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{{Short description|Anti-submarine aircraft family by Grumman}}
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{{Use dmy dates|date=March 2020}}
{{Infobox aircraft
 |name= AF Guardian
 |image= File:AF-2W AF-2S VS-25.jpg
 |caption= Hunter-Killer team of AF-2W (lower) and AF-2S
 |type= [[Anti-submarine warfare]] aircraft
 |national_origin= United States
 |manufacturer= [[Grumman]]
 |designer=
 |first_flight= 19 December 1945
 |introduction= October 1950
 |retired= 31 August 1955
 |status= 
 |primary_user= [[United States Navy]]
 |more_users=
 |produced=
 |number_built= 389
 |developed_from=
 |variants=
}}

The '''Grumman AF Guardian''' is the first purpose-built [[anti-submarine warfare]] (ASW) [[carrier-based aircraft]] to enter service with the [[United States Navy]].<ref name="Kowalski p. 3">Kowalski 1991, p. 3.</ref> It consisted of two airframe variants, one for detection gear, the other for weapons. The Guardian remained in service until August 1955, when it was replaced by the twin-engined [[Grumman S-2 Tracker]]. The Guardian was the largest single-engine piston-powered carrier aircraft ever to see service.<ref name="Donald and March p. 46"/>

==Design and development==
[[File:AF-2W VS-37 Jul1957.jpg|thumb|left|An AF-2W from VS-37 in flight circa July 1957]]

The original design concept for the aircraft that would become the Guardian, the [[Grumman TB2F|XTB2F]] of 1944, was for a twin-engined aircraft with a {{cvt|3600|lb|kg}} warload and a range of {{cvt|3700|mi|km}}.<ref name="Kowalski pp. 2–3">Kowalski 1991, pp. 2–3.</ref> This was considered to be too large for practical use from an {{Sclass|Essex|aircraft carrier}}, and was cancelled in 1945, replaced by a modified [[Grumman F7F Tigercat]], the [[Grumman XTSF|XTSF-1]].<ref name="VS"/>

However, this too was considered impractical,<ref>Norton 2008, p. 120.</ref> and another alternative, the internally developed Grumman Model G-70, was selected instead, being given the Navy designation XTB3F-1. This was designed as mixed-power aircraft, with a [[Pratt & Whitney Double Wasp]] radial engine in the nose and a [[Westinghouse J30|Westinghouse 19XB]] (J30) turbojet in the tail.<ref name="VS"/> Originally, the Westinghouse engine was to be the new X24C, which was to emerge as the [[Westinghouse J34|J34]]. When it became apparent the X24C delivery schedules would not meet the airframe schedule, the 19XB-2B was substituted. This was found to be unsuitable, and the jet engine was removed without ever having been used in flight.<ref name="VS"/> The XTB3F-1 carried a crew of two seated side by side and an armament of two 20&nbsp;mm [[cannon]] and {{cvt|4,000|lb|kg}} of [[bomb]]s, [[torpedo]]es, and [[rocket]]s, and made its first flight on 19 December 1945.<ref name="VS"/>

On 24 December 1945, the Navy changed the role of the aircraft from torpedo-bomber to anti-submarine warfare. All the required equipment could not be fitted into a single aircraft, consequently two variants would be produced, one as a "guppy" (hunter) and another as a "scrapper" (killer).<ref>Kowalski 1991, p. 16.</ref> The hunter aircraft would not carry any armament,<ref name="Donald and March p. 46">Donald and March 2001, p. 46.</ref> but instead two additional crew members and a ventral radome for [[AN/APS-20]] search [[radar]] and [[electronic countermeasures]] (ECM) consisting of an AN/APR-98 countermeasures receiver and AN/AP-70 bearing indicator.<ref>Kowalski 1991, p. 18.</ref> This aircraft, the XTB3F-1S, first flew in November 1948.<ref name="VS"/> The "killer" deleted the cannon of the torpedo bomber, but retained the bomb bay, added a third crewmember, a [[searchlight]], and short-range radar, and (as the XTB3F-2S) first flew in January 1949.<ref name="VS"/>

==Operational history==
[[File:AF-2S VS-25 NMNA.jpg|thumb|An AF-2S in the colors of VS-25 pictured while owned by Aero Union Corporation, circa 1978/79.]]

Redesignated as AF-2W (TB3F-1S) and AF-2S (TB3F-2S), the Guardian entered fleet service on 27 September 1950 with three aircraft delivered to [[VS-24]],<ref>Kowalski 1991, p. 14.</ref> with full service introduction shortly after<ref name="Swan2"/> with [[VS-25]].<ref name="wagner">Wagner 1982, p. 498.</ref> A total of 193 AF-2S Guardians were built.<ref name="Swan2"/> In 1952, the AF-3S (hunter) was introduced, fitting a [[magnetic anomaly detector]] (MAD) for the detection of submerged submarines; 40 of this variant were built.<ref name="Swan2"/> The last Guardian was delivered to the Navy in March 1953,<ref name="Swan2"/> with a total of 389 built.<ref name="VS">Goebel, Greg. {{usurped|1=[https://web.archive.org/web/20080605225040/http://www.vectorsite.net/avguard.html "Grumman AF Guardian."]}} ''VectorSite,'' 2009. Retrieved: 16 January 2011.</ref>

The Guardian saw service in the maritime patrol role during the [[Korean War]], however it proved unpopular with pilots, being underpowered and heavy on the controls; the aircraft suffered from a severely high accident rate.<ref name="VS"/> Shortly after the end of the war, it began to be replaced by the [[Grumman S-2 Tracker|Grumman S2F Tracker]],<ref name="Swan2"/> the U.S. Navy first purpose-built ASW airplane to combine the hunter and killer roles in a single airframe.<ref>Donald and March 2001, p. 50.</ref> The last AF retired from active service on 31 August 1955,<ref name="VS"/> but it remained in service with the US Naval Air Reserve until 1957.<ref name="VS"/>

==Variants==
[[File:AF-2S weapons bay.jpg|thumb|The underside of an AF-2S showing its opened weapons bay]]
; XTB3F-1
:Prototypes of two-seat torpedo bomber powered by one {{cvt|2300|hp|kW}} R-2800-46 engine and a Westinghouse turbojet; three built.<ref name="VS"/>
; XTB3F-1S & -2S
:Two modified XTB3F-1 prototypes with turbojet removed and ventral radome, later redesignated as XAF-1.<ref name="VS"/>
; AF-2S
:Production variant with {{cvt|2400|hp|kW}} R-2800-48 engine, 193 built.<ref name="Swan2">Swanborough and Bowers 1990, p. 246.</ref>
; AF-2W
:Hunter variant with search radar in a ventral radome, 153 built.<ref name="Swan2"/>
; AF-3S
:Hunter/Killer variant similar to AF-2S with retractable MAD boom, 40 built.<ref name="Swan2"/>
; Grumman Model G-90
: Proposed combined AF-2S/-2W version, cancelled.

==Operators==
[[File:Grumman AF Guardian001.jpg|thumb|Grumman AF Guardian in Aero Union colors at Pima]]
;{{USA}}
* [[United States Navy]]
* [[Aero Union]]

==Surviving aircraft==
[[File:Grumman AF Guardian, Naval Aviation Museum, Pensacola, Florida.jpg|thumb|right|AF-2 Guardian on display at the National Museum of Naval Aviation]]

After disposal by the U.S. Navy five Guardians saw many years service with Aero Union based at [[Chico, California]], in the forest firefighting role, the last being retired in 1978.
;On display
;;AF-2S
*123100 – [[National Naval Aviation Museum]] at [[NAS Pensacola]] in [[Pensacola, Florida]]. It was the seventh AF-2S produced. The aircraft was operated as a firefighter until 1978. It was acquired by the museum in 1980. It is displayed in the colors of its first Navy assignment, though still carries the number "30" on the cowling, which for many years was the aircraft's call-sign as a firefighting aircraft;<ref>[https://goodall.com.au/warbirds-directory-v6/grumman.pdf "AF-2S Guardian/Bu. 123100."] ''Warbird Directory: Grumman Page 26'' Retrieved: 21 September 2022.</ref>
*129233 – [[Pima Air and Space Museum]], [[Tucson, Arizona]].  This aircraft is displayed as it appeared while serving as an aerial firefighter with Aero Union in California.  During this period the distinctive empennage with twin vertical stabilizers on each horizontal tail were removed to make a more conventional appearance.<ref>[https://pimaair.org/museum-aircraft/grumman-af-2s/ "AF-2S Guardian/Bu. 129233."] ''Pima Air & Space Museum''. Retrieved: 23 December 2021.</ref>
*126731 – Static display at the [[Arizona Commemorative Air Force Museum]] in [[Mesa, Arizona]], as a memorial to VAdm [[James Stockdale|James B. Stockdale]], who flew this aircraft early in his Navy career.<ref>[https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=N9993Z "FAA Registry: N9993Z"] ''FAA.gov'' Retrieved: 29 July 2021.</ref><ref>[https://goodall.com.au/warbirds-directory-v6/grumman.pdf "AF-2S Guardian/Bu. 126731."] ''Warbird Directory: Grumman Page 26'' Retrieved: 21 September 2022.</ref>
*123088 - [[Chico Air Museum]], [[Chico, California]]. This aircraft was owned by Aero Union in California until its purchase by a private owner some time in the mid-1970s. After suffering major damage in a crash on 20 September 1981, it was grounded until being donated to the museum on 14 September 2010. It is currently undergoing restoration.<ref>[https://aerialvisuals.ca/AirframeDossier.php?Serial=5829] ''Aerial Visuals Airplane Dossier''. Retrieved: 1 August 2023.</ref>

==Specifications (AF-2S Guardian)==
[[File:Grumman AF-2S Guardian 3-view line drawing.png|frameless|right|3-view line drawing of the Grumman AF-2S Guardian]]

{{Aircraft specs
|prime units?=imp

|ref=''United States Navy Aircraft since 1911.'' <ref name="Swan navy p228">Swanborough and Bowers 1976, p. 228.</ref>

|crew=three<ref name="VS"/>
|length ft=43
|length in=4
|length m=13.21 
|span ft=60
|span in=8  
|span m=18.49
|span note=(about 25 ft-wings folded (7.62 m))  
|height ft=16
|height in=2
|height m=5.08 
|wing area sqft=560 
|wing area sqm=52.03 
|empty weight lb=14,580 
|empty weight kg=6,613 
|max takeoff weight lb=22,640 
|max takeoff weight kg=10,270 
|eng1 name=[[Pratt & Whitney R-2800]]-48W "Double Wasp"
|eng1 type=[[radial engine]]
|eng1 number=1
|eng1 hp=2,400 
|eng1 kw=1,790 
|max speed mph=253 
|max speed kts=276
|max speed kmh=510
|max speed note= at full throttle not to exceed 30 minutes at {{cvt|15000|ft|m}} with a gross weight {{cvt|21000|lb|kg}}
|range miles=1,500 
|range nmi=1,304
|range km=2,415
|ceiling ft=15,000 
|ceiling m=4600 
|climb rate ftmin=1,850 
|climb rate ms=9.4 
|bombs={{cvt|4000|lb|kg}} of bombs, torpedoes, and depth charges
|rockets=six {{cvt|5|in|mm}} unguided [[High Velocity Aircraft Rocket]]s (HVAR)
}}

==See also==
{{aircontent
|related=
|similar aircraft=
* [[Bréguet 960 Vultur]]
* [[Consolidated TBY Sea Wolf]]
* [[Douglas XTB2D Skypirate]]
* [[Fairey Gannet]]
* [[Fairey Spearfish]]
* [[Grumman TBF Avenger]]
* [[Grumman S-2 Tracker]] 
* [[Nakajima B6N]]
* [[Short Seamew]]
|see also=
*[[List of attack aircraft]]
*[[List of military aircraft of the United States]]
}}

==References==

===Notes and citations===
{{reflist}}

===Bibliography===
* Donald, David and Daniel J. March. ''Carrier Aviation Air Power Directory.'' Norwalk, CT: AIRtime Publishing, 2001. {{ISBN|1-880588-43-9}}.
* Goodall, Geoffrey. ''Warbirds Directory''. Victoria, Australia: Victoria Publishing, Fourth Edition 2005.
* Gunston, Bill. ''Grumman: Sixty Years of Excellence''. New York: Orion Books, 1988. {{ISBN|0-517-56796-2}}.
* Kowalski, Robert J. ''Grumman AF Guardian.'' Naval Fighters Series (#20). Simi Valley, CA: Steve Ginter Publishing, 1991, {{ISBN|0-942612-20-5}}.
* ''Pilot's Manual for Navy Model AF-2S Aircraft, AN 01-85DAB-1.'' Washington: Secretary of the Air Force and the Bureau of Aeronautics, 4 March 1951; reissued in digital DVD version as ''Grumman AF-2S Flight Manual, AN 01-85DAB-1, 1951.'' Richmond Hill, Ontario, Canada: Sicuro Publishing Inc., 2011.
* Salerno, Giorgio. ''Hand-in-Hand: US Navy 'Hunter-Killer' Anti-Sub Teams''. ''[[Air Enthusiast]]'' 111, May/June 2004, pp.&nbsp;32–37. {{ISSN|0143-5450}}
* Swanborough, Gordon and Peter M. Bowers. ''United States Navy Aircraft since 1911''. London: Putnam, Second edition, 1976. {{ISBN|0-370-10054-9}}.
* Swanborough, Gordon and Peter M. Bowers. ''United States Navy Aircraft since 1911''. London: Putnam, Third edition, 1990. {{ISBN|978-0-87021-792-0}}.
* Thruelsen, Richard. ''The Grumman Story''. New York: Praeger Publishers, Inc., 1976. {{ISBN|0-275-54260-2}}.
* Wagner, Ray. ''American Combat Planes.'' New York: Doubleday & Company, Third Edition, 1982. {{ISBN|0-385-13120-8}}.

==External links==
{{Commons category|Grumman AF Guardian}}
* [https://www.scribd.com/doc/55087821 (1951) AN 01-85DAB-1 Pilot's Handbook for Navy Model AF-2S Aircraft]{{dead link|date=March 2018 |bot=InternetArchiveBot |fix-attempted=yes }}
* {{usurped|1=[https://web.archive.org/web/20080605225040/http://www.vectorsite.net/avguard.html Grumman AF Guardian at Greg Goebel's Air Vectors]}}
* [https://web.archive.org/web/20070716171620/http://www.arizonawingcaf.com/pages/guardian.html AF2S Guardian at Arizona Wing Commemorative Air Force]

{{Grumman aircraft}}
{{USN attack aircraft}}
{{USN torpedo aircraft}}

[[Category:Grumman aircraft|A01F Guardian]]
[[Category:1940s United States anti-submarine aircraft]]
[[Category:Single-engined tractor aircraft]]
[[Category:Carrier-based aircraft]]
[[Category:Mid-wing aircraft]]
[[Category:Aircraft first flown in 1945]]
[[Category:Aircraft with retractable conventional landing gear]]
[[Category:Single-engined piston aircraft]]