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Weapons of Mass Destruction (WMD)


GAM-67 Crossbow

The GAM-67 was a pilotless drone initially designed as a high altitude target. The Crossbow was powered by a Continental J69 gas turbine and could achieve speeds approaching Mach 1. The Crossbow was also capable of being ground launched using a zero length rail system. The GAM-67 was controlled through ground control signals and an onboard autopilot. the American company Radioplane received from the Air Force a contract for the development of the project under the designation MX-2013. The Radioplane Model RP-54D Crossbow missile developed under the project received the designation B-67 in the US Air Force. After changing the designation system d in 1955, the missile was re-designated as GAM-67 Crossbow.

The Northrop Ventura division built improved jet and rocket propelled targets. In the late 1940s, the company developed a set of prototypes of the "Q-1" target series, which used pulsejet or small turbojet engines. In 1948, shortly after its formation, the USAF issued a tender for a high-speed target drone, similar to what the US Navy had been doing since the end of the Second World War. The development contract was awarded to Radioplane, who had good experience in drones. Radioplane proposed the RP-26, powered by an 11 inch Giannini XPJ39-GN-1 pulso-reactor. He had high, straight wings, drifting mono, and catapulted from the ground. It was ground controlled by an AN / APW-11 radar and parachuted. The RP-26 was designated XQ-1 by the USAF and 28 units were built. The first of these flew in 1950.

Radioplane embarked on a major modification of the concept. While retaining the engine, the fuselage was redesigned to give birth to the RP-50, which became YQ-1B for the USAF. The air intake was frontal and replaced the side sockets of the previous version, 6 copies were built, 2 of which could be catapulted from the ground. The YQ-1B flew for the first time in 1953 and the USAF began evaluating it the same year. But while tests proved the aircraft was defective, the USAF preferred the Ryan Q-2 Firebee (the future BQM-34) and the program was abandoned accordingly.

Although the Q-1 series was not put into production as a target, it did evolve into the USAF "RP-54D / XB-67 / XGAM-67 Crossbow" anti-radar missile, which was first flown in 1956. It was also considered as a platform for reconnaissance, electronic countermeasures, and decoy roles.

Radioplane worked for a while on a variant made of plastic and fiberglass, the XQ-3. It is almost certain that no copy was built. On the other hand, the YQ-1B served as the basis for the RP-54D, which was ordered as an anti-radar missile by the USAF under the designation B-67 "Crossbow". This same aircraft was designated GAM-67 (Guided Air Missile) in 1955, with the USAF deciding to use a separate designation for its missiles instead of aircraft designations.

Little is known of this missile except for the fact that it was powered by a turbojet originally said to be a Westinghouse J81 but later probably to be either a J83, J85 or Pratt and Whitney J-12 and that it was designed to home on to enemy surface-sited radars. In this role it thus became a countermeasures vehicle, capable of reducing the effectiveness of the enemy's electronic environment. It has been unofficially stated that Crossbow cruised at about 500 knots.

The Crossbow had a cigar-shaped fuselage, straight wings, a straight twin-fin tail, and an engine inlet under the belly. It was powered by a Continental J69 turbojet, which was a French Turbomeca Marbore II engine built in the US under license, with 4.41 kN (450 kgp / 1,000 lbf) thrust. Two Crossbows could be carried by a Boeing B-50 Superfortress bomber, while four Crossbows could be carried by a Boeing B-47 Stratojet bomber.

The Crossbow prototype was reported to have been in the assembly stage in June 1956, and during the summer of 1957 development prototypes were undergoing evaluation trials at Holloman AFB. Only 14 Crossbows were built before the program was cancelled in 1957, in favor of more sophisticated technology that ended up being cancelled in turn. However, it did point the way to the range of missions that would be performed by UAVs in later decades.

Prime contractor was Radioplane, a Division of Northrop Aircraft, Inc. (Radioplane was originally an associate company of Northrop holding corporate status). Bendix-Pacific had supplied telemetering equipment for this system.

Beginning the late 1950s, the GAM-67 was replaced by more efficient single purpose drones like the Boeing GAM-72 Quail decoy and the Teledyne Ryan Firebee (AQM-34L) reconnaissance vehicle. In a 1957 House of Representatives discussion it was indicated that Crossbow had been "reoriented" (sic), and it seems that, owing to lack of money, the program did not proceed beyond the development stage.

The program was cancelled in 1957, in favor of the Longbow, essentially a supersonic version of the same concept. Longbow was eventually cancelled as well. None of the alternative roles were taken up either, with all work on the concept ending in 1960.

Length, m 6.1
Diameter, mm 810
wing, m 3.86
Starting weight, kg 1220
Flight speed, M 0.86
Practical ceiling, m 12200
Range, km 480

GAM-67  Crossbow GAM-67  Crossbow GAM-67  Crossbow

GAM-67  Crossbow



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Page last modified: 26-08-2018 04:44:00 ZULU