Another civil aircraft was the DS, (or Doolittle Special), a single seater for James Doolittle, employed at the time by the Shell Oil Company, while the AP-7 was another racer, powered by a 1,200 hp (895 kW) R-1830 engine and used by Jacqueline Cochran to win the 1938 Bendix Trophy race and to set a women's air speed record. Seversky entered two aircraft based on the P-35 in a 1938 competition for a new fighter for the Air Corps. One was the XP-41 (which had the company designation AP-4D, which was a P-35 with a 1,200 hp (895 kW) R-1830-9 engine fitted with a two-stage supercharger) and the AP-4, which had a turbo-supercharger mounted in the belly of a deeper fuselage. The Air Corps preferred the AP-4D, which was ordered into production as the P-43 Lancer.