In collaboration with renowned developer Airplane Heaven, the Microsoft Flight Simulator team today introduced the latest installment in our Local Legends range: the Boeing Stratoliner 307. Boeing surprised the world in the late 1930s with the unveiling of the Stratoliner 307, a shimmering and inspiring one Monument to aeronautical engineering. Born out of the golden age of aviation, years of development and the focus of intense effort by Boeing designers and engineers, the Model 307 was in a class of its own as an airliner. The long-haul, four-engine aircraft was the world’s first high-altitude aircraft and the first to feature a pressurized cabin, allowing it to operate at altitudes of up to 20,000 feet above sea level. The aircraft completed its maiden flight on December 31, 1938 and entered scheduled service on July 4, 1940. Boeing made ten Stratoliners.
Boeing began development of the 307 in the mid-1930s in response to the airline industry’s demand for an aircraft that could operate at altitudes above most inclement weather events and fly comfortably over the passes of the Rocky Mountains. Engineers based it on the company’s B-17C bomber for its aerodynamic performance and particularly its long-range flight efficiency. Specifically, Boeing took over the bomber’s wings, engines, engine configuration, empennage and landing gear for the design. The notable difference from the B-17 was the fuselage. Boeing designed a circular cross-section fuselage for the 307 with a maximum diameter of 138 inches. The circular design allowed the pressurized cabin to accommodate high altitude flights and the large diameter allowed for comfortable seating configurations.
Constructed primarily of aluminum alloy, the 307 utilized stressed-skin technology, in which the metal exterior works in tandem with the aircraft frame to provide strength and flexibility, and to maintain pressure at altitude. The 307 could carry up to 33 passengers and five crew members, including two pilots and a then-new breed of aircraft crew, a flight engineer. The flight engineer was responsible for the technical aspects of aircraft operation, including cabin pressure, power settings, and electrical components.
The 307 used engine-driven pumps to maintain cabin pressure and could operate up to 20,000 feet above mean sea level while maintaining an internal pressure of 8,000 feet. Its name, a portmanteau of stratosphere and airliner, reflected its high-altitude mission. In the spacious cabin, in addition to comfortable reclining seats, there were also bunks, a galley, a toilet and a dressing room. The Stratoliner represented luxury travel very much in the spirit of ocean liner travel, an atmosphere that airlines wanted to emulate.
American industrialist Howard Hughes bought the first 307 Stratoliner to set flight records. He eventually converted it into a “flying penthouse”. Pan American Airlines (Pan Am) bought three (each designated S-307) and Trans World Airlines (TWA) bought five (each designated SA-307B). The Pan Am aircraft used Wright Cyclone engines with single-stage superchargers and the TWA models used Pratt & Whitney engines with two-stage sequential superchargers. The five that TWA bought were converted for military use during World War II. These airframes were operated by the US Army Air Force and were designated C-75. Subsequent sales to airlines and governments kept the 307 in service until 1975 when the last aircraft crashed.
Only one of the original ten Stratoliners has survived the years unscathed, a model originally flown by Pan Am called the Clipper Flying Cloud. Carefully restored to its original condition by 30 Boeing volunteers in the 1990s, it was flown from Seattle, Washington to Washington, DC, where it is permanently housed at the Smithsonian’s Steven F. Udvar-Hazy Center.
The Boeing 307 Stratoliner is 38 feet, 7 inches long, 20 feet, 9 inches high and has a wingspan of 107 feet, 3 inches. It is powered by four Wright GR-1820-G102A Cyclone radial engines, each producing up to 1,100 hp and driving 3-blade constant speed propellers. The 307 has a range of 1,300 miles, a service ceiling of 23,800 feet above sea level, a cruise speed of 222 miles per hour and a top speed of 250 miles per hour.
The Boeing 307 Stratoliner is available in four liveries: Boeing Delivery, Emerald Harbor, WorldTravel and AREA (Colombian). Climb in, power up the systems, start the engines, and then take to the skies in this classic—available today for $14.99. Heaven is calling!
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