A fleet of lifting-body research vehicles were flown at Dryden from 1963 to 1975 to validate the concept of flying a wingless craft back to Earth from space and landing it like a conventional aircraft at a pre-determined site. Aerodynamic lift - essential to flight in the atmosphere - was obtained from the shape of the vehicles rather than from wings, as on a normal aircraft. In 1962, Flight Research Center director Paul Bikle approved a program to build a lightweight, unpowered lifting body as a prototype to test the wingless concept. The M2-F1's half-cone shape looked like a "flying bathtub" and featured a plywood shell over a tubular steel frame. Initially towed aloft by a Pontiac convertible driven at speeds up to 120 mph across Rogers Dry Lake, the vehicle was later towed behind a C-47 and released for glide flights from greater altitudes. More than 400 ground tows and 77 aircraft tow flights were carried out with the M2-F1 before it was retired. A historical artifact now owned by the Smithsonian Institution National Air and Space Museum, the M2-F1 is on long-term loan to Dryden for display purposes. The success of the M2-F1 program led to development and construction of two heavyweight lifting bodies, the M2-F2 and the HL-10, that were carried to launch altitude beneath the wing of a modified B-52 and launched to complete rocket-powered flight profiles followed by a glide landing on the dry lakebed. The first flight of the M2-F2 (which looked much like the M2-F1) took place on July 12, 1966. On May 10, 1967, during the 16th flight, a landing accident severely damaged the vehicle and seriously injured NASA research pilot Bruce Peterson. It was subsequently rebuilt with modifications for improved control characteristics and re-designated M2-F3. During more than two-dozen flights, the M2-F3 reached a top speed of 1,064 mph (Mach 1.6) and a maximum altitude of 71,500 feet. It is now on display in the National Air and Space Museum in Washington, D.C. The HL-10 had a more streamlined aerodynamic shape than did the M2-series vehicles. It featured a longitudinally curved bottom and a laterally rounded top and had a delta planform. Following its maiden flight on Dec. 22, 1966, it set several program records, including the fastest speed reached by any of the lifting bodies - 1,228 mph (Mach 1.86) - and highest lifting body flight - 90,303 feet. Data from these flights contributed substantially to development of the space shuttles. The HL-10 is now on public display at the entrance to Dryden. In 1969 another shape, the bulbous X-24A, was introduced. It was flown 28 times, providing data that helped engineers to design a prototype Crew Return Vehicle some three decades later. The X-24A was later modified into a new configuration, the X-24B - nicknamed the "flying flatiron" - with a rounded top, flat bottom and a double-delta planform that ended in a pointed nose. To reduce the costs of constructing a new research vehicle, the new shape was built as a shell around the original X-24A vehicle. Significantly, it was used for two landings on the main concrete runway at Edwards Air Force Base, demonstrating that accurate unpowered re-entry vehicle landings were operationally feasible. Following its retirement in 1975, the X-24B was placed on display in the National Museum of the U.S. Air Force at Wright-Patterson Air Force Base, Ohio. Photo Description The X-24B is seen in flight over the high desert. NASA Photo
NASA Identifier: 299259main_EC75-4643_full
Glenn Research Center
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