The Curtiss F9C Sparrowhawk was a small biplane fighter that gained great fame after being used as a parasite fighter on the US airships Akronand Macon.
The F9C was designed in response to Navy Specification 96 of 10 May 1930, which called for a very lightweight ship-board or carrier fighter. Three aircraft were produced in response to this specification - the F9C, the Berliner-Joyce XFJ-1 and the General Aviation XFA-1. None of these aircraft actually met the original specifications and the contest was abandoned.
The F9C was saved by another Navy project. The Navy was building two rigid airships - Akronand Macon, each of which included an internal carrier bay with space for four small fighters. Little or no progress was made on the purpose-designed fighters intended for use in these airships and so the Navy was forced to look elsewhere. As luck would have it the F9C was small enough to fit through the hanger door on the two airships (a cross-shaped hole in the lower part of the structure).
The XF9C-1 had a metal monocoque fuselage, and fabric covered wings with a metal framework. It was powered by a 420hp Wright Whirlwind engine. It was a single bay staggered wing biplane, with the lower wing at the base of the fuselage and the upper wing just above the fuselage, with a very slight gull-wing effect in the centre. A single gun was mounted in the V between upper wings.
The XF9C-1 made its maiden flight on 12 February 1931. Between 31 March and 30 June it was tested as a standard aircraft, before being equipped with its skyhook. The idea was that the hook would catch on a retractable trapeze carried under the airship, which would then pull it up into the hanger. The fighter would be lowered from the airship on the same equipment. An experimental trapeze was attached to the airship USS Los Angeles, and on 27 October 1931 the XF9C-1 successfully attached itself to the trapeze while in flight.
While these tests were going on the Navy drew up specifications for an improved F9C while Curtiss built a second prototype as a private venture. This saw the engine changed to a 438hp Wright R-975-E3, the upper wing raised by four inches (giving it a more pronounced gull wing effect). It had a new single strut main undercarriage. Curtiss gave this aircraft the unofficial designation XF9C-2 (eventually adopted by the Navy).
The Navy ordered six production F9C-2s and the XF9C-2 prototype. The F9C-2 used the original tripod main undercarriage of the XF9C-1. The XF9C-2 prototype was also given this undercarriage and became a seventh F9C-2. The six production aircraft were delivered in September 1932.
The XF9C-1 and the six F9C-2s were allocated to the Akron, and saw some service with that airship. None were onboard when the Akron was lost at sea on 4 April 1933 and they were transferred to the Macon. Four of the Sparrowhawks were on the Macon when she too was lost at sea, on 12 February 1935.
This left three F9C-2s - two production aircraft and the redesignated prototype. After the loss of the Macon all three were redesignated as XF9C-2s, had their skyhooks removed and were used as general utility aircraft for a few years. The original XF9C-2 was eventually given to the Smithsonian, where it was given a new skyhook and put on display.
The F9C Sparrowhawk gained a great deal of publicity during its short service career, entirely because of its association with the two airships, but only a handful were ever built and the concept of a parasite fighter proved to be something of a dead end.
Engine: Wright R-975-E3 radial engine
Span: 25ft 5in
Length: 20ft 6 7/8in
Height: 10ft 11.5in
Empty weight: 2,089lb
Loaded weight: 2,770lb
Max speed: 176mph at 4,000ft
Climb Rate: 1,700ft/ min
Service ceiling: 19,200ft
Range: 350 miles
Armament: Two .3in Browning machine guns