The Boeing XP-7 was a modification of the last production Boeing PW-9D (S/N 28-41). The Curtiss V-1570 Conqueror powered XP-7 was first flown in November 1928. The performance of the XP-7 did not warrant production and the XP-7 was re-engined with a Curtiss D-12 converting it back to a PW-9D.