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Modeller's Guide to

Bell X-1 Experimental Aircraft

Part Two

n by Martin Waligorski


This page is a continuation of Modeller's Guide to Bell X-1 Experimental Aircraft, Part One, which covered development background and technical description of the type.

The initial series

There were three X-1s built with the designations as follows: X-1-1 serial no. 46-062, X-1-2 serial no. 46-063, X-1-3 serial no. 46-064. The aircraft were flown by eighteen pilots from 1946 to 1951.

X-1-1

The original X-1-1 was the one named Glamorous Glennis by Captain Yeager in honour of his wife. Not only was this machine the first to fly faster than sound, it also achieved the only ground take-off, and reached the maximum speed of the entire program, Mach 1.45.

This aircraft was equipped with a wing of 10% thickness. It took its first unpowered flight at January 25, 1946 at Orlando, Florida. The first powered flight was made on April 11, 1946 at Muroc. The aircraft was retired in May 1950 after making 82 flights - glide and powered - with ten different pilots.

Cockpit instruments of the X-1-1.

Photo: NASA

X-1-2

The X-1-2 was essentially identical to X-1-1. It was flight-tested by NACA and later modified to the X-1E configuration.

The aircraft made its first powered flight December 9, 1946, with Chalmers "Slick" Goodlin at the controls. Until October 1951 it completed 74 glide and powered flights with nine different pilots before being rebuilt as X-1E.

After 1948, both  X-1s were repainted white. This is the X-1-2 parked on the ramp at NACA High-Speed Flight Research Station in 1949.

Photo: NASA

 

Another photo of the X-1-2 showing some extra measuring equipment on the nose probe and  painted-on visual aids in form of black Xs. January 1952.

Photo: NASA

X-1-3

The X-1-3 (serial 46-064) had a different fuel system with "real" turbo-driven fuel pumps instead of a previous simplified solution using nitrogen under pressure. The system caused severe delays, and the aircraft arrived in Muroc in April 1951 - three years after the planned date. The first glide flight was made July 20, 1951. Nov. 9, 1951. The aircraft was nicknamed Queenie. Sadly, it was lost a few days later in an explosion on the ground that severely burned the pilot Joseph Cannon and wrecked the mother EB-50A.

Two photographs showing the X-1-3 during its first flight carried underneath the B-50 mother aircraft. Note the prominent  cut-out for the aircraft's fin behind the bomber's bomb bay. 

Photo: NASA

X-1E

After the loss of the X-1-3 and the X-1D (see below) the decision was made to upgrade the X-1-2. The aircraft was completely rebuilt and redesignated as the X-1E.

Visible modifications included and updated canopy, new wings with only 4% thickness and knife-sharp leading edge, and a rocket assisted ejection seat.

The plane was flown 26 times until November 1956, achieving the top speed of Mach 2.24.

The mock-up of X-1E  showing the new modified canopy. The contours of the original fuselage cutout can be still visible.

Photo: NASA

The second series

After the success of the original X-1 aircraft, Bell was ordered to build a second, modified series with the capability to double the performance of the first X-1. These planes were meant to fly at speeds exceeding Mach 2. The aircraft were powered by the refined Reaction Motors XLR-11-RM-5 engine.

X-1A on the Rogers Dry Lakebed in 1955. The longer fuselage and revised cockpit are clearly visible. Note also the nose probe move underneath the tip of the nose.

Photo: NASA

X-1A in flight in the initial natural metal livery of 1953. Note the frost stain on the fuselage.

Photo: NASA

X-1A


The modified cockpit interior of second series aircraft (this one belongs to the X-1B).

Photo: NASA

The X-1A was first flown in on February 21, 1953. The differences from the initial X-1 included longer fuselage with increased fuel capacity, taller fin, turbo-driven fuel pumps and a clear-view cockpit canopy . The new fuselage length was 35 feet 8 inches. 

The aircraft was involved in stability tests at supersonic speeds. It made a total of 15 glide and powered flights when it was destroyed following an in-flight explosion, the pilot having ejected.

X-1B

The X-1B proved the most successful of the second batch, surviving almost the entire duration of the program. It was flown 27 times starting from October 1954 and achieved a maximum speed of Mach 2.44. In 1958, cracks in the fuel tanks of the X-1B forced its grounding. 

Externally, the aircraft was almost identical to the X-1A except for having a slightly different wing. For the last three flights it also carried wingtip extensions.

The aircraft was fitted with special instrumentation for exploratory aerodynamic heating tests. It had over 300 thermal probes installed on its surface. The X-1B was also the first aircraft to fly with a system of small reaction rockets used for directional control, later used in the X-15 

Two photos showing the X-1B on Rogers Dry Lakebed.

Photo: NASA

X-1C

The X-1C was intended to be the only armed X-1 - a test bed for weapons able to operate at supersonic speeds. It was never completed, the development being cancelled while still in the mock-up stage.

X-1D

The X-1D was to be used for further testing of heat problems in high speed flight. It was delivered, but was lost in fuel explosion during preparations for the first powered flight.

Altogether, accomplishments with the second series of aircraft were limited, mostly due to the high accident rate.

X-1-2 on the ramp with the B-29 mother ship in 1949.

Photo: NASA

A roll-out of the Boeing B-29A mother ship with the X-1-2 mated and ready for flight. September 1949. The nose art of the B-29 depicts a stork carrying a bundle which is symbolic of the mother ship launching her "baby".

Photo: NASA

Air launch aircraft

Though originally designed for conventional ground takeoffs, all X-1 aircraft were air-launched from a B-29 or B-50 due to the limited fuel supply and the hazard of fuel explosion during ground handling. The ground take-off was attempted only once. Having lit all four chambers, the X-1 accelerated so fast that the wing flaps blew off before the pilot was able to retract the undercarriage.

The B-29 (later B-50) was adapted as mother aircraft. The X-1 was carried aloft in its bomb bay with no pilot onboard. A modified heavy bomb shackle was used as a releasing device. At the altitude of 8000 feet, the pilot would go down the small ladder, crawl into the X-1, seal the door, plug himself into all systems (electrical, oxygen, radio) and report being ready. After that the B-29 would climb further 25000 feet before releasing the aircraft.

The X-1 is mated with the Boeing B-29. The hooks and straps used at the beginning to hold the X-1 in place in the bomb bay can be seen just above the hand of the man with the hose.

Photo: NASA

Each of the X-1s had its own carrier aircraft: B-29A serial no. 45-21800 was the mother ship of X-1-1 and X-1-2. This modified Superfortress was also designated JTB-29A. The X-1-3 was carried by EB-50A serial no. 46-006.

Wouldn't this photo make for a great diorama subject? The X-1-3 Queenie is mated to the EB-50A no. 46-006 at Muroc in November 1951. The operation was complex involving lifting the entire bomber as shown This particular X-1 only flew twice before exploding and destroying both itself and the mother aircraft.

Photo: NASA

Conclusion

The most historic of all X-1 flights took place on October 14, 1947 at Muroc Air Force Base in Southern California (now known as Edwards AFB). After dropping away from the mother ship, Chuck Yeager lit off all the engine chambers and climbed on to 35000 feet. Then he turned off two of the chambers but continued climbing out to 42000 feet. Levelling the airplane he lit the 3rd chamber. 

At Mach 0.96, there was a degree of buffeting and shaking, like on the previous flights. And then, when he went a little faster the Mach meter went violently off the scale. Then suddenly all the buffeting smoothed out, and the pilot realised that he had gotten above the speed of sound. Yeager let it accelerate on to about Mach 1.07, and the airplane flew quite well, even regaining some elevator control. 

Having landed, Chuck Yeager called the whole experience a "piece of cake". A the time when the news reached the general public some seven months later, he and his colleagues would routinely break the sound barrier and fly as fast as Mach 1.45.

The greatest achievement of the X-1 program was for the first time demonstrating what we take for granted today: that with appropriate design technology it was possible for an aircraft to pass through the speed of sound - and not merely survive but be fully functional and controllable while doing so.

Glamorous Glennis resides today in the honourable spot underneath the roof of the National Air and Space Museum in Washington, DC.

The X-1 initiated an entire series of "X" aircraft. 
Aircraft are (left to right): D-558-2, D-558-1, X-5, X-1, XF-92A, and X-4.

Photo: NASA

Back to Modeller's Guide to Bell X-1 Experimental Aircraft, Part One

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