The Grumman F4F Wildcat was a pivotal American carrier-based fighter aircraft that entered service in 1940 with both the United States Navy and Marine Corps, as well as the British Royal Navy—where it was initially designated the Martlet.
Early Deployment & British Service
Initially ordered by France, the Wildcat was redirected to the British Royal Navy after France fell in 1940.
Entered British service as the Martlet, replacing slower two-seat fighters like the Fairey Fulmar.
Scored its first victory on Christmas Day 1940, downing a German Ju 88 over Scapa Flow—marking the first kill by a U.S.-built fighter in British service.
Wildcats aboard HMS Audacity pioneered escort carrier operations, successfully defending convoys from German Fw 200 Condors.
U.S. Navy & Marine Corps Combat Debut
First U.S. combat use was at Wake Island in December 1941, where Marine squadron VMF-211 used Wildcats to sink the Japanese destroyer Kisaragi and resist invasion.
Wildcats were the primary carrier-based fighter for the U.S. Navy in early Pacific battles, including:
Battle of Coral Sea (May 1942) – provided air cover and engaged Japanese aircraft.
Battle of Midway (June 1942) – flew from USS Yorktown, Enterprise, and Hornet, supporting dive bombers that sank four Japanese carriers.
Guadalcanal & Tactical Evolution
Wildcats formed the backbone of the Cactus Air Force at Henderson Field.
Despite being outperformed by the Mitsubishi A6M Zero, Wildcats proved resilient thanks to armour and self-sealing fuel tanks.
Escort Carrier Operations & Atlantic Theatre
Wildcats were ideal for escort carriers, which couldn’t accommodate larger aircraft like the Hellcat.
Played a key role in anti-submarine warfare, flying from carriers like USS Card and USS Santee to attack German U-boats in the Atlantic.
Wildcats participated in Operation Torch (North Africa, 1942) and Operation Judgement (Norway, 1945), the final FAA air raid in Europe.
Production & Variants
Over 7,800 Wildcats were built, including British Martlets and GM-produced FM variants.
From 1942, production shifted to General Motors’ Eastern Aircraft Division, which built the FM-1 and FM-2 variants for escort carrier use.
FM-2 featured a more powerful engine and lighter airframe, improving performance on smaller carriers.Variants
Variants
US Navy Types
Grumman F4F-1 / F4F-2
The Grumman F4F-1 began as a biplane fighter concept, but early trials revealed its performance was inferior to competing designs.
As a result, Grumman undertook a full redesign, producing the monoplane F4F-2, which marked a significant step toward modern naval aviation.
Despite the improved configuration, the F4F-2 was still outperformed by the Brewster F2A Buffalo, which secured the initial procurement contract from the U.S. Navy.
However, the platform’s potential became clear during the development of the F4F-3, which was equipped with a Pratt & Whitney R-1830-76 Twin Wasp radial engine featuring a two-stage supercharger.
This upgrade substantially enhanced its performance and operational viability, paving the way for the Wildcat series to serve effectively throughout World War II.
Grumman F4F-3 Wildcat
The F4F-3 was the first production monoplane fighter version of the Wildcat series to enter service with the U.S. Navy, marking a significant step forward in naval aviation capability.
Powered by a Pratt & Whitney R-1830-76 Twin Wasp radial engine equipped with a two-stage supercharger, the F4F-3 delivered much-improved altitude performance and reliability over its predecessor designs.
International Service and British Designations
Although initial export orders by France specified units with Wright Cyclone engines, the fall of France resulted in these aircraft being transferred to the Royal Navy’s Fleet Air Arm (FAA).
Designated by Grumman as G-36A, they featured:
Fixed wings
A revised engine cowling
British instrumentation and armament pending local installation
These aircraft were introduced into British service on 8 September 1940 as the Martlet I, though they were not identical to U.S. Navy Wildcats.
Martlet I units retained the F4F-3’s core armament of four 0.50 in (12.7 mm) M2 Browning machine guns, with 450 rounds per gun.
Subsequent British orders led to the G-36B, built with Twin Wasp engines and a modified cowling, redesignated Martlet II.
The Martlet III designation applied to ten G-36Bs with non-folding wings and an additional batch of thirty F4F-3As originally intended for Greece.
Later, the FAA differentiated these as Martlet III(A) and Martlet III(B) to reflect technical variances.
Armament and Operational Issues
Early Wildcats experienced frequent machine gun jamming, an issue common among wing-mounted weapons of the time.
Despite this flaw, dramatic combat successes were achieved:
On 20 February 1942, Lieutenant Edward O’Hare, flying an F4F-3 from USS Lexington, shot down five Mitsubishi G4M twin-engine bombers within minutes.
His wingman, however, was unable to engage due to weapon malfunction.
Service Highlights
Pearl Harbour Era (Dec 1941): Only Enterprise fielded a full Wildcat squadron (VF-6) equipped with F4F-3As.
VMF-211 Wildcats, positioned at Wake Island and Ewa Air Station, suffered losses in initial Japanese attacks, though surviving aircraft fiercely resisted enemy advances.
VMF-211’s Wildcats were credited with sinking the Japanese destroyer Kisaragi and disrupting the invasion force.
Battle of the Coral Sea (May 1942): F4F-3s of VF-2 and VF-42 aboard Yorktown and Lexington participated in critical carrier engagements against Japanese forces including Zuikaku, Shōkaku, and Shōhō.
These battles underscored the urgent need for expanded fighter coverage—most U.S. carriers carried fewer than 20 fighters, insufficient to protect both fleet and strike groups.
F4F-3A Subvariant
Due to a shortage of two-stage superchargers, Grumman developed the F4F-3A, which featured a less powerful R-1830-90 engine with a single-stage, two-speed supercharger:
Top speed
312 mph (502 km/h) at 16,000 ft (4,900 m)
Less popular among Navy pilots due to diminished performance
Entered British service as Martlet III(B)
Grumman F4F-3P Wildcat
(Photo Reconnaissance Variant)
The F4F-3P was a tactical photo reconnaissance adaptation of the standard F4F-3 Wildcat.
In June 1942, a total of 18 aircraft—17 F4F-3s and 1 F4F-3A—were converted for reconnaissance duties.
Modifications
Removal of reserve fuel tanks
Installation of Fairchild F-56 cameras
Retention of standard armament, including machine guns, making the variant combat-capable
Operational Use
Primarily operated by VMO-251, performing air defence missions from Espiritu Santo in the South Pacific beginning July 1942
By October 1942, the long-range, unarmed F4F-7 began replacing the F4F-3P in photo reconnaissance roles
A notable detachment of three F4F-3Ps from VMO-155 flew missions from the escort carrier USS Nassau (CVE-16) during the amphibious invasion of Attu Island, May 1943
Grumman F4F-3S “Wildcatfish”
The F4F-3S “Wildcatfish” was a floatplane adaptation of the standard Grumman F4F-3 Wildcat, developed for forward deployment in the Pacific where airfields were not yet established.
The concept drew inspiration from Japan’s A6M2-N “Rufe”, itself a float-equipped derivative of the Mitsubishi A6M2 “Zeke.”
Development Summary
Conversion basis
F4F-3, BuNo 4038 Modifications
Twin Edo-manufactured floats
added tailplane auxiliary fins for stability
Additional fin
A ventral fin was later installed to address lingering stability issues
First flight
28 February 1943
Performance Impact
Maximum speed
241 mph (388 km/h), significantly reduced due to added drag and weight
Already outclassed by the Zero in aerial combat, the performance reduction limited its viability
Operational Notes
Intended for remote island operations before airstrip construction
Ultimately rendered obsolete by the rapid pace of “Seabee” engineering efforts, which established airfields quickly.
Only one aircraft was ever converted, making the F4F-3S a unique experimental variant
Grumman F4F-4 Wildcat
Introduced in 1941, the F4F-4 was an enhanced variant of the Grumman Wildcat series, featuring the distinctive Sto-Wing folding wing system, patented by Grumman.
This innovation significantly improved carrier storage efficiency, allowing up to 50% more aircraft to be accommodated aboard U.S. fleet carriers by enabling five F4F-4s to occupy the space previously required for two F4F-3s.
Armament Configuration
Upgraded to six .50 in (12.7 mm) M2 Browning machine guns
Ammunition per gun reduced from 450 rounds (as on the F4F-3) to 240 rounds, dropping total firing time from 34 seconds to under 20 seconds
The armament upgrade was influenced by Royal Navy requirements for greater firepower in European theatres
Despite the increase, many U.S. pilots criticised the change, noting reduced firing time and additional weight;
Commander Jimmy Thach famously remarked: _”A pilot who cannot hit with four guns will miss with eight.”
Performance Characteristics
Maximum speed
Approximately 318 mph (512 km/h) at 19,400 ft (5,900 m)
Rate of climb
Claimed at 1,950 ft/min (590 m/min) by Grumman, but pilots often achieved only 500–1,000 ft/min (150–300 m/min) in combat scenarios
Additional weight from folding wings and armament led to reduced climb performance
Combat Service
Became the definitive Wildcat variant during early World War II
Played a key role in major naval engagements such as the Battle of Midway
Replaced F4F-3s in most Navy squadrons by June 1942, although VMF-221 continued operating F4F-3s during Midway
VF-42 aboard USS Yorktown was the final squadron converted to F4F-4s, just prior to Midway, while VF-3, under Thach, received their new F4F-4s en route to battle
Export Variant
The F4F-4B, created for contractual deliveries to the Royal Navy, featured a modified cowling and Wright Cyclone engine
In British service, this variant was designated the Martlet IV
Grumman XF4F-5 Wildcat
The XF4F-5 designation was assigned to a pair of early production F4F-3 Wildcats—specifically the third and fourth aircraft built (Bureau Numbers 1846 and 1847)—which were modified to test alternative powerplants.
These airframes were fitted with the Wright R-1820-40 Cyclone radial engine as part of an evaluation program exploring engine options for the Wildcat series.
The trials conducted with the XF4F-5 contributed to comparative assessments between Wright and Pratt & Whitney engines, ultimately affirming continued use of the R-1830 Twin Wasp in standard production models.
General Motors FM-1 / FM-2 Wildcat
Following Grumman’s transition to F6F Hellcat production in early 1943, the responsibility for continuing Wildcat manufacturing was assumed by General Motors’ Eastern Aircraft Division, which ultimately built 5,280 FM-series Wildcats for both the U.S. Navy and Fleet Air Arm.
By late World War II, the Wildcat was no longer competitive as a frontline fighter compared to newer designs like the F6F Hellcat (max speed: 380 mph / 610 km/h) and the F4U Corsair (max speed: 446 mph / 718 km/h).
However, its compact size, simplicity, and ruggedness made it ideal for use on escort carriers—smaller vessels equipped to carry only two aircraft types: FM-series Wildcats and General Motors-built TBM Avengers.
The Wildcat’s low landing speed and ability to launch without a catapult made it well-suited to short flight decks typical of these ships.
FM-1 Wildcat Configuration
Near-identical to the Grumman F4F-4 Armament
Reduced from six to four .50 in machine guns
Ordnance capability
Wing racks added for two 250 lb (110 kg) bombs or six rockets
FM-2 Wildcat
Based on
Grumman’s XF4F-8 prototype
Optimised for
Escort carrier operations
Engine
More powerful 1,350 hp (1,010 kW) Wright R-1820-56 radial
Design changes
Included a taller vertical tail fin to counter increased engine torque
Grumman F4F-7 Wildcat
(Photo Reconnaissance Variant)
The F4F-7 was a long-range photo reconnaissance variant of the Grumman Wildcat, developed to extend aerial intelligence capabilities over vast oceanic theatres.
To optimise for range and imaging missions
Armour and armament were entirely removed to reduce weight
Non-folding “wet” wings were installed, enabling an additional 555 US gallons (2,101 L) of fuel capacity
Total onboard fuel increased to approximately 700 US gallons (2,650 L), granting an impressive maximum range of 3,700 mi (5,955 km)
This variant retained the Wildcat’s core structural features but sacrificed combat capability for endurance and recon utility.
Only 21 units of the F4F-7 were produced, making it one of the rarer Wildcat subtypes.
Royal Navy Martlets Martlet Mk I
(Grumman G-36A)
The Martlet Mk I was the British designation for a batch of Grumman G-36A fighters originally ordered by France in late 1939.
A total of 81 aircraft were commissioned to equip France’s planned Joffre-class aircraft carriers, Joffre and Painlevé.
Due to export restrictions on the two-stage supercharged engine used in the U.S. Navy’s F4F-3, these aircraft were powered by the Wright R-1820-G205A, a nine-cylinder, single-row radial engine delivering 1,200 hp (890 kW) via a single-stage, two-speed supercharger.
French Modifications
(Pre-delivery)
Metric-calibrated instruments, French radio, and gun-sight
Unique throttle set-up
moved rearward to increase engine power per French design practice
Planned armament
six 7.5 mm Darne machine guns (two fuselage, four wing-mounted)
The first G-36A flew on 11 May 1940, but before any deliveries were completed, France surrendered.
The British subsequently acquired the entire order.
British Adaptation
Aircraft modified by Blackburn Aircraft
Standardised British equipment installed, including gunsights and catapult spools
American radio systems retained after tests proved superior
Armament updated to four .50 in (12.7 mm) Browning machine guns, all mounted in the wings
Most traces of French configuration removed, including throttle reconfiguration
Operational Use
Entered British service in August 1940 with 804 Naval Air Squadron, based at Hatston, Orkney Islands
Martlet Mk I lacked wing-folding mechanisms, limiting use to land bases, though limited carrier deployments occurred
882 Squadron operated six aboard HMS Illustrious (March 1942)
Illustrious transferred two Martlet Is to HMS Archer (April 1942)
one aircraft later retrofitted with folding wings during transit
Belgian Order
Belgium ordered at least 10 G-36As in 1940, intended for land use and modified similarly to French specifications, with tailhooks removed
Belgian surrender halted delivery
by 10 May 1940, the order was reassigned to the Royal Navy
Martlet Mk II
(Grumman G-36B)
The Martlet Mk II was the second Fleet Air Arm (FAA) variant of the Grumman Wildcat, based on the G-36B export fighter ordered by Britain prior to accepting the earlier Martlet Mk I into service.
A total of 100 aircraft were commissioned, each powered by the Pratt & Whitney R-1830-S3C4-G Twin Wasp radial engine, rated at 1,200 hp (890 kW) and utilising a single-stage, two-speed supercharger.
Design Adaptations
To facilitate carrier operations aboard Illustrious-class carriers—which had narrow elevator platforms—the FAA deferred delivery to incorporate Grumman’s patented Sto-Wing folding wing mechanism, as used on U.S. Navy F4F-4 Wildcats.
However, the first 10 units retained fixed wings, with folding-wing deliveries beginning in August 1941.
Further British-specific modifications included
Armour plating and self-sealing fuel tanks (not fitted on U.S. Navy F4F-3s)
Larger tailwheel for improved deck handling
Adaptation of British-style catapult spools, while retaining American “sting” tailhooks and single-point catapult interfaces
Distribution and Testing
36 aircraft shipped to the United Kingdom
54 aircraft dispatched to the Far East
Officially designated Martlet Mk II upon entry into service
Testing by the Aeroplane and Armament Experimental Establishment (A&AEE) yielded:
Max speed
293 mph (472 km/h) at both 5,400 ft (1,600 m) and 13,800 ft (4,200 m)
Climb rate
1,940 ft/min (9.9 m/s) at 7,600 ft (2,300 m) and 7,790 lb (3,530 kg)
Ceiling
31,000 ft (9,400 m)
Time to 20,000 ft (6,100 m): 12.5 minutes
Operational History
Martlet Mk II was the second monoplane fighter operated from British carriers following the Sea Hurricane IB.
Though most were deployed to the Far East, the variant saw varied operational use
HMS Audacity
(Sept–Dec 1941)
Operated six Martlets on open deck
Achieved notable success against Fw 200 Condors, including victories by legendary pilot Eric “Winkle” Brown
Demonstrated effectiveness of fighter cover against U-boat threats
Sunk by U-boat on 21 December 1941, with only two pilots surviving
HMS Illustrious
881 & 882 Squadrons supported operations against Madagascar in May 1942
HMS Indomitable
806 NAS provided air cover for Malta convoys in August 1942
Participated in the North African landings later that year
Martlet Mk III
(British Wildcat Variant)
The Martlet Mk III comprised two distinct groups of fixed-wing aircraft adopted by the Fleet Air Arm (FAA) during World War II, both derived from U.S. Navy Wildcat exports.
Martlet III(B)
Originally 30 F4F-3A Wildcats, ordered by Greece following the Italian invasion in November 1940
With Greece’s defeat in April 1941, the aircraft—then staged at Gibraltar—were redirected to British service
Taken on charge by the FAA and designated Martlet Mk III(B)
Lacking wing-folding mechanisms, they were assigned to shore-based operations, particularly in the Western Desert
Martlet III(A)
Ten fixed-wing G-36B aircraft also incorporated into FAA service
These units were designated Martlet Mk III(A) and likewise restricted to land-based roles due to non-folding wing design
Martlet Mk IV
(British F4F-4 Wildcat Variant)
The Martlet Mk IV was the Fleet Air Arm designation for 220 Grumman F4F-4 Wildcats acquired by the Royal Navy, modified to suit British operational standards.
These aircraft featured distinct technical and structural alterations from their U.S. Navy counterparts.
Technical Characteristics
Engine
Wright R-1820-40B Cyclone radial
Cowling
More compact and rounded profile, lacking lip intake
Flap configuration
One double-wide flap per side on the rear underside
This powerplant and cowling redesign created a unique silhouette, differentiating Martlet Mk IVs from earlier Martlet marks and standard U.S. Navy F4F-4s.
Performance Testing
(Boscombe Down Trials)
At test weight configurations of 7,350 lb (3,330 kg) and 7,740 lb (3,510 kg), trials yielded Metric Performance Value
————————————————————————–
Max speed @ 3,400 ft 278 mph (447 km/h)
Max speed @ 14,600 ft 298 mph (480 km/h)
Max climb rate @ 6,200 ft 1,580 ft/min (8.0 m/s)
Time to 20,000 ft 14.6 minutes
Service ceiling 30,100 ft (9,200 m)
These figures placed the Martlet Mk IV squarely within the performance envelope required for escort carrier and fleet protection duties.
Martlet Mk V
(Grumman FM-1 Wildcat)
The Martlet Mk V was the Fleet Air Arm designation for 312 FM-1 Wildcats acquired from General Motors’ Eastern Aircraft Division.
These aircraft represented a continuation of the Wildcat design tailored for British naval use, primarily operating from escort carriers.
Initially designated as Martlet V, the type was reclassified in January 1944 following a broader standardisation initiative to adopt American nomenclature for U.S.-supplied aircraft.
From that point onward, the Martlet V was officially known in Royal Navy service as the Wildcat V.
Wildcat Mk VI
(Fleet Air Arm Designation for FM-2)
The Wildcat Mk VI was the Air Ministry designation assigned to the General Motors FM-2 Wildcat in Fleet Air Arm (FAA) service during World War II.
This variant featured performance upgrades tailored for operations aboard escort carriers, including a more powerful Wright R-1820-56 radial engine, lightweight construction, and a taller tail for improved stability.
The Wildcat Mk VI offered enhanced manoeuvrability and was well-suited to the compact flight decks of smaller British carriers, serving primarily in anti-submarine and fleet protection roles late in the war.
