Grumman F3F from the left |
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The Grumman F3F was the company’s last biplane fighter produced for the US Navy and was the result of Grumman’s efforts to improving the flying characteristics of the F2F.
Grumman’s first successful aircraft had been the two-man Grumman FF naval fighter, which had made its maiden flight on 29 December 1931 and proved to be faster than the Navy’s fastest service fighter, the Boeing F4B-2. This produced both a production order for the FF, and interest in a single seat version of the design, the Grumman G-8. The Navy ordered a prototype of this design on 2 November 1932, as the XF2F-1. This made its maiden flight on 18 October 1933, and in Navy tests proved to be faster than the FF, although its short stubby fuselage caused some directional instability, and its spinning characteristics weren’t ideal.
Although the Navy was happy with the F2F and placed an order for 54 aircraft on 17 May 1934, Grumman wanted to improve the aircraft’s directional stability, spinning characteristics and make it more manoeuvrable. They were able to use the last aircraft from the F2F order as the prototype XF3F-1 (Grumman G-11), getting permission to do this three and half months before the first production F2F was delivered.
This aircraft was very similar to the FF and F2F, of all metal construction, with a semi-monocoque fuselage and fabric covered wings. Grumman’s first design for the Navy had been for floats to convert land planes into amphibians, which included a novel form of retractable undercarriage where the main wheels were pulled up into the sides of the forward fuselage, and this design was used on the FF, F2F and F3F (and in modified form on the F4F Wildcat). The XF3F-1 used the same Pratt & Whitney R-1535-72 Twin Wasp Junior as the F2F.
The main change made to the XF3F-1 was an increase in fuselage length of 1ft 10in and an increase in wing span of 3ft 6in. The undercarriage was modified, and used tires which were smaller but wider. There were also other more minor aerodynamic changes. The prototypes were slightly slower than the F2F.
The XF3F-1 had a tragic debut. It made its maiden flight on 20 March 1935 with test pilot Jimmy Collins at the controls, but two days later he was killed when the wings and engines came off the aircraft during a test dive. A second aircraft was built, with stronger wing roots and engine mounts, and made its maiden flight on 9 May. However on 17 May it crashed after the Grumman test pilot Lee Gehlbach was forced to bail out after the aircraft entered an unrecoverable flat spin.
However this time the aircraft wasn’t totally destroyed, and it only took three weeks to rebuilt it. This version had a larger rudder to improve recovery from spins. It was delivered to the Navy at Anacostia on 20 June, and on 24 August the Navy placed an order for 54 production aircraft.
F3F-1
The fifty-four F3F-1s were delivered in the first eight months of 1936. They were powered by a 650hp (700hp at take off) Pratt & Whitney R-1535-84 Twin Wasp which drove a hydraulic controllable pitch Hamilton Standard two blade propeller. They were armed with two 0.3in Browning machine guns.
As the F3F-1 began to enter service it suffered from a series of accidents, and in the summer of 1936 was restricted to maneuvers that wouldn’t stress it about 6G. One aircraft underwent testing at the Naval Aircraft Factory and as a result the upper wing beams and parts of the ailerons were strengthened on all aircraft.
The F3F-1s were delivered in the first eight months of 1936. They entered service with VF-5B on USS Ranger, followed by VF-6B on the Saratoga. On 1 July 1937 these squadrons were renumbered as VF-4 and VF-3 to match the hull number of their carriers.
The F3F-1 was briefly used by Marine Squadron VF-4M from January 1937 (VMF-2 from July 1937) while it was waiting for the F3F-2 to enter service. Soon after changing name the squadron converted to the F3F-2.
The final squadron to get the F3F-1 was the newly formed VF-7 (USS Wasp (CV-7)), which received half of VF-3’s aircraft in December 1939 when that squadron converted to the Brewster F2A-1 Buffalo. VF-7 eventually had fifteen F3F-1s and two F2F-1s, and would be the last unit to operate the type, handing its last F3F-1s to Training Command on 10 February 1941 as it converted to the Grumman F4F-3.
XF3F-2
In November 1935 the Navy issued a request for a proposal for a new single seat fighter to replace the F2F and F3F-1. Grumman put forward another biplane, the G-16, and on 2 March 1936 were given a contract to built one prototype, as the XF4F-1. However three months later Brewster were given a contract for the prototype of what became the monoplane Brewster Buffalo. This worried Grumman, who came up with two new proposals. The most important was for the contract for the biplane XF4F-1 to be replaced with one for the monoplane Grumman G-18. This was accepted, and this became the XF4F-2, the first Grumman Wildcat. The second was to be allowed to give the last F3F-1 a supercharged engine, which they believed would give the F3F similar performance to the original XF4F-1.
The Navy also approved this plan, and on 28 July 1936 an order was placed to convert the last F3F-1 into the prototype XF3F-2. This used a larger diameter single-row two-speed supercharged 850 Wright XR-1820-22 Cyclone radial engine, driving a three blade controllable pitch propeller. This required a change in the shape of the nose. The prototype was also given more fuel.
Grumman had already been working on this prototype, and it was delivered to Anacostia on 27 July 1936, two days before the contract was signed (its maiden flight was even earlier, on 21 July!) However problems with the carburettor delayed the trails until January 1937. When the trials began the new engine gave the F3F-2 an improved top speed of 255mph and raised the service ceiling to 30,200ft.
F3F-2
81 F3F-2s were ordered on 23 March 1937. They were delivered between 27 July 1937 and 11 May 1938. However it still needed work to solve problems with carbon monoxide in the cockpit and with oil cooling, so didn’t enter fleet service until 4 November 1937.
The production aircraft had a new larger rudder to cope with the increase torque from the new engine, a new canopy and windscreen. It was powered by a Wright R-1820-22 Cyclone that provided 950hp at take-off. Top speed rose to 256mph and its service ceiling to 32,400ft. It was armed with one .30in and one .50in machine gun and could carry two 110lb bombs under the wings.
The first aircraft to reach an operational fleet joined VF-6 (Enterprise) on 29 November 1937, becoming the commanding officer’s aircraft. VF-6 and marine squadron VMF-2 were both fully equipped with the F3F-2 during 1938. VMF-1 at Quantico also received the type. VF-5 on Yorktown also used four, alongside its F3F-3s.
The F3F-2 began to be replaced by the Brewster F2A-2 and Grumman F4F-3 in October 1940. VF-6 replaced its aircraft with the F4F-3 early in 1941 and VMF-2 replaced its on 10 October 1941, making it the last naval aviation fighter squadron operating biplanes.
After leaving front line service the F3F-2 was used by Training Command, and the last one was retired in November 1943, once again outliving the F3F-3.
XF3F-3
The original plan was for the F3F-2 to be the last biplane fighter ordered, but in the summer of 1938 both the Brewster F2A and Grumman F4F were running behind schedule. Grumman had already anticipated this and in May 1938 the 65th production F3F-2 had been returned to them to became the prototype XF3F-2. This aircraft had a more powerful Cyclone engine and a number of minor drag reducing modifications.
F3F-3
Twenty-seven F3F-3s were ordered on 21 June 1938, becoming the last fighter biplane ordered for any US service. They were delivered between 16 December 1938 and 10 May 1939, but were only in front line service for just over a year. They were powered by a 950hp Wright R-1820-22 Cyclone air-cooled radial engine, and armed with the same mix of .30in and .50in guns as the F3F-2. It was 8mph faster than the F3F-2, but it had mainly been ordered to fill a gap in fighter numbers rather than for any improvement in performance. It was the last fighter biplane ordered for any US service, and deliveries began in December 1938.
The majority of the 27 aircraft went to VF-5 on the Yorktown where they remained in service until 20 June 1941, the last in frontline service. A handful were also used by VMF-2, VF-4 and VF-6 but they were phased out sooner.
Once their front line service was over the F3F-3s were using as advanced fighter trainers, mainly as NAS Corpus Christi, Texas.
By the end of 1941 23 F2Fs and 117 F3Fs were in use at various Naval Air Stations as hacks or training aircraft, but they had all gone by the end of 1943.
F3F-3
Engine: Wright R-1820-22
Power: 950hp
Crew: 1
Span: 32ft
Length: 23ft 2in
Height: 9ft 4in
Empty weight: 3,285lb
Gross weight: 4,795lb
Max speed: 264mph at 15,200ft
Climb Rate: 2,750ft/ min
Service ceiling: 33,200ft
Endurance:
Range: 980 miles
Armament: Ome fixed forward firing 0.30in gun and one fixed forward firing 0.50in gun
Bomb load: Two 110lb bombs under wings