Curtiss XP-22 Hawk

The Curtiss XP-22 Hawk was a 1930s American experimental biplane fighter built by Curtiss for evaluation by the United States Army Air Service.

XP-22 Hawk
Role	Experimental biplane fighter
Manufacturer	Curtiss Aeroplane and Motor Company
Primary user	United States Army Air Forces
Number built	1
Variants	Curtiss P-6 Hawk

Design and development

In 1929, the AAC ordered three P-11 Hawks for testing of the 600 hp (447 kW) H-1640 Chieftain engine. This engine proved a failure, and before completion, one of the three was converted to use a 9-cylinder 575 hp (429 kW) Cyclone, being completed as the YP-20. Testing with the R-1820 was prolonged, so the Army acquired another of the three P-11s, instead. This became the XP-22.

A number of changes were made for installing the 700 hp (520 kW) Curtiss V-1570 Conqueror engine. The radiator was relocated, a new cowl was fitted, and the tail was given more fin and less rudder area, and featured a steerable tailwheel, rather than the original skid. For these changes, Curtiss charged only US$1.^[1]

During testing, the XP-22 underwent a number of alterations and improvements, including a change from a three-strut landing gear to a single streamlined strut, later fitted with wheel pants. Fillets were added where struts joined the wing and the tail was briefly reduced in area, to P-6 standard.^[1] The XP-22 was also the Army's first fighter capable of 200 mph (320 km/h), achieving 202 mph (325 km/h).^[2]

Operational history

In June 1931, the AAC held a competition to evaluate the P-6, P-12, YP-20, and XP-22. The XP-22 came out the winner, earning a contract for 45 aircraft as the Y1P-22. Following the trials, the XP-22 donated a nose and landing gear graft to the YP-20, which became the XP-6E, and the 45 production aircraft were completed to this standard.

Operators

 United States

• United States Army Air Forces

Specifications (XP-22 Hawk)

Data from U.S.Fighters,^[2] Curtiss Aircraft 1907–1947^[3]

General characteristics

• Crew: 1
• Length: 23 ft 7 in (7.19 m)
• Wingspan: 31 ft 6 in (9.60 m)
• Height: 8 ft 10 in (2.69 m)
• Airfoil: Clark Y^[4]
• Empty weight: 2,597 lb (1,178 kg)
• Max takeoff weight: 3,354 lb (1,521 kg)
• Powerplant: 1 × Curtiss V-1570-23 Conqueror V-12 water-cooled piston engine, 575 hp (429 kW)
• Propellers: 2-bladed propeller

Performance

• Maximum speed: 202 mph (325 km/h, 176 kn)
• Service ceiling: 26,500 ft (8,100 m)

Armament

• Guns: 2x 0.300 in (7.62 mm) machine-guns in the fuselage sides

References

1. Fitzsimons 1978, p. 1255.
2. Jones 1975, p. 58.
3. Bowers, Peter M. (1979). Curtiss aircraft, 1907-1947. London: Putnam. p. 262. ISBN 0370100298.
4. Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.

Further reading

• Donald, David, ed. Encyclopedia of World Aircraft. Etobicoke, Ontario, Canada: Prospero Books, 1997. ISBN 1-85605-375-X.
• Fitzsimons, Bernard, ed. "Hawk, Curtiss Models 34 and 35 P-1 to P-6 and F6C". Illustrated Encyclopedia of Weapons and Warfare. Volume 12, pp. 1255–1256, London: Phoebus Publishing, 1978.
• Jones, Lloyd S. U.S. Fighters: 1925-1980s. Fallbrook, California: Aero Publishers, Inc., 1975. ISBN 0-8168-9200-8.