The Flying Stove Pipe
The Lockheed X-7 (dubbed the “Flying Stove Pipe” was an American unmanned test bed of the 1950s for ramjet engines and missile guidance technology. The first test flight took place on April 26, 1951.
The X-7 was carried aloft by a B-29 or B-50 Superfortress carrier aircraft. A booster ignited after launch and propelled the vehicle to a speed of 1,000 mph (1,625 km/h). The booster was then jettisoned, and the underslung ramjet took over from that point. The X-7 eventually returned to Earth, its descent slowed by parachute. A maximum speed of 2,881 miles per hour (4,637 km/h), or Mach 4.31, was attained, setting a record for fastest air-breathing aircraft at the time. A total of 130 X-7 flights were conducted from April 1951 to July 1960.
This Youtube clip below shows footage from the first X-7 test flight which took place in 1951.