Bell X-1

https://en.wikipedia.org/wiki/Bell_X-1

The Bell X-1 was a rocket engine–powered aircraft, designated originally as the
XS-1, and was a joint National Advisory Committee for Aeronautics–U.S. Army Air
Forces–U.S. Air Force supersonic research project built by Bell Aircraft.
Conceived during 1944 and designed and built in 1945, it achieved a speed of
nearly 1,000 miles per hour (1,600 km/h; 870 kn) in 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) in 1954. The
X-1, piloted by Chuck Yeager, was the first manned airplane to exceed the speed
of sound in level flight and was the first of the X-planes, a series of American
experimental rocket planes (and non-rocket planes) designated for testing of new
technologies and often kept secret.

The XS-1 was first discussed in December 1944. Early specifications for the
aircraft were for a piloted supersonic vehicle that could fly at 800 miles per
hour (1,300 km/h) at 35,000 feet (11,000 m) for two to five minutes. 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 aircraft's designers built a rocket plane after considering alternatives.
Turbojets could not achieve the required performance at high altitude. An
aircraft with both turbojet and rocket engines would be too large and complex.
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 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.

Swept wings were not used because too little was known about them. As the design
might lead to a fighter the XS-1 was intended to take off from the ground, but
the end of the war made the B-29 Superfortress available to carry it into the
air. After the rocket plane experienced compressibility problems during 1947, it
was modified with a variable-incidence tailplane following technology transfer
with the United Kingdom. American author Richard P. Hallion has cast doubts on
the British contribution to the X-1, countering the British view that the X-1
design benefitted from work on the M.52, and stating the X-1 was flying before
the British handed over the M.52 data following its cancellation.

Following conversion of the X-1's horizontal tail to all-moving (or
"all-flying"), test pilot Chuck Yeager verified it experimentally, and all
subsequent supersonic aircraft would either have an all-moving tailplane or be
"tailless" delta winged types.


Role
Experimental rocket plane

National origin
United States

Manufacturer
Bell Aircraft

First flight
19 January 1946

Status
Retired

Primary users
United States Air Force
National Advisory Committee for Aeronautics

Number built
4

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, with
the B-29 dropping the aircraft at 29,000 feet (8,800 m) and the XS-1 landing 12
minutes later at about 110 miles per hour (180 km/h). In March 1946 the #1
rocket plane was returned to Bell Aircraft in Buffalo, New York for
modifications to prepare for the powered flight tests. Four more glide tests
occurred at Muroc Army Air Field near Palmdale, California, which had been
flooded during the Florida tests, before the first powered test on 9 December
1946. Two chambers were ignited, but the aircraft accelerated so quickly that
one chamber was turned off until reignition at 35,000 feet (11,000 m), reaching
Mach 0.795. After the chambers were turned off the aircraft descended to 15,000
feet (4,600 m), where all four chambers were briefly tested. 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.

Specifications (Bell X-1)

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

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

Specifications (Bell X-1E)

General characteristics
Crew: one
Length: 31 ft (9.4488 m)
Wingspan: 22 ft 10 in (6.9596 m)
Height: 10 ft 10 in (3.3 m)
Wing area: 115 ft² (10.684 m²)
Empty weight: 6,850 lb (3,107.107 kg)
Loaded weight: 14,750 lb (6,690.487 kg)
Powerplant: 1 × Reaction Motors RMI LR-8-RM-5 rocket, 6,000 lbf (26.7 kN)

Performance
Maximum speed: 1,450 mph (Mach 2.24) (2,333.548 km/h)
Range: 4 minutes 45 seconds (powered endurance)
Service ceiling: 90,000+ ft (27,432+ m)




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