A Fireflash missile at the Royal Air Force Museum Cosford (2014)
|Place of origin||United Kingdom|
|Used by||United Kingdom|
|Number built||c. 300|
|Weight||150 kilograms (330 lb)|
|Length||111.75 inches (2,838 mm)|
|Engine||Two solid fuel rocket motors|
|Wingspan||28.11 inches (714 mm)|
|1.9 miles (3.1 km)|
|Speed||Mach 2 (max)|
Fireflash was the United Kingdom's first air-to-air guided missile to see service with the Royal Air Force. It was briefly deployed during the 1950s. Constructed by Fairey Aviation, the missile utilised radar beam riding guidance.
Produced in response to a Ministry of Supply requirement for a guided air-to-air missile, the project began in 1949 under the name Blue Sky. It was initially developed under the designation Pink Hawk. Blue Sky itself was a de-rated version of the Red Hawk missile.
About 300 missiles had been produced by 1955, but the Royal Air Force soon decided not to retain the type in its inventory. Many of the 300 missiles were expended in testing by 6 JSTU at RAF Valley and Woomera, South Australia from 1955–1957 using Meteor NF11 trials aircraft and subsequently by the Supermarine Swift fighters of No. 1 Guided Weapons Development Squadron at RAF Valley. The Fireflash was deployed on a very limited scale by the RAF in August 1957, and "had a limited capability against piston-engine bombers." The RAF deployed the later and more effective de Havilland Firestreak infra-red missile from August 1958.
The Fireflash was a beam riding missile - it was designed to fly down a radio beam emitted by the launch aircraft, which the pilot would keep aimed at the target.
It had a very unusual configuration: the missile body was unpowered. It was propelled by a pair of rocket boosters on the forward fuselage that were jettisoned 1.5 seconds after launch.[Note 1] The missile body, now travelling at around Mach 2, would coast the remaining distance to its target under guidance from the launch aircraft (the missile was unguided during the boost phase).[Note 2] The rocket engine nozzles were slightly offset to rotate the missile - this increased accuracy by evening out the effect of any slight asymmetry in thrust.
This configuration drastically limited both range and flight duration, but was used because of fears that ionised particles in the hot, rocket motor exhaust stream would interfere with the guidance radar signals; further development showed the fears were unfounded.
Steering was accomplished by four rudders in a cruciform configuration. These were moved by four pairs of pneumatic servos, operated by solenoid valves. An air bottle, pressurized to 3,000 pounds per square inch (21,000 kPa), supplied air for the servos and also supplied the air that spun the three, air-blown gyroscopes in the missile's inertial navigation system. A high pressure air supply from the aircraft was also required to spin the gyros before the missile was launched.
The purpose of the control system was to keep the missile centred in the guidance beam emitted by the launch aircraft. The pilot of the aircraft would keep the beam aligned with the target using his gunsight, which was harmonized with the axis of the radio beam. An advantage of this system was that it would be unaffected by the target aircraft using radar countermeasures such as chaff. The missile's receiver, fitted at the rear, only detected signals from the launch aircraft.
- A cordite charge within a cylinder drove a piston, that sheared the pin that attached each rocket to the missile
- The unusual configuration (an unpowered guided munition that coasts to the target after boosted to high speed by a rocket) was also used decades later in the British Starstreak missile
- Boyne, Walter J, Air Warfare: an International Encyclopedia, Volume 1, pub ABC-CLIO Inc, 2002, ISBN 1-57607-345-9 p267.
- "Fairey Fireflash - Air to Air Missile". Royal Air Force Museum. Retrieved 29 December 2012.
- Flight (1957), p. 227
- "Blue Sky 4". Etko Electronics. Retrieved 29 December 2012.
- "Fireflash". Flight. 72 (2534): 223–228. 16 August 1957.
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