The Grumman S-2 Tracker (S2F prior to 1962) was the first purpose-built, single airframe anti-submarine warfare (ASW) aircraft to enter service with the United States Navy.
Designed and initially built by Grumman, the Tracker was of conventional design propeller-driven with twin radial engines, a high wing that could be folded for storage on aircraft carriers, and tricycle undercarriage.
The type was exported to a number of navies around the world. Introduced in 1952, the Tracker and its E-1 Tracer derivative saw service in the U.S. Navy until the mid-1970s, and its C-1 Trader derivative until the mid-1980s, with a few aircraft remaining in service with other air arms into the 21st century.
Argentina and Brazil are the last countries to still use the Tracker.
The Tracker was intended as a replacement for the Grumman AF Guardian, which was the first purpose-built aircraft system for ASW, using two airframes for two versions, one with the detection gear, and the other with the weapon systems.
The Tracker combined both functions in one aircraft.
Grumman’s design (model G-89) was for a large high-wing monoplane with twin Wright Cyclone R-1820 nine-cylinder radial engines, a yoke type arrestor hook and a crew of four.
Both the two XS2F-1 prototypes and 15 S2F-1 production aircraft were ordered at the same time, on 30 June 1950.
The first flight was conducted on 4 December 1952, and production aircraft entered service with VS-26, in February 1954.
Follow-on versions included the WF Tracer and TF Trader, which became the Grumman E-1 Tracer and Grumman C-1 Trader in the tri-service designation standardization of 1962.
The S-2 carried the nickname “Stoof” (S-two-F) throughout its military career; and the E-1 Tracer variant with the large overhead radome was colloquially called the “stoof with a roof.”.
Grumman produced 1,185 Trackers and another 99 aircraft carrying the CS2F designation were manufactured in Canada under license by de Havilland Canada.
U.S.-built versions of the Tracker were sold to various nations, including Australia, Japan, Turkey and Taiwan.
The Tracker had an internal torpedo bay capable of carrying two lightweight aerial torpedoes or one nuclear depth charge.
There were six underwing hard points for rocket pods and conventional depth charges or up to four additional torpedoes.
A ventrally mounted retractable radome for AN/APS-38 radar and a Magnetic Anomaly Detector (MAD) AN/ASQ-8 mounted on an extendable rear mounted boom were also fitted.
Early model Trackers had an Electronic Support Measures (ESM) pod mounted dorsally just aft of the front seat overhead hatches and were also fitted with a smoke particle detector or “sniffer” for detecting exhaust particles from diesel-electric submarines running on snorkel.
Later S-2s had the sniffer removed and had the ESM antennae moved to four rounded extensions on the wingtips.
A 70-million-candlepower searchlight was mounted on the starboard wing.
The engine nacelles carried JEZEBEL sonobuoys in the rear (16 in early marks, 32 in the S-2E/G).
Early Trackers also carried 60 explosive charges, dispensed ventrally from the rear of the fuselage and used to create sound pulses for semi-active sonar (JULIE) with the AN/AQA-3 and later AQA-4 detection sets, whereas the introduction of active sonobuoys (pingers) and AN/AQA-7 with the S-2G conversion saw these removed.
Smoke dispensers were mounted on the port ventral surface of the nacelles in groups of three each.
Variants
XS2F-1
Two prototype anti-submarine warfare aircraft powered by 1,450 hp R-1820-76WA engines.
YS2F-1
Designation of the first 15 production aircraft used for development, redesignated YS-2A in 1962.
S2F-1
Initial production variant with two 1,525 hp R-1820-82WA engines, re-designated S-2A in 1962.
S2F-1T
Trainer conversion of S2F-1, redesignated TS-2A in 1962.
S2F-1U
Utility conversion of S2F-1, redesignated US-2A in 1962.
S2F-1S
S2F-1 conversion with Julie/Jezebel detection equipment, redesignated S-2B in 1962.
Survivors converted to US-2B after removal of ASW gear.
S2F-1S1
S2F-1S fitted with updated Julie/Jezebel equipment, redesignated S-2F in 1962.
S2F-2
As S2F-1 with asymmetrical (port-side) extension of bomb bay, slightly enlarged tail surfaces, most redesignated S-2C in 1962.
S2F-2P
Photo reconnaissance conversion of S2F-2, redesignated RS-2C in 1962.
S2F-2U
Utility conversion of S2F-2/S-2C, redesignated US-2C in 1962.
Some were used as target tugs.
S2F-3
Enlarged forward fuselage, enlarged tail surfaces, additional fuel capacity, and enlarged engine nacelles bays for 32 sonobuoys, redesignated S-2D in 1962.
S2F-3S
As S2F-3 but with Julie/Jezebel equipment, redesignated S-2E in 1962.
YS-2A
YS2F-1 redesignated in 1962.
S-2A
S2F-1 redesignated in 1962.
TS-2A
S2F-1T training version redesignated in 1962 and 207 conversion from S-2A.
US-2A
S-2A converted as light transports/target tugs, 51 conversions.
S-2B
S2F-1S redesignated in 1962.
US-2B
Utility and target tug conversions of S-2A and S-2B; most S-2Bs were converted and 66 S-2As.
S-2C
S2F-2 redesignated in 1962.
RS-2C
S2F-2P photo-reconnaissance version redesignated in 1962.
US-2C
S2F-2U utility version redesignated in 1962.
S-2D
S2F-3 redesignated in 1962.
YAS-2D/AS-2D
Proposed self-contained night attack aircraft to be developed under Operation Shed Light; none produced.
ES-2D
Electronic trainer conversion of the S-2D.
US-2S
Utility conversion of the S-2D.
S-2E
S2F-3S redesignated in 1962.
S-2F
S2F-1S1 redesignated in 1962.
US-2F
Transport conversion of S-2F.
S-2G
S-2E conversions with updated electronics (primarily AN/AQA-7 DIFAR sonobuoy processor and AN/ARR-75 sonobuoy receiver)
CS2F-1
Initial production run of anti-submarine warfare aircraft for Canada based on S2F-1.
A total of 42 built by De Havilland Canada.
CS2F-2
Improved version of CS2F-1 with Litton Industries tactical navigation equipment.
A total of 57 were built by De Havilland Canada.
CS2F-3
New designation given to 43 CS2F-2 aircraft upgraded with additional electronics.
CP-121
New designation given to all CS2F-1, -2, and -3 aircraft following unification of Canadian military in 1968.
Military S-2T Turbo Tracker For Argentina
Upgraded S-2E with new engines and military equipment by IAI in the 1990s for the Argentine Navy.
6 upgraded.
Military S-2T Turbo Tracker For Taiwan
Upgraded S-2E/S-2G with new engines and military equipment by Grumman from 1986 to 1992 for the ROC Air Force.
27 upgraded.
S-2T Turbo Tracker
Civil conversion
S-2AT
Civil firefighter conversion with turboprop engines.
S-2ET
Civil conversion
Marsh Aviation S-2F3AT Turbo Tracker
Turboprop conversion, powered by two Garrett TPE331 engines.
A total of 22 are operated by the CDF.
Conair Firecat or Turbo Firecat
Civil conversion as a single-seat firefighting aircraft.
Specifications
Crew
4
Length
43 ft 6 in (13.26 m)
Wingspan
72 ft 7 in (22.12 m)
Height
17 ft 6 in (5.33 m)
Wing area
485 sq ft (45.1 m2)
Empty weight
18,315 lb (8,308 kg)
Gross weight
23,435 lb (10,630 kg)
Max take-off weight
26,147 lb (11,860 kg)
Powerplant
2 × Wright R-1820-82WA,
9-cylinder air-cooled radial piston engines,
1,525 hp (1,137 kW) each
Performance
Maximum speed
243 kn (280 mph, 450 km/h) at sea level
Cruise speed
130 kn (150 mph, 240 km/h)
Range
1,173 nmi (1,350 mi, 2,172 km)
Endurance
9 hours endurance
Service ceiling
22,000 ft (6,700 m)
Armament
4,800 lb (2,200 kg) of payload could be carried in the internal bomb bay and on 6× underwing hardpoints
