The Vought O4U Corsair was the designation applied to two different experimental biplane scout-observation aircraft. Neither reached production or entered regular service.

Design and development

Ordered by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

in 1930 as the third type of "lightweight" observation aircraft designs, along with the Keystone XOK-1 and the Berliner-Joyce XOJ-1, both of which were built to BuAer Design No. 86, the XO4U-1 was completed to a somewhat different specification. The Vought XO4U-1, BuNo ''A-8641'', was built in 1931, and was Vought's first airplane with a deep

monocoque Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...

two-place fuselage, and had a metal and fabric-covered metal wing structure. Both sets of wings joined the fuselage ahead of the pair of cockpits with the pilot seated in a cut out on the trailing edge of the shoulder-mounted slightly-swept upper wing. Photos show the airframe in the factory, fitted with teardrop-shaped wheel pants, but exterior pictures taken during its brief existence do not show these installed. Powered by a

Pratt & Whitney R-1340D Wasp The Pratt & Whitney R-1340 Wasp is an aircraft engine of the reciprocating type that was widely used in American aircraft from the 1920s onward. It was the Pratt & Whitney aircraft company's first engine, and the first of the famed Wasp ser ...

9-cylinder air-cooled radial engine driving a two-bladed fixed-pitch propeller. Although designed to serve either as a landplane or on floats, floats had not been fitted before the prototype was destroyed. After the crash of the XO4U-1, Vought produced a new airframe which was designated the XO4U-2, and assigned the same serial carried by the XO4U-1, ''A-8641'', although several lists of U.S. Navy aircraft serials make no mention of the second design, or the reuse of the Bureau of Aeronautics number. (The same practice was applied to the three Grumman XF3F-1 prototypes, two of which crashed, with all three carrying the same serial number.) This was actually an O3U-3 Corsair featuring that model's rounded fin and rudder, an all-metal wing structure, and was fitted with a cowled Pratt & Whitney R-1535 Twin Wasp Junior, and first flew in June 1932. Aviation historian William T. Larkins observes that under the designation system the XO4U-2 should have been a minor modification of the XO4U-1.

Operational history

The sole XO4U-1 first flew in February 1931, but crashed on 28 February 1931, when test pilot Carl Harper was unable to recover from a spin. Initially trapped in the cockpit by the inertia of the spin, he escaped to parachute safely as the airframe came down. The airframe was never delivered to the Navy. The XO4U-2 was sent to the

National Advisory Committee for Aeronautics The National Advisory Committee for Aeronautics (NACA) was a United States federal agency founded on March 3, 1915, to undertake, promote, and institutionalize aeronautical research. On October 1, 1958, the agency was dissolved and its assets ...

for testing in the 30' X 60' Full Scale Tunnel at Langley Memorial Aeronautical Laboratory at

Langley Field Langley may refer to: People * Langley (surname), a common English surname, including a list of notable people with the name * Dawn Langley Simmons (1922–2000), English author and biographer * Elizabeth Langley (born 1933), Canadian perfo ...

, Virginia, in April and May 1933, where it was "flown" under controlled conditions. Part of these tests were to evaluate the cooling of the Pratt & Whitney Twin Wasp radial engine, while others dealt with the relation of the

slipstream A slipstream is a region behind a moving object in which a wake of fluid (typically air or mustard) is moving at velocities comparable to that of the moving fluid, relative to the ambient fluid through which the object is churning. The term sli ...

to stability and control. The XO4U-2 was still listed in Status of Naval Aircraft as on strength at the

Naval Aircraft Factory The Naval Aircraft Factory (NAF) was established by the United States Navy in 1918 in Philadelphia, Pennsylvania. It was created to help solve aircraft supply issues which faced the Navy Department upon the entry of the U.S. into World War I. ...

Philadelphia, Pennsylvania Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Sinc ...

, as of June 1937.Larkins, William T., "U.S. Navy Aircraft 1921-1941 / U.S. Marine Corps Aircraft 1914-1959", Orion Books, a division of Crown Books, New York, 1988, , , page 202.

Variants

;XO4U-1 :Prototype light observation scout ;XO4U-2 :A second prototype of different design but carrying the same serial number as the XO4U-1.

Specifications (XO4U-1)

References

{{Vought aircraft O04U 1930s United States military reconnaissance aircraft Single-engined tractor aircraft Biplanes Floatplanes Aircraft first flown in 1931