The design that was to become the Curtiss C-46 began as a response to the development of twin engine, low wing metal passenger planes in the mid-1930s (i.e. the Douglas DC-2). Curtiss designed the Model CW-20 as a passenger plane capable of carrying 36 passengers. The prototype had a twin tail (similar to the Beech C-45), but after initial flight testing in the spring of 1940, the plane was extensively modified. One major change was the replacement of the twin tail with a conventional tail design. The Air Corps was interested in the improved design and ordered 46 planes in July 1940. The Air Corps bought the prototype CW-20 a year later in June 1941 and designated it C-55. The first C-46 was delivered to the Air Corps in the summer of 1942.
The C-46 was an improved version of the CW-20 with 2,000-hp Pratt & Whitney Double Wasp radial engines replacing the 1,700-hp Wright Cyclones on the prototype. The C-46 fuselage was designed as two circular cross sections meeting at the cargo floor level. Initially, a fairing was fitted over the crease in the fuselage to improve streamlining, but was quickly dropped from the production aircraft since it didn't have any significant effect on the aircraft's performance. The C-46 had a crew of four -- pilot, co-pilot, navigator and radio operator -- and could carry between 38 and 50 troops, depending on the interior configuration. A large cargo door allowed up to five tons of cargo to be carried and was big enough to allow jeeps, small trucks and even light planes to be carried.
Only 25 of the 46 planes ordered were completed as C-46s. The rest were upgraded to C-46A standards on the assembly line. In anticipation of the United States eventual entry into World War II, the Air Corps had an immediate need for large cargo aircraft in the early 1940s. As a consequence, the C-46 had very little flight testing before production started. Design improvements were incorporated into the design as they were ready -- differences were documented in the block number. The C-46A, for example, had 21 different block numbers and was built by three different companies.
TECHNICAL NOTES: Engines: Two Pratt & Whitney R-280O-43 Double Wasp radials of 2,000 hp each Maximum speed: 264 mph Cruising speed: 170 mph Range: 2,500 miles Service Ceiling: 27,500 ft. Span: 108 ft. 0 in. Length: 76 ft. 4 in. Height: 21 ft. 9 in. Weight: 50,675 lbs. loaded weight Crew: Four (pilot, co-pilot, navigator and radio operator) Passenger Capacity: 38 to 50 depending on configuration Serial Numbers: 41-5159 to 41-5183