Directory of U.S. Military Rockets and Missiles|
Appendix 1: Early Missiles and Drones
|Copyright © 2003 Andreas Parsch|
The Grebe was part of the Kingfisher family of guided anti-ship/anti-submarine weapons, which was developed under the prime contract of the National Bureau of Standards (NBS). Originally projected as Kingfisher E in 1946, it was subcontracted to Goodyear, and redesignated in September 1947 as SUM-2 (SUM-N-2 from early 1948) Grebe. Grebe was the only ship-launched missile in the Kingfisher family, the others (including the AUM-N-2 Petrel (Kingfisher C), AUM-N-4 Diver (Kingfisher D) and AUM-N-6 Puffin (Kingfisher F)) all being air-launched.
|Photo: U.S. Navy|
|XSUM-N-2 (wings folded) *|
The Kingfisher E specification in 1946 called for a subsonic rocket-boosted heavy MK 35 torpedo, which was to be launched from surface ships. By 1948, the payload had been changed to a lighter MK 41 torpedo, and a long-range version with a pulsejet sustainer propulsion was also planned. The SUM-N-2 was launched in the direction of a sonar-detected target, and after a preset distance, it began its terminal dive to release its homing torpedo. Grebe was mainly intended for use against deep-diving submarines.
Twenty XSUM-N-2 prototypes were built, and flight-tested around 1950. Grebe never became operational, reportedly because none of the then existing sonars could match the missile's range. However, the date of termination of the SUM-N-2 program is unclear, because source  quotes both 1950 and 1953.
Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!
Data for XSUM-N-2 (with pulsejet, unless noted):
|Length||5.00 m (16 ft 5 in)|
|Wingspan||4.27 m (14 ft)|
|Finspan||1.52 m (5 ft)|
|Diameter||53 m (21 in)|
|Weight||1360 kg (3000 lb); rocket only: 1130 kg (2500 lb)|
|Speed||Mach 0.26; rocket only: Mach 0.5|
|Range||36500 m (40000 yds); rocket only: 4500 m (5000 yds)|
|Propulsion||Sustainer: Pulsejet; booster: solid-fueled rocket|
|Warhead||68 kg (150 lb) high-explosive in 600 kg (1330 lb) MK 41 homing torpedo|
 Norman Friedman: "US Naval Weapons", Conway Maritime Press, 1983
 Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
 Bill Gunston: "The Illustrated Encyclopedia of Rockets and Missiles", Salamander Books Ltd, 1979
Back to Directory of U.S. Military Rockets and Missiles, Appendix 1