Boeing 377 Stratocruiser 377-10-26

The 377-10-26 was the version for Pan American World Airways, the launch airline. Twenty new aircraft were built, joined by the 377-10-19 prototype once it had been brought up to the same standard. They are distinguished by their circular windows.

With the 377-10-26 Pan Am opened the type's scheduled flights between San Francisco and Honolulu in April 1949. By the end of that year Pan Am, BOAC and American Overseas Airlines were flying 377s across the Atlantic, while Northwest Orient flew them within the United States. In 1956 Pan Am's 377s linked Los Angeles and San Francisco with Sydney, stopping at Honolulu, Canton Island and Suva. By 1958 the airline was using them between Seattle and Fairbanks, Juneau and Ketchikan in Alaska, and between Seattle and Whitehorse in the Yukon.

The 377 shared the C-97's double-bubble fuselage cross-section, shaped like a figure-8 with the smaller lobe below, and 190 m³ of interior volume split between two passenger decks. The lower deck served as a lounge seating fourteen. The aircraft introduced higher cabin pressure and air conditioning: the superchargers on the four Pratt & Whitney R-4360s increased power at altitude and allowed constant cabin pressure.

Within six years of first delivery the Stratocruiser had carried 3,199,219 passengers, completed 3,597 transcontinental flights and 27,678 transatlantic crossings, and flown 273,362,494 km. It was one of the most advanced, capable and luxurious propeller transports ever built, and also one of the most expensive to operate and least reliable: catastrophic propeller failures, propeller pitch control failures leading to overspeed incidents, and poor engine thermal design with aerodynamic consequences. The propellers were the subject of Airworthiness Directives in 1955, 1957 and 1958.

The Aero Spacelines Pregnant Guppy, Super Guppy and Mini Guppy all came from 377-10-26 airframes. This census does NOT record them as Boeing 377 variants: they are DERIVED TYPES, built by another manufacturer, with their own designations, new fuselage structures and, in several cases, turboprop powerplants. They warrant independent sheets. The same criterion excludes the Boeing C-97 Stratofreighter, which is the 377's military ancestor rather than a version of it.