Grumman F4F Wildcat

F4F-3. Meanwhile the first mass produced F4F-3 (BuNo 1844) was test-flown in February 1940 with a Pratt & Whitney R-1830-76 engine (1200 hp). The first production examples were thoroughly flight tested at NAS Anacostia as well as at the Pratt & Whitney plant. Two planes built according to the requests of the Bureau of Aeronautics also participated. The fifth and sixth machines already had a reinforced undercarriage and an armored cockpit. The trials continued despite a tragic incident – on 17 December the XF4F-3 prototype crashed and its pilot, Lt(jg) W. C. Johnson was killed in the accident. He had accidentally cut off the fuel instead of lowering the flaps because the switches were adjacent to one another. After the accident they were moved further apart. At first the standard version had neither self-sealing fuel tanks nor cockpit armor.
The tests ended in January 1941. The plane, armed with four half-inch guns, was considered fit to serve on aircraft carriers but still needed modifications. The problems that needed attention included a slight longitudinal instability, along with vibrations in the canopy. In addition there were concerns over the cartridge feeders’ faulty power supply during gravity overload, bad cockpit ventilation that let in too many exhaust fumes; inadequate rear fuselage ventilation which didn’t eliminate the liquefaction of fuel along with a weak tail wheel.
The maximum speed of 533 kph was a little disappointing, as it was 30 kph less than expected. However the service ceiling of 11 300 meters and the take-off run of only 60 meters, particularly useful for a shipborne type, both made quite an impression.
On 5 December 1940 the first F4F-3 joined carrier squadron VF-4 on the USS Ranger. Soon afterwards F4F-3’s were also in service with VF-7 on the USS Wasp. Deliveries were so sluggish that by mid-January 1941 the US Navy had only received 22 planes.
Like any new design, Grumman’s fighter had its share of teething problems. The first flights of the F4F-3 revealed new headaches. Besides the double-stage supercharger, the most dangerous complications were two cases of wing floats inflating of their own accord. Ens. Harry Howell died in one of these accidents. Lt. Seymour Johnson was killed when his oxygen system malfunctioned. Another unexpected problem arose when a cockpit canopy glazing pane shattered during a dive. The pilot of the F4F-3, Ens. Wally Malden was wounded in the face. All of the side glazing was instantly replaced and by 28 May 1941 the inflatable floats were removed. Two months earlier a directive was issued that all F4F-3’s be equipped with gun cameras.

 5. The Wildcat float-plane’s characteristics didn’t improved even after installing an additional fin. [Via Andre R. Zbiegniewski]

F4F-3s were produced until 1943. Beginning with the 101st plane, they were given an improved Pratt & Whitney R-1830-86 engines (1200 hp) with a double-stage, double-speed supercharger.

Martlet Mk.II. Meanwhile, another serious problem came up. The British had ordered 100 G-36B planes but during the completion of the contract they changed their order requesting folding wings and two additional 12.7 mm machine guns. Due to the fact that the hangars on British aircraft carriers had lower ceilings, it was decided that a manual mechanism would be used for folding the wings backwards while simultaneously turning the wings’ leading edge downwards. The pitot tube was moved from the right wing leading edge under the wing.
Talks with the British lasted so long that when a consensus was reached the construction of the first ten Martlets Mk.II was too advanced to equip them with folding wings. Yet in March 1941 the FAA took delivery of these aircraft and allocated them serials AM954-963 and the unofficial name “non-standard Martlet Mk.II”. They were still armed with four half-inch guns, while the remaining 90 planes – with folding wings – were armed with six machine guns. All were powered by Pratt & Whitney S3C4-G engines fitted with a single-stage, double-speed supercharger and a Curtiss Electric propeller. The last machines were delivered in April 1942.

F4F-3A. Buyers from abroad were interested in a version with the GR-1820-G205A engine, which induced the US Navy to try it out at home. In April 1940 they were fitted in BuNo 1846 and 1847, designated XF4F-5. They only achieved 492 kph, which did not impress the commission. The planes were later tested with a Wright R-1820-54 engine with a turbo supercharger (BuNo 1846) and with a Wright XR-1820-48 engine with a double-stage supercharger (BuNo 1847).
Subsequent tests with various engines were carried out on a XF4F-6 (BuNo 7031), which was equipped with a Pratt & Whitney R-1830-90 Twin Wasp engine rated at 1200 hp with a double-speed single-stage supercharger. Tested in the fall of 1940, the prototype achieved a speed of 513 kph but proved more reliable than its predecessor. The US Navy signed a contract for 95 F4F-3A’s, deliveries commencing in March, 1941. By the end of the following year the contract size rose to an astonishing number of 578 F4F-3s and F4F-3As.