The C-73 Designation for Boeing 247D airliners “drafted” into military service with the USAAF.
Variants
Model 280
Original proposal of Boeing 247 with 14 seats and 700 hp P&W Hornet engines.
Model 247
Twin engined civil transport airliner.
Initial production version
247A
Powered by new 625 hp P&W Wasp, on special order for Deutsche Lufthansa in 1934.
247E
This designation was given to the first Boeing 247 aircraft, it was used to test a number improvements, that were later incorporated into the Boeing 247D
247D
Original one off was a race aircraft designed for the MacRobertson Air Race, use of Hamilton Standard variable pitch propellers allowed for a 7 mph (11 km/h) gain, the 247D configuration incorporated in production series bearing the same name.
247Y
Armed version, one exported to China, second used for trials.
Specifications
Crew
3
Capacity
10 passengers, baggage and 400 lb (181 kg) of mail
Length
51 ft 7 in (15.72 m)
Wingspan
74 ft 1 in (22.58 m)
Height
12 ft 1.75 in (3.7021 m)
Wing area
836.13 sq ft (77.679 m2)
Airfoil
Boeing 106B
Empty weight
8,921 lb (4,046 kg)
Max take-off weight
13,650 lb (6,192 kg)
Fuel capacity
273 US gal (227 imp gal; 1,030 l)
Powerplant
2 × Pratt & Whitney R-1340 S1H1-G Wasp 9 cylinder air cooled radial piston engines,
500 hp (370 kW) each at 2,200 rpm at 8,000 ft (2,438 m)
