Boeing Model 307 / C-75 Stratoliner

1st Flight 1938

The Boeing Model 307 Stratoliner was an American commercial transport aircraft that entered commercial service in July 1940.

It was the first to offer a pressurized cabin, allowing it to cruise at an altitude of 20,000 ft (6,000 m), well above many weather disturbances.

The pressure differential was 2.5 psi (17 kPa), so at 14,700 ft (4,480 m) the cabin air pressure was equivalent to an altitude of 8,000 ft (2,440 m).

The Model 307 had capacity for a crew of six and 33 passengers.

The cabin was nearly 12 ft (3.6 m) across.

It was the first land-based aircraft to include a flight engineer as a crew member (several flying boats had included a flight engineer position earlier).

In addition to its civilian service it was also flown as the Boeing C-75 Stratoliner by the United States Army Air Forces, who used it as a long-range cargolift aircraft.

Variants

300

Original concept designation of 307.

307

Equipped with Wright Cyclone GR-1820-G102 engines with single-speed supercharger, five crew.

307B

Equipped with Wright Cyclone GR-1820-G105A engines with two-speed supercharger for improved high altitude performance, seven crew.

C-75

Five Trans World 307Bs were pressed into service with the USAAF as military transports, the cabin pressurization was removed to save weight.

307B-1

Following military service, the C-75s were overhauled and updated with B-17G wings and tail plane, four Wright Cyclone GR-1820-G606 engines, and B-29-type electronics.

Specifications

Crew

Five

Capacity

38 passengers in daytime, 25 by night

Length

74 ft 4 in (22.6 m)

Wingspan

107 ft 0 in (32.63 m)

Height

20 ft 9.5 in (6.33 m)

Wing area

1,486 sq ft (138 m2)

Empty weight

30,000 lb (13,608 kg)

Gross weight

45,000 lb (20,420 kg)

Powerplant

4 × Wright GR-1820-G102A radial engines, 1100 hp (820 kW) each

Performance

Maximum speed

241 mph (387 km/h, 209 kn)

Cruise speed

215 mph (344 km/h, 187 kn)

Range

1,750 mi (2,820 km, 1,520 nmi)

Service ceiling

23,300 ft (7,110 m)

Wing loading

28 lb/sq ft (138 kg/m2)

Power/mass

0.098 hp/lb.

…………………………………………………………………………………………………………………………………………………………………………………………………………………………………

Share on facebook

Share on facebook