Page 4 - The Future of Aerospace is X - X-Planes 2021

Bell X-1:

Program changed history, established research aircraft concept

When most people think of the Bell by the same aerodynamic problems, a result, a NACA team was incorpo-
X-1, they think of then-Capt. Chuck and their data proved to be unreliable rated into the program.
Yeager breaking the sound barrier on in this regime. As a result, a few indi- The first glide flight of the X-1 oc-
Oct. 14, 1947. viduals — John Stack of NACA, Ezra curred on Jan. 19, 1946, at Pinecastle
However, the X-1 program involved Kotchner of the Army Air Forces, and Field, Fla., flown by Bell test pilot
seven different variants of the aircraft, Walter Diehl of the Navy — realized Jack Woolams because Muroc Army
and multiple flights from the program’s a specialized research aircraft offered Air Field had been flooded. The X-1-1
first flight on Jan. 19, 1946, through the only feasible means of getting su- was air launched from a B-29. Wool-
1958. personic aeronautical data. ams made a total of 10 glide flights
The first generation X-1 aircraft The Army Air Forces selected Bell to test the X-1’s low speed handling
changed aviation history in numerous Aircraft to build three X-1 aircraft. before it was returned to Bell Aircraft
ways, and not simply because they The fuselage was the same shape in Buffalo, N.Y., in March 1946 for
were the first aircraft to fly faster than as a 0.50 caliber machine gun bullet, installation of the rocket engine, and
the speed of sound. which was known to be stable at su- modifications to prepare it for pow-
Rather, they established the concept personic speeds. The X-1 wings were ered flight tests. The aircraft was de-
of the research aircraft, built solely for straight, rather than swept back, and livered to Muroc in October 1946.
experimental purposes, and unham- relatively thin for the time. The X-1- The first group of NACA engineers
pered by any military or commercial 1 (serial number 46-062) had a wing arrived at Muroc Field (now Edwards Air Force photograph
requirements. Although subsequent with an 8 percent thickness/chord ratio. Air Force Base, Calif.), in Septem- Chuck Yeager in front of the X-1 that he nicknamed the Glamorous Glennis.
X-planes were built for a wide range The X-1-2 (serial number 46-063) had ber 1946 in preparation for the initial
of purposes — technology or concept a 10 percent ratio wing. The X-1 was flights of the X-1-2.
demonstrators, unmanned test missiles, powered by an XLR-11 rocket engine, Bell test pilot Chalmers “Slick” its thinner wing, to conduct an accel- took his first powered flight in the X-1-
and even as prototypes in all but name which had four chambers and burned Goodlin made the first glide flight in erated program to reach Mach 1.1 as 1 on Aug. 29, reaching Mach 0.85.
— the X-1s were built to go faster than liquid oxygen (LOX) and a mixture the X-1-2 on Oct. 11, 1946. After a quickly as possible. NACA would pro- Over the next six weeks, Yeager
an aircraft had ever flown before. of alcohol and water. In 1945, rockets total of four glide flights, he made the vide support, such as technical advice came closer to Mach 1, reaching Mach
The X-1 resulted from technological were viewed with suspicion by some first powered flight on Dec. 9, reaching and data analysis. NACA would then 0.997 on Oct. 10. For the NACA en-
challenges facing aircraft designers in engineers. Both NACA and Navy pre- a speed of Mach 0.79. By June 1947, undertake a slower-paced, more de- gineers, used to a more cautious step-
the late 1930s and early 1940s. Aircraft ferred a jet-powered research aircraft, Bell had proven the airworthiness of tailed series of research flights at tran- by-step approach, Yeager and the Air
had begun to experience both subson- rather than one using a rocket, as the both X-1s up to speeds of Mach 0.8. sonic (near the speed of sound) speeds, Force seemed to be acting in haste.
ic and supersonic airflow over their Army Air Forces had selected. The contract freed the company from using the X-1-2 and its thicker wing. Still, on Oct. 14, Yeager reached a
wings. This created a range of undesir- The X-1-1 was delivered by Bell in responsibility above this speed. Capt. Charles E. “Chuck” Yeager speed of Mach 1.06 at 43,000 feet, be-
able characteristics: compressibility, December 1945. At the same time, the On June 30, 1947, Army Air Forces was selected as the pilot for flights to
increased drag, trim changes, severe Army Air Forces asked that NACA and NACA representatives agreed on Mach 1. coming the first man to fly supersonic.
turbulence, and loss of control effec- personnel oversee the instrumentation a two-phase flight program. The Army He made his first glide flights on Air Force officials designated the flight
tiveness. Wind tunnels were affected and data analysis of the X-1 flights. As Air Forces would use the X-1-1, with Aug. 6, 7 and 8, 1947. Yeager under- See X-1, Page 6

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