XM-21 Firebee
| Type: | Prototype target drone |
| Guidance: | Radio remote control |
| Propellant: | Liquid-fueled turbojet |
| Altitude: | 40,000 feet (12.1km) |
| Speed: | Mach 0.8 (236m/s) |
| Length: | 209 inches (5.3m) |
| Wingspan: | 136 inches (3.5m) |
| Weight: | 2,285 pounds (1,036kg) |
| First Launch at White Sands: | 5 August 1959 |
The XM-21, developed by the Ryan Aeronautical Company, was the Army’s developmental variant of the Navy’s KDA-1 Firebee, which itself was a variant of the Air Force’s XQ-2 Firebee. The first batch of thirty-five XM-21s was awarded in December 1952. Delivery of the first drone was made in December 1953 and the last was in December 1955. Four of the thirty-five drones were lost during air-launch flight tests at Holloman Air Force Base in the next few months. The remaining thirty-one drones were transferred back to White Sands Missile Range for ground- launch tests, the first of which, an unguided dummy drone, occurred on 5 August 1959.
At launch, the XM-21 was sent up a slanted 81-foot (24.7m) rail by an Aerojet X-102F rocket booster, which would fall away from the drone after being expended. For its sustaining and cruising phase of flight, the XM-21 was powered by a liquid-fuel Fairchild J44 turbojet that was able to propel the drone from a minimum speed of 140 knots (72m/s) to near-sonic maximum speeds of 500 knots (250m/s). The Army’s Firebee was also developed with the ability to pick up a seven-foot long, one-foot diameter target from the ground that would trail behind the drone on a 1,800-foot (550m) line. Called the “Towbee,” this inexpensive radar target could mimic enemy targets as large as bomber aircraft, offering a cheap and expendable alternative to shooting down propelled drones. For recovery, the XM-21 used a two-stage parachute system that would minimize the impact of landing, allowing the drone to be used again.
The three services’ Firebees, which had their post-1963 designations changed to the AQM/BQM/MQM-34, were used worldwide, with testing bases located in the Arctic, the Japanese island of Okinawa, Cold Lake in Alberta, Canada, and White Sands Missile Range. Improved Firebee models are still in use as target drones by the US Department of Defense.
