De Havilland Firestreak

Firestreak
Type	air-to-air missile
Place of origin	United Kingdom
Service history
In service	1957–1988
Used by	United Kingdom, Kuwait, Saudi Arabia.
Production history
Designed	1951
Manufacturer	de Havilland Propellers
Specifications
Weight	136 kg (300 lb)
Length	3.19 metres (10 ft 6 in)
Diameter	0.223 m (8.8 in)
Warhead	22.7 kg (50 lb) annular blast fragmentation
Detonation mechanism	proximity infrared
Engine	Magpie solid fuel motor
Wingspan	0.75 m (30 in)
Operational range	4 miles (6.4 km)
Speed	Mach 3
Guidance system	rear-aspect infrared
Steering system	control surface
Launch platform	fixed-wing aircraft

The de Havilland Firestreak is a British first-generation, passive infrared homing (heat seeking) air-to-air missile. It was developed by de Havilland Propellers (later Hawker Siddeley) in the early 1950s and was the first such weapon to enter active service with the Royal Air Force (RAF) and Fleet Air Arm, equipping the English Electric Lightning, de Havilland Sea Vixen and Gloster Javelin. It was a rear-aspect, fire and forget pursuit weapon, with a field of attack of 20 degrees either side of the target.

The Firestreak was the third heat seeking missile to enter service, after the AIM-4 Falcon and AIM-9 Sidewinder which both entered service the previous year. In comparison to those designs, the Firestreak was much larger and heavier, carrying a much larger warhead. It had otherwise similar performance in terms of speed and range. Limitations of the design led to an improved version, the Hawker Siddeley Red Top, but this never completely replaced Firestreak. Firestreak remained in service until 1988, when it was retired along with the last RAF Lightnings.

Firestreak was the result of a series of projects begun with the OR.1056 Red Hawk missile. When this proved too ambitious for the then state of the art, a lower performance specification was released in 1951 as OR.1117, and given the Ministry of Supply rainbow codename Blue Jay.

Blue Jay developed as a fairly conventional-looking missile with cropped delta wings mounted just aft of the midpoint and small rectangular control surfaces in tandem towards the rear. Internally, things were considerably more complex. The rear-mounted controls were operated by nose-mounted actuators via long pushrods. The actuators were powered by compressed air from bottles at the rear. The lead telluride (PbTe) IR seeker was mounted under an eight-faceted conical arsenic trisulphide "pencil" nose and was cooled to −180 °C (−292.0 °F) by anhydrous ammonia to improve the signal to noise ratio. The unusual faceted nose was chosen when a more conventional hemispherical nose proved prone to ice accretion. There were two rows of triangular windows in bands around the forward fuselage, behind which sat the optical proximity fuzes for the warhead. The warhead was at the rear of the missile, wrapped around the exhaust of the Magpie rocket.