View source for Skyflash

{{Use dmy dates|date=June 2017}}
{{Infobox weapon
|is_missile=yes
|is_UK=yes
|name=Skyflash
| image= Za254.jpg
| image_size = 300
|caption=Prototype Panavia Tornado ADV aircraft with semi-recessed Skyflash missiles
|origin= United Kingdom
|type=Medium-range [[air-to-air missile]]
|used_by=
|manufacturer=[[BAe Dynamics]]
|designer=[[Hawker Siddeley]], [[Marconi Electronic Systems|Marconi Space & Defence Systems]]
|unit_cost= £150,000 per missile
|propellant=
|production_date=
|service=1978–2006
|engine=Rocketdyne solid propellant rocket motor
|engine_power=
|weight= 193 kg (425 lb)
|length=3.68 m (12 ft 1 in)
|height=
|diameter=203 mm
|wingspan=1.02 m (3 ft 6 in)
|speed= Mach 4
|vehicle_range=45 km (28 mi)
|ceiling=
|altitude=
|filling=39.5 kg (87 lb)
|guidance=Marconi inverse monopulse semi-active radar homing
|detonation=
|launch_platform=
}}

The '''Skyflash''', or '''Sky Flash''' in marketing material, was a medium-range [[semi-active radar homing]] [[air-to-air missile]] derived from the US [[AIM-7 Sparrow]] missile and carried by [[Royal Air Force]] [[McDonnell Douglas F-4 Phantom II in UK service|McDonnell Douglas  F-4 Phantom]]s and [[Panavia Tornado ADV|Tornado F3s]], Italian [[Italian Air Force|''Aeronautica Militare'']] and [[Royal Saudi Air Force]] Tornados and Swedish [[Swedish Air Force|''Flygvapnet'']] [[Saab 37 Viggen|Saab Viggens]].

Skyflash replaced the original Raytheon [[conical scanning]] seeker with a [[Marconi Electronic Systems|Marconi]] [[inverse monopulse seeker]] that worked with the F-4's radar. Monopulse seekers are more accurate, less susceptible to jamming, and able to easily pick out targets at low altitudes. It offered significantly better performance than the original seeker, allowing [[British Aerospace]] to dispense with upgrades to the warhead that were carried out in the US to address poor accuracy.

Skyflash was tested in the US, but after trials against experimental monopulse seekers from Raytheon, the [[United States Navy]] elected to order a different monopulse-equipped version of the Sparrow, the AIM-7M. Both Skyflash and AIM-7M were later replaced by the more capable [[AMRAAM]].

==History==
[[File:Saab 37 Viggen 37301 001.jpg|thumb|Swedish Air Force JA37 Viggen with a pair of underwing Skyflash missiles]]

Skyflash came out of a British plan to develop an [[inverse monopulse seeker]] for the Sparrow AIM-7E-2 by [[General Electric Company]] (GEC) and the [[Royal Aircraft Establishment]] (RAE) at the end of the 1960s. Having shown this was feasible, Air Staff Requirement 1219 was issued in January 1972,<ref>Gibson 2007, p. 45</ref> with the project code XJ.521. The contractors were [[Hawker Siddeley]] and [[Marconi Electronic Systems|Marconi Space & Defence Systems]] (the renamed GEC guided weapons division) at [[Stanmore]].<ref>Gibson 2007, p. 46</ref> Major changes from the Sparrow were the addition of a Marconi semi-active inverse monopulse radar seeker, improved electronics, adapted control surfaces and a [[Thorn EMI]] active radar [[fuze]]. The rocket motors used were the [[Bristol Aerojet]] Mk 52 mod 2 and the [[Rocketdyne]] Mk 38 mod 4 rocket motor; the latest is the Aerojet Hoopoe.

Tests of the resulting missile showed it could function successfully in hostile [[electronic countermeasure]]s (ECM) environments and could engage targets under a wide variety of conditions. It could be launched from as low as 100 m to attack a high-altitude target or launched at high level to engage a target flying as low as 75 m. In testing, it repeatedly intercepted target drones at 1,000 ft altitude, the minimum altitude that the tracking cameras could be set to.<ref>{{cite magazine |url=https://www.flightglobal.com/pdfarchive/view/1977/1977%20-%200950.html |title=Sky Flash Countdown |first=Doug |last=Richardson |date=9 April 1977 |magazine=Flight International |pages=894–896}}</ref>

The missile entered service on the [[McDonnell Douglas Phantom in UK service|F-4 Phantom]] in 1978 as what was later called the 3000 Pre TEMP series (Tornado Embodied Modification Package). In 1985, these aircraft were replaced with the [[Panavia Tornado ADV]]. Both the Phantom and the Tornado carried the Skyflash in semi-recessed wells on the aircraft's underbelly to reduce drag. In the Tornado, however, [[Frazer-Nash]] hydraulic trapezes projected the missile out into the slipstream prior to motor ignition. This widened the missile's firing envelope by ensuring that the launch was not affected by turbulence from the fuselage. Skyflash was therefore converted to the 5000 TEMP series to incorporate the Frazer-Nash recesses in the body of the missile, Launch Attitude Control electronics in the autopilot section and improved wing surfaces. The Tornado-Skyflash combination became operational in 1987 with the formation of the first Tornado F.3 squadron.<ref>{{Cite web|url=http://www.flightglobal.com/pdfarchive/view/1988/1988%20-%202838.html|title=''Flight'' 1 October 1988}}</ref>

From 1988 a further modification (6000 series) nicknamed "SuperTEMP" included the Hoopoe rocket motor to change the missile's flight profile from boost-and-glide (with a 3-second burn) to boost-sustain-glide (3 second boost - 4 second sustain), increasing its range from 17nm to 18.4nm at a height of 30,000ft and at a height 5,000ft the range increase was more substantial, raising from 14nm to 16nm. The maximum flight time was also raised from 40 to 50-60 seconds.<ref>Tornado F.3 Tactics Manual (Oct 1987)</ref> 

In RAF service the missiles were usually carried in conjunction with four short-range air-to-air missiles, either [[AIM-9 Sidewinder]]s or [[ASRAAM]]s.

A version with an active [[Thales Group|Thomson CSF]]-developed radar seeker and inertial mid-course update capability, Skyflash Mk 2 (called Active Skyflash), was proposed for both the RAF and Sweden.<ref name="auto">Gibson 2007, p. 47</ref> British interest ended with the [[1981 Defence White Paper|1981 Defence Review]];<ref>{{Cite web|url=http://www.flightglobal.com/pdfarchive/view/1981/1981%20-%202515.html|title=''Flight'' 1 August 1981}}</ref> [[British Aerospace]] (BAe) kept the proposal around until the early '90s but there were no buyers.

Further advanced Sky Flash derivatives were studied under the code name S225X,<ref>{{Cite web|url=http://www.flightglobal.com/pdfarchive/view/1993/1993%20-%200539.html|title=''Flight'' 30 March 1993}}</ref> and a ramjet-powered version, the [[S225XR]] became the basis for the [[MBDA Meteor]].<ref name="auto"/>

In [[1996 in aviation|1996]] the RAF announced the launch of the Capability Sustainment Programme which called for, among other things, the replacement of the Skyflash with the [[AIM-120 AMRAAM]]. AMRAAM incorporates an active seeker with a strapdown inertial reference unit and computer system, giving it fire-and-forget capability. The first Tornado ADV F.3 with limited AMRAAM capability entered service in 1998. In 2002, a further upgrade enabled full AMRAAM capability.<ref name="auto"/> The first mention of AMRAAM as a replacement for Skyflash dates back to 1986.<ref>{{Cite web|url=http://www.flightglobal.com/pdfarchive/view/1986/1986%20-%200336.html|title=''Flight'' 8 February 1986}}</ref>

==Former operators==
; {{ITA}}
* [[Italian Air Force]]
; {{SAU}}
* [[Royal Saudi Air Force]]
; {{SWE}}
* [[Swedish Air Force]] Made under license as the Rb 71
; {{UK}}
* [[Royal Air Force]]

==References==
{{Commons category|Skyflash AAM}}

===Notes===
{{reflist}}

===Bibliography===
*{{Cite book
  | last1 = Gibson| first1 = Chris
  | first2 = Tony| last2 = Buttler
  | title = British Secret Projects: Hypersonics, Ramjets and Missiles
  | publisher = Midland Publishing
  | year= 2007
  | pages = 47–53
  | isbn = 978-1-85780-258-0 }}

==See also==
{{UKmissiles}}

[[Category:Air-to-air missiles of the United Kingdom]]
[[Category:Cold War air-to-air missiles of the United Kingdom]]
[[Category:Beyond-visual-range air-to-air missiles]]
[[Category:General Electric Company]]
[[Category:Military equipment introduced in the 1970s]]