Bell X-1

The Bell X-1, designated originally as XS-1, was a joint National Advisory Committee for Aeronautics-U.S. Army Air Forces-U.S. Air Force supersonic research project built by the Bell Aircraft Company. Conceived during 1944 and designed and built during 1945, it achieved a speed of nearly 1,000 miles per hour (1,600 km/h; 870 kn) during 1948. A derivative of this same design, the Bell X-1A, having greater fuel capacity and hence longer rocket burning time, exceeded 1,600 miles per hour (2,600 km/h; 1,400 kn) during 1954. The X-1 was the first manned airplane to exceed the speed of sound in level flight and was the first of the so-called X-planes, a series of American experimental rocket planes designated for testing of new technologies and often kept secret.

Bell X-1
Class Aircraft
Type Utility
Manufacturer Bell Aircraft
Origin United States of America
Country Name Origin Year
United States of America 1946
Country Name Operational Year Retirement Year
United States of America View
ManufacturerName Production From Production To Quantity
Bell Aircraft View

On 16 March 1945, the U.S. Army Air Forces Flight Test Division and the National Advisory Committee for Aeronautics (NACA) contracted with the Bell Aircraft Company to build three XS-1 (for "Experimental, Supersonic", later X-1) aircraft to obtain flight data on conditions in the transonic speed range.

The X-1 was in principle a "bullet with wings", its shape closely resembling a Browning .50-caliber (12.7 mm) machine gun bullet, known to be stable in supersonic flight. The pattern shape was followed to the extent of seating its pilot behind a sloped, framed window inside a confined cockpit in the nose, with no ejection seat. After the rocket plane experienced compressibility problems during 1947, it was modified with a variable-incidence tailplane(based on the Miles M.52 project data) .

The rocket propulsion system was a four-chamber engine built by Reaction Motors, Inc., one of the first companies to build liquid-propellant rocket engines in the U.S.. This rocket burned ethyl alcohol diluted with water with a liquid oxygen oxidizer. Its thrust could be changed in 1,500 lbf (6,700 N) increments by using just one or more than one of its chambers. The fuel and oxygen tanks for the first two X-1 engines were pressurized with nitrogen gas, but the rest used steam-driven turbopumps. The all-important fuel turbopumps were necessary to increase the chamber pressure and thrust while making the engine lighter.

Variants

  • X-1A
  • X-1B
  • X-1C
  • X-1D
  • X-1E

Bell Aircraft chief test pilot Jack Woolams became the first person to fly the XS-1. He made a glide-flight over Pinecastle Army Airfield, in Florida, on 25 January 1946. Woolams completed nine more glide-flights over Pinecastle before March 1946, when the #1 rocket plane was returned to Bell Aircraft in Buffalo, NY, for modifications to prepare for the powered flight tests. These were performed at Muroc Army Air Field in Palmdale, California. After Woolams' death on 30 August 1946, Chalmers "Slick" Goodlin was the primary Bell Aircraft test pilot for the X-1-1 (serial 46-062). He made 26 successful flights in both X-1s from September 1946 through June 1947.

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

Mach 1 flight

The first manned supersonic flight occurred on October 14, 1947, less than a month after the U.S. Air Force had been created as a separate service. Air Force Captain Charles "Chuck" Yeager piloted aircraft #46-062 that he had nicknamed Glamorous Glennis for his wife. The airplane was drop launched from the bomb bay of a modified B-29 Superfortress bomber and reached Mach 1.06 (700 miles per hour (1,100 km/h; 610 kn)). Following burnout of the engine, the plane glided to a landing on the dry lake bed. This was XS-1 flight number 50.

The three main participants in the X-1 program won the National Aeronautics Association Collier Trophy in 1948 for their efforts. Honored at the White House by President Truman were Larry Bell for Bell Aircraft, Captain Yeager for piloting the flights, and John Stack for the contributions of the NACA.

The story of Yeager’s October 14 flight was leaked to a reporter from the magazine Aviation Week, and The Los Angeles Times featured the story as headline news in their 22 December issue. The magazine story was released on 20 December. The Air Force threatened legal action against the journalists who revealed the story, but none ever occurred.

On January 5, 1949, Yeager used Aircraft #46-062 to perform the only conventional (runway) launch of the X-1 program, attaining 23,000 ft (7,000 m) in 90 seconds.

Legacy

The research techniques used for the X-1 program became the pattern for all subsequent X-craft projects. The X-1 project assisted the postwar cooperative union between U.S. military needs, industrial capabilities, and research facilities. The flight data collected by the NACA from the X-1 tests then proved invaluable to further US fighter design throughout the latter half of the 20th century.

Role Experimental rocket plane
Manufacturer Bell Aircraft Company
First flight 19 January 1946
Status Retired
Primary users U.S. Air Force
National Advisory Committee for Aeronautics


General characteristics

  • Crew: one
  • Length: 30 ft 11 in (9.4 m)
  • Wingspan: 28 ft (8.5 m)
  • Height: 10 ft (3.3 m)
  • Wing area: 130 ft² (12 m²)
  • Empty weight: 7,000 lb (3,175 kg)
  • Loaded weight: 12,225 lb (5,545 kg)
  • Max. takeoff weight: 12,250 lb (5,557 kg)
  • Powerplant: one × Reaction Motors XLR-11-RM3 liquid-propellant rocket, 6,000 lbf (1,500 lbf per chamber) (26.7 kN) each
  • Color : International Orange (same color as the Golden Gate Bridge)

Performance

  • Maximum speed: 957 mph (Mach 1.26) (1,541 km/h)
  • Range: five minutes (powered endurance)
  • Service ceiling: 71,902 ft (21,916 m)
  • Wing loading: 94 lb/ft² (463 kg/m²)
  • Thrust/weight: 0.49

End notes