Boeing 247/C-73

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)

Propellers

2-bladed variable pitch propellers

Performance

Maximum speed

200 mph (320 km/h, 170 kn)

Cruise speed

189 mph (304 km/h, 164 kn) at 12,000 ft (3,658 m)

Range

745 mi (1,199 km, 647 nmi)

Service ceiling

25,400 ft (7,700 m)

Absolute ceiling

27,200 ft (8,291 m)

Rate of climb

1,150 ft/min (5.8 m/s).

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