Boeing 307 Stratoliner Pressurized Airliner
HistoryLink.org Essay 3598
Boeing’s little known 307 Stratoliner, affectionately dubbed "the flying whale" for its portly lines, ushered in a new aviation era when it entered into airline service in mid-1940. It was the first in-service pressurized airplane and airliner. It is cabin pressurization (termed cabin supercharging at the time), along with air conditioning and heating that enables today’s high altitude passenger jet airliner flights above the weather and turbulence, where the thin air and sub-zero cold could kill passengers within minutes were they unprotected. The Seattle-built, propeller driven Stratoliner took the first practical step on the journey to safe high altitude passenger flight. Although only 10 aircraft were built, it was very successful in airline service; one was reported still carrying passengers in 1986. Remarkably, at least two airframes survive today, the restored Pan American Airways NC19903 Clipper Flying Cloud, which began flying again on July 11, 2001, and the fuselage of the Howard Hughes special model, which is now a yacht. As luck would have it, the Flying Cloud was the first in-service pressurized airplane and airliner.
- a pressurized strategic bomber;
- pressurized turbojet powered fighters;
- a pressurized transport/airliner;
- aircraft employing power boosted control surfaces.
Germany and the United Kingdom operationally deployed pressurized propeller-driven bombers and fighters, which were modifications of earlier aircraft. Today’s high performance turbine-engined civil and military aircraft are pressurized and utilize powered flight controls.
- First operational airplane with hydraulically boosted control surfaces -- elevators and rudder;
- Fastest scheduled long range airline service -- up to 220 mph cruise, flown by TWA model SA-307Bs beginning in 1940;
- First airliner (SA-307B) with geared two speed engine superchargers able to cruise at high altitude with passengers in complete comfort beginning in 1940;
- First four-engine landplane airliner in U.S. scheduled long-range service;
- Wide body fuselage -- wider at 138 inches/11.5 feet overall than its turbojet powered namesake, the 367-80 Dash Eighty 707 prototype tanker/airliner at 132 inches/11.0 feet.
Boeing Archives; Boeing S-307 Maintenance Manual (Seattle, 1940); S-307 Clipper Flying Cloud restoration project in Boeing’s plant 2: Einar Moen/leadman, Ed Heineman/volunteer; PAA newspaper, March 1940; Bob Stubbs/PAA flight engineer; Ralph Connerly/PAA S-307 1940s radio operator; Dave Drimmer/owner of the yacht Cosmic Muffin; The Seattle Daily Times, June 23, 1938; Kenneth Munson, World Aircraft From 1919 to 1935 (London, U.K.: Blandford Press Ltd., 1982); Airliners From 1919 To The Present Day (London, U.K.: Blandford Press Ltd., 1982); Bill Gunston, Combat Aircraft of World War II (London, U.K.: Salamander Books Ltd., 1978); Giorgio Bignozzi, "The Italian Fortress," Air International, December 1986; Joachim Dressel and Manfried Griehl, Junkers Ju 86 (Atglen, PA: Schiffer Pub. Ltd., 1998); Clarence L. Johnson, Development of the Lockheed Constellation (Burbank, CA: Lockheed Corp., 1944); Air Transport, May 1945; Aviation Magazine (1923-1940); The New 1000 H.P. Wright Cyclone (Patterson, NJ: Wright Aero. Corp., 1936?); Pratt and Whitney Engine Handbook (Hartford, CT: Pratt and Whitney Aircraft Co., November 1927); Pratt & Whitney Operators Handbook; Wasp and Hornet, Wasp Junior (Hartford, CT: Pratt and Whitney Aircraft Co., March 1, 1930); "Man's Farthest Aloft," National Geographic, January 1936; David M. Carpenter, Flame Powered: The Bell XP-59A Airacomet and the General Electric I-A Engine (New York, NY: Jet Pioneers of America, 1992); Stanley R. Mohler and Bobby H. Johnson, Wiley Post, His Winnie Mae, and the World's First Pressure Suit (Washington D.C.: Smithsonian Institution Press, 1971); H. A. Taylor, Fairey Aircraft Since 1915 (London, U.K.: Blandford Press Ltd., 1988); Graham White, Allied Aircraft Piston Engines of World War II (Warrendale, PA: Society of Automotive Engineers, Inc., 1995); Frank L. Greene, The Grumman F4F-3 Wildcat, Profile No. 53 (Surrey, U.K.: Profile Pub. Ltd., 1965); Richard Thruelsen, The Grumman Story (New York, NY: Praeger Publishers, Inc., 1976); The Boeing Company Website (www.Boeing.com); (www.TWA.com); National Air and Space Museum (www.nasm.edu); Boeing/Douglas Division Archives; Bobbi Trout (record setting aviatrix who conceived and tested the first successful electrically heated flying suit); Los Angeles County Natural History Museum; Seattle Museum of Flight Technical Library; National Air & Space Museum aeronautics department; Boeing Public Relations/jet airliner pressurization data - via Bill Seil; Author's 1998 volunteer work on the Flying Cloud restoration project and visit to the yacht Cosmic Muffin.
By Anthony E. Pomata, October 03, 2001