Grumman F4F cat

The Grumman F4F cat was an American carrier-based fighter aircraft that began service with both the United States Navy and the British Royal Navy (as the Martlet) in 1940. First used in combat by the British in Europe, the cat was the only effective fighter available to the United States Navy and Marine Corps in the Pacific Theater during the early part of World War II in 1941 and 1942. (Although the Brewster Buffalo was the Navy's first monoplane fighter, it proved disappointing in combat. It was withdrawn very early in the war and replaced by cats as they became available.) With a top speed of 318 mph (512 km/h), the cat was outperformed by the faster and more nimble 331 mph (533 km/h) Mitsubishi Zero, but its ruggedness, coupled with tactics such as the Thach Weave, resulted in an air combat kill-to-loss ratio of 5.9:1 in 1942 and 6.9:1 for the entire war.

Lessons learned from the cat were applied to the faster F6F Hellcat which could outperform the Zero on its own terms. The cat continued to be built throughout the remainder of the war to serve on escort carriers, where larger and heavier fighters could not be used.

Grumman fighter development began with the two-seat Grumman FF biplane. The FF was the first US naval fighter with a retractable landing gear. The wheels retracted into the fuselage, leaving the tires visibly exposed, flush with sides of the fuselage. Two single-seat biplane designs followed, the F2F and F3F, which established the general fuselage outlines of what would become the F4F cat. In 1935, while the F3F was still undergoing flight testing, Grumman started work on its next biplane fighter, the G-16. At the time, the Navy favored a monoplane design, the Brewster F2A-1, ordering production early in 1936, however an order was also placed for Grumman's G-16 (given the navy designation XF4F-1) as a backup in case the Brewster monoplane proved to be unsatisfactory.

It was clear to Grumman that the XF4F-1 would be inferior to the Brewster monoplane, so Grumman abandoned the XF4F-1, designing instead a new monoplane fighter, the XF4F-2.[3][5] The XF4F-2 would retain the same, fuselage-mounted, hand-cranked landing gear as the F3F, with its relatively narrow track. (The unusual landing gear design was originally created in the 1920's by Leroy Grumman for Grover Loening. It was on all of Grumman's fighter biplanes (from the FF-1 through the F3F) of the 1930s and on the J2F Duck amphibious flying boat as well.[6][N 1]) Landing accidents caused by failure of the gear to fully lock into place were distressingly common.

The overall performance of Grumman's new monoplane was felt to be inferior to that of the Brewster Buffalo. The XF4F-2 was marginally faster, but the Buffalo was more maneuverable. It was judged superior and was chosen for production.[5] After losing out to Brewster, Grumman completely rebuilt the prototype as the XF4F-3 with new wings and tail and a supercharged version of the Pratt & Whitney R-1830 "Twin Wasp" radial engine.[5][8] Testing of the new XF4F-3 led to an order for F4F-3 production models, the first of which was completed in February 1940. France also ordered the type, powered by a Wright R-1820 "Cyclone 9" radial engine, but France fell before they could be delivered and the aircraft went instead to the British Royal Navy, who christened the new fighter the "Martlet." The US Navy officially adopted the plane on 1 October 1941 as the "cat." Both the British and US Navy's F4F-3's, armed with four .50 in (12.7 mm) Browning machine guns, joined active units in 1940.

The cat's successor was the F6F Hellcat, a complete redesign which dropped Grumman's distinctive, hand-cranked, fuselage-retracting landing gear arrangement, replacing it with landing gear which was hydraulically retracted backward into the wings. The Hellcat, which first flew in 1942, almost completely outclassed the Zero, surprising many Japanese pilots who, on their first encounter with the new fighter, often mistook it for the older, slower cat. (Later in the war, US Navy would also introduce another higher-performance fighter, the F4U Corsair, which could match the top speed of the fastest land-based planes of the day.)

The F4F cat (known in British service as the Martlet) was taken on by the British Fleet Air Arm as part of an interim replacement for the Fairey Fulmar. The Fulmar was a two seat fighter with good range but at a performance disadvantage against single seater fighters; navalised Supermarine Spitfires were not being made available because of the greater need of the Royal Air Force. In the European theater, the cat scored its first combat victory on Christmas Day 1940, when a land-based Martlet destroyed a Junkers Ju 88 bomber over the Scapa Flow naval base.[10] This was the first combat victory by a US-built fighter in British service in World War II.[10] The type also pioneered combat operations from the smaller escort carriers.

Six Martlets went to sea aboard the converted former German merchant vessel HMS Audacity in mid-1941 and shot down several Luftwaffe Fw 200 Condor bombers during highly effective convoy escort operations.[12] These were the first of many cats to see shipboard combat.

The Fleet Air Arm was later to abandon the practice of using its own unique names for US-provided aircraft in British naval service, and began to use the US Navy's aircraft names instead.[13][14] In March 1945, cats shot down four Messerschmitt Bf 109s over Norway, the FAA's last victory with a cat.

The cat was outperformed by the Mitsubishi Zero, its major opponent in the early part of the Pacific Theater, but held its own partly because, with relatively heavy armor and self-sealing fuel tanks, the Grumman airframe could survive far more damage than its lightweight, unarmored Japanese rival.[15] Many US Navy fighter pilots also were saved by the cat's ZB homing device, which allowed them to find their carriers in poor visibility, provided they could get within the 30 mi (48 km) range of the homing beacon.[16]

In the hands of an "expert pilot" using tactical advantage, the cat could prove to be a difficult foe even against the formidable Zero.[17] After analyzing Fleet Air Tactical Unit Intelligence Bureau reports describing the new carrier fighter, USN Commander "Jimmy" Thach devised a defensive strategy that allowed cat formations to act in a coordinated maneuver to counter a diving attack, called the "Thach Weave."

Four US Marine Corps cats played a prominent role in the defence of Wake Island in December 1941. USN and USMC aircraft were the fleet's primary air defence during the Battles of Coral Sea and Midway, and land-based cats played a major role during the Guadalcanal Campaign of 1942-43.[5] It was not until 1943 that more advanced naval fighters capable of taking on the Zero on more even terms, the F6F Hellcat and F4U Corsair, reached the South Pacific theatre.

Grumman's cat production ceased in early 1943 to make way for the newer F6F Hellcat, but General Motors continued producing cats for both US Navy and Fleet Air Arm use. From 1943 onward, cats equipped with bomb racks were primarily assigned to escort carriers for use against submarines and attacking ground targets, though they would also continue to score kills against Japanese fighters, bombers and kamikaze aircraft. Larger fighters such as the Hellcat and the Corsair and dedicated dive bombers were needed aboard fleet carriers, and the cat's slower landing speed made it more suitable for shorter flight decks.[19] In the Battle off Samar, fleet carriers had failed to destroy a battleship-led force, but it was lightly armed Avengers and FM fighters from escort carriers of Taffy 3 which found themselves backed against the wall in the path of a much larger Japanese fleet away from Leyte Gulf. By resorting to tactics such as strafing ships including the bridge of the Japanese battleship Yamato, the combined efforts of what was only equipped as a slow light escort force turned back the Japanese fleet. At first, GM produced the FM-1 (identical to the F4F-4, but with four guns). Production later switched to the improved FM-2 (based on Grumman's XF4F-8 prototype) optimized for small-carrier operations, with a more powerful engine, and a taller tail to cope with the increased torque.

In all, 7,860 cats were built.[20][N 2] The British received 300 Eastern Aircraft FM-1s as the Martlet V in 1942/43 and 340 FM-2s as the cat VI.[21] In total, nearly 1,200 cats would serve with the FAA. By January 1944, the Martlet name was dropped and the type was identified as "cat."

During the course of the war, Navy and Marine F4Fs and FMs flew 15,553 combat sorties (14,027 of these from aircraft carriers[22]), destroying 1,327 enemy aircraft at a cost of 191 cats (an overall kill-to-loss ratio of 6.9:1).[23] True to their escort fighter role, cats dropped only 154 tons of bombs during the war.

The original Grumman F4F-1 design was a biplane, which proved inferior to rival designs, necessitating a complete redesign as a monoplane named the F4F-2. This design was still not competitive with the Brewster F2A Buffalo which won initial US Navy orders, but when the F4F-3 development was fitted with a more powerful version of the engine, a Pratt & Whitney Twin Wasp R-1830-76, featuring a two-stage supercharger, it showed its true potential.

US Navy orders followed as did some (with Wright Cyclone engines) from France; these ended up with the Royal Navy's Fleet Air Arm after the fall of France and entered service on 8 September 1940. These aircraft, designated by Grumman as G-36A, had a different cowling from other earlier F4Fs and fixed wings, and were intended to be fitted with French armament and avionics following delivery. In British service initially, the aircraft were known as the Martlet I, but not all Martlets would be to exactly the same specifications as US Navy aircraft. All Martlet Is featured the four .50 in (12.7 mm) M2 Browning machine guns of the F4F-3 with 450 rpg. The British directly ordered and received a version with the original Twin Wasp, but again with a modified cowling, under the manufacturer designation G-36B. These aircraft were given the designation Martlet II by the British. The first 10 G-36Bs were fitted with non-folding wings and were given the designation Martlet III. These were followed by 30 folding wing aircraft (F4F-3As) which were originally destined for the Hellenic Air Force, which were also designated Martlet IIIs.[12][25] On paper, the designation changed to Marlet III(A) when the second series of Martlet III was introduced.

Poor design of the armament installation on early F4Fs caused these otherwise reliable machine guns to frequently jam, a problem common to wing-mounted weapons of many US fighters early in the war.[26][N 4] It was an F4F-3 flown by Lieutenant Edward O'Hare that in a few minutes shot down five Mitsubishi twin-engine bombers attacking Lexington off Bougainville on 20 February 1942. But contrasting with O'Hare's performance, his wingman was unable to participate because his guns would not function.

A shortage of two-stage superchargers lead to the development of the F4F-3A, which was basically the F4F-3 but with a 1,200 hp (890 kW) Pratt & Whitney R-1830-90 radial engine with a more primitive single-stage two-speed supercharger. The F4F-3A, which was capable of 312 mph (502 km/h) at 16,000 ft (4,900 m), was used side by side with the F4F-3, but its poorer performance made it unpopular with US Navy fighter pilots. The F4F-3A would enter service as the Martlet III(B).

At the time of Pearl Harbor, only Enterprise had a fully equipped cat squadron, VF-6 with F4F-3As. Enterprise was then transferring a detachment of VMF-211, also equipped with F4F-3s, to Wake. Saratoga was in San Diego, working up for operations of the F4F-3s of VF-3. 11 F4F-3s of VMF-211 were at the Ewa Marine Air Corps Station on Oahu; nine of these were damaged or destroyed during the Japanese attack. The detachment of VMF-211 on Wake lost seven cats to Japanese attacks on 8 December, but the remaining five put up a fierce defense, making the first bomber kill on 9 December. The destroyer Kisaragi was sunk by the cats,[28] and the Japanese invasion force retreated.

In May 1942, the F4F-3s of VF-2 and VF-42, onboard Yorktown and Lexington, participated in the Battle of the Coral Sea. Lexington and Yorktown fought against the Zuikaku, Shōkaku and the light carrier Shōhō in this battle, in an attempt to halt a Japanese invasion of Port Moresby on Papua. During these battles, it became clear that attacks without fighter escort amounted to suicide, but that the fighter component on the carriers was completely insufficient to provide both fighter cover for the carrier and an escort for an attack force. Most US carriers carried less than 20 fighters.[citation needed]

This floatplane version of the F4F-3 was developed for use at forward island bases in the Pacific, before the construction of airfields. It was inspired by appearance of the A6M2-N "Rufe", a modification of the Mitsubishi A6M2 "Zeke". BuNo 4083 was modified to become the F4F-3S "catfish". Twin floats, manufactured by Edo Aircraft Corporation, were fitted. To restore the stability, small auxiliary fins were added to the tailplane. Because this was still insufficient, a ventral fin was added later.[29]

The F4F-3S was first flown 28 February 1943.[30] The weight and drag of the floats reduced the maximum speed to 241 mph (388 km/h). As the performance of the basic F4F-3 was already below that of the Zero, the F4F-3S was clearly of limited usefulness. In any case, the construction of the airfields at forward bases by the "Seabees" was surprisingly quick. Only one was converted.

A new version, the F4F-4, entered service in 1942 with six machine guns and folding wings which allowed more aircraft to be crammed on a carrier, increasing the number of fighters that could be parked on a surface by more than a factor of 2. The F4F-4 was the definitive version that saw the most combat service in the early war years, including the Battle of Midway. The F4F-3 was replaced by the F4F-4 in June 1942, during the Battle of Midway; only VMF-221 still used them at that time.[citation needed]

This version was less popular with American pilots because the same amount of ammunition was spread over two additional guns, decreasing firing time.[31] With the F4F-3's four .50 in (12.7 mm) guns and 450 rpg, pilots had 34 seconds of firing time; six guns decreased ammunition to 240 rpg, which could be expended in less than 20 seconds. The increase to six guns was attributed to the Royal Navy, who wanted greater firepower to deal with German and Italian foes. Jimmy Thach is quoted as saying, "A pilot who cannot hit with four guns will miss with eight."[32] Extra guns and folding wings meant extra weight, and reduced performance: the F4F-4 was capable of only about 318 mph (512 km/h) at 19,400 ft (5,900 m). Rate of climb was noticeably worse in the F4F-4; while Grumman optimistically claimed the F4F-4 could climb at a modest 1,950 ft (590 m) per minute, in combat conditions, pilots found their F4F-4s capable of ascending at only 500 to 1,000 ft (150 to 300 m) per minute.[16] Moreover, the F4F-4's folding wing was intended to allow five F4F-4s to be stowed in the space required by two F4F-3s. In practice, the folding wings allowed an increase of about 50% in the number of cats carried aboard US fleet aircraft carriers. A variant of the F4F-4, designated F4F-4B for contractual purposes, was supplied to the British with a modified cowling and Wright Cyclone engine. These aircraft received the designation of Martlet IV.

General Motors / Eastern Aircraft produced 5,280 FM variants of the cat.[2] Grumman's cat production ceased in early 1943 to make way for the newer F6F Hellcat, but General Motors continued producing cats for both US Navy and Fleet Air Arm use. Late in the war, the cat was obsolescent as a front-line fighter compared to the faster (380 mph/610 km/h) F6F Hellcat or much faster (446 mph/718 km/h) F4U Corsair. However, they were adequate for small escort carriers against submarine and shore threats. These relatively modest ships carried only two types of aircraft (along with the GM-built Avengers). The cat's lower landing speed and ability to take off without a catapult made it more suitable for shorter flight decks.[19] At first, GM produced the FM-1, identical to the F4F-4, but reduced the number of guns to four, and added wing racks for two 250 lb (110 kg) bombs or six rockets. Production later switched to the improved FM-2 (based on Grumman's XF4F-8 prototype) optimized for small-carrier operations, with a more powerful engine (the 1,350 hp (1,010 kW) Wright R-1820-56), and a taller tail to cope with the torque.

Tasked with supporting ground forces off Leyte, sorely under-armed planes from escort carriers such as Gambier Bay in the "Taffy" task groups found themselves up against a major surface fleet which they helped turn back in the Battle off Samar. Four FM-2 cats from Shamrock Bay's Composite Squadron 94 (VC-94) helped shoot down a number of kamikaze planes attacking Laffey off Okinawa before running out of ammunition.

The F4F-7 was a photoreconnaissance variant, with armor and armament removed. It had non-folding "wet" wings that carried an additional 555 gal (2,101 L) of fuel for a total of about 700 gal (2,650 L), increasing its range to 3,700 mi (5,955 km). A total of 21 were built.[

The F2M-1 was a planned development of the FM-1 by General Motors / Eastern Aircraft to be powered by the improved XR-1820-70 engine, but the project was cancelled before any aircraft were built.

At the end of 1939, Grumman received a French order for 81 aircraft of model G-36A, to equip their new Joffre-class aircraft carrier — Joffre and Painlevé. The main difference with the basic model G-36 was due to the unavailability for export of the two-stage supercharged engine of F4F-3. The G-36A was powered by the nine-cylinder, single-row R-1820-G205A radial engine, of 1,200 hp (890 kW) and with a single-stage two-speed supercharger

The G-36A had also French instrumentation, radio, and gunsight. The throttle was modified to conform to French pre-war practice: the throttle lever was moved towards the pilot, (i.e., backward), to increase engine power. The armament which was to be fitted in France was six 7.5 mm (.296 in) Darne machine guns (two in the fuselage and four in the wings). The first G-36A was flown on 11 May 1940.

After the defeat of France, all contracts were taken over by Britain. The throttle was modified again, four 0.50 in (12.7 mm) guns were installed in the wings, and most traces of the original ownership removed.[35] The Martlets were modified for British use by Blackburn, which continued to do this for all later marks. British gunsights, catapult spools, and other items were installed.[36] After initial attempts to fit British radio sets, it was decided to use the much superior American equipment.

The first ones entered service in August 1940, with 804 Naval Air Squadron, then stationed at Hatson in the Orkney Islands. The Martlet Mk I did not have a wing folding mechanism, and was therefore only used from land bases. In 1940, Belgium also placed an order for at least 10 Martlet Mk 1s. These were to be modified with the removal of the tailhook, however, after the surrender of Belgium, none were delivered and by May 10, 1940, the aircraft order was transferred to the Royal Navy.

Before the Fleet Air Arm took on charge the Martlet Mk Is it had already ordered 100 G-36B fighters. The British chose the Pratt & Whitney R-1830-S3C4-G engine to power this aircraft; this too had a single-stage, two-speed supercharger. The FAA decided to accept a delay in delivery to get folding wings, which were vitally important if the Martlet was to be used from British carriers with their small hangar decks. Nevertheless, the first 10 received had fixed wings. The first Martlet with folding wings was not delivered before August 1941.

In contrast to F4F-3, the British aircraft were fitted with armor and self-sealing fuel tanks. The Mk II also had a larger tailwheel. For carrier operations, the "sting" tail hook and attachment point for the American single-point catapult launch system were considered important advantages. Nevertheless, the Martlets were modified to have British-style catapult spools.

The Martlet was the only single-seat, monoplane carrier fighter available to the British fleet until the introduction of the Sea Hurricane II in 1942.

The majority of the Martlet Mk IIs were sent to the Far East. The first shipboard operations of the type in British service were in September 1941, on board of HMS Audacity, a very small escort carrier with a carrier deck of 420 ft (130 m) by 59 ft (18 m), no elevators and no hangar deck. The six cats were parked on the deck at all times. On its first voyage, it served as escort carrier for a convoy to Gibraltar. On 20 September, a German FW 200 was downed. On the next voyage, four Fw 200 Condors fell to the guns of the Martlets. Operations from Audacity also demonstrated that the fighter cover was useful against U-boats. Audacity was sunk by an U-boat on 21 December 1941, but it had proven the usefulness of escort carriers.

In May 1942, the 881 and 882 squadrons on HMS Illustrious, participated in operations against Madagascar. In August 1942, 806 NAS on HMS Indomitable provided fighter cover for a convoy to Malta. Later in that year they participated in the landings in French North Africa.

The first 30 F4F-3As were released for sale to Greece, after the Italian invasion in November 1940. However, at the defeat of Greece in April 1941 the aircraft had only reached Gibraltar. They were taken over by the FAA as Martlet Mk III. As these aircraft did not have folding wings, they were only used from land bases. They served in a shore-based role in the Western Desert.