Directory of U.S. Military Rockets and Missiles|
Appendix 4: Undesignated Vehicles
|Copyright © 2004 Andreas Parsch|
The SD-4 Swallow supersonic reconnaissance drone was built in 1960 under a U.S. Army contract. The SD-4, which was to be part of the AN/USD-4 surveillance drone system, was a delta-wing design powered by a single Pratt & Whitney JT12A-3 turbojet. The Swallow was zero-length launched with the help of two solid-fueled rocket boosters, and could be recovered by parachute. Similar to Republic's earlier SD-3 Snooper drone, it had interchangeable nose sections for photographic, radar or infrared surveillance equipment.
The AN/USD-4 program was cancelled by the U.S. Army in January 1961, and it is not clear whether any SD-4 vehicles were actually test-flown.
Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!
Data for SD-4:
|Length||9.27 m (30 ft 5 in)|
|Wingspan||3.51 m (11 ft 6 in)|
|Weight||1590 kg (3500 lb)|
|Ceiling||18300 m (60000 ft)|
|Range||480 km (300 miles)|
|Propulsion||Pratt & Whitney JT12A-3 turbojet; 12.9 kN (2900 lb)|
 Joshua Stoff: "The Thunder Factory", Motorbooks Intl., 1990
 Norman J. Bowman: "The Handbook of Rockets and Guided Missiles", Perastadion Press, 1963
 Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
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