(336 kW) Pratt & Whitney R-1340 Wasp radial, and one sold to Japan as the Japan Hawk with the V-1570 inverted Vee piston engine P-11 Three ordered with the Curtiss H-1640 Chieftain engine of 600 hp (447 kW), two were completed with the V-1570 and redesignated P-6D XP-17 P-1 used as a testbed for the experimental Wright V-1470 air-cooled inverted vee YP-20 P-11 converted with a Wright Cyclone radial XP-21 Two conversions of the XP-3A used to test the 300 hp (224 kW) Pratt & Whitney R-985 Wasp Junior radial, one became the XP-21A when modified with the R-975, and the other was converted to the P-1F standard XP-22 Temporary designation for a P-6A used to test new radiator installations for the V-1570-23 and converted back to a P-6A XP-23 Model 63, unfinished P-6E with light alloy monocoque fuselage, improved tail, and a turbocharged G1V-1570C with a geared propeller and the turbocharger removed. Later redesignated YP-23 Operators Republic of China Air Force operated 50 Hawk II. Cuban Air Force received three P-6S fighters with the 450 hp (336 kW) Wasp radial engine. Japan bought one P-6S, possibly updated with a Conqueror engine. Royal Netherlands East Indies Army Air Force received eight examples of a P-6D with the Conqueror engine in 1930, another six were license-built by Aviolanda in 1931 and sent to Dutch East Indies as well. Three P-6 were lost before war: two in midair collision on 27 February 1936 and one probably after crash-landing 5 February 1935. United States Army Air Corps Bolivian Air Force used the P-6S during the Chaco War. On 22 December 1932 a P-6 Hawk from Fortín Vitriones attacked Paraguayan gunboat ARP Tacuary which was anchored at Bahía Negra near () Surviving aircraft A single P-6E survives. The aircraft was donated to the Smithsonian National Air and Space Museum by Mr. Edward S. Perkins of Anniston, Alabama and restored by the School of Aeronautics at Purdue University. It is on indefinite loan and display at the National Museum of the United States Air Force at Wright-Patterson AFB near Dayton, Ohio. Originally s/n 32-261 and assigned to the 33rd Pursuit Squadron, it was dropped from records at Tampa Field, Florida, in September 1939. It was restored and marked as 32-240 of 17th Pursuit Squadron, missing on a flight over Lake Erie on 24 September 1932. Specifications (P-6E) See also References Notes Bibliography Bowers, Peter M.