Editing AIM-7 Sparrow (section)

===Sparrow III===
[[File:Sparrow III launch F3H-2M NAN2-59.jpg|thumb|[[F3H Demon]] launching a Sparrow III in 1958]]

Concurrently with the development of the Sparrow I, in 1951 [[Raytheon]] began work on a [[semi-active radar homing|semi-active radar-homing]] version, the '''AAM-N-6 ''Sparrow III'''''. The first of these weapons entered [[United States Navy]] service in 1958.

The '''AAM-N-6a''' was similar to the -6, and included changes to the guidance electronics to make it effective at higher closing speeds. It was originally designed to take the [[Thiokol]] LR44-RM-2 liquid-fuel rocket motor, but the decision was made to retain the solid fuel rocket motor.<ref>{{cite magazine |last=Pfeiffer |first=Mary |date=January 1962 |title=Liquid Rockets |url=https://www.history.navy.mil/content/dam/nhhc/research/histories/naval-aviation/Naval%20Aviation%20News/1960/pdf/jan62.pdf |access-date=2024-03-13 |magazine=Naval Aviation News |publisher=Chief of Naval Operations and Bureau of Naval Weapons |location=Washington D.C. |page=13}}</ref><ref>{{Cite journal |last=Davies |first=Harold |date=2007 |title=Reaction Motors (Thiokol) Family of Packaged Liquid Rocket Engines |journal=Journal of Spacecraft and Rockets |language=en |volume=44 |issue=6 |pages=1271–1284 |doi=10.2514/1.30134 |issn=0022-4650}}</ref> The -6a was also selected to arm the Air Force's ''F-110A Spectre'' ([[F-4 Phantom]]) fighters in 1962, known to them as the '''AIM-101'''. It entered production in 1959, with 7500 being built.

With an improved Rocketdyne solid-fuel motor, the '''AAM-N-6b''' started production in 1963. The new motor significantly increased the maximum range to {{convert|35|km|mi}} for head-on attacks. This new missile also improved tail-on performance, with the AAM-N-6a being capable of firing on only targets with 300&nbsp;ft/sec closing velocity, and AAM-N-6b being capable of firing on targets with a 300 knot opening velocity (-300 knot closing velocity or higher).<ref>{{cite report |url=https://documents.theblackvault.com/documents/dod/readingroom/11/356.pdf |title=AIR-TO-AIR ENCOUNTERS IN SOUTHEAST ASIA. |author= |date=April 1968 |publisher= |volume=IV |page=151 |docket= |quote= |author-link= |access-date=2024-03-13 }}</ref>

During this year the Air Force and Navy agreed on standardized naming conventions for their missiles. The Sparrows became the AIM-7 series. The original Sparrow I and aborted Sparrow II became the '''AIM-7A''' and '''AIM-7B''', despite both being out of service. The -6, -6a, and -6b became the '''AIM-7C''', '''AIM-7D''', and '''AIM-7E''' respectively.

25,000 AIM-7Es were produced and saw extensive use during the [[Vietnam War]], where its performance was considered disappointing. The mixed results were a combination of reliability problems (exacerbated by the tropical climate), limited pilot training in fighter-to-fighter combat, and restrictive rules of engagement that generally prohibited BVR (beyond visual range) engagements. The P<sub>k</sub> (kill probability) of the AIM-7E was less than 10%; US fighter pilots shot down 59<ref group=Note>Figure includes probables and bi-planes, which some sources exclude</ref> aircraft out of the 612 Sparrows fired.<ref>Michel III p. 286, 287</ref> Of the 612 AIM-7D/E/E-2 missiles fired, 97 (or 15.8%) hit their targets, resulting in 56 (or 9.2%) kills. Two kills were obtained beyond visual range.<ref>{{Cite web |url=http://www.dtic.mil/ndia/2006psa_winter_roundtable/watts.pdf |title=Barry D. Watts: ''Six Decades of Guided Munitions'', Precision Strike Association, 25 January 2006, p. 5 |access-date=26 April 2014 |archive-url=https://web.archive.org/web/20130720010705/http://www.dtic.mil/ndia/2006psa_winter_roundtable/watts.pdf |archive-date=20 July 2013 |url-status=dead  }}</ref>

In 1969, an improved version, the E-2, was introduced with clipped wings and various changes to the fuzing. Considered a "dogfight Sparrow", the AIM-7E-2 was intended to be used at shorter ranges where the missile was still travelling at high speeds, and in the head-on aspect, making it much more useful in the visual limitations imposed on the engagements. Even so, its kill rate was only 13% in combat, leading to a practice of ripple-firing all four at once in hopes of increasing kill probability. Its worst tendency was to detonate prematurely about 1,000 feet ahead of the launching aircraft, but it also had many motor failures, erratic flights, and fuzing problems. An E-3 version included additional changes to the fuzing, and the E-4 featured a modified seeker for use with the [[F-14 Tomcat]].