The Budd RB-1 Conestoga was a twin-engine, stainless steel cargo aircraft designed for the United States Navy during World War II by the Budd Company of Philadelphia, Pennsylvania. Although it did not see service in a combat theater, it pioneered design innovations in American cargo aircraft, later incorporated in modern military cargo airlifters. Design and development World War II created a great demand for military transport aircraft in the United States. Because of initial fears of a shortage of aluminum, the War Department explored the use of other materials for aircraft construction. Budd, the developer of the shotweld technique for welding stainless steel and a manufacturer of stainless steel railroad cars, automobile, bus, and truck bodies, hired an aeronautical engineering staff and worked with the U. S. Navy to develop a new twin-engine transport aircraft constructed primarily of stainless steel. The U.S. Navy accepted the proposal for the new aircraft, and placed an order for 200, to be designated RB-1. The U.S. Army Air Forces (USAAF) followed with an order for 600, designated C-93. The Conestoga was a twin-engine high-wing monoplane with tricycle landing gear. The elevated flight deck was contained in a distinctive, almost hemispherical nose section. Its two Pratt & Whitney R-1830-92 air cooled 14-cylinder, twin-row, radial engines, the same engines fitted to the C-47, drove three-bladed Hamilton Standard Hydromatic constant-speed, full-feathering propellers and powered a 24-volt electrical system. While the fuselage was thin-gauge stainless steel, only a portion of the wing was made of the metal; the trailing section of the wing and all control surfaces were fabric-covered. Innovations The RB-1/C-93 was radical for its day, introducing many of the features now standard in military transports. The flight deck could accommodate three crew members, pilot and copilot side-by-side, the navigator behind them. Stairs connected the flight deck to the cargo area, which was long with an unobstructed cross-section of 8 × 8 feet (2.4m) throughout its length. Cargo loading and unloading could be accomplished in two ways: through 40 × 60 inch (102 × 152 cm) doors on both sides of the fuselage or by an electrically operated 10 × 8 foot (3.0 × 2.4 m) ramp at the aft end of the cargo area under the upswept tail, a similar development to what had been initially fitted to the Germans' own Ju 90 four-engined transport aircraft as their Trapoklappe ramp in 1939. The RB-1's loading ramp,