Editing AIM-7 Sparrow (section)

==Development==
===Sparrow I===
[[File:Douglas XF3D-1 Skyknight in flight with four AAM-N-2 Sparrow missiles, circa in the early 1950s.jpg|thumb|left|Sparrow I's during tests on a [[Douglas F3D Skyknight]] in the early 1950s]]

The Sparrow emerged from a late-1940s [[United States Navy]] program to develop a guided rocket weapon for air-to-air use. In 1947 the Navy contracted [[Sperry Corporation|Sperry]] to build a [[beam riding|beam-riding]] version of a standard {{convert|5|in|mm|adj=on|sigfig=3}} [[HVAR]], the standard unguided aerial rocket, under  '''Project Hotshot'''. The weapon was initially dubbed '''KAS-1''', then '''AAM-2''', and — from 1948 on — '''AAM-N-2'''. The airframe was developed by the [[Douglas Aircraft Company]]. The diameter of the HVAR proved to be inadequate for the electronics, leading Douglas to expand the missile's airframe to {{convert|8|in|mm|adj=on|sigfig=3}} diameter. The prototype weapon began unpowered flight tests in 1947, and made its first aerial interception in 1952.<ref name=Designation_Systems/>

After a protracted development cycle the initial '''AAM-N-2 Sparrow''' entered limited operational service in 1954 with specially modified [[Douglas F3D Skyknight]] all-weather carrier night fighters.<ref>{{cite book|title=Guided Missiles Ride Navy Jet|url=https://books.google.com/books?id=sdwDAAAAMBAJ&pg=PA116|date=November 1954|publisher=Hearst Magazines|page=116}}</ref> In 1956, they were joined by the [[McDonnell F3H Demon|McDonnell F3H-2M Demon]] and [[Vought F7U Cutlass]] [[fighter aircraft]]. Compared to the modern versions, the Sparrow I was more streamlined and featured a bullet-shaped airframe with a long pointed nose.

Sparrow I was a limited and rather primitive weapon. The limitations of beam-riding guidance (which was slaved to an optical sight on single-seater fighters and to radar on night fighters) restricted the missile to attacks against targets flying a straight course and made it essentially useless against a maneuvering target. Only about 2,000 rounds were produced to this standard.

===Sparrow II===
[[File:Sparrow 2 Missile.jpg|thumb|Sparrow 2 Missile]]
As early as 1950, Douglas examined equipping the Sparrow with an active radar seeker, initially known as '''XAAM-N-2a ''Sparrow II''''', the original retroactively becoming '''''Sparrow I'''''. In 1952, it was given the new code '''AAM-N-3'''. The active radar made the Sparrow II a "fire and forget" weapon, allowing several to be fired at separate targets at the same time.

By 1955, Douglas proposed going ahead with development, intending it to be the primary weapon for the [[F5D Skylancer]] [[interceptor aircraft|interceptor]]. It was later selected, with some controversy, to be the primary weapon for the Canadian [[Avro Arrow]] supersonic interceptor, along with the new Astra fire-control system. For Canadian use and as a second source for US missiles, [[Canadair]] was selected to build the missiles in [[Quebec]].

The small size of the missile forebody and the K-band AN/APQ-64-radar limited performance, and it was never able to work in testing. After considerable development and test firings in the U.S. and Canada, Douglas abandoned development in 1956. Canadair continued development until the Arrow was cancelled in 1959.

===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]].

===Vietnam War (1965–1973) records===
{| class="wikitable"
|+ [[United States Air Force]] AIM-7 aerial combat kills<ref name="McCarthy Jr., p. 148-157"/>
! scope="col" width="140pt" | Missile firing aircraft
! scope="col" width="100pt" | Model
! scope="col" width="140pt" | Aircraft shot down
! scope="col" width="300pt" | Comments
|-
| F-4C Phantom II
| AIM-7D
| 1 MiG-17
| [[555th Tactical Fighter Squadron]] (TFS)
|-
| F-4C
| AIM-7E
| 3 MiG-17s,<br />10 MiG-21s
| [[389th TFS]], [[433rd Weapons Squadron|433rd TFS]], [[480th TFS]], [[555th TFS]]
|-
| F-4D
| AIM-7E
| 4 MiG-17s,<br />2 MiG-21s
| [[433rd Weapons Squadron|433rd TFS]], [[435th TFS]], [[555th TFS]]
|-
| F-4D
| AIM-7E-2
| 18 MiG-21s,<br />3 [[MiG-19]]s
| [[4th TFS]], [[13th TFS]], [[34th TFS]], [[523rd TFS]], [[555th TFS]]
|-
| F-4E
| AIM-7E-2
| 8 MiG-21s,<br />1 MiG-19
| [[4th TFS]], [[35th TFS]], [[58th TFS]], [[366th TFS]], [[555th TFS]]
|}

{| class="wikitable"
|+[[United States Navy]] AIM-7 aerial combat kills<ref name="McCarthy Jr., p. 148-157">McCarthy Jr., p. 148-157</ref>
! scope="col" width="140pt" | Missile firing aircraft
! scope="col" width="100pt" | Model
! scope="col" width="140pt" | Aircraft shot down
! scope="col" width="300pt" | Comments
|-
| F-4B Phantom II
| AIM-7D
| 4 [[MiG-17]]s (includes 2 probables)
| US fighters launched from [[USS Ranger (CV-61)|USS ''Ranger'']], [[USS Midway (CV-41)|USS ''Midway'']], [[USS Coral Sea (CV-43)|USS ''Coral Sea'']]
|-
| F-4B
| AIM-7E
| 2 [[An-2]] (Antonov [[Biplane]]s),<br />2 [[MiG-21]]s, 1 MiG-17
| US fighters launched from [[USS Constellation (CV-64)|USS ''Constellation'']] and [[USS Enterprise (CVN-65)|USS ''Enterprise'']]
|-
| F-4J
| AIM-7E-2
| 1 MiG-21
| US fighters launched from [[USS Saratoga (CV-60)|USS ''Saratoga'']]
|}

{| class="wikitable" style="text-align:right;"
|+ Kill count summary
! Category
! USAF
! USN
! Combined
|-
| An-2s
| {{N/A}}
| 2
| 2
|-
| MiG-17s
| 8
| 5
| 13
|-
| MiG-19s
| 4
| {{N/A}}
| 4
|-
| MiG-21s
| 38
| 3
| 41
|-
| Total
| 50
| 10
| 60
|}

===Post Vietnam===
Work began in the mid-1960s on a new version in an attempt to address the weapon's limitations. The '''AIM-7F''', which entered service in 1976, had a dual-stage rocket motor for longer range and [[solid-state electronics]] for greatly improved reliability. The reduction in volume from the new guidance system also enabled a larger warhead to be fitted, improving the missile's lethality.

The issues encountered by AIM-7 were not exclusive to the US either, with both [[British Aerospace]] and the Italian firm [[Alenia Aeronautica|Selenia]] developing improved missiles at the behest of their national governments as the [[Skyflash|BAe Skyflash]] and [[Alenia Aspide|Selenia Aspide]]. Notably, both missiles incorporated more reliable [[inverse monopulse seeker]]s, a feature American AIM-7s would not gain until the 1980s.

The most common version of the Sparrow today, the '''AIM-7M''', entered service in 1982 and featured a new inverse monopulse seeker (matching the capabilities of Skyflash and Aspide), active radar [[proximity fuse]], digital controls, improved [[electronic countermeasures|ECM]] resistance, and better low-altitude performance. It was used to good advantage in the 1991 [[Gulf War]], where it scored many USAF air-to-air kills. Of 44 missiles fired, 30 (68.2%) hit their intended targets resulting in 24/26 (54.5%/59.1%) kills. 19 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. 7 |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>

The '''AIM-7P''' is similar in most ways to the M versions, and was primarily an upgrade for existing M-series missiles. Changes were mainly to the software, improving low-level performance. A follow-on Block II upgrade added a new rear receiver allowing the missile to receive mid-course correction from the launching aircraft.{{citation needed|date=July 2023}} Plans initially called for all M versions to be upgraded, but currently P's are being issued as required to replace M's lost or removed from the inventory.{{citation needed|date=July 2023}}

The U.S. Navy planned to operate the missile through 2018.<ref>{{cite web |title=Air Intercept Missile (AIM)-7 Sparrow |url=https://www.navair.navy.mil/product/Air-Intercept-Missile-AIM-7-Sparrow |website=NAVAIR |access-date=24 October 2024}}</ref>

The Sparrow is now being phased out with the availability of the active-radar [[AIM-120 AMRAAM]], but is likely to remain in service for several years.{{when|date=July 2023}}{{citation needed|date=July 2023}}

===Variants===
{| class="wikitable" style="text-align:center;"
|+ AIM-7 variants<ref>{{Cite web|url=http://www.designation-systems.net/dusrm/m-7.html|title=Raytheon AIM/RIM-7 Sparrow|website=www.designation-systems.net|access-date=2016-08-23|archive-url=https://web.archive.org/web/20160303202152/http://www.designation-systems.net/dusrm/m-7.html|archive-date=3 March 2016|url-status=live}}</ref>
|-
!
! AAM-N-2 (AIM-7A)
! AAM-N-3 (AIM-7B)
! AIM-7C
! AIM-7E
! AIM-7F
! AIM-7M/P
! RIM-7M/P
|-
! Length
| 3.74 m (147.3&nbsp;in)
| 3.85 m (151.7&nbsp;in)
| colspan="5" | 3.66 m (144&nbsp;in)
|-
! Wingspan
| 0.94 m (37&nbsp;in)
| colspan="6" | 1.02 m (40&nbsp;in)
|-
! Finspan
| 0.88 m (34.8&nbsp;in)
| ?
| colspan="4" | 0.81 m (32&nbsp;in)
| 0.62 m (24.3&nbsp;in)
|-
! Diameter
| colspan="7" | 0.203 m (8&nbsp;in)
|-
! Weight
| 143&nbsp;kg (315&nbsp;lb)
| 176&nbsp;kg (389&nbsp;lb)
| 172&nbsp;kg (380&nbsp;lb)
| 197&nbsp;kg (435&nbsp;lb)
| colspan="3" | 231&nbsp;kg (510&nbsp;lb)
|-
! Speed
| colspan="2" | Mach 2.5
| colspan="5" | Mach 4
|-
! Range
| 10&nbsp;km (5.4&nbsp;nm)
| 7&nbsp;km (4&nbsp;nm)
| 11&nbsp;km (6&nbsp;nm)
| 30&nbsp;km (16&nbsp;nm)
| colspan="2" | 70&nbsp;km (38&nbsp;nm)
| 26&nbsp;km (14&nbsp;nm)
|-
! Propulsion
| colspan="3" | Aerojet [[1.8KS7800]] solid rocket
| Rocketdyne MK 38/MK 52 <br/>solid rocket
| colspan="3" | Hercules MK 58 dual-thrust solid rocket
|-
! Warhead
| colspan="2" | 20&nbsp;kg (45&nbsp;lb)
| colspan="2" | 30&nbsp;kg (65&nbsp;lb) MK 38 continuous rod
| 39&nbsp;kg (86&nbsp;lb) MK 71 <br/>continuous rod
| colspan="2" | 40&nbsp;kg (88&nbsp;lb) WDU-27/B <br/>blast-fragmentation
|}

<gallery mode="packed">
File:Australian F-18A Hornet launches Sparrow missile c1990.jpg|An Australian F-18A Hornet fires an AIM-7 Sparrow missile.
File:F-4C 154 FIS AIM-7E AIM-9P 1980.JPEG|AIM-7Es being loaded on a Hawaii ANG F-4C in 1980
File:F-4G 37FW AIM-7F AGM-65A AGM-88 1988.JPEG|AIM-7Ms on a 37th TFW F-4G in 1988
File:AIM-7 wing install.jpg|Wings being installed on an AIM-7
File:Loading AIM-7.jpg|An AIM-7M being loaded
File:USAF F-15C fires AIM-7 Sparrow 2.jpg|A USAF F-15C fires an AIM-7 Sparrow.
</gallery>

=== Proposals ===
'''Sparrow X''' was a subvariant of the Sparrow I armed with the same nuclear warhead as the [[AIR-2 Genie|MB-1 Genie]] was proposed in 1958 but was cancelled shortly thereafter.

'''AIM-7F Multishot''' was a proposal under the US Navy's F-4X program of the 1960s to equip the then under development missiles and their launch platforms with a datalink for [[track-via-missile]] guidance akin to that of [[AIM-54 Phoenix]], which would enable multiple AIM-7 missiles to be guided simultaneously. As each missile would only need terminal illumination from the F-4's radar, it could engage multiple aircraft simultaneously as long as it kept all targets within view of its radar.<ref>McDonnell, January 1967. F-4X For U.S. Navy. Retrieved 5 April 2025.</ref> As this modification would have required all-new solid state electronics for the [[AN/AWG-10]] radars on the launching F-4s, it was not pursued.

'''AIM-7R''' was to add an [[infrared homing]] seeker to an otherwise unchanged AIM-7P Block II. A general wind-down of the budget led to it being cancelled in 1997.