The Curtiss F8C Helldiver was the first purpose-built dive bomber to be produced for the US Navy, and despite originally sharing its designation with the Navy's version of the O-1 Falcon observation biplane was actually an entirely new design.
The first F8C was a two-seat fighter/ bomber, based on the O-1 Falcon. This was produced in 1928 in two versions - the F8C-1 and F8C-3. Soon after entering service these aircraft were redesignated as observation aircraft, as the OC-1 and OC-2 respectively.
The Helldiver shared the F8C designation because it was funded as part of the same contract. The Navy ordered three prototypes of an aircraft based on the XA-4 Falcon, an attack aircraft based on the O-1. The first two of these were completed as XF8C-1s, but the third became the XF8C-2.
Although the XF8C-2 was a new design, there was a clear family resemblance to the earlier Falcon, as well as to the F7C Seahawk carrier fighter. All three aircraft had the same basic wing layout, with a straight even chord lower wing, staggered back from the upper wing. The upper wing had a straight central section and swept back outer sections. On the Falcon the outer end of the upper wing was about level with the lower wing, but on the Helldiver the upper wing was positioned further forward. The upper and lower wings were roughly equal in area on the Helldiver.
The XF8C-2 was powered by the Pratt & Whitney R-1340 Wasp air cooled radial engine. The fuselage was built around a framework of welded steel tubes, the tails had aluminium frames and the wings wooden frames. It was armed with two fixed forward firing machine guns and one or two flexibly mounted guns on a Scarff ring. The fuel tanks were built into the sides of the fuselage alongside the pilot's cockpit. The aircraft could carry two 116lb bombs under the wings or one 500lb bomb under the fuselage.
The first prototype made its maiden flight in November 1928. It crashed while being tested by Curtiss and was replaced by a second XF8C-2, with the same serial number. The XF8C-4 followed in April 1929. This had a slightly modified tail, an updated engine and a Townend ring.
Early production F8C-4s entered service with Navy squadron VF-1B on the USS Saratoga. They then went to the Marine Corps, before going to Reserve units in 1931.
Two XF8C-2 prototypes were produced - the second to replace the first after it was destroyed.
They were followed by one XF8C-4 prototype, with a R-1340-88 engine and Townend ring.
Twenty five production F8C-4s were built, with deliveries starting in May 1930. Early aircraft served on the Saratoga, but most were used by the Marine Corps on land.
The F8C-5 was ordered as a land-based observation aircraft. Sixty three were ordered, and they were soon redesignated as the O2C-1. See O2C article for more details.
The designation XF8C-6 was given to two F8C-5s that were given wing flaps and leading-edge slots. They kept the -6 designation until the flaps and slots were removed, when they reverted to their original -5 designation.
In August-September 1930 Curtiss produced two prototypes of Helldivers powered by Wright R-1820 Cyclone engines. Both were than bought by the Navy. The first became the XF8C-7, then XO2C-2 and was used as a VIP transport.
VIP transport with Wright R-1820-64 Cyclone (later becomes XO2C-2)
The second Cyclone Helldiver became the first XF8C-8. It later became an O2C-2, then was used as the basis of the XS3C-1/ XF10C-1. Two more Cyclone powered aircraft were ordered at the same time, and after a brief spell as XF8C-8s also became O2C-2s.
Engine: Pratt & Whitney R-1340-88
Span: 32ft 0in
Length: 25ft 7.5in
Height: 19ft 3in
Empty weight: 2,513lb
Loaded weight: 3,783lb
Max speed: 137mph
Climb Rate: 1,030ft/ min
Service ceiling: 19,800ft
Range: 455 miles at 6,000ft
Armament: Four .30in machine guns
Bomb load: 500lb