The Curtiss YP-20 was an American

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a ...

fighter project developed by

Curtiss Curtiss Aeroplane and Motor Company (1909 – 1929) was an American aircraft manufacturer originally founded by Glenn Hammond Curtiss and Augustus Moore Herring in Hammondsport, New York. After significant commercial success in its first decad ...

for the

United States Army Air Service The United States Army Air Service (USAAS)Craven and Cate Vol. 1, p. 9 (also known as the ''"Air Service"'', ''"U.S. Air Service"'' and before its legislative establishment in 1920, the ''"Air Service, United States Army"'') was the aerial war ...

Design and development

In 1929, three Curtiss P-11 Hawks were ordered with 600 hp (447 kW)

Curtiss H-1640 Chieftain The Curtiss H-1640 Chieftain was an unusual American 12-cylinder radial aero engine designed and built by the Curtiss Aeroplane and Motor Company in the mid-1920s.Gunston 1989, p. 46 Design and development The H-1640 was an air-cooled 12 cylind ...

engines. These proved a failure, and before completion, the third was converted to use a 9-cylinder 575 hp (429 kW) Wright

Cyclone In meteorology, a cyclone () is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above (opposite to an an ...

, being completed as the YP-20. Testing with the R1820 was prolonged, so the Army's intention to promptly switch to a

V-1570 Conqueror engine and redesignate the aircraft XP-22 was dropped; another P-11 was chosen for that instead. Except for the engine change and its

Townend ring A Townend ring is a narrow- chord cowling ring fitted around the cylinders of an aircraft radial engine to reduce drag and improve cooling. Development The Townend ring was the invention of Dr. Hubert Townend of the British National Physica ...

cowling A cowling is the removable covering of a vehicle's engine, most often found on automobiles, motorcycles, airplanes, and on outboard boat motors. On airplanes, cowlings are used to reduce drag and to cool the engine. On boats, cowlings are a cove ...

, the YP-20 was not drastically different from the P-6 from which both it and the P-11 derived, though the YP-20 had more fin and less

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally air or water). On an aircraft the rudder is used primarily to counter adve ...

area, and featured a steerable

tailwheel Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Term ...

, rather than the original skid.Fitzsimons, p.1255. Later, a crankcase cover, gear strut fairings, and

wheel pants An aircraft fairing is a structure whose primary function is to produce a smooth outline and reduce drag.Crane, Dale: ''Dictionary of Aeronautical Terms, Third Edition'', page 206. Aviation Supplies & Academics Inc, Newcastle Washington, 1997. ...

were added. In June 1931, the AAC held a competition to evaluate the P-6, P-12, XP-22, and YP-20. The XP-22 came out the winner, but the YP-20 was given a nose and landing gear graft from the XP-22, becoming the XP-6E (P-6E prototype). With the addition of a

supercharger In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement. The current categorisation is that a supercharger is a form of forced indu ...

Design and development

Operators

Specifications (original YP-20)

References

Further reading