Curtiss R-600 Note: This item is currently in storage. The Curtiss R-600 "Challenger" air-cooled engine, rated at 180 hp, was used in experimental versions of the PT-5 and PT-11 trainers during the 1929-1931 period. Although the R-600 was installed in only two military airplanes, it is historically significant because it was the Air Corps' first twin-row radial engine. This engine is on loan by the Curtiss-Wright Corp., Woodbridge, N.J. Click here to return to the Featured Accessions index.