Forty years ago today — March 19, 1970 — USAF test pilot Major Jerauld R. Gentry made the first powered flight in the X-24A lifting body.
(X-24A with rocket engine ignited after being dropped from the B-52 carrier aircraft. NASA image.)
The same B-52 used in the X-15 program (and later in the Pegasus program*) carried the X-24A to about 40,000 ft (13,860 m) altitude, where it was dropped and its rocket engine took the rest of the way through its flight profile. It then glided to a landing on the dry lakebed at Edwards AFB.
Over the life of the program, the X-24A made 28 powered flights, reaching a maximum speed of 1,036 mph (1,667 km/hr) and a maximum altitude of 71,407 ft (21,765 m). According to the project description on this page, NASA later used the X-24A’s shape as the basic profile for the X-38 Crew Return Vehicle demonstrator.
___
*Full disclosure: When I was stationed at Edwards (1986-90), I was on the Flight Readiness Review committee for the first Pegasus launch from that same B-52.
by 
