Editing Infrared homing (section)

===Post-war designs===
[[File:Hughes MX904 Falcon missile.jpg|thumb|right|The [[AIM-4 Falcon]] was the first IR guided missile to enter service. The translucent dome allows the IR radiation to reach the sensor.]]
[[File:Sidewider missile 20040710 145400 1.4.jpg|thumb|right|The [[AIM-9]] Sidewinder closely followed Falcon into service. It was much simpler than the Falcon and proved far more effective in combat.]]
[[File:Firestreak AAM - Elvington - BB.jpg|thumb|right|[[Firestreak]] was the third IR missile to enter service. It was larger and almost twice as heavy as its US counterparts, much of this due to a larger warhead.]]

In the post-war era, as the German developments became better known, a variety of research projects began to develop seekers based on the PbS sensor. These were combined with techniques developed during the war to improve accuracy of otherwise inherently inaccurate radar systems, especially the [[conical scanning]] system. One such system developed by the [[US Army Air Force]] (USAAF), known as the "Sun Tracker", was being developed as a possible guidance system for an [[intercontinental ballistic missile]]. Testing this system led to the [[1948 Lake Mead Boeing B-29 crash]].<ref name=smithsonianmag70888901>{{cite journal |first=Julian |last=Smith |title=Dive Bomber |journal= Smithsonian Magazine |date=October 2005 |url=http://www.smithsonianmag.com/history/dive-bomber-70888901}}</ref>

USAAF project MX-798 was awarded to [[Hughes Aircraft]] in 1946 for an infrared tracking missile. The design used a simple reticle seeker and an active system to control roll during flight. This was replaced the next year by MX-904, calling for a supersonic version. At this stage the concept was for a defensive weapon fired rearward out of a long tube at the back end of [[bomber aircraft]]. In April 1949 the [[AAM-A-1 Firebird|Firebird]] missile project was cancelled and MX-904 was redirected to be a forward-firing fighter weapon.<ref>{{cite journal |first= Sean |last= O'Connor |title= Arming America's Interceptors: The Hughes Falcon Missile Family |date= June 2011 |website= Airpower Australia |pages= 1 |url= http://www.ausairpower.net/Falcon-Evolution.html |access-date= 2015-09-14 |archive-date= 2015-09-08 |archive-url= https://web.archive.org/web/20150908124557/http://www.ausairpower.net/Falcon-Evolution.html |url-status= live }}</ref> The first test firings began in 1949, when it was given the designation AAM-A-2 (Air-to-air Missile, Air force, model 2) and the name Falcon. IR and [[semi-active radar homing]] (SARH) versions both entered service in 1956, and became known as the [[AIM-4 Falcon]] after 1962. The Falcon was a complex system offering limited performance, especially due to its lack of a proximity fuse, and managed only a 9% kill ratio in 54 firings during [[Operation Rolling Thunder]] in the [[Vietnam War]].<ref name="Dunnigan-2014">{{cite book |first1=James |last1=Dunnigan |first2=Albert |last2=Nofi |title= Dirty Little Secrets of the Vietnam War |publisher= Macmillan |date= 2014 |pages=118–120}}</ref> However, this relatively low success rate must be appreciated in the context of all these kills representing direct hits, something that was not true of every kill by other American AAMs.

In the same year as MX-798, 1946, [[William B. McLean]] began studies of a similar concept at the Naval Ordnance Test Station, today known as [[Naval Air Weapons Station China Lake]]. He spent three years simply considering various designs, which led to a considerably less complicated design than the Falcon. When his team had a design they believed would be workable, they began trying to fit it to the newly introduced [[Zuni (rocket)|Zuni 5-inch rocket]]. They presented it in 1951 and it became an official project the next year. [[Wally Schirra]] recalls visiting the lab and watching the seeker follow his cigarette.{{sfn|Hollway|2013}}  The missile was given the name [[AIM-9 Sidewinder|Sidewinder]] after a local snake; the name had a second significance as the [[Crotalus cerastes|sidewinder]] is a [[pit viper]] and hunts by heat, and moves in an undulating pattern not unlike the missile.<ref name=airspacemag57687913>{{cite journal |first=Preston |last=Lerner |title=Sidewinder |journal=Air and Space Magazine |date=November 2010 |url=http://www.airspacemag.com/military-aviation/sidewinder-57687913/?no-ist |access-date=2015-09-11 |archive-date=2015-10-02 |archive-url=https://web.archive.org/web/20151002230107/http://www.airspacemag.com/military-aviation/sidewinder-57687913/?no-ist |url-status=live }}</ref> The Sidewinder entered service in 1957, and was widely used during the Vietnam war. It proved to be a better weapon than the Falcon: B models managed a 14% kill ratio, while the much longer-ranged D models managed 19%. Its performance and lower cost led the Air Force to adopt it as well.<ref name="Dunnigan-2014"/><ref>{{cite encyclopedia |first=Marcelle |last=Size Knaak |title=F-4E |encyclopedia= Encyclopedia of US Air Force aircraft and missile systems  |publisher= US Air Force History Office, DIANE Publishing |year=1978 |page=278 }}</ref>

The first heat-seeker built outside the US was the UK's [[de Havilland Firestreak]]. Development began as OR.1056 [[Red Hawk missile|Red Hawk]], but this was considered too advanced, and in 1951 an amended concept was released as OR.1117 and given the code name [[Blue Jay (missile)|Blue Jay]]. Designed as an anti-bomber weapon, the Blue Jay was larger, much heavier and flew faster than its US counterparts, but had about the same range. It had a more advanced seeker, using PbTe and cooled to −180&nbsp;°C (−292.0&nbsp;°F) by [[anhydrous ammonia]] to improve its performance. One distinguishing feature was its faceted nose cone, which was selected after it was found ice would build up on a more conventional hemispherical dome. The first test firing took place in 1955 and it entered service with the [[Royal Air Force]] in August 1958.<ref>{{Cite book  | last1 = Gibson| first1 = Chris  | first2 = Tony| last2 = Buttler  | title = British Secret Projects: Hypersonics, Ramjets and Missiles  | publisher = Midland  | date= 2007  | pages = 33–35 }}</ref>

The French [[R.511|R.510]] project began later than Firestreak and entered experimental service in 1957, but was quickly replaced by a radar-homing version, the R.511. Neither was very effective and had short range on the order of 3&nbsp;km. Both were replaced by the first effective French design, the [[R.530]], in 1962.<ref>{{cite journal |title=Matra R.511 |journal=Flight International |page=714 |date=2 November 1961}}</ref>

The Soviets introduced their first infrared homing missile, the [[Vympel K-13]] in 1961, after reverse engineering a Sidewinder that stuck in the wing of a Chinese [[MiG-17]] in 1958 during the [[Second Taiwan Strait Crisis]]. The K-13 was widely exported, and faced its cousin over Vietnam throughout the war. It proved even less reliable than the AIM-9B it was based on, with the guidance system and fuse suffering continual failure.<ref name="Dunnigan-2014"/>