The Curtiss P-2 Hawk was essentially a Curtiss P-1 modified with a V-1400 engine with an exhaust-driven turbo-supercharger. There were 5 P-2 aircraft built (S/N 25-420 through 25-424). The P-2's were ordered at the same time as the original 10 XP-1's. One year after completion, 3 P-2's were reengined with Curtiss D-12, V-1150s and redesignated P-1's. The fourth P-2 (S/N 25-423) was reengined with a Curtiss V-1570 Conqueror and became the XP-6.