Air racing rivalry between the US Army and Navy did stimulate technological progress. The R-3 was one of the first aircraft with fully retractable main landing gear. It was designed at the Engineering Division of the USAAS by Alfred Verville and manufactured by the Lawrence Sperry Aircraft Company. Powered by the inferior Wright H-3 engine, the three R-3s built were unsuccessful in the 1922 Pulitzer Trophy race. 22-328 is seen here at the 1923 race, which it did not finish. This plane had received a Curtiss D-12 engine and managed a FAI speed record over 500 km in March 1923. It won the 1924 Pulitzer race, but that edition was less competitive. Photo from: Museum of Flight