History - Supersonic Flight USAF Bell X-2

From the AF.mil website - Supersonic history and tragedy as the written story goes...
Though the caption from the photo's EXIF doesn't reflect the facts in the story...
Tom -

Photo Caption - An X-2 rocket plane in flight during the mid-1950s. (Courtesy NASA photo)

First supersonic flight of the X-2
Posted 5/17/2010

On April 25, 1956, the X-2 completed its first supersonic flight. 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,
or 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 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 in Hampton, Va., available to evaluate various aspects of the
X-2 design. The NACA was also responsible for scientific instrumentation of the X-2.

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
employed 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.

A B-50A bomber was modified to carry the X-2 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, the
X-2 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. 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 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.

On Aug. 5, 1954, the X-2 was carried aloft for another captive flight beneath the
B-50. Later that day, the X-2 was carried aloft for a second time and released. Pete
Everest 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.

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
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.

Source: NASA's Dryden Flight Research Center fact sheets