of Angle-of-Attack and Angle-ofSideslip Sensors in the YF-12A Airplane from Analysis of Dynamic Maneuvers.” NASA TN D7819, October 1974.
79

Gilyard, Glenn B.; Donald T. Berry; and Daumants Belte. “Analysis of a Lateral-Directional

Airframe/Propulsion System Interaction of a Mach 3 Cruise Aircraft.” AIAA Paper No. 72-961,

September 1972.

Gilyard, Glenn B. and John W. Smith. “Flight Evaluation of a Mach 3 Cruise Longitudinal Autopilot.” AIAA Paper No. 74-910, August 1974.

Gilyard, Glenn B. and John W. Smith. “Flight Experience with Altiutude Hold and Mach Hold

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80

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81

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1976.

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82

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August 1973.

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1973.

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Aircraft Inlet Control System by Frequency-Response and Transient Testing.” NASA TM X3142, December 1974.

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Using Relief Valves to Increase the Transient Stability of a Mixed-Compression Inlet. NASA TP1083.

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Neiner, George H.; Robert C. Siedel; and Dale J. Arpasi. “Wind-Tunnel Evaluation of Experimental Controls on YF-12 Aircraft Flight Inlet by Frequency-Response and Transient Testing.”

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Ochieano, Mario and Russell S. Kaneko. “Survey of Titanium Structural Shapes Fabrication

Concepts.” NASA CR-132384.
83

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YF-12 Aircraft.” NASA Flight Research Center Working Paper.

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Powers, Bruce G. “Phugoid Characteristics of a YF-12 Airplane with Variable-Geometry Inlets

Obtained in Flight Tests at a Mach Number of 2.9.” NASA TP-1107, December 1977.

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Thick Boundary Layer Flow for Transonic and Supersonic Mach Numbers.” NASA CP-2054,

Vol. 1. Proceedings of the YF-12 Experiments Symposium, August 1978.

Powers, Sheryll Goecke. “Flight-Measured Pressure Characteristics of Aft-Facing Steps in

High Reynolds Number Flow at Mach Numbers of 2.20, 2.50, and 2.80 and Comparison with

Other Data.” NASA TM-72855, May 1978.

Presley, L.; P. Cutler; and R. Sorenson. “Predicted and Measured Flow Fields Upstream of the

YF-12 Inlet and Inlet Internal Flow Solutions.” NASA CP-2054, Vol. 1. Proceedings of the

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1980.

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84

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85

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1971.
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87

Appendix 3: Interview transcripts

These interviews are edited for readability, with titles and other information provided in square brackets, but the substance of the interviews remains unchanged.

Gene J. Matranga, interviewed by Peter Merlin on 30 May 2000:

Merlin: To get started, why don’t you give me a little background on how you became involved in

the YF-12 research program?

Matranga: It was the fall of 1967, on a late Friday afternoon. [Flight Research Center Director]

Paul Bikle called me into his office and he and [head of the Research Division] Joe Weil were

sitting around his desk. They asked me the question: Would I be willing to go do a three-month

program with the Air Force on the SR-71? Bikle made the qualifier that we probably wouldn’t be

able to publish anything that we learned, because of the classified nature of the program, but he

wanted to try to get NASA involved with the SR-71. He said to go home and think about it over the

weekend and give him an answer on Monday morning.

At the time, I was doing the general aviation program, and we had a coordinated small

scale/full scale analytical prediction of the flying qualities of the Piper PA-30. So, it was an interesting challenge. I thought about it, not very long, over the weekend. On Monday, I came back and

said sure, I would be willing to do anything they needed me to do.

So Bikle made the arrangements for me to go over and talk to the Air Force people and get

briefed into the program. What they were looking for was technical assistance to do the Category II

evaluation of the SR-71. That’s the basic evaluation of the plane’s stability and control, and performance. So, I went over and got briefed and talked to Col. Robert “Fox” Stephens, the commander

of the SR-71/F-12 Test Force, and three or four of his technical people. Bob Sudderth, a civilian

with the Air Force was doing the stability and control work. Dick Abrams, also a civilian with the

Air Force, was doing the performance work. There were military people working in parallel with

them. They were just starting into the Category II program, so I was really getting in on the ground

floor.

I asked if I could bring any additional help with me, and they were eager to have all the help

we could provide. So, I made arrangements for Bill Schweikhard to help with the performance

work. I did the stability and control work. As we got involved in it, we realized we needed some

additional help. We brought in Terry Larsen and Jack Ehernberger to do meteorological work and

basic upper atmosphere physics work to support the stability and control, and performance studies.

One of the things we learned very early in the game was that we were seeing some strange

effects as the airplane banked at high speed, and Schweikhard suspected that we were seeing erroneous instrument readings as a result of sideslip on the airplane. He asked if the airspeed boom had

ever been calibrated in the wind tunnel, and the answer was “no.” So, we talked to the people at

NASA Ames Research Center and made arrangements to calibrate the boom in their Mach 3 wind
88

tunnel.

When we went up there to do that, we talked with Lloyd Jones who was in charge of their

high-speed wind tunnel. Lloyd explained to us how we really got involved in the program. He

had been very instrumental in getting NASA involved again. Lockheed had done the basic windtunnel work at Ames, and packed up all the data and brought it back to their Burbank facility.

Lloyd wanted access to that data, and we were just the tools to help him do that. It was fine with

us. So, as we went along, we documented the fact that the airspeed boom now had the corrections

that nobody had done until that time. We went off into the program and got the wind-tunnel data

for Mr. Jones, and made it available to him. He was cleared for the program, so that was not a

problem. And, off we went.

We started off with the longitudinal stability and the performance work. Sudderth and I

worked very well together. We had to do most of the analysis using oscillograph records from the

Air Force instruments, and hand plotting the data. It was not nearly as automated as the NASA

system was at the time. Bill Schweikhard did the same sort of thing from the performance standpoint. Sudderth usually rode in the back seat of the airplane for the tests of stability and control,

and Abrams sat in the back seat for performance work.

The Air Force had about four pilots involved at the time. “Fox” Stephens, the squadron

commander, did his share of the flying. Bill Skliar did a share of the flying. We later got Bill

Campbell involved in it. It seems there were a couple of other pilots that I don’t remember.

One of the other people involved in this was Maj. Sam Ursini. He had been the back seat

guy for a good chunk of the YF-12 testing. He was involved with missile launch, and evaluation

of the tracking system and missile system in the YF-12A. Early in the game, Sam took me over

to see the F-12 airplanes, which were in storage in Building 1810, halfway between the control

tower and the NASA facility. The two airplanes had been sitting there for almost two years. They

periodically ran the systems to keep them operational, but there was no flight activity, and Sam

was basically the only Air Defense Command troop that was involved in the program at the time.

So, as we went along, we identified things we from NASA would be interested in doing

that the Air Force had no interest in at all. At the same time, there was the competition among

Boeing, Douglas, and Lockheed for the Supersonic Transport, the SST. So, we made the proposal to NASA Headquarters that we would try to be the filter for data out of the SR-71 program

to Douglas and Boeing, since Lockheed already had access to the data. It was pretty well agreed

to. The Air Force said, “yeah, we can do that.” They wanted to sit in on all the discussions and

make sure that we didn’t tell them anything that we shouldn’t be telling, but they were generally

agreeable to that sort of arrangement.

We plodded along in the program for the better part of a year, and the Air Force had pretty

well completed the Category II testing. So, we recommended that for the subsequent series of

tests, we put a NASA instrumentation system on the airplane. We proposed to instrument the

airplane more completely, and use the automatic data reduction capability in the much more

modern NASA instrumentation. The Air Force wasn’t terribly thrilled with the idea. We went

back and talked to Col. Ben Bellis, who was head of the SR-71 System Program Office at the
89

time. He was not really interested at all, but he suggested that he had the two YF-12 airplanes in

storage. He wasn’t doing anything with them, and didn’t expect to do anything with them. Bellis

asked us to put together a proposal for what we wanted to do. So, we did it. Bill Schweikhard and

I put the plan together. We talked with Joe Weil and Paul Bikle, and got their agreement. Then, we

went back to Bellis with the proposal, and he said it looked reasonable.

So, the question then was “how does this arrangement work?” Typically, the way NASA

had done business was to have the Air Force provide the airplane and funding for the program, and

NASA would do all the technical work. Well, the Air Force said, “we’re not going to fund anything.” They were hard pressed enough just to keep the SR-71 program alive, without being able

to fund anything else. So, we went back and talked with Bill Aiken at NASA Headquarters. We

told Bill that this was the kind of program we could do, and that we guessed it would cost about

three to four million dollars a year to conduct the program. We advised Bill that the YF-12 data

would be available to the winner of the SST competition, and NASA would be a big hero for being

able to provide this data that otherwise was not available. Bill said he would see if he could find

money to fund the program, and he did.

We worked out an arrangement, and put together a Memorandum of Understanding between NASA and the Air Force. The agreement basically was that the Air Force would provide the

airplanes for us, and that we would share the flying activity. There would be Air Force flight crews

and NASA flight crews, but NASA would foot the bill for operating the airplanes.

At that stage of the game, we decided that there was something else we needed to do. We

figured that we had better talk to Kelly Johnson at the Lockheed Skunk Works and find out if he

would be amenable to all this. So, I was invited to go down and talk to Kelly, and explain what we

wanted to do with the airplane. The way Kelly operated was that he had one representative from

the government, and he had a few of his people from the Lockheed side sit in and listen to the

presentation. He was in no way tolerant of a gaggle of government people coming down and

overwhelming his organization, which was relatively small.

I went down to Burbank and talked to Kelly. When I walked into his conference room, he

had about a dozen people there. He proceeded to berate me for about a half-hour, telling me what

a dumb thing it was that NASA wanted to do. He just thought it was a gross waste of government

money that would be better spent doing other things. He essentially concluded by asking, “well,

what do you have to say for yourself?” And, I said: “Kelly, answer me a question. What is the

angle of attack at the engine face? Because that affects the distortion, and we know there are

problems with unstart.” He thought for a couple of minutes, and he said, “if you can answer that,

you have a program.” We had a program.

I went back to Lockheed later with Bill Schweikhard. We sat down with Burt McMaster,

who was head of aeronautics; Dave Campbell, head of propulsion; Ben Rich, chief thermodynamicist; and Kelly Johnson. So, two people from NASA and four people from Lockheed, and we

laid out a program. We recognized that it would take a while to develop propulsion system instrumentation for the aircraft, and we decided to use this time to investigate steady-state heating ef-
90

fects on the aircraft structure.

In all the X-15 work, flight conditions always were transient. The vehicle went to high

speed in a matter of two to three minutes. It slowed down in a matter of three to five minutes.

Everything was always transient because the temperature was always increasing or decreasing.

The YF-12, on the other hand, could stay at Mach 3 for 15 minutes. We could get steady-state

temperature data, which would augment the X-15 data immeasurably. It would answer many questions about the theories for predicting high-speed temperatures, so Kelly agreed that we should

look into that. He was interested because he didn’t know the actual conditions in the airplane either.

All he knew was that it worked. We were going to fill in a lot of information that would be useful

for future things, such as the SST.

So, that was basically the first thing we set out to do while we tried to develop instrumentation for the propulsion work. We needed to have instrumentation that would survive temperatures

of about 1,000 degrees Fahrenheit, and be able to provide frequency response up to 100 cycles, 100

Hertz, something like that. There was no instrumentation small enough scale to fit in the engine

inlet. Sensors to do that sort of thing were probably about an inch and a half to two inches in

diameter, and maybe six inches long. We wanted something that was a quarter inch in diameter, and

maybe an inch long, in order to fit in a rake that would sit in the inlet. We went on to a program to

develop the sensor, and it was recognized that it was going to take a year or so. We instrumented the

first YF-12 with strain gauges and thermocouples, and we started flying the airplanes.

The Air Force got the Air Defense Command involved in the program because the F-12 was

built for air defense purposes to launch missiles as an interceptor. A very interesting political game

was being played by the Air Force. The Air Defense Command sent in a full bird colonel named

Hugh “Slip” Slater, and he was the senior colonel in the Air Force part of the program. So, even

though “Fox” Stephens was a colonel, and was commander of the Test Force, Slater came in and he

was senior to Stephens. He had rank on him in the Air Force hierarchy.

Merlin: Slater had also commanded the A-12 unit, the 1129th Special Activities Squadron.

Matranga: Yes. He had commanded the A-12 unit when it was in development. He brought Ronald

“Jack” Layton with him. Layton had been the senior A-12 pilot, with 300 hours of Mach 3 flight

time. He also brought along a couple of backseaters, Maj. Gary Heidelbaugh and Maj. Sam Ursini.

They were all from Air Defense Command. We also had “Fox” Stephens and some of his backseaters

from Air Force Systems Command. Bill Campbell came into the Test Force about this time, because Stephens was scheduled to rotate out. Campbell was going to take over from him.

I recall that Joe Rogers made the first flight in the YF-12 after they had been in storage for

over two years. The first flight worked like a dream. It was really remarkable that the airplane, after

sitting that long, had no problems on the first flight. It had been well checked out. We had brought

Larry Barnett, and a number of other NASA people, to work along with the Air Force crew. The Air

Force officer who was in charge of maintenance on the airplane was astounded at the abilities of

our NASA mechanics. We had wonderful working relations with the Air Force.

On one of the early flights, we asked Bill Campbell to do some sideslips for us in the

transonic region, and he bent the ventral fin. The leading edge of the ventral bent around double,
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and everybody was much taken aback over that.

Merlin: That would have been flight number eight of YF-12A #935 (11 February 1970).

Matranga: Yes. I knew it was sometime early in the game. So, we flew a series of flights without

the ventral on 935 [3 March 1970 to 22 March 1971]. This limited us to something on the order of

Mach 2.5 instead of Mach 3. Lockheed began analysis of the problem. They had their ideas and

[Flight Research Center (FRC) engineer] Don Kordes had his ideas, and Kelly Johnson, in his

own way, always prevailed, so they refurbished things his way. I don’t remember the exact sequence of it, but we put the Lockheed modified ventral on, did a sideslip in the transonic region,

and the whole thing came off [27 February 1975]. Don Kordes said “I think it’s time to give my

idea a try.” This was way down the road, because it took time to do all this, but the beefed up

ventral with the Kordes fixes on it worked fine.

We went into the structures program, and did a limited stability and control program. Don

Berry and Glenn Gilyard [from the FRC] got some fundamental stability and control data, and we

did the flying with all the strain gauges and thermocouples. We put some deflection devices on the

YF-12 so we could measure how much the structure deformed. Then we heated the airplane. We

had Lockheed build this big oven that we put around the airplane. Controlling the heat lamps in

the oven, we heated the airplane to the same kinds of conditions that it was experiencing in flight.

We measured the deflections, temperatures, and loads so that we could separate the aerodynamic

loads from the thermal loads.

At about that time, we got the instrumentation and started testing it in YF-12 #935. We had

planned on putting it in #936, but the Air Force lost that airplane in June 1971. Jack Layton and

Billy Curtis were returning to Edwards at the end of a test flight when they had an indication of

fire in one of the nacelles. They did a fly-by, and the control tower confirmed that there was a lot

of flame coming out of the back end of the airplane. Layton was concerned that the fire had

weakened the structure to the point where the wing might come off at touchdown. He made the

judgement that he and Curtis had to get out of the airplane. They punched out over the lakebed,

and the airplane crashed. In retrospect, we looked at the nacelles and temperatures were up in the

neighborhood of 2,500 degrees. The metal was distorted, and it was kind of marginal as to whether

he could have made a successful landing. I can’t recall anybody faulting Layton for the judgement

that he made. The cause of the fire was determined to be a broken fuel line.

Now, we only had one airplane. At that stage of the game, we wondered what to do about

it. I was aware that there were ten A-12 airplanes sitting in a hangar in Palmdale. But, Kelly

Johnson wanted no part of us operating the A-12. He felt that it had been designed quickly, and

not as thoroughly as either the YF-12 or SR-71. He recommended that we use the number two

SR-71. It was non-standard, and therefore couldn’t go into operational service.

So, we got together with the Air Force and talked about that, and there was a question

because we were only authorized to have YF-12 airplanes and not SR-71 airplanes. We suggested

that if we put the older “J” engines in the airplane instead of the newer “K” engines, it would

reduce the performance. Since the inlets on the YF-12 and SR-71 were the same, we would still

have the inlet conditions of the YF-12. The nose flow was slightly different, but what went on
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inside the inlet would be the same. We could, therefore, consider that this was YF-12 information. We agreed to give the airplane a new designation, a new tail number, and that we would

always use the “J” engines so there would be no question of us giving away SR-71 data.

We called the airplane a “YF-12C” and gave it the number 937. That was the game that

was played. We instrumented that airplane and did all the performance work that Bill Schweikhard

wanted to do. We wanted the extra Mach 3 time that the SR-71 could provide, contrasted with the

YF-12. The SR-71 would go an extra five minutes at Mach 3. It increased our capability by a

third.

About that time, the Air Force was ready to move to Palmdale with the supporting activities. The Category II, Category IV, and Category VI tests had all been accomplished, so it was

just developmental operational testing that was moved to Palmdale. At that stage of the game, we

moved to a hangar up in the NASA area. We had previously operated out of Hangar 1414. I don’t

think #937 ever operated out of 1414.

At one point, we took a salvaged nacelle, and sent it back to NASA Lewis Research

Center. The Lewis people put it in their Mach 3 wind tunnel and ran a test of the full-scale inlet.

The people at Ames ran a 1/3-scale model at Mach 3. So, we had a full-scale “model”, a 1/3-scale

model, and flight test data from the airplane. We had ideal conditions for making a comparison

between wind-tunnel testing and flight testing. That program went off very, very well. The instrumentation worked, and we got what we wanted out of it.

We went from there into a whole series of aerodynamics experiments. We put boundary

layer rakes on the airplane. [FRC engineers] Ed Saltzman and Sheryll Powers came up with what

they called an aft step experiment, looking at the drag behind a rise on the back of the airplane.

We built a new ventral fin made of Lockalloy. The Langley people came up with a new landing

gear mechanism that we tested. The airplane really became an aerodynamic testbed for a whole

variety of things.

We developed computer programs for aerodynamics, and for loads and structures. We

contracted with Lockheed to create a NASTRAN computer program for structures work to match

what we did in the flight heating conditions. Across the board, we developed the capability of

analysis, model testing, and flight testing to answer the questions of how to predict all of this

stuff. I think we laid a foundation for future work. I can’t think of any program that had the

equivalence of complete analytical, flight and wind-tunnel comparisons. It’s textbook stuff that I

think will be used for the foreseeable future.

Let’s talk about people. As I said, we really had no conflicts with the Air Force on what

we wanted to do. We had good relations with “Fox” Stephens, Bill Campbell, and Joe Rogers.

“Slip” Slater was very, very easy going in his own way. If you knew how to give him the right

deference, you got the answer without much trouble. All the working-level people were fine.

Lockheed was very helpful. We developed a wonderful relationship with Kelly Johnson.

I think we established our technical credibility with him. He came up with ideas for us. We gave

him revelations that he found very intriguing. Burt McMaster in the stability and control area was
93

great. Ben Rich became a very close personal friend. Dave Campbell was an excellent engineer.

Henry Combs did all the coordinating for us in the Lockheed hierarchy. Bill Fox, who was our

interface in the flight test world, was my equivalent at Lockheed. They were all wonderful people.

Merlin: Was it difficult to transfer the YF-12 data to other agencies due to the security classification issues?

Matranga: No. I think we understood the sensitivity on the part of the Air Force and worked that

issue fairly well. The only ones we really had to interface with were the Boeing people. The

decision had been made that Boeing would build the SST, so we had made arrangements with the

Air Force to give Boeing a briefing. We put together what we thought were the pertinent facts that

would be of use to them in the design of the SST. We cleared that with the Air Force, and we had

a two-day briefing for Boeing. We gave them a rundown on all the theories that seemed to apply,

the problems that we had encountered, and the problems that we thought they should be looking

for. We were disappointed because the Boeing people seemed to be bored silly. I got the impression that they were told by their management to go down and listen to this but that they were not

particularly interested.

About two years later, we had some of those same people come back to us with questions.

So, we went through it all over again. Once they had experienced the problems, then they were

receptive and ready to listen to us. Interestingly enough, Bob Sudderth, who had worked with me

on stability and control for the SR-71, went to work for Boeing on the SST program. He transferred that information in his head, so we had fewer questions from them in the stability and

control area.

Merlin: What would you say are some of the lessons learned during the YF-12 program?

Matranga: Instrumentation, first of all. The instrumentation was very inadequate to begin with,

and it cost a lot of money to develop new instrumentation and make it work. We had to cool

instrumentation that supposedly would have withstood the temperatures. There was a lot of development necessary.

Stability and control. The effects of the inlet on the stability of the airplane turned out to be

much more profound than Lockheed had originally thought. The air that was dumped out of the

forward bypass doors moved forward for about a foot or so before it mixed with the boundary

layer. This startled everybody. We didn’t realize that there was that much separation just ahead of

the bypass areas. We put control over the bypass doors under a computer program. The Air Force

found that useful enough that they implemented it on all the operational airplanes. It increased the

range of the airplane.

Atmospheric science. We documented the upper atmosphere conditions better than anyone had done previously. In fact, we had a remarkable flight once when we had a very cold day at

altitude. Bill Campbell was able to fly at Mach 3 without afterburner. That was a remarkable

accomplishment in my book, but it was strictly a function of temperature at altitude.

Boundary layer studies. The boundary layer work documented the differences between
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small-scale wind-tunnel models and what was really happening in flight. We confirmed the fact

that the airplane grew about a foot at high Mach number. I just look back at the design that Kelly

did in the late 1950s to build the original airplanes. He designed everything with his great intuition, based on his gut feel. That’s remarkable. Kelly was one of the remarkable people that I have

had the very good fortune to be involved with. He was a dictator. It had to be his way, but he was

a remarkable fellow.

Merlin: What contributions did the YF-12 research make to later aircraft development?

Matranga: It would have helped the SST. The SST program was cancelled before a prototype

was built. The YF-12 answered some questions about the inlets. We did some design work after I

went to work at Lockheed, and we certainly used the lessons learned from the YF-12 in the design

of those inlets. We went to square inlets, rather than round inlets, because the round inlets leaked

like a sieve. There was no way to keep the air from leaking out of them, and we determined that we

could seal much better by going to square inlets. We certainly had the advantage of being able to

schedule the geometry of the inlets better and to apply the bleed off the inlet to keep a better

boundary layer. So, the lessons learned about the inlet were applied to those designs, and it would

have made a significant difference.

It was the same situation with the boundary layer work. Prior to the YF-12, all we had to

work with was small-scale model data. We found significant discrepancies between the smallscale model and the full-scale airplane. We theorized that it was probably due to imperfections on

the airplane’s surfaces. It certainly wasn’t a smooth surface. There were lumps and bumps and

waves that obviously had an effect on it. A wind-tunnel model was a nice smooth, rigid structure.

The airplane certainly was not that.

Merlin: Were predictive methods developed to compensate for that?

Matranga: Well, . . . the answer to the question is “yes,” but that is still an art at this stage of the

game. It requires interpretation on the part of very skilled people like Ed Saltzman to make sense

out of that.

Merlin: What would you say was the most rewarding thing about working on the YF-12 program?

Matranga: From my standpoint, the most rewarding thing was the freedom of activity that Paul

Bikle gave me. I was the dictator for NASA on the YF-12 program. Bikle essentially gave me free

reign to run the program as I saw fit, and to make sure we didn’t run afoul of the Air Force or other

NASA centers.

It was tremendously rewarding for me to have the people at Ames, Lewis, and Langley

cooperate so well in the program. Bill Aiken gave me the money to run the program. It turned out

to cost about five million dollars a year, rather than the three million we had estimated, at the

height of the development. It backed down to about three million when we were just flying the

airplane as it was. I can recall the Lewis people especially, when they did the full-scale inlet and I

provided them with something on the order of a million dollars to do the test. They said: “we’ve
95

never had this kind of cooperation from anybody before.”

From my standpoint, this was an Agency program, and I had the responsibility to use that

Agency money the best way I saw fit. If it didn’t go to the Flight Research Center, if it went to

Lewis instead, then so be it. It created a working relationship that I’ve never seen anywhere else

with the other centers. We had that relationship with everybody. It was great. They supported us,

too. Toward the end of the program, times got kind of lean, and there were people with knives out

looking to slice things away. It was kind of nice to have someone from Lewis stand up and say:

“Wait a minute, wait a minute, we have an interest in that. Let’s make sure that money is there.” It

was very rewarding.

Berwin Kock, interviewed by Peter Merlin on 14 June 2000

Merlin: How did you became involved in the YF-12 program?

Kock: Well, about late 1975 or ‘76, I was managing the DAST [Drones for Aerodynamic and

Structural Testing] program and Gene Matranga, the first YF-12 program manager, had been promoted up to Director of Projects. Ming Tang had succeeded him. For some reason, they needed to

make a change, and Gene asked me if I would like to manage the YF-12 program. I said “great,

wonderful,” so I really didn’t lobby for it or anything like that. A few years earlier, I had done a

brief study about launching a Mach 8 hypersonic research vehicle off the back of a YF-12, so I had

some familiarity with the program.

Merlin: Was that the HT-4?

Kock: Yes, that’s what it was. So, Gene Matranga made the decision to put me in charge.

Merlin: Whatever happened to the HT-4 proposal?

Kock: It didn’t go anywhere. I think it was a combination of things. One is that launching things

off the back of a Mach 3 airplane was dangerous. There was some previous history that said there

was some difficulty doing that sort of thing. In fact, Lockheed crashed an airplane when they were

doing that kind of thing earlier with the D-21. I just don’t think NASA was ready to step up to that

kind of risk at the time.

Merlin: At the time when you were working with the YF-12, was the Air Force still involved in

the program?

Kock: Yes. The Air Force had an active role. We used a lot of their assets to implement our

program. We had some Air Force people assigned to the program. They also had a security office

at Norton Air Force Base that supported us. They did a lot of our contracting for us with Lockheed,

Pratt & Whitney, and the other companies that were involved. We funneled money to them, and

shared in the contracting exercise. Also, they provided logistics and support, such as tankers for

aerial refueling. They had their own program, and we had ours. We joined together in these spe-
96

cific areas.

Merlin: What were some of the areas of research you worked with involving the YF-12 aircraft?

Kock: The first one I worked on when I came onboard involved the ventral fin. We had broken

the fin off in flight and were just in the process of installing a new one made of Lockalloy. We

did integrated inlet, autothrottle, autopilot, control work, and the Coldwall experiment. I don’t

know if you are familiar with that.

Merlin: I am. There was some trouble with the insulation blowing off prematurely quite often.

Ultimately, some data was collected. Do you consider the Coldwall to have been a successful

project?

Kock: Well, I’ll quote Ed Saltzman, who is one of our premier aerodynamicists here. He says

it’s “probably the best pure science program” we had ever done up to that time. We got good

data for him. It worked very well at the end. In terms of getting data, it was painful to get there,

but it was a good experiment. We got good data.

But, to continue the other theme, we also did a landing gear dynamics study. Typically,

the spring constant damping in landing gear is designed for handling the touchdown maneuver.

When you taxi, you want a different set of spring constants and damping to reduce fatigue loads

on the airplane. So, we varied the landing gear dynamics somewhat on the YF-12.

At one point, we did a structural dynamics test. The B-1 bomber has these little vanes, or

canards, underneath the cockpit area to smooth out the ride. We wanted to do a science experiment to understand the interaction of aerodynamics and structural dynamics. So, we put similar

vanes on the YF-12. Ming Tang was the principal investigator on that. It was about the last thing

we did in the program.

Merlin: What happened to the program then?

Kock: Basically, Center Director Dave Scott decided that he would rather we do integrated

controls research on the F-15, as opposed to spending more money on YF-12 high-speed aircraft technology. At the same time, it was getting harder and harder to sell in Washington. This

was in 1978. Bill Aiken was the Director of Aeronautics at that time. Ron Smith was the person

in his office who worked on the YF-12 program. They concluded that there was just not enough

support to keep it at its previous funding level. So, the two of them, together, kind of spelled a

death knell for the program.

Merlin: Were researchers at Dryden anxious to continue with it if they could have?

Kock: Yes, they were, but there were two problems. We didn’t have a long list of experiments

to do on the airplane. Our researchers had kind of exhausted their options, I guess. The other

problem was that the whole Supersonic Transport technology program was running into some
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difficulties. There was soft support for high-speed kinds of research in the country. That kind of

airplane is expensive to operate. All of that kind of came together, and indicated that it was time

to end it.

Merlin: What would you say were some of the lessons learned from the YF-12?

Kock: Well, first of all, exotic airplanes generate a lot of enthusiasm on their own, regardless of

the technology involved. The YF-12 was an intriguing, exciting airplane to be associated with.

So, that’s the first lesson.

The second lesson, I guess, is that if you are going to do quality research, it takes a lot of

money. So, fund it right.

The third lesson is that contractor and government teams can work together very well. We

had a great relationship with the Air Force. You’ve got to strive to get that kind of relationship.

I guess the fourth thing is that classified programs limit your ability to garner supporters

and advocates. It was a special access program. Much of what we did, we could talk about, but

there was a lot we could not talk about. It never got fully integrated into the Supersonic Transport

research program because the people working on that could not gain total access to the YF-12

program. That boundary complicated our efforts to formulate experiments, conduct experiments,

and keep money flowing into the program.

There was a process set up whereby we could write reports. There were a lot of things

about performance, how experiments were integrated, and such, that we could not write about. It

was hard, but we managed to produce an incredible amount of reports.

Merlin: How did YF-12 research contribute to programs that came along later?

Kock: The program did a lot of fundamental science work on things like boundary layer behavior, heat transfer, and skin friction. All of that is generically applicable to a lot of airplanes. We did

autopilot work that is applicable to planes that fly fast, and I think that benefited many of them.

The biggest effort in the whole program was the heating test that was done before I came onboard.

Obviously, that has relevance to aircraft and spacecraft that get hot. I think that generations of

aircraft benefited from our providing a fundamental understanding of that sort of thing. We also

developed the NASTRAN program that I think was an industry standard for structural analysis.

There was a lot of good work that I think was applied in areas we are not even aware of.

Merlin: Can you tell me anything about the other people you worked with?

Kock: I got to know Ben Rich personally. The people down at the Skunk Works were the best of

the best in the industry at the time. Gene Matranga was one of the most dynamic individuals on

the NASA side. Fitz Fulton, premier test pilot, and Don Mallick, and Vic Horton did a lot to help

the program. Bill Aiken at Headquarters was widely respected. There were lots of good people

involved.
98

Merlin: Was the Center management at Dryden helpful?

Kock: We had a good relationship with Center management, but things were changing about that

time. It was a period of transition. Paul Bikle left about 1973, and we were going through Center

Directors rapidly. Each of them brought a different perspective. Some of them didn’t understand

the flight research mission of this center. They came from a different world. They were good

managers, but they didn’t quite grasp what we were about.

Merlin: What would you say, for yourself, was the most rewarding aspect of the YF-12 program?

Kock: There were several things. First of all, that airplane was, and is, a magnificent engineering

accomplishment. Just to be associated with the YF-12 was a reward in itself. Another thing it let

me do was get an insight into the Lockheed Skunk Works. At the time, the Skunk Works was “The

Place.” They did all these exotic and challenging things, with great people, so that was immensely

rewarding. Also, the YF-12 project had an esprit de corps that was truly unique. Everybody was

enthused, and wanted to come to work. It was great.

Personally, it marked a transition in my career growth from more routine kinds of work to

something that was on the forefront of technology. It was the largest project on the Center at the

time. It brought in 40 percent of the total money that the Center had. It was the project that kept

the Center going.

The hardest part of the whole thing was when it ended. I had stretched the program as far

as I could with the money that was available. I had a great team of contractors and civil servants.

It was really hard to take care of these people, to find places for them to go as we were winding

down. That was really hard.

And, the ending didn’t work out terribly well with some of the folks at the Skunk Works.

They were of the opinion that NASA didn’t work hard enough to keep it alive, so there were some

strained relationships that developed out of that.

All in all, a great experience. A great program. Good work. Good people. That’s about it.
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Appendix 4: Don Mallick describes

 YF-12 flight operations

This material has been excerpted from Mallick’s unpublished manuscript “The

Smell of Kerosene.” It has been edited, out of its original order, to preserve the

narrative flow. He read the edited version and enthusiastically endorsed it.

On the morning of a test flight, I would set the alarm for about 3:00 a.m. and get on the road

to Edwards by 3:30 a.m. Usually, I would meet Fitz Fulton at his home in Lancaster and we would

car-pool together.

Flight planning and briefings were intense and thorough before each flight. It was standard

procedure to have a set of “back up” test cards to be conducted at lower altitude and slower speeds

in the event that some malfunction prevented us from flying the high-speed flight. This gave a

little fall-back and allowed us to gather some flight data even on a flight that could not get to high

speed. Actually, we did not have to fall back on these cards too often, and usually our mishaps or

problems in flight required that we return for landing ASAP without a lot of delay.

There would be a meeting of the research engineers and operational people, which included

the pilots and flight test engineers. The research engineers would present a briefing on what test

data they would like to gather in the upcoming flight. There was interchange between the research

engineers and operational people even before this meeting to ensure that the data requested was

reasonable and achievable. The flight test engineer and flight test pilot would suggest what type of

maneuver would be used to gather the required data. At this meeting, entitled the Technical or

Tech Brief, the initial flight test cards were already made up. These cards presented the test maneuvers required and their sequence during the flight.

The Tech Briefing would normally occur a minimum of three days before the flight to allow

all concerned parties to study the test points and cards and make inputs for changes prior to the

test flight. As the pilot, I began a comprehensive review of the test cards with all of the planned

test points. At this point, a simulator could have been used to practice the test flight, but there was

not a Blackbird simulator available at Dryden. The flight test cards were cardboard 5-by-7-inch

cards that were inserted in a checklist-type book that was attached to the right leg of my pressure

suit with Velcro material. The fact that the Blackbirds had their own checklists, one normal and

one for emergencies, added to the problem for the pilot keeping this material ready in the cockpit.

The aircraft’s normal checklist was attached to the top left thigh of the pressure suit. I referred

continually during the flight to both of these checklists to make sure that the normal aircraft

functions were completed along with the test points. The aircraft emergency checklist was placed

in a side console pocket for reference if needed. In an emergency situation, the test card and

normal checklist were put aside in favor of the emergency check list.

Because of the lack of a simulator and the fact that each flight was busy and time-critical, I

had designed a substitute for the simulator at my desk at home. I had pictures of the aircraft

cockpit and consoles laid out in photos and, prior to each flight, I sat at this desk or pseudo-
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simulator and mentally ran through the aircraft’s normal checklist and the test cards while reaching for and visually noting the positions of each switch that would be activated during the flight.

Depending on the complexity of the flight, I would go through this practice a number of times

until I was familiar with the test flight procedures and sequences.

On the morning of the flight, we would have our final briefing. This was named the Crew

Briefing, and it included any last-minute changes in the test cards. Note: The pilots tried to

encourage everyone to keep their last-minute changes to a minimum because any late changes

could screw up prior planning. The crew briefing also included current weather, tanker information and a review of certain emergency procedures, including planned alternate landing fields in

the event of a problem that would not allow us to return to Edwards AFB. After the Crew Brief,

as we called it, the flight crew would proceed to the pressure suit van and “suit up” for the flight.

The pilot and flight test engineer quickly became very attached to his pressure suit, in that it was

their key to survival. Even though it was bulky, cumbersome, and reduced the pilot’s visibility, it

was comforting to wear the suit while flying in this hostile environment. Vic Horton and Ray

Young were two flight test engineers assigned in the pilots office who served as our “backseaters.”

Although Fitz and I flew with both Ray and Vic, we gravitated into two teams for the Blackbirds:

Fitz/Vic and Don/Ray. We flew the majority of our flights with these two teams.

Following the crew briefing, the pilot and flight test engineer would proceed to the pressure

suit van, which would drive out to the parked Blackbird. On the drive out, the personal equipment people would help us into the pressure suits and run a pressure check on the test equipment

in the van. When the aircraft crew chief reported ready for pilot entry, the personal equipment

men, two per crewmember, would accompany us to the aircraft, assist us into the aircraft and

hook us up to the radio, oxygen, and ejection seat. An oxygen flow check and suit pressure check

were also performed in the aircraft. When the “suit people” left, you were completely tied in,

hooked up, and ready to go.

The next step was to complete the pre-start checklist, which was rather long for the Blackbird. Once that was complete and the ground crew ready, the engines were started. Following

engine start, another series of post-start checks was performed on the aircraft systems, including

the all-important flight controls, auto-pilot, and SAS systems. About 40 minutes from the time

you entered the aircraft, you were ready for taxi, barring any problems. The Blackbird, unlike the

XB-70, had an adequate nose-steering system. The visibility for taxi was good and the aircraft

was of such a size that it was no problem on ground handling. The canopies were closed prior to

leaving the chocks.

We normally conducted our test flights early in the morning for several reasons. Takeoff

temperatures were of concern to us, especially in the summer. We were taking off with full fuel,

which meant a heavy aircraft in a long takeoff run with higher runway temperatures. Edwards has

a 15,000-foot runway, a plus. We did, however, like to take off with the ambient temperatures

below 70 degrees in that it provided a margin of safety in the event of an engine loss after takeoff.

This was a NASA operational decision and all involved agreed that it was reasonable and livable.

We did have an Air Force tanker for the mission, but we liked to apply that tanker support after

the first long flight-test leg. In that way, we were able to get two full flights for the price of one.
101

The onboard air-data recorders on the NASA Blackbirds were good for a little over two hours of

data, and if we put our tanker in the middle of the mission, it permitted us to fill our data tapes.

Line-up for takeoff was made squarely on the runway centerline. With the before-takeoff

checklist completed and the engines increased to military power, the engines were checked for

proper operation and the brakes released. Almost immediately, both throttles were lifted slightly

and advanced to minimum afterburner; the afterburners would light very close together but

seldom simultaneously. As each one lit, the nose of the aircraft would swing in the opposite

direction, even with the nose steering engaged. When both afterburners were lit in the minimum

setting, they were immediately advanced to maximum afterburner for takeoff. At full fuel, the

aircraft accelerated at a moderate rate. Nose rotation was started about 175 knots and was held

about ten degrees above the horizon; the aircraft became airborne around 210 knots. The landing

gear was retracted and the throttles reduced to military power for a climb at 250 knots. Once past

10,000 feet, the aircraft was again accelerated to about 400 knots for the climb to altitude. The

climb was made in military power, switching over to a Mach 0.9 climb to about 22,000 feet and

the afterburners were selected. The climb continued at 0.9 Mach to about 34,000 feet where a

gentle nose down attitude was introduced with about a 3,500-foot-per-minute rate of descent.

The acceleration continued in this descent, and the aircraft was flown at around 29 to 30 thousand feet as it accelerated to 450 KEAS (about 1.2 Mach at this altitude). Once on the 450

KEAS, the Blackbird was allowed to start its climb and continue accelerating to cruise altitude

and Mach number, about 75,000 feet and 3.2 Mach. The reason for this descending acceleration

was to keep the aircraft’s angle of attack as low as possible during the transition through this

critical, high-drag region. The complete process from takeoff to cruise took between 20 and 30

minutes, depending on the day and atmospheric temperatures. The Blackbird, like all jet aircraft,

liked very cold days at altitude, where the accelerations went much faster and used less gas. On

a hot day at altitude, it took the old girl a lot longer to get up and go. Even before level-off at the

test conditions, I would be reviewing the first test point and completing any steps that were

possible in preparation for it.

The first leg was north toward the Canadian border and the second leg was south to rendezvous with the tanker near Tonopah, Nevada. I flew a lot of Blackbird refuelings during my ten

years with NASA. I found it a demanding task, one that required a lot of concentration. It usually

took about 12 to 14 minutes on the boom to top off the Blackbird tanks, and I can say that I was

usually ready to go back into the climb-accelerate mode and on to other things when that time

was up. The YF-12 Blackbird had poor visibility during refueling. The pilot’s seat would not

lower enough to allow the pilot to see the tanker by looking upward. Therefore, the pilot had to

bend his torso forward and arch his head back to view the tanker, no easy task with the pressure

suit helmet. The flight control response and damping of the Blackbird were satisfactory in this

lower speed area, especially at the lighter gross weights. When the Blackbird fuel load was

between a half and a full load, a new characteristic appeared that was structural. If too large a

pitch input was made, a small but discernible bending wave was felt to go through the fuselage

structure. The pilot had to be careful and not fight this with large stick inputs, but to reduce his

inputs and allow it to dampen. During the time on the boom taking gas, you would occasionally

feel this structural wave activate and then dampen. The effect would also be aggravated by

turbulence in the air. The increasing inertia with increasing fuel load would decrease the aircraft’s
102

response to throttle movement. A weight change of 55 to 60 thousand pounds was not unusual for

a refueling. When you were nearing a full load of fuel and the Blackbird had drifted back in the

normal refueling envelope, you would push both throttles to full military and then wait and watch

as the power application slowed the drift back and slowly started the aircraft forward to its proper

position.

If I was flying the Blackbird, Fitz would be a primary chase in the F-104, and the opposite

if Fitz was flying the Blackbird. Early in the program, NASA management suggested that the

Blackbird pilot not flying the Blackbird that day should be in the control room, but Fitz and I both

believed that we could support each other more by being in the air in another aircraft, and our

desires were granted. The primary chase would be in an F-104, and would take off right behind

the Blackbird. After takeoff, the F-104 would join up and look the Blackbird over for all gear

doors closed and all other portions of the aircraft looking normal. As the Blackbird began its

acceleration through Mach 1, the F-104 chase would slowly drop behind to conserve fuel, keeping the Blackbird in sight visually for miles by watching the contrail left behind it. If a problem

had developed in this area, the F-104 would rejoin the Blackbird and provide chase support to

escort it home. As the Blackbird climbed higher and faster, it would go above contrail level and

the chase would normally call out the fact that no more contrails were visible. The Blackbird pilot

would call back his altitude to mark the level at which the contrails disappeared. This was usually

around 60 to 65 thousand feet. From this point, the F-104 chase would set his engine power for

maximum endurance and he would hold just west of Beatty, Nevada, the refueling area for the

Blackbird.

Once the Air Force KC-135 tanker was spotted entering the refuel track, the chase would

make radio contact and join up with the tanker in a loose formation. This arrangement, allowed

the chase to watch for the returning Blackbird coming southbound into the refueling track, and

there were occasions when the chase assisted the Blackbird pilot by calling out the tanker’s clock

angle and range to assist the Blackbird pilot in getting a visual on the tanker. Both Fitz and I

appreciated this because at times after a descent in the Blackbird with a little moisture on the

pressure suit visor, long-range visibility from the Blackbird was not that great. As the Blackbird

joined the tanker formation, the chase again looked him over for general integrity and that there

were no fluids leaking from the aircraft. After the Blackbird received its fuel and broke away

from the tanker, the chase pilot gave the Blackbird one final look over, checked that the refueling

door was closed and wished him a good second leg. At this point, the F-104 was low on gas and

ready to return to Edwards. Sometimes the primary chase pilot would park his empty F-104 and

get immediately into another F-104 waiting for him, take off to greet the Blackbird as it entered

the Edwards area for landing after its second flight test leg.

Once off the tanker and cleared to climb, we lit the afterburners and started our climb

acceleration from the tanker altitude of around 22,000 feet. This test leg would be a little longer

than the first after takeoff, because we did not have to burn the takeoff and climb fuel to get us to

22,000 feet. Normally in the turn at the north end of the track, we did not do any unique test

maneuvers because the primary desire was to get the nose pointed south. That sometimes took a

70-mile turn at the Mach 3.2. During the turn, I finally had a little time to look around outside the

aircraft. Up to that point, I had been busy establishing test conditions and taking data, and practi-
103

cally everything was flown on instruments. The outside or real horizon was used as a back-up to

the instrument horizon that I was flying in the cockpit. On lower, slower-flying airplanes, the

pilot could do a pretty good job of flying just with the visual reference to the outside world. Not

so on the Blackbird; the speed was too great and fractions of a degree in pitch would result in

large altitude excursions. This aircraft was operated on instruments regardless of the weather.

The aircraft had a good autopilot, and it was used whenever possible to relieve the pilot

workload. The turn was usually on autopilot, but the majority of the flight was flown manually by

the pilot due to the requirements of the various test points. The view outside was spectacular,

especially if the weather was nice and there was not too much cloud cover. It was amazing just

how far you could see, the slight curvature of the earth at high altitude and the beautiful shades of

blue in the sky. The sky color ran from a light to a very dark blue, almost black as you looked

upward. But the turn seemed to end quickly and it was back to work on the test points. In fact,

prior to rolling out of the turn, the next test point was being set up. It was the same procedure

southbound, getting as many test points completed as possible. The start of decent point was

critical in that we had to be on altitude and in a certain location prior to meeting our tanker. The

descent and slowdown to the tanker covered about 250 miles, and that time was busy working

with clearances with the Federal Aviation Administration (FAA), sometimes accomplished through

communications through our own control room and sometimes with direct communications with

the FAA. Our problem was that we had to descend through a major east-west jet airway and

coordinate the crossing with other traffic. Once we dropped below about 25,000 feet, we were

clear of the traffic and we shortly entered the Air Force test area which was void of commercial

air traffic. We operated on a see-and-be-seen basis but were provided Edwards Approach Control

Radar advisories.

The cockpit on the Blackbird was relatively large, designed for a pilot in a full pressure suit.

It was possible to reach all of the switches and buttons with little effort with the exception of those

on the consoles alongside and slightly behind the pilot. The pressure suit made these a little

tough, but possible to reach. The flight instruments were of the tape or vertical variety. I had

experience with these in the XB-70, and although I preferred the round dials, I had no problem

flying the tapes. The visibility outside the aircraft was good looking forward and up, but it was

limited looking back or down. There was a small periscope in the top of the canopy that could be

extended to allow the pilot to check his engine nacelles and verticals. It was difficult to use, but

again, it was possible. The periscope was to be retracted at high Mach numbers, but I forgot it on

several occasions and it didn’t slow the aircraft down a bit. (It was only an inch in diameter and

extended only an inch or two outward). The forward canopy was angular and had thick glass and

a thin dark splitter plate to prevent reflections. I thought that this combination along with the

pressure suit helmet visor might give problems with visibility during takeoff and landings, but I

was wrong. There was no problem. I was never sure if my left eye looked out the left of the

splitter plate and my right eye looked out the right, but I had no problem with judging heights

during landings.

The pilot scans numerous instruments in the cockpit in order to assimilate and react to the

information presented. This information relates to what the aircraft is doing with changes in

attitudes, altitudes, and velocities. In addition, he must monitor the performance of all the aircraft
104

systems, including flight controls, fuel, hydraulic, electric and propulsion systems. It seems like

almost an impossible task, but it is possible by setting a priority in the pilot’s scan.

The description of the scan is pilot’s eye movement over all these instruments as his mind

sees and digests the information. The scan is a continuing situation, providing the pilot’s mind

with updated information. The way the pilot prioritizes this is to give the most critical factors,

such as aircraft attitude and speed, a first priority, aircraft propulsion a second priority, and other

aircraft systems such as fuel and electrical a third priority, and so on. In addition to the instruments, there is a series of warning lights to alert the pilot to any problems. The scan is continuous as is the pilot’s response to it in controlling the aircraft by making inputs to the flight controls, throttles and other systems switches. Fortunately, the Blackbirds had a very good autopilot. On autopilot, the pilot’s task is reduced to monitoring the aircraft’s position and motions,

and fine-tuning the autopilot with small inputs. The climb acceleration was one area that I was

able to utilize the autopilot in the NASA mission, and I was quite happy to have the help. During

the test points on the heat-loads program, the aircraft was hand-flown because of the unique

inputs required for the data points.

The low-speed handling qualities of the Blackbird were fine, and the approach and landing

speeds were much like the F-104’s. Control response in the landing configuration was excellent

and stability was very good. There was no angle-of-attack indicator in the Blackbird; the primary approach reference was the airspeed indicator. It did not seem difficult to set a desired

airspeed and control the glide path with throttle. If you could fly a good pattern in an F-104, you

could fly an excellent one in the Blackbird. The flare and touchdown were similar to those of

other delta-wing-configured aircraft. It had good ground-effect and feel, and smooth landings

were the norm with this aircraft. The high-speed flight characteristics were good. The control

systems design provided a feel and response to the pilot that was quite normal over the complete

flight range.
105

Appendix 5: Don Mallick describes unstarts

Excerpted from Mallick’s unpublished manuscript “The Smell of Kerosene”

On my second flight to high Mach number in ship 60-6936, I experienced a series of

unstarts and restarts in the Mach range that rattled my head and other parts. The fact that the

Blackbird can operate in a low sub-sonic to Mach 3.2 speed range is impressive. One of the

systems that makes this possible is the inlet computer and control that automatically positions

the spike and controls the shock wave’s location, and the by-pass doors that control the air

pressure and flow in the inlet. (Both of these are critical to provide the engine with “prepared”

air with a high static-pressure and a subsonic Mach number.) The pilot has manual controls to

do this function manually, but it requires a great deal of time and attention. The function of these

engine inlets and controls is very much like a wind tunnel in front of the engine. (What occurs in

the inlet affects the engine, and also, things that occur in the engine can reflect forward to the

function of the inlet.) At supersonic speeds, when everything is running smoothly with the inlet

and engine, the inlet is said to be “started” and running not unlike a wind tunnel. When something occurs that upsets the inlet flow to a point that the position of the normal shock wave

moves forward from its optimum position, the inlet is said to be “unstarted.” The normal shock

wave is located in the smallest area of the inlet, and it is the last shock wave prior to the airflow

going subsonic and entering the engine. There are numerous other shock waves involved, starting with the outer or Mach shock controlled by the spike position.

The unstart condition is not a gradual thing; it happens immediately with a bang. When the

inlet unstarts and loses its smooth flow, there is a large directional input to the aircraft and also

some pitch-up moment. At certain Mach numbers around 2.3 to 2.6, the input to the aircraft is so

violent that it can snap the pilots head and helmet against the inside of the canopy. The flight

control stabilization is quite an aid to the pilot, in that it has a great deal of directional power and

input to counter the initial directional divergence that accompanies an unstart. In addition, a

special “cross tie” feature is included in the inlet controls to automatically unstart the other inlet

to reduce aircraft directional divergence. The cross-tie is active above Mach 2.3, and even with

this feature, unstarts can only be described as violent under certain flight conditions. In other

supersonic flight conditions, they are less violent, but still disconcerting. As a comparison, an

inlet unstart in the XB-70 was less violent. On the XB-70, in fact, a failure of one engine out of

the three might not unstart the inlet; it would just alter the position of the throat and bypass

doors. The XB-70s engines were also located near the centerline as compared to the Blackbird’s

mid-wing location. The Blackbird unstarts were unique and, at times, a little scary. The inlet

control system also had a feature that was called auto re-start. When the inlet unstarted, the

computer control automatically retracted the spikes and opened the bypass doors to a position

associated with a lower Mach number. The spike would then move forward slowly and the

bypass doors closed down as the shocks were re-positioned. If the original cause of the unstart

was gone, the inlet would restart with the airflow re-established to the engine. The Pratt &

Whitney engines were quite forgiving to all of these goings on in the inlet, and they had a

special feature on the fuel control to reduce the fuel flow to the engines during unstart. The

natural tendency of the engine during a reduction in airflow during unstart was to exceed the

design temperature limit and cause damage to the engine. This feature was called “de-rich.”
106

On one occasion, the aircraft went through the automatic restart, but the problem that caused

the unstart was still present. The inlets unstarted again. After several cycles, I selected a manual

restart position and held the inlets in this “safe” condition while the aircraft slowed. About this

time, poor old Sam [Ursini, in the back seat], who couldn’t hold it back any longer, said, “Mallick,

what in the hell is going on up there?” I calmly said, “Sam, as soon as I find out, I’ll tell you.” As

it turned out, I released the inlets out of manual and the next restart worked; we were back in

business. One of the disconcerting things about the inlet unstarts was that after a flight, ground

checks would sometimes reveal nothing wrong with the inlet controls or computers. The problem

was dismissed with the belief that the computer was controlling the inlets too close to the unstart

boundary.

On one exciting ride for me, I was close into Edwards before I reached my 30-minute soaktime at Mach 3. I decided, however, that I had airspace enough to complete the maneuver and still

slow down for landing at Edwards. As I pulled up to the 1.5g pull-up and the aircraft’s nose came

up through the horizon, the inlets unstarted and the engines went into a partial stall condition. The

cabin pressure dropped to a point where our pressure suits began inflating. The nose of the aircraft continued upward for a period much too long to be comfortable to me, considering I had

immediately applied full-forward stick. As the nose finally started to come down, the inlets automatically made an attempt at restart, which failed. After several more attempts, the inlets restarted, the engines cleared their stall and I was able to commence a turn back to Edwards.

Unfortunately, as all of this was going on I was heading out of the Edwards test area toward

the Los Angeles Control area, which had many airliners operating at any given time of day. One

of our operating rules (a very good one), was to have an FAA representative in our control room

during the flights. He was in contact with the various FAA centers that controlled the airspace we

operated in and around. This really paid off on this mission, in that the FAA coordinator integrated my intrusion into Los Angeles Center airspace and indicated that I should stay above

45,000 feet until I returned to the Edwards Airspace if possible. It was possible, and that alleviated the situation. I turned back toward Edwards from over Pasadena, California, still humming

along at 50,000 feet altitude and well over Mach 2. After the flight, I went over the flight control

data traces with the engineers to determine how long I had held full-forward stick until the aircraft nose attitude had started down. It turned out only about eight to ten seconds. With both inlets

unstarted, the pressure suit inflated, and a lot of “shakin’” going on, it had seemed like ten minutes to me at the time. For a moment or two, I wasn’t really sure the aircraft was responding to my

input and I was concerned about who was in control.

Several hours after landing and debriefing at NASA, I learned of a phone call that indicated

that we had not escaped all notice with our flight that day. As I completed the 180-degree turn

back toward Edwards, our shock wave had broken a large plate glass window in a bar in Pasadena. Fortunately, no one was injured by flying glass and NASA picked up the repair check

because we knew the abnormal flight path projected a pretty strong sonic boom on the ground.

We were happy that there was only one window broken, or perhaps just one reported.
107

Documents
108

DOCUMENT 1 – Letter, Eldon E. Kordes, [Flight Research Center] Chairman, YF-12

Structural Dynamics Group, to L. Sternfield, Code RAS, NASA Headquarters, subj: NASA

Research and Development Program related to YF-12, 11 September 1969.
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124

DOCUMENT 2 – Memorandum of Understanding, USAF-NASA YF-12 Research and Development Program, 5 June 1969.
125
126
127
128
129

DOCUMENT 3 – NASA Management Instruction, USAF-NASA Agreement—Loan of YF-12A

Aircraft, Serial Number 60-6935.
130
131
132
133
134
135
136

DOCUMENT 4 – Extract from YF-12A flight manual (declassified), concerning the air inlet system.
137
138
139
140
141
142

ADP Advanced Development Projects

AEW Airborne Early Warning

AFB Air Force Base

AICS Automatic Inlet Control System

ALT Approach and Landing Tests

CAPA Central Airborne Performance Analyzer

CAPCS Cooperative Airframe/Propulsion Control System

CCV Control Configured Vehicle

CIA Central Intelligence Agency

Co-Op Cooperative Controls

DFBW Digital Fly-By-Wire

DFRC Dryden Flight Research Center

DPR Duct Pressure Ratio

F Fahrenheit

FATOLA Flexible Aircraft Takeoff and Landing Analysis

FCF Functional Check Flight

FCO Fire Control Officer

FLEXSTAB Computer program to appraise effect of flexibility on

stability and control characteristics of a supersonic airplane

FMU Functional Mock-Up

FRC Flight Research Center, earlier name for DFRC

HTLL High Temperature Loads Laboratory

KEAS Knots Equivalent Air Speed

LAMS Loads Alleviation and Mode Control System

L/D Lift over Drag

LLRV Lunar Landing Research Vehicle

MOU Memorandum Of Understanding

NAS Naval Air Station

NASTRAN NASA Structural Analysis computer program

OFT Orbital Flight Test

PCM Pulse Code Modulation

PIO Pilot-Induced Oscillation

RSO Reconnaissance Systems Officer

SAS Stability Augmentation System

SCAR Supersonic Cruise Aircraft Research

SST Supersonic Transport

STI Systems Technology, Incorporated

TEB Tri-ethyl borane

TIFS Total In-Flight Simulator

TIGT Turbine Inlet Gas Temperature

USAF United States Air Force

List of Acronyms
143

Index

Abrams, Richard (Dick), 87

accident (YF-12A, 60-6936), 20, 20 n., 21 ill., 65, 91

Adelsbach, LeRoy J., 44

aerial refueling, 24 ill., 100, 101-102

aft-facing step experiment, 32-33, 32 ill., 33 ill.

Air Force Flight Dynamics Laboratory (AFFDL), 42

Air Inlet Control System (AICS), 22

Aiken, William (Bill), 89, 94, 96, 97

AIM-47 missile, 2

Airplanes:

A-12, 1, 1 n., 1 ill., 2, 2 ill., 3, 5, 6, 7 n.,17-18,

18 n., 20, 31, 90, 91

B-1, 96

B-70 (XB-70), 7, 10, 11, 39, 100, 103, 105

F-8 DFBW, 29

F-12B, 5-6

F-104, 102, 104

F-111, 7

KC-135Q, 24 ill., 102

M-21 (mothership for D-21 drone), 30, 31, 31 ill.

NB-52B, 10

NB-52E CCV, 30

NC-131H TIFS, 29

U-2, 1

X-15, 7, 11, 13, 90

YF-12C (origin of designation), 20, 22 ill., 92

Albers, James A., 16, 17 n., 45

Albrecht, William P. (Bill), 10 ill.

Ames Research Center, 1, 1 n., 1 ill., 9, 16, 41, 44,

87-88, 94

Arnaiz, Henry H., 45

ASG-18 (also AN/ASG-18), 2, 4 ill., 8

Ashkenas, Irving L., 29

Barnett, Lorenzo C. (Larry), 44 ill., 51, 55, 90

Bellis, Col. Benjamin (Ben), 88

Berry, Donald T. (Don), 91

bibliography, 73-86

Bikle, Paul F., 8, 87, 89, 94, 98

Black, Capt. Thomas, 26

Bohanan, Larry M., 7

Brownlow, James D., 45

Bruno, John M., 44 ill.

Campbell, David (Dave), 89, 92

Campbell, William (Bill), 50, 51, 52, 62, 63, 90,

92, 93

Carden, Huey, 26

Carter, Alan, 41

Category II tests (SR-71), 7, 7 n., 8, 87, 88, 92

Central Airborne Performance Analyzer (CAPA),

22-23, 23 n.

Central Intelligence Agency (CIA), 1, 1 n., 17

Childs, Harry R., 10 ill.

Coldwall experiment, 34 ill., 34-37, 36 ill., 37 ill.,

43 ill., 96

Combs, Henry G., 30, 93

Cooperative Airframe/Propulsion Control System

(CAPCS), 40-41

Cooperative controls (Co-Op) research, 40-41

Curtis, Al, 41

Curtis, Maj. Billy A., 20, 51, 63-65, 91

D-21 drone, 3-32, 95

Dana, William H. (Bill), 29, 39, 50, 60

Digital Fly-By-Wire (DFBW), 29

DiMarco, Richard, 29

Dishman, Gus, 26

dual-mode adaptive landing gear, 27-28, 45

Eastham, James D., 2, 3

Eaton, Robert (Bob), 10 ill.

Eckert, E. R. G. (reference enthalpy method), 36

Ehernberger, Jack, 47, 87

Enevoldson, Einar K., 29, 39, 50, 60

engine air inlet system, 3-4, 16, 17, ill., 18, 18 ill., 19,

19 ill., 20, 20 n., 21, 43-44, 93, 136, 137 ill.,

138, 139 ill.140, 141 ill.

Evenson, Maj. Mervin L., 50, 66

Flexible Aircraft Takeoff and Landing Analysis

(FATOLA), 24-25, 25 n., 26

FLEXSTAB, 41

flight crews (list), 50-51

flight logs, 50-72

Fox, William (Bill), 10 ill., 18 n., 26, 93

Frazier, Maj. William J., 51, 72

Frost, LeRoy P., 44 ill.

Fulton, Fitzhugh L., Jr., 10, 10 ill., 26, 28, 44 ill., 45

ill., 47, 50, 52-61, 66-72, 97, 99, 100, 102

Furr, Billy, 44 ill.

Gemenhardt, Glenn, 44 ill.

Gibbs, Byron D., 44 ill.

Gilyard, Glenn B., 91

Goddard Spaceflight Center, 41

Gordon, James C., 44 ill.

Grace, Charles A., Jr., 44 ill.
144

heater, (fuselage) 12 ill., (forebody), 13 ill., 14, 14

ill., 15

Heidelbaugh, Maj. Gary I., 51, 61-65, 90

High Temperature Loads Laboratory (HTLL), 13-15,

32, 43

Honeywell, 21-22

Horton, Victor W., 10, 10 ill., 26, 28, 29, 39, 44 ill., 45

ill., 47, 51-61, 66-72, 97, 100

HT-4 High-Speed Transport demonstrator proposal,

30 ill., 30-32, 95

Hughes, 2

Ishmael, Stephen D. (Steve), 47, 50, 61

Jewett, Lt. Col. Calvin F. (Cal), 50, 72

Johnson, Clarence L. (Kelly), 1, 2, 2 n., 6, 9, 30-32,

89, 90, 91, 92

Johnson, President Lyndon B., 2, 2 n.

Jones, Lloyd, 88

JP-7 fuel, 4, 24

KEDLOCK, 2

Kock, Berwin P., 9, 9 n., (interview) 95-98

Kordes, Eldon E. (Don), 91, 108

Krier, Gary E., 39, 50, 60

Langley Research Center, 9, 16, 26, 30, 38, 41, 92, 94

Larsen, Terry, 47, 87

Layton, Col. Ronald J. (Jack), 20, 50, 54, 63-65,

90, 91

Lewis Research Center, 9, 16, 45, 92, 94, 95

Load Alleviation and Mode Suppression system

(LAMS), 39-40, 40 ill., 42 ill.

loan agreement (YF-12A), 129-135

Lockalloy, 37, 37 ill., 92, 96

Lockheed Advanced Development Projects (ADP),

26, 30-31

Louett, John W., 44 ill.

Lunar Landing Research Vehicle (LLRV)

Mallick, Donald L., 10, 10 ill., 11, 26, 28, 34, 35 ill.,

36, 50, 52-61, 63, 64, 66-72, 97, (describes

flight operations) 99-104, (describes unstarts)

105-106

Manke, John A., 39, 50, 60

Matranga, Gene J., 5, 8, 9, 10 ill., 13, 13 n., 18 n., 26,

43, 44, 46, 47, (interview) 87-95

Mayesh, Jack, 10 ill.

McDonald, Thomas C., 44 ill.

McDonnell Douglas Astronautics Corporation, 25

McGehee, Robert (Bob), 26

McKay, James M. (Jim), 26, 41

McMaster, Burt, 89, 92

McMaster, John R., 30, 30 n.

McMurtry, Thomas C. (Tom), 39, 50, 60

McNamara, Robert, 5

McNeer, Maj. Charles J., 51, 66

memorandum of understanding (MOU), 8, 8, n.,

89, 124-128

Merkner, Ralph A., 44 ill.

MiG-25, 8

Miller, R. L., 7

missiles, 2

NASA Structural Analysis (NASTRAN) program,

41, 42, 92, 96

OXCART, 1, 1n, 2, 17-18, 18n

Park, William (Bill), 32

phugoids, 21, 21 n.

plastic laminates, 3

Polentz, Perry, 41

Powers, Sheryll Goecke, 92

Pratt & Whitney J58 engine, 3, 16 ill., 17 ill., 20, 20 n.

Pratt & Whitney RL-10 engine, 30

Reynolds Number, 16, 16 n.

Rich, Ben, 89, 92, 97

Rifenberry, John R., 44 ill., 45 ill.

Rogers, Col. Joseph W. (Joe), 51, 62, 90, 92

Saltzman, Ed, 92, 94

Schweikhard, William (Bill), 8, 87, 88, 89, 92

Scott, David (Dave), 96

serial number list (A-12, YF-12A, SR-71), 7

shaker vanes, 40, 42, 47

Skliar, William (Bill), 88

Skunk Works (also see Lockheed ADP), 1 n., 2 n.,

32 n., 97, 98

Slater, Col. Hugh C. (Slip), 51, 61, 62, 90, 92

Smith, Ron, 96

Space Shuttle, (Approach and Landing Tests) 29,

(landing simulation) 24, 28-29, 39

Spalding-and-Chi Method for determining skin friction coefficients, 36

Stephens, Col. Robert (Fox), 87, 88, 90, 92

Sudderth, Robert (Bob), 87, 88, 93

Sullivan, Col. James V., 47, 48 ill., 51, 61, 72

Supersonic Cruise Aircraft Research (SCAR), 38-39

Supersonic Transport (SST), 8, 16, 25, 26, 41, 88,

89, 93, 94, 96
145

Swann, Michael R., 47, 51, 61

Systems Technology, Incorporated (STI), 29

Tang, Ming, 95, 96

Teper, Gary L., 29, 29 n.

Thompson, Milton O. (Milt), 29, 29 n., 46, 46 n.

Torick, Ray, 32

Total In-Flight Simulator (TIFS), 29

triethylborane (TEB), 4

unstart 4, 19, 23, 37, 105-106

Uppstrom, Col. Richard, 47, 48 ill., 51, 61

Ursini, Maj. Sammel M. (Sam), 51, 52, 61, 62, 88,

90, 106

USAF Museum, 47, 48

van Driest, Edward R. (equations for estimating tur

bulent hear transfer), 36

ventral fin (loss of), 34-35, 35 ill.

Watts, Joe D., 10 ill.

Weil, Joseph (Joe), 87, 89

Williams, Walter C., 46

wind-tunnel, 1, 1 n., 1 ill., 9, 16, 43, 44, 45, 45 n.,

87-88

world records, 2

YF-12 research program plan, 108-123

Young, William R. (Ray), 10 ill., 11, 26, 28, 29, 34,

36, 39, 51-61, 66-72, 100
146

About the Author

Peter W. Merlin has worked as an archivist in the NASA Dryden Flight Research Center History Office since

June 1997. He originally joined the staff as an archivist for the Dryden Film/Video Collection, under contract

to Woodside Summit Group, Inc. Since May 1998, he has cataloged documents in the Dryden Historical

Reference Collection, joining Analytical Services & Materials, Inc. in April 1999. As a freelance writer

Merlin has published numerous articles in a variety of periodicals, covering subjects from aerospace history to

nuclear weapons accidents. He received his B.S. degree in Aeronautical Studies from Embry-Riddle Aeronautical University in 1987. Merlin is a member of the Flight Test Historical Foundation and the National Atomic

Museum Foundation. As a founding member of the X-Hunters Aerospace Archeology Team, he also specializes in recovering historic aircraft artifacts from the southwestern United States, especially the area around

Edwards Air Force Base, California. Merlin occasionally lectures on aerospace history and prehistoric archeology.

Monographs in Aerospace History

Launius, Roger D., and Gillette, Aaron K. Compilers. The Space Shuttle: An Annotated Bibliography. (Monographs in Aerospace History, No. 1, 1992).

Launius, Roger D., and Hunley, J.D. Compilers. An Annotated Bibliography of the Apollo Program. (Monographs in Aerospace History, No. 2, 1994).

Launius, Roger D. Apollo: A Retrospective Analysis. (Monographs in Aerospace History, No. 3, 1994).

Hansen, James R. Enchanted Rendezvous: John C. Houbolt and the Genesis of the Lunar-Orbit Rendezvous

Concept. (Monographs in Aerospace History, No. 4, 1995).

Gorn, Michael H. Hugh L. Dryden’s Career in Aviation and Space. (Monographs in Aerospace History, No. 5,

1996).

Powers, Sheryll Goecke. Women in Flight Research at the Dryden Flight Research Center, 1946-1995 (Monographs in Aerospace History, No. 6, 1997).

Portree, David S.F. and Trevino, Robert C. Compilers. Walking to Olympus: A Chronology of Extravehicular

Activity (EVA). (Monographs in Aerospace History, No. 7, 1997).

Logsdon, John M. Moderator. The Legislative Origins of the National Aeronautics and Space Act of 1958:

Proceedings of an Oral History Workshop (Monographs in Aerospace History, No. 8, 1998).

Rumerman, Judy A. Compiler. U.S. Human Spaceflight: A Record of Achievement, 1961-1998 (Monographs in

Aerospace History, No. 9, 1998).

Portree, David S.F. NASA’s Origins and the Dawn of the Space Age (Monographs in Aerospace History, No. 10,

1998).

Logsdon, John M. Together in Orbit: The Origins of International Cooperation in the Space Station Program

(Monographs in Aerospace History, No. 11, 1998).

Phillips, W. Hewitt. Journey in Aeronautical Research: A Career at NASA Langley Research Center (Monographs in Aerospace History, No. 12, 1998).
147

Braslow, Albert L. A History of Suction-Type Laminar-Flow Control with Emphasis on Flight Research (Monographs in Aerospace History, No. 13, 1999).

Logsdon, John M. Moderator. Managing the Moon Program: Lessons Learned from Project Apollo (Monographs in Aerospace History, No. 14, 1999).

Perminov, V.G. The Difficult Road to Mars: A Brief History of Mars Exploration in the Soviet Union (Monographs in Aerospace History, No. 15, 1999).

Tucker, Tom. Touchdown: The Development of Propulsion Controlled Aircraft at NASA Dryden (Monographs in

Aerospace History, No. 16, 1999).

Maisel, Martin D.; Demo J. Giulianetti; and Daniel C. Dugan. The History of the XV-15 Tilt Rotor Research

Aircraft: From Concept to Flight. (Monographs in Aerospace History #17, NASA SP-2000-4517, 2000).

Jenkins, Dennis R. Hypersonics Before the Shuttle: A History of the X-15 Research Airplane. (Monographs in

Aerospace History #18, NASA SP-2000-4518, 2000).

Chambers, Joseph R. Partners in Freedom: Contributions of the Langley Research Center to U.S. Military

Aircraft in the 1990s. (Monographs in Aerospace History #19, NASA SP-2000-4519, 2000).

Waltman, Gene L. Black Magic and Gremlins: Analog Flight Simulations at NASA’s Flight Research Center.

(Monographs in Aerospace History #20, NASA SP-2000-4520, 2000).

Portree, David S.F. Humans to Mars: Fifty Years of Mission Planning, 1950-2000. (Monographs in Aerospace

History #21, NASA SP-2001-4521, 2001).

Thompson, Milton O. Flight Research: Problems Encountered and What They Should Teach Us. (Monographs

in Aerospace History #22, NASA SP-2001-4522, 2001).

Tucker, Tom. The Eclipse Project (Monographs in Aerospace History #23, NASA SP-2000-4523, 2000).

Siddiqi, Asif A. Deep Space Chronicle: Robotic Exploration Missions to the Planets (Monographs in Aerospace

History #24, NASA SP-2001-4524, 2001).

Those monographs still in print are available free of charge from the NASA History Division, Code ZH, NASA

Headquarters, Washington, DC 20546. Please enclosed a self-addressed 9x12" envelope stamped for 15

ounces for these items.

Reference Works, NASA SP-4000:

Grimwood, James M. Project Mercury: A Chronology. (NASA SP-4001, 1963).

Grimwood, James M., and Hacker, Barton C., with Vorzimmer, Peter J. Project Gemini Technology and Operations: A Chronology. (NASA SP-4002, 1969).

Link, Mae Mills. Space Medicine in Project Mercury. (NASA SP-4003, 1965).

The NASA History Series
148

Astronautics and Aeronautics, 1963: Chronology of Science, Technology, and Policy. (NASA SP-4004, 1964).

Astronautics and Aeronautics, 1964: Chronology of Science, Technology, and Policy. (NASA SP-4005, 1965).

Astronautics and Aeronautics, 1965: Chronology of Science, Technology, and Policy. (NASA SP-4006, 1966).

Astronautics and Aeronautics, 1966: Chronology of Science, Technology, and Policy. (NASA SP-4007, 1967).

Astronautics and Aeronautics, 1967: Chronology of Science, Technology, and Policy. (NASA SP-4008, 1968).

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Newkirk, Roland W., and Ertel, Ivan D., with Brooks, Courtney G. Skylab: A Chronology. (NASA SP-4011,

1977).

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NASA Resources, 1958-1968. (NASA SP-4012, 1976, rep. ed. 1988).

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SP-4012, 1988).

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SP-4012, 1988).

Gawdiak, Ihor Y., with Fedor, Helen. Compilers. NASA Historical Data Book, Volume IV: NASA Resources,

1969-1978. (NASA SP-4012, 1994).

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Space Transportation, Human Spaceflight, and Space Science. (NASA SP-4012, 1999).

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and Space Research and Technology, Tracking and Data Acquisition/Space Operations, Commercial

Programs, and Resources, 1979-1988 (NASA SP-2000-4012, 2000).

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Astronautics and Aeronautics, 1971: Chronology of Science, Technology, and Policy. (NASA SP-4016, 1972).
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Astronautics and Aeronautics, 1972: Chronology of Science, Technology, and Policy. (NASA SP-4017, 1974).

Astronautics and Aeronautics, 1973: Chronology of Science, Technology, and Policy. (NASA SP-4018, 1975).

Astronautics and Aeronautics, 1974: Chronology of Science, Technology, and Policy. (NASA SP-4019, 1977).

Astronautics and Aeronautics, 1975: Chronology of Science, Technology, and Policy. (NASA SP-4020, 1979).

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Astronautics and Aeronautics, 1977: Chronology of Science, Technology, and Policy. (NASA SP-4022, 1986).

Astronautics and Aeronautics, 1978: Chronology of Science, Technology, and Policy. (NASA SP-4023, 1986).

Astronautics and Aeronautics, 1979-1984: Chronology of Science, Technology, and Policy. (NASA SP-4024, 1988).

Astronautics and Aeronautics, 1985: Chronology of Science, Technology, and Policy. (NASA SP-4025, 1990).

Noordung, Hermann. The Problem of Space Travel: The Rocket Motor. Stuhlinger, Ernst, and Hunley, J.D.,

with Garland, Jennifer. Editor. (NASA SP-4026, 1995).

Astronautics and Aeronautics, 1986-1990: A Chronology. (NASA SP-4027, 1997).

Astronautics and Aeronautics, 1990-1995: A Chronology. (NASA SP-2000-4028, 2000).

Management Histories, NASA SP-4100:

Rosholt, Robert L. An Administrative History of NASA, 1958-1963. (NASA SP-4101, 1966).

Levine, Arnold S. Managing NASA in the Apollo Era. (NASA SP-4102, 1982).

Roland, Alex. Model Research: The National Advisory Committee for Aeronautics, 1915-1958. (NASA SP-4103,

1985).

Fries, Sylvia D. NASA Engineers and the Age of Apollo. (NASA SP-4104, 1992).

Glennan, T. Keith. The Birth of NASA: The Diary of T. Keith Glennan. Hunley, J.D. Editor. (NASA SP-4105,

1993).

Seamans, Robert C., Jr. Aiming at Targets: The Autobiography of Robert C. Seamans, Jr. (NASA SP-4106,

1996)

Project Histories, NASA SP-4200:

Swenson, Loyd S., Jr., Grimwood, James M., and Alexander, Charles C. This New Ocean: A History of Project

Mercury. (NASA SP-4201, 1966; rep. ed. 1998).

Green, Constance McL., and Lomask, Milton. Vanguard: A History. (NASA SP-4202, 1970; rep. ed. Smithsonian

Institution Press, 1971).

Hacker, Barton C., and Grimwood, James M. On Shoulders of Titans: A History of Project Gemini. (NASA

SP-4203, 1977).
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Benson, Charles D. and Faherty, William Barnaby. Moonport: A History of Apollo Launch Facilities and Operations. (NASA SP-4204, 1978).

Brooks, Courtney G., Grimwood, James M., and Swenson, Loyd S., Jr. Chariots for Apollo: A History of Manned

Lunar Spacecraft. (NASA SP-4205, 1979).

Bilstein, Roger E. Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles. (NASA

SP-4206, 1980, rep. ed. 1997).

SP-4207 not published.

Compton, W. David, and Benson, Charles D. Living and Working in Space: A History of Skylab. (NASA SP-4208,

1983).

Ezell, Edward Clinton, and Ezell, Linda Neuman. The Partnership: A History of the Apollo-Soyuz Test Project.

(NASA SP-4209, 1978).

Hall, R. Cargill. Lunar Impact: A History of Project Ranger. (NASA SP-4210, 1977).

Newell, Homer E. Beyond the Atmosphere: Early Years of Space Science. (NASA SP-4211, 1980).

Ezell, Edward Clinton, and Ezell, Linda Neuman. On Mars: Exploration of the Red Planet, 1958-1978. (NASA

SP-4212, 1984).

Pitts, John A. The Human Factor: Biomedicine in the Manned Space Program to 1980. (NASA SP-4213, 1985).

Compton, W. David. Where No Man Has Gone Before: A History of Apollo Lunar Exploration Missions. (NASA

SP-4214, 1989).

Naugle, John E. First Among Equals: The Selection of NASA Space Science Experiments. (NASA SP-4215,

1991).

Wallace, Lane E. Airborne Trailblazer: Two Decades with NASA Langley’s Boeing 737 Flying Laboratory.

(NASA SP-4216, 1994).

Butrica, Andrew J. Editor. Beyond the Ionosphere: Fifty Years of Satellite Communication. (NASA SP-4217,

1997).

Butrica, Andrews J. To See the Unseen: A History of Planetary Radar Astronomy. (NASA SP-4218, 1996).

Mack, Pamela E. Editor. From Engineering Science to Big Science: The NACA and NASA Collier Trophy

Research Project Winners. (NASA SP-4219, 1998).

Reed, R. Dale. With Lister, Darlene. Wingless Flight: The Lifting Body Story. (NASA SP-4220, 1997).

Heppenheimer, T.A. The Space Shuttle Decision: NASA’s Search for a Reusable Space Vehicle. (NASA SP4221, 1999).

Hunley, J.D. Editor. Toward Mach 2: The Douglas D-558 Program. (NASA SP-4222, 1999).

Swanson, Glen E. Editor. “Before this Decade is Out...”: Personal Reflections on the Apollo Program (NASA

SP-4223, 1999).
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Tomayko, James E. Computers Take Flight: A History of NASA’s Pioneering Digital Fly-by-Wire Project. (NASA

SP-2000-4224, 2000).

Center Histories, NASA SP-4300:

Rosenthal, Alfred. Venture into Space: Early Years of Goddard Space Flight Center. (NASA SP-4301, 1985).

Hartman, Edwin, P. Adventures in Research: A History of Ames Research Center, 1940-1965. (NASA SP-4302,

1970).

Hallion, Richard P. On the Frontier: Flight Research at Dryden, 1946-1981. (NASA SP- 4303, 1984).

Muenger, Elizabeth A. Searching the Horizon: A History of Ames Research Center, 1940-1976. (NASA SP-4304,

1985).

Hansen, James R. Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917-1958. (NASA

SP-4305, 1987).

Dawson, Virginia P. Engines and Innovation: Lewis Laboratory and American Propulsion Technology. (NASA

SP-4306, 1991).

Dethloff, Henry C. “Suddenly Tomorrow Came...”: A History of the Johnson Space Center. (NASA SP-4307,

1993).

Hansen, James R. Spaceflight Revolution: NASA Langley Research Center from Sputnik to Apollo. (NASA

SP-4308, 1995).

Wallace, Lane E. Flights of Discovery: 50 Years at the NASA Dryden Flight Research Center. (NASA SP-4309,

1996).

Herring, Mack R. Way Station to Space: A History of the John C. Stennis Space Center. (NASA SP-4310, 1997).

Wallace, Harold D., Jr. Wallops Station and the Creation of the American Space Program. (NASA SP-4311,

1997).

Wallace, Lane E. Dreams, Hopes, Realities: NASA’s Goddard Space Flight Center, The First Forty Years (NASA

SP-4312, 1999).

Dunar, Andrew J., and Stephen P. Waring. Power to Explore: A History of the Marshall Space Flight Center

(NASA SP-4313, 1999).

Bugos, Glenn E. Atmosphere of Freedom: Sixty Years at the NASA Ames Research Center Astronautics and

Aeronautics, 1986-1990: A Chronology. (NASA SP-2000-4314, 2000).

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Corliss, William R. NASA Sounding Rockets, 1958-1968: A Historical Summary. (NASA SP-4401, 1971).

Wells, Helen T., Whiteley, Susan H., and Karegeannes, Carrie. Origins of NASA Names. (NASA SP-4402, 1976).

Anderson, Frank W., Jr. Orders of Magnitude: A History of NACA and NASA, 1915-1980. (NASA SP-4403, 1981).
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1989).

Logsdon, John M. Editor. With Lear, Linda J., Warren-Findley, Jannelle, Williamson, Ray A., and Day, Dwayne

A. Exploring the Unknown: Selected Documents in the History of the U.S. Civil Space Program, Volume I, Organizing for Exploration. (NASA SP-4407, 1995).

Logsdon, John M. Editor. With Day, Dwayne A., and Launius, Roger D. Exploring the Unknown: Selected

Documents in the History of the U.S. Civil Space Program, Volume II, Relations with Other Organizations. (NASA SP-4407, 1996).

Logsdon, John M. Editor. With Launius, Roger D., Onkst, David H., and Garber, Stephen E. Exploring the

Unknown: Selected Documents in the History of the U.S. Civil Space Program, Volume III, Using

Space. (NASA SP-4407, 1998).

Logsdon, John M. General Editor. With Ray A. Williamson, Roger D. Launius, Russell J. Acker, Stephen J.

Garber, and Jonathan L. Friedman. Exploring the Unknown: Selected Documents in the History of the

U.S. Civil Space Program, Volume IV, Accessing Space. (NASA SP-4407, 1999).

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Anne Neuport. Exploring the Unknown: Selected Documents in the History of the U.S. Civil Space

Program, Volume V, Exploring the Cosmos. (NASA SP-2001-4407, 2001).

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4408, 2000).
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