Boeing 247
The Boeing 247 is a twin-engine, all-metal airliner that first flew on February 8, 1933, and is called the world's first modern airliner by the National Air and Space Museum. It entered service with United Air Lines in 1933, about 50 percent faster than its competitors, but only 75 were built, 60 of them for Boeing's own airline group. Shut out of the type, Trans World Airlines turned to Douglas, whose DC series soon made the 247 obsolete in its turn.
Why It Mattered
The National Air and Space Museum calls the Boeing 247 the world's first modern airliner. It entered service with United Air Lines in 1933, about half again as fast as the airliners it competed against. Its all-metal, low-wing airframe and retractable landing gear set a pattern that the Smithsonian credits with launching a new generation of commercial airliners, beginning with the Douglas DC-2. United's predecessor companies ordered sixty of the type, taking the early production run for themselves and leaving rival airlines unable to obtain it. One of those rivals, Trans World Airlines, went to Douglas for a competing aircraft, and the DC series that resulted made the 247 obsolete in its turn.
Design Notes
Boeing developed the 247 by taking the transport potential of its successful B-9 twin-engine bomber rather than following the trimotor airliners of the day. The airframe was an all-metal, low-wing monoplane with retractable landing gear, and the improved 247D pioneered controllable-pitch propellers and wing de-icer boots. Two supercharged Pratt & Whitney Wasp radials of 550 hp gave the 247D a top speed of 200 mph and a cruise of 189 mph. Ten passengers and three crew rode in a soundproofed cabin fitted, for the first time, with air conditioning. The cabin had one structural flaw: the main wing spar ran through it, and passengers had to step across a spar partway down the aisle. The design had also been cut down before it flew: first planned as a 14-passenger aircraft with Hornet engines, it was redrawn smaller around Wasp engines after review by United's pilots.
Operational History
The first 247 flew on February 8, 1933. On May 22 that year it entered cross-country service, flying from San Francisco to New York in 19 1/2 hours where the journey had previously taken 27 hours. Production stayed small: 75 were built, and Boeing sold the first 60 to its affiliated Boeing Air Transport. In October 1933 a United 247 on Flight 23 was destroyed by a nitroglycerin-based explosive device over Chesterton, Indiana, killing all seven people aboard; the loss is described as probably the first sabotage of a commercial airliner. The first production 247D, flown by Roscoe Turner and Clyde Pangborn, placed third overall and second in the transport category in the 1934 MacRobertson Race from England to Australia. Boeing answered Douglas with the improved 247D, but the type lacked the growth potential to compete and was relegated to shorter route segments and smaller airlines. It remained in airline service until the Second World War, when several were converted into C-73 transports and trainers, and the Royal Canadian Air Force's 121 Squadron operated seven 247Ds as medium transports early in the war.
Afterlife
Some 247s were still flying in the late 1960s as cargo transports and business aircraft. By 2016 only four examples were reported to remain in the world, and the Museum of Flight's 247D in Seattle was the only one flyable. That aircraft, under restoration from 1979 and flown again from 1994, made its last flight on April 26, 2016, to the museum's Boeing Field campus, where it was retired for permanent display. The Smithsonian's example is the Turner and Pangborn race aircraft: after United service it passed to the Civil Aeronautics Authority, which used it for fourteen years before presenting it to the museum in 1953. It is displayed in the America by Air exhibition wearing its commercial registration on one side and its 1934 racing numeral on the other.