de Havilland Firestreak
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.
|Place of origin||United Kingdom|
|Used by||United Kingdom, Kuwait, Saudi Arabia.|
|Manufacturer||de Havilland Propellers|
|Mass||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|
|Engine||Magpie solid fuel motor|
|Wingspan||0.75 m (30 in)|
|4 miles (6.4 km)|
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.
The first airborne launch of Blue Jay took place in 1955 from a de Havilland Venom, the target drone - a Fairey Firefly - being destroyed. Blue Jay Mk.1 entered service in 1957 with the RAF, where it was named Firestreak. Firestreak was deployed by the Royal Navy and the RAF in August 1958; it was the first effective British air-to-air missile.
For launch, the missile seeker was slaved to the launch aircraft's radar (Ferranti AIRPASS in the Lightning and GEC AI.18 in the Sea Vixen) until lock was achieved and the weapon was launched, leaving the interceptor free to acquire another target. A downside was that the missile was highly toxic (due to either the Magpie rocket motor or the ammonia coolant) and RAF armourers had to wear some form of CRBN protection to safely mount the missile onto an aircraft. "Unlike modern [1990s] missiles, ... Firestreak could only be fired outside cloud, and in winter, skies were rarely clear over the UK."
Two Firestreak variants were studied but not adopted: the Mk.2 with a new motor, and the Mk.3 with increased wingspan and reduced top speed, for use with rocket-powered interceptors such as the Saunders-Roe SR.177 and Avro 720, according to Specification F.124T.
Firestreak was developed into Blue Jay Mk.4 (later renamed Blue Vesta), again intended for use by rocket-powered interceptors against high-speed Soviet bombers. In the end, Specification F.124T was cancelled but Blue Jay Mk.4 development continued. Blue Jay Mk.4 ultimately entered service as the Red Top in 1964. Despite Red Top being intended to replace Firestreak, Firestreak remained in limited service until the final retirement of the Lightning in 1988; the carriage of these missiles improved the aircraft's aerodynamics.
Red Top was faster and had a longer range than Firestreak, and "was capable of all aspect homing against super-sonic targets." An important difference between Firestreak and Red Top was the electronics technology used. Firestreak electronics used thermionic valves, which were "wired in" to the control / guidance electronics and required a system of cooling pipes to remove the heat generated by the valve filaments. For this reason, the Firestreak missile on ground test was cooled by Arcton and in flight by ammonia pumped through the missile from the parent aircraft. The Red Top electronics were constructed using transistors which were heated instead and the IR sensor in its dome-shaped Homing Head was cooled by purified air at 3,000 psi (21 MPa) filtered to 3 μm.
- Gibson 2007, p. 33
- Gibson 2007, p. 34
- Boyne, Walter J, Air Warfare: an International Encyclopedia, Volume 1, pub ABC-CLIO Inc, 2002, ISBN 1-57607-345-9 p267.
- Gibson 2007, p. 35
- Black, Ian, The Last of the Lightnings, pub PSL, 1996, ISBN 1-85260-541-3, p141.
- Gibson, Chris; Buttler, Tony (2007). British Secret Projects: Hypersonics, Ramjets and Missiles. Midland Publishing. pp. 33–35. ISBN 978-1-85780-258-0.