Fairchild AUM-N-2/AQM-41 Petrel

The Petrel was an early standoff anti-shipping missile, which was used by the U.S. Navy with moderate success for a brief period in the 1950s, before it was converted to a target drone.

The history of Petrel dates back to August 1944, when the U.S. Navy BuOrd (Bureau of Ordnance) initiated the Kingfisher project to develop a family of standoff torpedo weapons. This included the Kingfisher C, designated as SWOD (Special Weapons Ordnance Device) MK 15, which was to be an air-lauched jet-powered torpedo-carrying missile. In late 1947, Kingfisher C was designated as AUM-2 (changed to AUM-N-2 in early 1948) and renamed Petrel. After a long development period, in which several completely different configurations were studied, tests of the XAUM-N-2 by the Naval Bureau of Standards began in 1951. In 1954, development was transferred to Fairchild, and in April 1956 the AUM-N-2 finally became operational.


Photo: The Cradle of Aviation Museum		Photo: U.S. Navy
AUM-N-2

Petrel was essentially a MK 21 homing torpedo, fitted with a nose cone containing the guidance equipment, a Fairchild J44 turbojet, and wooden wings and fins. Despite its AUM (Air-to-Underwater Missile) designation, it was suitable for use against surface ships (and surfaced submarines) only. It was carried by Lockheed P2V-6B Neptune aircraft (later redesignated as P2V-6M, and then MP-2F). After launch, it dove to an altitude of about 60 m (200 ft), and continued to the target at a speed of Mach 0.5, using semi-active radar guidance. When it had closed to a distance of about 1400 m (4500 ft), the engine was stopped, all flying surfaces and the engine were discarded, and the torpedo dropped into the water, where it homed on the target.

Photo: © Brian Lockett, Goleta Air & Space Museum

AUM-N-2

In the late 1950s, enemy surface ships were considered a relatively minor threat by the U.S. Navy when compared to the Soviet submarine force. Therefore, the Petrel wasn't a high-priority weapon, and it was initially assigned to reserve units. The AUM-N-2 had also severe operational shortcomings. Its rather low speed and semi-active guidance required the launching aircraft to come relatively close to the target, which would have made the use of Petrel against ships with sophisticated air defenses problematic. In January 1959, the AUM-N-2 was withdrawn from the operational inventory. Existing Petrel airframes were then used as air-launched target drones, but were not redesignated in the KD (Target Drone) series.

Drawing: Kevin Wornkey

AQM-41A (without wings)

In June 1963, the remaining Petrel targets were redesignated as AQM-41A, but the last of the Petrels was probably gone soon after.

Specifications

Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for AUM-N-2 (AQM-41A):

Length	7.31 m (24 ft)
Wingspan	4.06 m (13 ft 2 in)
Diameter	61 cm (24 in)
Weight	1700 kg (3800 lb)
Speed	600 km/h (325 kts)
Range	32 km (20 miles)
Propulsion	Fairchild J44 turbojet; 4.4 kN (1000 lb)
Warhead	AUM-N-2: MK 21 homing torpedo; 900 kg (2000 lb) AQM-41A: none

Main Sources

[1] Norman Friedman: "US Naval Weapons", Conway Maritime Press, 1983
[2] Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
[3] Bill Gunston: "The Illustrated Encyclopedia of Rockets and Missiles", Salamander Books Ltd, 1979
[4] Norman J. Bowman: "The Handbook of Rockets and Guided Missiles", Perastadion Press, 1963

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Last Updated: 17 September 2005