The Curtiss C-55 was the designation given to the prototype of the Curtiss Model CW-20/ C-46, after it was given a new tail and purchased by the USAAF.
The aircraft was originally built as the prototype CW-20T. Work on this design began in 1935, in an attempt to produce a competitor to the Boeing 247 and Douglas DC-2. The new aircraft was to be a pressurized airliner, capable of carrying 36 passengers and 8,200lb of cargo. The fuselage had a ‘double-lobe’ cross section, made up of two overlapping circular sections, with the passengers in the larger upper lobe. On the prototype the crease between the two circular sections was covered over. The aircraft had a streamlined nose, with the cockpit windows built into the lines of the fuselage instead of producing a ‘step’ in the nose. The prototype was originally built with a high mounted twin tail, with dihedral on the horizontal surfaces and a fin and rudder at each end.
The CW-20T made its maiden flight on 26 March 1940. It soon attracted USAAF interest, and in July 1940 the first batch of 46 aircraft were ordered, as the C-46. In the meantime Curtiss continued to work on the prototype, making the most obvious changes at the tail, where a more conventional single fin and rudder was installed, while the horizontal tail was lowered, and made straight. The original twin tail had not lived up to expectations at low speeds or when flying on ene engine.
The USAAF then purchased the modified prototype in June 1941, when it became the C-55 (serial number 41-21041).
The C-55 didn’t remain in Army hands for long, It was soon returned to Curtiss, who then sold it to British Overseas Airway in September 1941. In their hands it became the St Louis, with the British registration number G-AGDI. The aircraft was flown across the Atlantic on 12 November 1941, taking nine hours 40 minutes to reach Prestwick. It entered service as a long haul aircraft, and during 1942 was used to fly between Gibraltar and Malta. However it didn’t survive terribly long in British service, and was scrapped on 29 October 1943.
Engine: Two Wright R-2600-17A air cooled radials
Power: 1,700hp each
Crew: 4 crew and 36 passengers
Span: 108ft 1in
Length: 76ft 4in
Height: 21ft 9in
Empty weight: 27,600lb
Gross weight: 40,000lb
Max speed: 254mpg at 7,000ft
Cruising speed: 222mph at 10,000ft
Climb Rate: 1,500ft/ min
Service ceiling: 26,900ft
Range: 1,500 miles