Bell X-1
The first piloted flight at beyond the speed of sound (Mach 1) was made on October 14, 1947, in a Bell X-1
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Updated On: 9/17/2007Print

The first piloted flight at beyond the speed of sound (Mach 1) was made on October 14, 1947, in a Bell X-1.

The Bell X-1, originally designated XS-1, was a joint NACA-U.S. Army Air Forces/US Air Force supersonic research project and the first aircraft to exceed the speed of sound in controlled, level flight. It was the first of the so-called X-planes, an American series of experimental aircraft designated for testing of new technologies and usually kept highly secret.

Design and Development

XS-1
Chuck Yeager in front of the X-1, which he named Glamorous Glennis after his wife.
XLR-11 rocket engineOn 16 March 1945 the United States Army Air Forces' Flight Test Division and the National Advisory Committee for Aeronautics (NACA) (now NASA) contracted Bell Aircraft to build three XS-1 (for "Experimental, Supersonic", later X-1) aircraft to obtain flight data on conditions in the transonic speed range. The XS-1 was the first high-speed aircraft built purely for aviation research purposes and was never intended for production.

The X-1 was in principle a "bullet with wings" that closely resembled the shape of the Browning .50-caliber machine gun bullet that was known to be stable in supersonic flight. The aircraft also featured an all-moving tailplane that allowed it to pass through the sound barrier safely. The pattern shape was followed to the point of removing a canopy. Instead, the pilot sat behind a sloped, framed window inside a confined cockpit in the nose. To modern eyes, the X-1 has a markedly stubby look, but in 1947 the diminutive airframe represented state-of-the-art in streamlining. It was only 31 feet long with a 28-foot wingspan.


History
Bell Aircraft Chief Test Pilot, Jack Woolams became the first to fly the XS-1, in a glide flight over Pinecastle Army Airfield, in Florida, on 25 January 1946. Woolams would complete nine additional glide flights over Pinecastle before March 1946, when the #1 aircraft was returned to Bell for modifications in anticipation of the powered flight tests, planned for Muroc Army Air Field (now Edwards Air Force Base) in California. Following Woolams' death on 30 August 1946, Chalmers "Slick" Goodlin was the primary Bell Aircraft test pilot of X-1-1. He made 26 successful flights in both of the X-1 aircraft from September 1946 until June 1947.

The Army Air Force was unhappy with the cautious pace of flight envelope expansion and Bell Aircraft's flight test contract for aircraft #46-062 was terminated and was taken over by the Army Air Force Flight Test Division on 24 June after months of negotiation. Goodlin had demanded a $150,000 bonus for breaking the sound barrier.Flight tests of the X-1-2 (serial number 46-063) would be conducted by NACA to provide design data for later production high-performance aircraft.

On 14 October 1947, just under a month after the United States Air Force had been created as a separate service, the tests culminated in the first manned supersonic flight, piloted by Air Force Captain Charles "Chuck" Yeager in aircraft #46-062, which he had christened ‘Glamorous Glennis’, after his wife. The rocket-powered aircraft was launched from the belly of a specially modified B-29 and glided to a landing on a runway. XS-1 flight number 50 is the first one where the X-1 recorded supersonic flight, at Mach 1.06 peak speed; however, Yeager and many other personnel record the possibility that Flight #49 (also with Yeager piloting), which reached a top recorded speed of Mach 0.997, may have in fact passed the Sound Barrier. (The measurements were not accurate to three significant figures and no sonic boom was recorded for that flight.)

As a result of the X-1's initial supersonic flight, the National Aviation Association voted its 1948 Collier Trophy to be shared by the three main participants in the program. Honored at the White House by President Truman were Larry Bell for Bell Aircraft, Captain Yeager for piloting the flights and John Stack of NACA for the NACA contributions.

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