NASA 

National Aeronautics and 

Facts

Space Administration 

Dryden Flight Research Center 

P.O. Box 273

Edwards, California 93523 

Voice 661-276-3449 

FAX 661-276-3566 

pao@dfrc.nasa.gov FS-2003-06-0079 DFRC 

Bell X-2 Starbuster 

NASA Photo E-5749. X-2 on transprtation dolly. 

The Bell X-2 was a rocket-powered, swept-wing research aircraft designed to investigate the structural 

effects of aerodynamic heating as well as stability and control effectiveness at high speeds and altitudes. The program was developed jointly in 1945 by Bell Aircraft Corporation, the U.S. Air Force and 

the National Advisory Committee for Aeronautics (NACA) to explore aerodynamic problems of supersonic flight and to expand the speed and altitude regimes obtained with the earlier X-1 series of research aircraft. 

In 1946, the NACA Pilotless Aircraft Research Division (PARD) began testing rocket launched X-2 

models at Wallops Island, Va., to gather stability and control data. Additional tests helped NACA and 

Bell engineers design a pilot escape system for the X-2. The NACA made its spin tunnel and supersonic wind-tunnels at the Langley Memorial Aeronautical Laboratory, Hampton, Va., available to 

evaluate various aspects of the X-2 design. The NACA was also responsible for scientific instrumentation of the X-2. 

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Two X-2 airframes, nicknamed “Starbuster,” were 

built at Bell’s plant in Wheatfield, N.Y., using stainless steel and K-monel (a copper-nickel alloy). The 

vehicles were designed to employ a two-chamber 

Curtiss-Wright XLR25 throttleable liquid-fueled 

rocket engine. It had a variable thrust rating from 

2,500 to 15,000 pounds. The X-2 was equipped with 

an escape capsule for the pilot. In an emergency, the 

entire nose assembly would jettison and deploy a 

stabilizing parachute. Once at a safe altitude, the pilot 

would then manually open the canopy and bail out. 

Although the Air Force approved the final escape 

system design, NACA representatives were concerned 

that it might prove dangerous to use. 

NASA Photo E-2820. X-2 drop from B-50 Mothership. 

A Boeing B-50A bomber was modified to carry the X2 to launch altitudes around 30,000 feet. The pilot then 

climbed into the X-2, dropped away from the bomber, 

and ignited the engines if it was a planned powered 

flight. After engine burnout, the pilot guided the X-2 

to an unpowered landing on the surface of Rogers Dry 

Lake at Edwards Air Force Base, Calif. 

Because of a decision to install the first available 

engine in airframe 46-674, airframe 46-675 was 

delivered to Edwards first for glide tests. It arrived at 

Edwards on April 22, 1952. After two captive flights, 

Bell test pilot Jean L. “Skip” Ziegler made the first 

glide flight on June 27. A rough landing caused some 

damage to the aircraft and the second glide flight was 

delayed until Oct. 8. Two days later, Air Force test 

pilot Maj. Frank K. “Pete” Everest successfully completed the third glide flight of the X-2. 

Following the unpowered tests, the X-2 was returned 

to Bell’s plant in New York. The engine had not yet 

been installed in the first X-2, 46-674, so it was 

installed in the second shortly after it returned to 

Wheatfield. Captive flights with the new engine were 

carried out over Lake Ontario. During a flight to check 

the liquid oxygen system, an explosion resulted in the 

loss of the X-2 and severe damage to the B-50. Skip 

Ziegler and B-50 crew member Frank Wolko were 

both killed. The X-2 fell into Lake Ontario and was 

not recovered. The B-50A was damaged beyond 

economic repair and was subsequently replaced with a 

modified B-50D. 

The remaining X-2, with its engine finally installed, 

made its initial captive flight on July 13, 1954, at 

Wheatfield, N.Y. The following day, it began its 

journey to Edwards beneath the B-50D. The aircraft 

arrived on July 15 and technicians at the NACA High 

Speed Flight Station (HSFS) began to install instrumentation to gather handling qualities data. On the 

advice on the NACA, the Air Force purchased a 

Goodyear Electronic Digital Analyzer (GEDA) analog 

computer. Richard E. Day, NACA project engineer for 

the X-2, programmed the GEDA and turned it into a 

rudimentary flight simulator for the aircraft. 

On Aug. 5, 1954, the X-2 was carried aloft for anNASA Photo E-5743. X-2 on ramp with B-50 and support 

crew. 

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NASA Photo E-749. X-2 on lakebed after landing on skids. 

other captive flight beneath the B-50. Later that day, 

the X-2 was carried aloft for a second time and released. Pete Everest, now a lieutenant colonel, made a 

successful glide flight that ended in a rough landing on 

the lakebed. The vehicle sustained minor damage and 

was returned to Wheatfield for repair. 

The X-2 returned to Edwards on Jan. 16, 1955, and 

captive flights resumed on Feb. 5 for propellant 

system checks. After several captive missions, two 

more glide flights were accomplished in March and 

April. Damage to the aircraft during landing required 

the X-2 to return to New York once again. 

The first attempt at a powered flight took place on 

Oct. 25, 1955, but a nitrogen leak resulted in a decision to change the flight plan. Everest completed the 

mission as a glide flight. An aborted second attempt 

ended as a captive flight. Everest finally made the first 

powered X-2 flight on Nov. 18, igniting only the 

5,000-pound-thrust chamber. His maximum speed 

during the mission was Mach 0.95. Following several 

aborted attempts, Everest completed a second powered 

flight on March 24, 1956, this time only igniting the 

10,000-pound-thrust rocket chamber. 

Both chambers were used for the first supersonic X-2 

flight on April 25. The airplane reached a speed of 

Mach 1.40 and a maximum altitude of 50,000 feet. 

Everest completed three flights in May that pushed the 

airplane’s speed envelope to Mach 2.53. On May 25, 

1956, a new pilot was checked out in the X-2, Capt. 

Iven C. Kincheloe. He made a successful supersonic 

flight, but had to shut the engine down prematurely 

due to a malfunction. In June, the airplane was 

grounded for installation of engine nozzle extensions 

to improve performance. Everest made a supersonic 

checkout of the modified X-2 on July 12. Everest’s 

final X-2 flight, on July 23, 1956, earned him the title 

“Fastest Man Alive.” While gathering data on aerodynamic heating, Everest achieved a speed of Mach 2.87 

at 68,000 feet. 

Kincheloe now assumed the role of X-2 project pilot 

for a series of high-altitude missions. After two 

aborted flight attempts, he successfully accomplished 

a climb to 87,750 feet while gathering stability data on 

Aug. 3, 1956. That same day, NACA director Hugh 

L. Dryden requested that the Air Force loan the X-2 to

the NACA for research purposes. The Air Force 

continued to fly the airplane while attempting to 

achieve its maximum altitude capability. While a 

flight on Aug. 8, failed to exceed 70,000 feet, another 

attempt on Sept. 7 reached an altitude of 126,200 feet. 

This earned Kincheloe the title “First of the Spacemen” and a record that stood until the advent of the 

X-15 program. Kincheloe made three additional flight 

attempts, but each ended in an abort. 

The Air Force was due to transfer the X-2 to the 

NACA in mid-September and preparations were 

underway. Researchers at the NACA High Speed 

Flight Station were anxious to use the X-2 for heating 

investigations in the Mach 2 to Mach 3 range and 

study handling characteristics at extreme altitudes and 

speeds. The Air Force, however, asked for an extension of their program so that another pilot could be 

NASA Photo E-2822. X-2 in flight. 

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checked out. As Capt. Milburn G. “Mel” Apt practiced 

simulated missions on the GEDA, representatives 

from the Air Force, the NACA, and Bell agreed on a 

flight plan. 

On Sept. 27, 1956, Apt became the first person to fly 

faster than three times the speed of sound. The engine 

burned slightly longer than expected and Apt flew a 

near perfect flight profile, allowing him to reach a 

speed of 2,094 mph (Mach 3.196). Elation was short 

lived. For some reason, Apt initiated a sharp turn back 

toward Edwards. This resulted in a control divergence 

known as inertial coupling. The X-2 began to tumble 

uncontrollably. Apt jettisoned the escape capsule, but 

was unable to extract himself before it struck the 

ground. Apt’s death cast a shadow over the most 

spectacular achievement of the program. 

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