accessed by manually operated clamshell doors, along with the tricycle landing gear, meant cargo could be loaded/unloaded at truck-bed height. A manually operated two-ton (1814 kg) hoist for unloading trucks and a one-ton winch for pulling cargo up the ramp were also provided in the cargo area. The aircraft could accommodate: 24 paratroopers, or 24 stretchers and 16 sitting wounded, or 9,600 pounds of cargo, or a 1½ ton truck, or The largest ambulance in use by the U.S. military. Operational history The prototype first flew from the Budd Red Lion Factory Airfield in Philadelphia, Pennsylvania on 31 October 1943, piloted by Guy Miller. The prototype had a takeoff run when empty of just , and could carry a maximum payload of with a takeoff run of . However, the aircraft demonstrated greater than expected fuel consumption; the range with a standard payload was only , with a maximum payload. Three prototype aircraft: NX37097, NX41810, and NC45354 were built; one was used for testing radio equipment, while the other two were used for flight test evaluations. During testing, a few aircraft had difficulty with the simultaneous deployment of the right and left landing gear. With the same engines as the C-47, but heavier (empty), the aircraft was relatively underpowered; it was reportedly said that, for an aircraft built by a railroad car company, it indeed handled like one. At the Budd factory and airfield in Philadelphia, Pennsylvania, there were construction delays due to cost overruns and problems with stainless steel fabrication. By late 1943, aluminum production had been increased with the construction of new processing facilities, and other more conventional cargo aircraft (such as the Curtiss C-46 Commando and the Douglas C-47 Skytrain) were being produced in large numbers. This caused the Army to cancel its order for the C-93 and the Navy to reduce its RB-1 order from 200 to 25, of which 17 were delivered in March 1944. On 13 April 1944, during a Naval Air Training Command (NATC) evaluation flight of RB-1 prototype U.S. Navy NX37097 at Patuxent River NAS, Maryland, the aircraft crashed, killing one of the crew. The aircraft was damaged beyond repair and written off, but the pilot reported that the stainless steel construction of the aircraft contributed to saving his life. Production RB-1 aircraft never entered squadron service with the Navy, but a few were briefly used by Naval Air Stations as utility