Model 75A - company-owned demonstrator aircraft flown with several engine fits

Model 75B - prototype with Wright R-1820 engine

Model 75D - first prototype, Wright R-1670 engine

Model 75H - internal company designation for a simplified export version with fixed landing gear, two slightly differing aircraft built, first sold to China, second to Argentina

Model 75J - company-owned 75A temporarily fitted with an external supercharger

Model 75K - Unbuilt version, it was going to be powered by a Pratt & Whitney R-02180 Twin Hornet engine.

Model 75P - production P-36A (serial 38-010) fitted with Allison V-1710 liquid-cooled engine, prototype for Curtiss P-40

Model 75R - company-owned 75A temporarily fitted with R-1830-SC2-G engine with turbosupercharger, attained 330 mph (530 km/h) but proved complex and unreliable

Curtiss P-36's involved in pre-WWII manuevers. Source: Unknown

Y1P-36 (Model 75E) - USAAC prototype, Pratt & Whitney R-1830 engine

P-36A (Model 75L) - USAAC version, P-26A-3 mounted four 0.30 in machine guns in the wings in addition to fuselage armament

P-36B - production P-36A fitted with an R-1830-25 engine producing 1,100 hp (820 kW), reached 313 mph (504 km/h), returned to original P-36A configuration

P-36C - an additional 0.30 in machine gun installed in each wing with external ammunition boxes under the wings, R-1830-17 engine with 1,200 hp (895 kW), last 30 production aircraft were completed as P-36Cs

XP-36D - production P-36A modified with 2 x 0.50 in machine guns in the nose and 4x 0.30 in machine guns in the wings

XP-36E - production P-36A armed with 4 x 0.30 in machine guns in the wings, retained standard fuselage guns

XP-36F - production P-36A fitted with 2 x 23 mm Madsen cannons under the wings, reverted to P-36A because guns imposed an unacceptable performance penalty with top speed of only 265 mph (427 km/h)

P-36G - Hawk 75A-8 used by Norway for training in Canada, later to Peru. Wright R-1820-G205A with 1,200 hp (895 kW).

Hawk 75A-1 - 1st production batch for France, 4 x 7.5 mm machine guns, R-1830-SC-G engine with 900 hp (671 kW), 100 built

Hawk 75A-2 - 2nd production batch for France, either R-1830-SC-G engine or 1,050 hp (783 kW) R-1830-SC3-G engine, 6 x 7.5 mm machine guns, 100 built

Hawk 75A-3 - 3rd production batch for France, similar with Hawk 75A-2, 135 built

Hawk 75A-4 - Last production batch for France, Hawk 75A-2 with Wright R-1820-G205A Cyclone engine with 1,200 hp (895 kW). 285 built, 81 delivered to France, others to Great Britain as Mohawk IV

A Royal Air Force Curtiss Mohawk Mk.IV fighter (s/n BB977) in India in January 1943.
[Source: Library Of Congress]

Hawk 75A-5 - built under license in China (production was later moved to India), absorbed into RAF as Mohawk IV

Hawk 75A-6 - version for Norway, captured aircraft sent to Finland

Hawk 75A-7 - version for Netherlands East Indies: 1,200 hp Cyclone, 4 x 7.7 mm (two in nose, one in each wing) and 2 x 100 lb bombs.

Hawk 75A-8 - Export version for Norway. Later redesignated P-36G.

Hawk 75A-9 - 10 aircraft delivered to Persia, captured still in crates and used by RAF in India as Mohawk IVs

Hawk 75M - simplified version with fixed landing gear and Wright R-1820 Cyclone engine for China, built by both Curtiss and Central Aircraft Manufacturing Company in China

Hawk 75N - simplified version for Siam (Thailand)

Hawk 75O - simplified version for Argentine, 29 built by Curtiss with additional 200 built under license locally by Fabrica Militar de Aviones

Hawk 75Q - two additional simplified demonstrators for China

XP-37 - Allison V-1710 liquid-cooled engine, cockpit moved to the rear of the fuselage

YP-37 - service test version of XP-37, 13 built

XP-42 (Model 75S) - testbed for streamlining cowlings around air-cooled engines

Persyn, Kari, & Thomas. P-36 Hawk Aces of World War 2. Oxford: Osprey Pub. (2009)
Green, William. War Planes of the Second World War, Vol. Four: Fighters. London: MacDonald & Co. Ltd., 1961