USA: Experimental Aircraft: Bell X-1, X-1A, X-1B, X-1C, X-1D, and X-1E


(NACA Photo)

Bell X-1 being released from Boeing B-29 Superfortress.

The X-planes are a series of experimental United States aircraft and rockets, used to test and evaluate new technologies and aerodynamic concepts. They have an X designator within the US system of aircraft designations, which denotes the experimental research mission.Not all US experimental aircraft have been designated as X-planes; some received US Navy designations before 1962, while others have been known only by manufacturers' designations, non-'X'-series designations, or classified codenames.

The X-planes concept officially came into being in 1944, as a joint programme between the National Advisory Committee for Aeronautics (NACA), the US Navy (USN) and the US Army Air Force (USAAF), in order to pursue research into high-speed aircraft.[2] NACA later became the National Aeronautics and Space Administration (NASA) and the USAAF became the United States Air Force (USAF). Other organizations such as the Defence Advanced Research Projects Agency (DARPA) and the US Marine Corps (USMC) have also since sponsored X-plane projects.

The first experimental aircraft specification, for a transonic rocket plane, was placed in 1945, and the first operational flight of an X-plane took place when the Bell X-1 made its first powered flight nearly three years later at Muroc Air Force Base, California, now known as Edwards Air Force Base. The majority of X-plane testing has since taken place there.X-planes have since accomplished many aviation "firsts" including breaking speed and altitude barriers, varying wing sweep in flight, implementing exotic alloys and propulsion innovations, and many more.

New X-planes appeared fairly regularly for many years until the flow temporarily stopped in the early 1970s. A series of experimental hypersonic projects, including an advanced version of the Martin Marietta X-24 lifting body, were turned down. Eventually issues with the Rockwell HiMAT advanced UAV led to a crewed X-plane with forward sweep, the Grumman X-29, which flew in 1984.

Some of the X-planes have been well publicized, while others, such as the X-16, have been developed in secrecy. The first, the Bell X-1, became well known in 1947 after it became the first aircraft to break the sound barrier in level flight. Later X-planes supported important research in a multitude of aerodynamic and technical fields, but only the North American X-15 rocket plane of the early 1960s achieved comparable fame to that of the X-1.  X-planes 8, 9, 11, 12, and 17 were actually missiles used to test new types of engines, and some other vehicles were unoccupied or UAVs (some were remotely flown, some were partially or fully autonomous). (Wikipedia)

Bell X-1

(NACA Photo)

Bell X-1 aircraft (Serial No. 46-062)

The Bell X-1 (Bell Model 44) is 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.

(Ad Meskens Photo)

Bell X-1-1, Air Force( Serial Number 46-062) Glamorous Glennis, is currently displayed in the Boeing Aviation Hangar of the Steven F. Udvar-Hazy Center in Dulles, where it was moved during renovations to the National Air and Space Museum. The aircraft was flown to Washington, D.C., beneath a B-29 and presented to what was then the American National Air Museum in 1950.

(USAF Photo)

The Bell X-1 aircraft (Serial No. 46-062), nicknamed Glamorous Glennis and flown by Chuck Yeager, was the first piloted 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) designed for testing new technologies. On 5 January 1949, Yeager used Aircraft (Serial No. 46-062) to perform the only conventional (runway) launch of the X-1 program, attaining 23,000 ft (7,000 m) in 90 seconds.

The first manned supersonic flight occurred on 14 October 1947, over the Mojave Desert in California, less than a month after the U.S. Air Force had been created as a separate service. Captain Charles "Chuck" Yeager piloted USAF aircraft (Serial No. 46-062), nicknamed Glamorous Glennis for his wife. The airplane was drop launched from the bomb bay of a B-29 and reached Mach 1.06 (700 miles per hour (1,100 km/h; 610 kn)).[1] Following burnout of the engine, the plane glided to a landing on the dry lake bed.[19]: 129–130  This was XS-1 flight number 50.Duration: 3 minutes and 5 seconds.3:05Subtitles available.CCYeager exceeded Mach 1 on 14 October 1947 in the X-1.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.  (Wikipedia)

Later variants of the X-1 were built to test different aspects of supersonic flight; one of these, the X-1A, with Yeager at the controls, inadvertently demonstrated a very dangerous characteristic of fast (Mach 2 plus) supersonic flight: inertia coupling. Only Yeager's skills as an aviator prevented disaster; later Mel Apt would lose his life testing the Bell X-2 under similar circumstances.

(NACA Photo)

U.S. Air Force. XS-1s Number 1 and 2 in the loading pit. Each plane was lowered into a pit so the B-29 mothership in the background could be rolled into position above it, then the XS-1 would be raised and fastened to the B-29’s bomb bay for flight. Later renamed them X-1s.

(Niagara Aerospace Museum)

Jack Woolams with the second Bell XS-1 (Serial No. 46-063).

(NACA Photo)

Bell X-1-2 (Serial No. 46-063), on the Rogers Dry Lakebed at Muroc Air Force Base, California in 1949.

(NACA Photo)

Bell X-1-2 (Serial No. 46-063), with X markings for measurement records.

(NACA Photo)

Bell X-1-2 (Serial No. 46-063). 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.

Bell X-1A (Bell Model 58A)

(NACA Photo)

Bell X-1A resting in the belly of a Boeing B-29 Superfortress.

(NACA Photo)

Ordered by the Air Force on 2 April 1948, the Bell X-1A (Serial Number 48-1384) was intended to investigate aerodynamic phenomena at speeds greater than Mach 2 (681 m/s, 2,451 km/h) and altitudes greater than 90,000 ft (27 km), specifically emphasizing dynamic stability and air loads. Longer and heavier than the original X-1, with a stepped canopy for better vision, the X-1A was powered by the same Reaction Motors XLR-11 rocket engine. The aircraft first flew, unpowered, on 14 February 1953 at Edwards AFB, with the first powered flight on 21 February. Both flights were piloted by Bell test pilot Jean "Skip" Ziegler.After NACA started its high-speed testing with the Douglas Skyrocket, culminating in Scott Crossfield achieving Mach 2.005 on 20 November 1953, the Air Force started a series of tests with the X-1A, which the test pilot of the series, Chuck Yeager, named "Operation NACA Weep". These culminated on 12 December 1953, when Yeager achieved an altitude of 74,700 feet (22,800 m) and a new airspeed record of Mach 2.44 (equal to 1620 mph, 724.5 m/s, 2608 km/h at that altitude). Unlike Crossfield in the Skyrocket, Yeager achieved that in level flight. Soon afterwards, the aircraft spun out of control, due to the then not yet understood phenomenon of inertia coupling. The X-1A dropped from maximum altitude to 25,000 feet (7,600 m), exposing the pilot to accelerations of as much as 8g, during which Yeager broke the canopy with his helmet before regaining control.

(NACA Photo)

Bell X-1A.

On 28 May 1954, Maj. Arthur W. Murray piloted the X-1A to a new record of 90,440 feet (27,570 m).The aircraft was transferred to NACA during September 1954, and subsequently modified. The X-1A was lost on 8 August 1955, when, while being prepared for launch from the RB-50 mothership, an explosion ruptured the plane's liquid oxygen tank. With the help of crewmembers on the RB-50, test pilot Joseph A. Walker successfully extricated himself from the plane, which was then jettisoned. Exploding on impact with the desert floor, the X-1A became the first of many early X-planes that would be lost to explosions.

(NACA Photo)

Bell X-1A.

Bell X-1B

(NASA Photo)

NACA 800, a modified Boeing B-29 Superfortress (Serial No. 45-21800), with the Bell X-1B, at Edwards Air Force Base, 8 April 1958.

(NACA Photo)

The Bell Aircraft Corporation X-1B rocket-powered research aircraft, one of the growth versions of the original X-1 series, is shown in this 1957 photo on the bed of Rogers Dry Lake adjacent to the NACA High-Speed Flight Station. The X-1B offered an ideal testbed for a test reaction control installation. In November 1957, NACA technicians finished installing reaction controls on the X-1B. NACA test pilot Neil A. Armstrong made three flights in the airplane to experience the reaction controls performance. Since cracks in the fuel tanks of the X-1B forced its grounding in 1958, reaction control research shifted to the Lockheed F-104 Starfighter.

(Jaydec Photo)

The Bell X-1B was one of a series of rocket-powered experimental airplanes designed to investigate supersonic flight problems. The X-1B’s flight research primarily related to aerodynamic heating and the use of small “reaction” rockets for directional control.

The X-1B made its first powered flight in October 1954. A few months later, the U.S. Air Force transferred the X-1B to the NACA (National Advisory Committee for Aeronautics), predecessor to NASA (National Aeronautics and Space Administration), which conducted the heating and control tests. The X-1B tests played an important role in developing the control systems for the later X-15.

On test missions, the X-1B was carried under a "mother" airplane and released between 25,000-35,000 feet. After release, the rocket engine fired under full throttle for less than five minutes. After all fuel (an alcohol-water mixture) and liquid oxygen had been consumed, the pilot glided the airplane to earth for a landing. The X-1B made its last flight in January 1958, and it was transferred to the museum a year later. (NMUSAF)

(Clemens Vasters Photo)

X-1B, (Serial No. 48-1385), is on display in the Research & Development Hangar at the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio.

(USAF Photos)

(Don Popp, USAF Photos)

(NMUSAF Photos)

Bell X-1B.

Bell X-1C (Bell Model 58C)

(Wiki Fandom Photo)

Illustration of the Bell X-1C.

The Bell X-1C (Serial No. 48-1387) was intended to test armaments and munitions in the high transonic and supersonic flight regimes. It was canceled while still in the mockup stage, as the development of transonic and supersonic-capable aircraft like the North American F-86 Sabre and the North American F-100 Super Sabre eliminated the need for a dedicated experimental test vehicle.

Although similar in general construction to the other X-1 airframes, the X-1C differed by being fitted with large vertical yaw damping surfaces to the upper and lower skins of each wing, combined with a retractable ventral fin under the rear fuselage. In addition, the nose compartment was designed to accommodate many different types of armament fit, as opposed to the test instrumentation used on the other X-1s.

(NACA Photo)

Bell X-1D( Bell Model 58D)

The Bell X-1D (Serial No. 48-1386) was the first of the second generation of supersonic rocket planes. Flown from an EB-50A (s/n #46-006), it was to be used for heat transfer research. The X-1D was equipped with a new low-pressure fuel system and a slightly increased fuel capacity. There were also some minor changes of the avionics suite.On 24 July 1951, with Bell test pilot Jean "Skip" Ziegler at the controls, the X-1D was launched over Rogers Dry Lake, on what was to become the only successful flight of its career. The unpowered glide was completed after a nine-minute descent, but upon landing, the nose landing gear failed and the aircraft slid ungracefully to a stop. Repairs took several weeks to complete and a second flight was scheduled for mid-August. On 22 August 1951, the X-1D was lost in a fuel explosion during preparations for the first powered flight. The aircraft was destroyed upon impact after it was jettisoned from its EB-50A mothership.

Bell X-1E

(NACA Photo)

Bell X-1-3, aircraft (Serial No. 46-064), being mated to the B-50 mothership for a captive flight test on 9 November 1951. While being de-fueled after this flight it exploded, destroying itself and the B-50, and seriously burning Joe Cannon. X-1-3 had completed only a single glide-flight on 20 July.[

The X-1E was the result of a reconstruction of the X-1-2 (Serial No. 46-063), in order to pursue the goals originally set for the X-1D and X-1-3 (Serial No. 46-064), both lost by explosions during 1951. The cause of the mysterious explosions was finally traced to the use of Ulmer leather[35] gaskets impregnated with tricresyl phosphate (TCP), a leather treatment, which was used in the liquid oxygen plumbing. TCP becomes unstable and explosive in the presence of pure oxygen and mechanical shock This mistake cost two lives, caused injuries and lost several aircraft.

(NACA Photo)

The X-1E, christened Little Joe, with pilot Joe Walker.

(NACA Photo)

Bell X-1E.

The changes included:A turbopump fuel feed system, which eliminated the high-pressure nitrogen fuel system used in '062 and '063. Concerns about metal fatigue in the nitrogen fuel system resulted in the grounding of the X-1-2 after its 54th flight in its original configuration.[38]A re-profiled super-thin wing (3⅜ inches at the root), based on the X-3 Stiletto wing profile, enabling the X-1E to exceed Mach 2.[39]A 'knife-edge' windscreen replaced the original greenhouse glazing, an upward-opening canopy replaced the fuselage side hatch and allowed the inclusion of an ejection seat.The addition of 200 pressure ports for aerodynamic data, and 343 strain gauges to measure structural loads and aerodynamic heating along the wing and fuselage.[38]The X-1E first flew on 15 December 1955, a glide-flight controlled by USAF test pilot Joe Walker. Walker left the X-1E program during 1958, after 21 flights, attaining a maximum speed of Mach 2.21 (752 m/s, 2,704 km/h). NACA research pilot John B. McKay took his place during September 1958, completing five flights in pursuit of Mach 3 (1,021 m/s, 3,675 km/h) before the X-1E was permanently grounded after its 26th flight, during November 1958, due to the discovery of structural cracks in the fuel tank wall. (Wikipedia)

(NACA Photo)

The X-1 series aircraft were air-launched from a modified Boeing B-29 or a B-50 Superfortress bombers. Bell X-1E is mated to its mothership which is lifted on hydraulic jacks to afford access to the specially configured bay underneath.

(Mike Freer - Touchdown-aviation Photo)

Bell X-1E, (Serial No. 46-063), is on display in front of the NASA Armstrong Flight Research Center headquarters building at Edwards Air Force Base, California. It is usually seen in episodes of the TV series I Dream of Jeannie, which was set at Cape Kennedy, Florida.

If you found this valuable, consider supporting the author.