Grumman AF Guardian

AF Guardian
Hunter-Killer team of AF-2W (lower) and AF-2S
Role	Anti-submarine aircraft
National origin	United States
Manufacturer	Grumman
First flight	19 December 1945
Introduction	October 1950
Retired	31 August 1955
Status	Replaced by S-2 Tracker
Primary user	United States Navy
Number built	389

The Grumman AF Guardian was the first purpose-built anti-submarine warfare (ASW) carrier-based aircraft to enter service with the United States Navy. It consisted of two airframes, one for detection gear, the other for weapons. The Guardian remained in service until August 1955, when it was replaced by the twin-engine Grumman S-2 Tracker. The Guardian was the largest single-engine piston-powered carrier aircraft ever to see service.

Design and development

A AF-2W from VS-37 in flight circa July 1957

The original design concept for the aircraft that would become the Guardian, the XTB2F of 1944, was to be a twin-engined aircraft with a 3,600 lb (1,633 kg) warload and a range of 3,700 mi (5,950 km). This was considered to be too large for practical use from an Essex class aircraft carrier, and was canceled in 1945, replaced by a modified Grumman F7F Tigercat, the XTSF-1.

However, this too was considered impractical, and another alternative, the internally-developed Grumman Model G-70, was selected instead, being given the Navy designation XTB3F. This was designed as mixed-power aircraft, with a Pratt & Whitney Double Wasp radial engine in the nose and a Westinghouse 19XB turbojet in the tail. This was found to be unsuitable and the jet engine was removed without ever having been used in flight. The XTB3F-1S carried a crew of two seated side-by-side and an armament of two 20 mm cannon and 4,000 lb (1,814 kg) of bombs, torpedoes and/or rockets, and made its first flight on 19 December 1945.

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). The hunter aircraft would not carry any armament, but instead two additional crew members and a ventral radome for APS-20 search "eyes" (radar) and Electronic Countermeasures (ECM) "ears", consisting of an APR-98 Countermeasures Receiver and AP-70 Bearing Indicator. This aircraft, the XTB3F-1S, first flew in November 1948. 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.

Operational history

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,with full service introduction shortly after with VS-25. A total of 193 AF-2S Guardians were built. 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. The last Guardian was delivered to the Navy in March 1953, with a total of 389 built.

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. Shortly after the end of the war, it began to be replaced by the Grumman S2F Tracker, the first purpose-built single airframe ASW airplane to serve the U.S. Navy. The last AF retired from active service on 31 August 1955, but it remained in service with the US Naval Air Reserve until 1957.

Variants

The underside of an AF-2S showing its opened weapons bay

XTB3F-1

Prototypes of two-seat torpedo bomber powered by two 2,300 hp R-2800-46 engines and a Westinghouse turbojet; three built.

XTB3F-1S

Two modified XTB3F-1 prototypes with turbojet removed and ventral radome , later re-designated as XAF-1.

AF-2S

Production variant with 2,400 hp R-2800-48 engines, 193 built.

AF-2W

Hunter variant with search radar in a ventral radome, 153 built.

AF-3S

Hunter/Killer variant similar to AF-2S with retractable MAD boom, 40 built.

Grumman Model G-90

Proposed combined AF-2S/-2W version, cancelled.

Operators

Grumman AF Guardian in Aero Union colors at Pima

United States

• United States Navy
• Aero Union

Survivors and aircraft on display

AF-2 Guardian on display at the National Museum of Naval Aviation

Remains of Grumman AF Guardian at Pima

After disposal by the U.S. Navy five Guardians saw many years service with Aero Union based at Chico California in the forest fire-fighting role, the last being retired in 1978.

• An ex-Aero Union AF-2S, BuNo 123088, civil registration N3143G, is currently dismantled, and in storage in Ocala, Florida. While owned by Aero Union this aircraft was converted into a fire-bomber, but never saw service in that role. It is owned by Aero-Trans Corporation. This is the same aircraft advertised for sale by Aero Union in July 2003.
• An ex-Aero Union AF-2S, BuNo 126731, civil registration N9993Z, is currently owned by the Commemorative Air Force. The aircraft was restored in 1997, and flew briefly with the CAF as "Navy 126731/SM/10". The aircraft is currently on static display with its wings folded at the CAF's Mesa facility in Mesa, Arizona.
• An AF-2S, BuNo 126759, civil registration N3144G, is in open storage in Tulare, California.
• An ex-Aero Union AF-2S, BuNo 126792, civil registration N9995Z, is currently in the collection of Jimmy Leeward, and located at the Leeward Air Ranch at Ocala, Florida. This aircraft had flown as Tanker #E21 with Aero Union until 1977. It was owned by the EAA Aviation Foundation in Oshkosh, Wisconsin from 1984 until 1986, when it was acquired by Jimmy Leeward. It currently flies as "Navy 126792".
• An ex-Aero Union AF-2S, BuNo 129233, civil registration N9994Z, is preserved at the Pima Air Museum, Tucson, Arizona. The aircraft is displayed in incorrect Aero Union fire-fighting markings as "N9995Z Tanker E21", the aircraft that is now at the Leeward Air Ranch (see above).
• Another ex-Aero Union AF-2S, BuNo 123100, civil registration N3144G, is on display at the National Museum of Naval Aviation 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 non-historical number "30" on the cowling, for many years the aircraft's call-sign while operating as a fire fighting aircraft;

On 30 March 1954, after encountering engine trouble while on a rescue mission, pilot Lt. John W. Miller with his two crew, Bill Burris and Walter G. Brown ditched an AF Guardian in the water near Santa Cruz Island. A rescue helicopter picked them up that afternoon but the Grumman AF Guardian remains in 60 ft of water to become a living reef and no efforts have been made since to recover the aircraft.

Specifications (AF-2S Guardian)

Data from United States Navy Aircraft since 1911

General characteristics

• Crew: 3 (4 in AF-2W variant)
• Length: 43 ft 4 in (13.21 m)
• Wingspan: 60 ft 8 in (18.49 m)
• Height: 16 ft 2 in (5.08 m)
• Wing area: 560 ft² (52.03 m²)
• Empty weight: 14,580 lb (6,613 kg)
• Max. takeoff weight: 22,640 lb (11,567 kg)
• Powerplant: 1 × Pratt & Whitney R-2800-48W "Double Wasp" radial engine, 2,400 hp (1,790 kW)

Performance

• Maximum speed: 253 mph at full throttle not to exceed 30 minutes at 15,000 ft, gross weight 21,000 pounds (276 kn, 510 km/h)
• Range: 1,500 mi (1,304 nmi, 2,415 km)
• Service ceiling: 15,000 ft (9,900 m)
• Rate of climb: 1,850 ft/min (9.4 m/s)

Armament

• Rockets: 16× 5 in (127 mm) unguided High velocity aircraft rocket (HVAR) rockets
• Bombs: 4,000 lb (1,814 kg) of bombs, torpedoes, and depth charges

See also

• List of attack aircraft
• List of military aircraft of the United States
  

Aircraft of comparable role, configuration and era

• Breguet Vultur
• Consolidated TBY Sea Wolf
• Douglas XTB2D Skypirate
• Fairey Gannet
• Fairey Spearfish
• Grumman TBF Avenger
• Grumman S-2 Tracker
• Nakajima B6N
• Short Seamew
  

References

Notes

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.
• 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 978-0870217920.
• 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

• (1951) AN 01-85DAB-1 Pilot's Handbook for Navy Model AF-2S Aircraft
• Grumman AF Guardian at Greg Goebel's Air Vectors
• AF2S Guardian at Arizona Wing Commemorative Air Force