XP-6
Model 34P, modified from a P-1 with a Curtiss V-1570-17 Conqueror engine
XP-6A
Model 34K, same as XP-6 but with untapered wings and wing radiators to reduce drag
P-6A
18 ordered by the U.S. Army, nine were fitted with Prestone- rather than water-cooled V-1570 engines
XP-6B
P-1 converted to take the V-1670 engine
P-6C
cancelled
XP-6D
XP-6B converted to take a turbocharged V-1570-C
P-6D
P-6As, (six of the seven surviving), re-engined in 1932 with turbocharged V-1570-C installed in 1932
XP-6E
Model 35, also designated Y1P-22, ordered in July 1931 as P-6E prototype
P-6E
46 delivered in 1931–1932, equipped the 17th and 33rd Pursuit Squadrons
XP-6F
Modified XP-6E with a supercharger and an enclosed cockpit
XP-6G
P-6E with a V-1570F
XP-6H
P-6E with 4 × .30 in (7.62 mm) machine guns mounted in the wings
P-6S
Hawk I, three sold to Cuba with the 450 hp (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
XP-6
Model 34P, modified from a P-1 with a Curtiss V-1570-17 Conqueror engine
XP-6A
Model 34K, same as XP-6 but with untapered wings and wing radiators to reduce drag
P-6A
18 ordered by the U.S. Army, nine were fitted with Prestone- rather than water-cooled V-1570 engines
XP-6B
P-1 converted to take the V-1670 engine
P-6C
cancelled
XP-6D
XP-6B converted to take a turbocharged V-1570-C
P-6D
P-6As, (six of the seven surviving), re-engined in 1932 with turbocharged V-1570-C installed in 1932
XP-6E
Model 35, also designated Y1P-22, ordered in July 1931 as P-6E prototype
P-6E
46 delivered in 1931–1932, equipped the 17th and 33rd Pursuit Squadrons
XP-6F
Modified XP-6E with a supercharger and an enclosed cockpit
XP-6G
P-6E with a V-1570F
XP-6H
P-6E with 4 × .30 in (7.62 mm) machine guns mounted in the wings
P-6S
Hawk I, three sold to Cuba with the 450 hp (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
Curtiss P-6 Hawk