Directory of U.S. Military Rockets and Missiles|
Appendix 1: Early Missiles and Drones
|Copyright © 2003-2005 Andreas Parsch|
Among the various guided missile studies initiated by the U.S. Army Air Force in 1945 was Consolidated-Vultee's project MX-774, which was about supersonic surface-to-surface missiles. After the development contracts for cruise-type winged missiles went to Martin (MX-771, SSM-A-1/TM-61 Matador) and Northrop (MX-775, SSM-A-3/SM-62 Snark), Convair was awarded a contract to develop and test a ballistic research missile under project MX-774. The effort was named Hiroc (High-Altitude Rocket) and the vehicle received the designation RTV-A-2 in 1947. However, the program was formally cancelled in June 1947, but Convair was allowed to complete and fly three test vehicles using available funds.
|Photo: Robert Bradley Collection|
The RTV-A-2 was powered by a Reaction Motors XLR35-RM-1 four-chamber liquid-fueled rocket motor, and had a cylindrical body with four fixed stabilizing fins. The Hiroc pioneered several new design techniques which would later be used in the SM-65/HGM-16 Atlas. It featured a gimballed rocket nozzle to steer the vehicle by thrust-vectoring instead of weight- and drag-increasing control fins, and had a separable nose cone for the payload. The rocket had no structurally separate fuel tanks, using instead the airframe itself as tank walls. The light weight, pressure stabilized tank structure as later used on the Atlas was considered, but not implemented. The RTV-A-2 used telemetry to transmit flight data to the ground, and the nose cone was designed to be recoverable by parachute.
The first RTV-A-2 flew in July 1948, followed by the other two rockets in September and December that year. All three flights were only partially successful (mainly because of engine failures), but helped a lot to validate the new design concepts.
Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!
Data for RTV-A-2:
|Length||9.63 m (31 ft 7 in)|
|Finspan||2.08 m (6 ft 10 in)|
|Diameter||76 cm (30 in)|
|Weight||1860 kg (4100 lb)|
|Speed||3200 km/h (2000 mph)|
|Ceiling||> 65 km (40 miles)|
|Propulsion||Reaction Motors XLR35-RM-1 liquid-fueled rocket; 35.5 kN (8000 lb)|
 Jay Miller: "The X-Planes X-1 to X-45", Midland Publishing, 2001
 Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
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