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.