- Northrop HL-10, Peter C. Hoag
- 1976 kilometre(s) per hour
- Vereinigte Staaten (Edwards Air Force Base)
The fastest lifting-body aircraft is the Northrop HL-10, which reached a speed of Mach 1.86 (1,976 km/h; 1,228 mph) on 18 February 1970. The wingless aircraft was flown by NASA test pilot Pete Hoag (USA) as part of a study into potential designs for future spacecraft.
Lifting Body aircraft are designed with no wings and a fuselage that is curved to act as a lift-producing airfoil. This design does not produce enough lift to handle a conventional take-off, but it does have the advantage of producing very little drag. These features make lifting bodies well suited for aerodynamic spacecraft re-entry, as they can handle hypersonic flight and re-entry forces, but can also generate enough lift to perform gliding runway landings.
NASA invested heavily in lifting-body research in the late 1960s and early 1970s, during the same period that they were developing the Space Shuttle. A series of peculiar-looking aircraft (the first was nicknamed the "flying bathtub") were flown from a B-52 mothership, climbing to high altitudes using rocket motors in order to simulate the profile of a re-entering spacecraft.
The HL-10 was one of the most successful of the lifting body designs NASA tested, and was used for 37 flights in total. It was powered by the same XLR-11 rocket engine that was used in the Bell X-1 (the first supersonic aircraft). The design came from NASA's in-house team, but it was built by external contractor Northrop.
The lifting body concept was not used for the final design of the Space Shuttle, largely because the decision to include the system's main engines on the shuttle itself meant that it would have to have large cylindrical fuel tanks that couldn't be easily fitted into the tapering fuselage of a lifting body. Nonetheless, data gathered from the lifting-body program was vital to the development of the shuttle.
Today several agencies and companies are actively working on lifting-body re-entry vehicles. The Sierra Nevada Dream Chaser is probably the most far along in terms of development, having been accepted for NASA's commercial resupply program for the ISS.