The G-89 was a twin-engine aircraft with a crew of four that could carry a variety of torpedoes, depth charges, and mines in an internal bomb bay or on wing racks. It could also carry 5-inch rockets on the latter. The aircraft carried sonobuoys, used to detect submarine sounds and transmitting them by radio, in the rear of the engine nacelles. Initially named the Sentinel, the G-89 was renamed Tracker before entering USN service. The Navy designated the plane S2F-1, and it soon earned the nickname “Stoof” (S-two-F). The S2F-1 first flew in December 1952, and the first Navy squadrons were outfitted with the plane in February 1954. Grumman built 1,169 Trackers between December 1952 and December 1967, and de Havilland of Canada built another 100 under license. In September 1962, all USN S2F-types were re-designated S-2s.

A highly successful design, the Tracker series of aircraft flew over 22 years in the active US Navy. Eight S-2 squadrons flew in the Vietnam War. The last deployment of Trackers aboard an aircraft carrier in an ASW role was in 1975. The Naval Air Training Command retired their TS-2A’s in 1979, and the last flight of a Tracker in US naval service was in 1986. Export versions served with 14 foreign air arms, and Argentina flew S-2E Trackers in the 1982 Falklands War. Some foreign service aircraft were re-engined with turbine-propeller power plants. Today, several privately owned Trackers may be seen on the airshow circuits. Both radial engine and turboprop versions have flown as forest fire-fighters in the United States, Canada, and France.

Combat Air Museum’s US-2A was built as an S2F-1 at Grumman’s Bethpage, Long Island, New York factory, the famous “Bethpage Iron Works.” Assigned USN Bureau Number (BuNo) 136486, it was accepted by the Navy May 31, 1956. The plane flew over 24 years with the US Navy and Navy Reserves and served its final three years of naval service as a non-flying instructional airframe. The aircraft was modified to an S2F-1S in 1959 with the installation of AQA-3 Jezebel long-range acoustic search equipment and an improved Julie explosive echo-ranging system. In September 1962, the S2F-1S designation became S-2B. In 1963, the plane’s designation became S-2F with further updating of the Jezebel/Julie installation. 136486’s last conversion came in 1968. All ASW gear was removed, and it became a target towing utility transport, designated US-2A. In February 1972, the plane made an unintentional wheels-ups landing, causing extensive structural damage to its lower fuselage. It was repaired and returned to flying duties several months later. 136486’s naval flying career ended in 1980 when assigned to Naval Air Reserve Training Center, Olathe (Gardner), Kansas.

Olathe used the Tracker as a “training device” until declaring it surplus in October 1982. On January 23, 1983, the Naval Air Systems Command placed the US-2A on loan to Combat Air Museum. Two Museum members flew the aircraft to Forbes Field on September 24, 1983. In January 1989, Naval Air Systems Command transferred the aircraft to the General Services Administration and the Kansas State Agency for Federal Surplus Property, who, in turn, placed the Tracker on Conditional Transfer to Combat Air Museum. The Museum became sole owner of the BuNo 136486 in July 1986.

This aircraft is owned by Combat Air Museum.

Assignments
June 1956	Air Antisubmarine Squadron VS-31, the Topcats, Naval Air Station (NAS) Quonset Point, Rhode Island Deployments aboard ASW Support (CVS) aircraft carriers USS LEYTE (CVS 32) and USS WASP (CVS 18)
May 1958	Air Antisubmarine Squadron VS-32, the Norsemen, NAS Quonset Point. Deployments aboard USS WASP (CVS-18)
June 1959	Overhaul and Repair (O&R), Bureau of Aeronautics (BUAER) Maintenance and Supply (M&S) and Bureau of Weapons (BUWEPS) Fleet Reserve (FR), NAS Pensacola, Florida
March 1960	VS-31, NAS Quonset Point
June 1960	Air Antisubmarine Squadron VS-28, the Hukkers, with deployments aboard USS WASP (CVS 18)
July 1962	Naval Air Reserve Training (NART), NAS Willow Grove, (Horsham) Pennsylvania
February 1963	O&R BUWEPS FR, NAS Pensacola
October 1963	NART, NAS Willow Grove
July 1966	Military Aircraft Storage and Disposal Center, Davis-Monthan Air Force Base (AFB), (Tucson) Arizona
December 1967	Naval Air Rework Facility (NARF), NAS Pensacola
March 1968	NAS Quonset Point
March 1970	Naval Air Facility (NAF) Washington, D.C., located at Andrews AFB, (Camp Springs) Maryland
May 1972	NARF, NAS Quonset Point
July 1972	NAF Washington, D.C.
July 1973	NAF Detroit, (Mount Clemens) Michigan
January 1975	Naval Air Reserve Unit (NARU), NAF Washington, D.C.
March 1975	NAS South Weymouth, Massachusetts
May 1975	NARU, NAS Point Mugu, California
September 1975	NARU, NAS Whidbey Island, (Oak Harbor) Washington
March 1976	NAF Detroit
July 1980	Naval Air Reserve Center Olathe, (Gardner) Kansas
September 1983	Combat Air Museum
TECHNICAL NOTES:	(S-2A)
Manufacturer:	Grumman
Basic Role:	Antisubmarine Search and Strike aircraft
Crew:	Pilot, co-pilot/navigator, radio/radar operator, MAD (Magnetic Anomaly Detector) operator
Power Plant:	Two 1,525 hp (1,137kW) each Wright Cyclone, R-1820, nine-cylinder, air-cooled, radial engines
Maximum speed:	272 mph (438km/h)
Cruising speed:	149 mph (240km/h)
Service ceiling:	22,800 ft (6,949m)
Wingspan	: 69 ft 8 in (21.23m)
Length:	42 ft (12.8m)
Height:	16 ft 3.5in (4.97m)
Wing Area:	485 sq ft (45.06 sq m)
Weights:	Empty: 17,357 lbs (7873kg) Combat: 22,222 lbs (10.080kg) Gross: 24,408 lbs (11,071kg)
Range:	968 miles (1,123km)
Armament:	Maximum weapons load: 4,810 lbs (2,182kg); Fuselage weapons bay for one Mk 34, or one Mk 41, or two Mk 43 torpedoes, or one Mk 24 mine; Six underwing stores for four Mk 19 mines, or four Mk 43 torpedoes, or four Mk 54 depth charges, or six high velocity aircraft rockets (HVARs); Eight sonobuoys in each engine nacelle.
Serial number:	US Navy BuNo. 136486 (FAA Reg. Number N486GT)