prototype P-6 Hawk was a P-2 Hawk re-engined with a Curtiss
V-1570 Conqueror engine. The prototype placed second in the
1927 National Air Race averaging 189 mph.
The definitive P-6, initially designated the XP-22,
was a P-6 in which the engine was modified for prestone (glycol)
cooling. Redesignated the P-6E, this aircraft was the
last fighter biplane produced in quantity for the U.S. Army Air
The nickname "Hawk" was used by Curtiss
for all its fighters. The U.S. Army Air Corps did not give
aircraft official names until early in World War II.