Boeing 307 Stratoliner

Boeing 307/C-75 Stratoliner
General information
TypeAirliner
National originUnited States
ManufacturerBoeing
StatusRetired
Primary usersTranscontinental & Western Air
Number built10
History
Introduction dateJuly 4, 1940 with Pan American Airways
First flightDecember 31, 1938
Retired1975
Developed fromBoeing B-17 Flying Fortress

The Boeing Model 307 Stratoliner (or Strato-Clipper in Pan American service, or C-75 in USAAF service) is an American stressed-skin four-engine low-wing tailwheel monoplane airliner derived from the B-17 Flying Fortress bomber, which entered commercial service in July 1940. It was the first airliner in revenue service with a pressurized cabin, which with supercharged engines, allowed it to cruise above the weather. As such it represented a major advance over contemporaries, with a cruising speed of 220 mph (350 km/h) at 20,000 ft (6,100 m) compared to the Douglas DC-3's 160 mph (260 km/h), at 8,000 ft (2,400 m) then in service. When it entered commercial service it had a crew of five to six, including two pilots, a flight engineer, two flight attendants and an optional navigator, and had a capacity for 33 passengers, which later modifications increased, first to 38, and eventually to 60.