X-24A lifting body
The genesis of Martin’s X-24 lifting body program came from an early 1960s USAF need for a film-return vehicle for reconnaissance satellites that could make maneuvering reentries, thus making the job of recovery forces easier. This evolved into Martin’s SV-5 lifting body shape, which was first flown as the subscale SV-5D/X-23A PRIME test articles, lofted on suborbital trajectories by Atlas missiles.
The small vehicles were followed up by the larger, manned X-24A, delivered in August 1967. However, it would not be until April 1969 that the new lifting body would make its first glide flight, with powered flights following in March 1970, using an ancient XLR-11 rocket engine. A maximum speed of Mach 1.6 was achieved.
The last manned lifting body (at least so far) the X-24B was the result of the USAF Flight Dynamics Laboratory’s work into hypersonic lifting bodies with high lift to drag ratios – the resulting “flying flatiron” shape was formed the basis for many proposed hypersonic vehicle designs over the years.
In order to conduct flight testing of the FDL-8 shape without creating a whole new aircraft, the USAF contracted with Martin in 1971 to rebuild the X-24A with a new external shell contoured to the FDL shape. As rebuilt, the X-24B made its first glide flight in August 1973, and after several attempts, flights using the XLR-11 began in November of that year. By the time that the program ended two years later, the X-24B had been flown to Mach 1.7, and had demonstrated the capability of landing on the concrete main runway at Edwards.
B.K. Thomas, Jr. “USAF Nears Manned Lifting Body Tests” Aviation Week & Space Technology July 10, 1967 p.99-101 2 photos
“X-24A Lifting Body Delivered to USAF” Aviation Week & Space Technology July 24, 1967 p.46 3 photos
Photo: “USAF/Martin X-24A launched from B-52” Aviation Week & Space Technology August 31, 1970 front cover
“X-24 Flies Supersonically” Aviation Week & Space Technology October 19, 1970 p.20
Michael L. Yaffee “X-24B LIfting Body Nearing Completion” Aviation Week & Space Technology September 4, 1972 p.77-79 1 photo
“X-24B in Unpowered Flight at Edwards” Aviation Week & Space Technology October 8, 1973 p.43 3 photos
“Hypersonic Research Project Urged” Aviation Week & Space Technology July 14, 1975 p.47 1 illustration
Jon Lopez “Scratchbuilding a Martin Marietta X-24B Lifting Body in 1/72 scale” FineScale Modeler January 1989 p.34-37, includes 1/72 scale plans.