Grumman F3F

F3F
An F3F-1 of VF-4 in the late 1930s.
Role	Fighter aircraft
Manufacturer	Grumman
Designer	Leroy Grumman
First flight	20 March 1935
Introduction	1936
Retired	November 1943
Primary users	United States Navy United States Marine Corps
Produced	1936–1939
Number built	147
Unit cost	$20,424 (as of 1935)
Developed from	Grumman F2F

The Grumman F3F was the last American biplane fighter aircraft delivered to the United States Navy (indeed, the last biplane fighter delivered to any American military air arm), and served between the wars. Designed as an improvement on the single-seat F2F, it entered service in 1936. It was retired from front line squadrons at the end of 1941 before it could serve in World War II, and was first replaced by the Brewster F2A Buffalo. The F3F which inherited the Leroy Grumman-designed retractable main landing gear configuration first used on the Grumman FF served as the basis for a biplane design ultimately developed into the much more successful F4F Wildcat. When it entered combat, the Wildcat quickly replaced the Buffalo as the primary fighter of the Navy and Marines in the first part of World War II, and continued to be produced throughout the conflict.

The Navy's experience with the F2F revealed issues with stability and unfavorable spin characteristics, prompting the 15 October 1934 contract for the improved XF3F-1, placed before F2F deliveries began. The contract also required a capability for ground attack, in addition to the design's fighter role. Powered by the same Pratt & Whitney R-1535-72 Twin Wasp Junior engine as the F2F, the fuselage was lengthened and wing area increased over the earlier design. A reduction in wheel diameter allowed greater fuselage streamlining, eliminating the prominent bulge behind the cowling of the F2F.

The prototype, BuNo. 9727, was delivered and first flown on 20 March 1935 with company test pilot Jimmy Collins making three flights that day. Two days later, six dive-recovery flights took place; on the 10th, the aircraft's pullout at 8,000 ft (2,438 m) registered 14 g on the test equipment. The aircraft broke up in midair, crashing in a cemetery and killing Collins. A second, strengthened prototype was built, but it crashed on 9 May of the same year following the pilot's bailout during an unsuccessful spin recovery. The second prototype was rebuilt in three weeks, flying on 20 June 1935. An order for 54 F3F-1 fighters was placed on 24 August of that year, following the conclusion of the flight test program.