Two great revolutions transformed aeronautics at mid-century: the invention of the jet engine, and the development of high-speed aerodynamic theory enabling the development of transonic and supersonic aircraft. Though the Gloster E.28/39 was not the first jet airplane to fly—that distinction goes to the Heinkel He 178, flown in August 1939—it was the most influential of the first jet airplanes flown, as its engine had a far greater impact on turbojet engine development than the engine flown in the He 178. While the He 178's engine proved a dead end technically (as Germany emphasized axial, not centrifugal, compressors), the Whittle engine used in the E.28/39 influenced international gas turbine design—being, for example, the first jet engine used by America's own first jet aircraft, the Bell XP-59A of 1942. The X.28/39 was strictly a research aircraft, intended to verify the merits of the gas turbine, using an engine developed by Royal Air Force Wing Commander Frank Whittle. On May 15, 1941, it became the first British turbojet aircraft to fly. In April 1941, U.S. Army Air Corps Major General Henry H. “Hap” Arnold visited England and became aware of Gloster and Whittle’s work. He immediately arranged for importation of Whittle engine technology to the United States, and it formed the basis for the first U.S. jet airplane, the Bell XP-59A Airacomet. The E.28/39 demonstrated the practicality of a turbojet-powered airplane, and from this demonstration sprang Gloster’s next jet project, the F.9/40, better known to history as the Meteor. For its influence on British and U.S. aircraft design, and through that, upon Soviet, Chinese, and French design, the E.28/39 is the most significant of early jet test beds.
William Green, The Jet Aircraft of the World (Hanover House, 1957);
Andrew Nahum, Frank Whittle: Invention of the Jet (Icon Books, 2004);
Walter J. Boyne and Donald S. Lopez, The Jet Age (Smithsonian, 1979).
12. North American XP-86 Sabre
The North American F-86 Sabre is justly famous as America’s first swept-wing jet fighter, triumphing over the MiG-15 in swirling dogfights over the Yalu River during the Korean War. The Sabre was the world’s first aircraft designed with a swept wing deliberately to attain a high-speed advantage. The first to fly was the prototype XP-86, in October 1947. The low-speed, swept wing, intended to impart inherent longitudinal stability, had appeared before the First World War. The advantages of the high-speed swept wing were to delay transonic drag rise and shock wave formation and, if sharply swept, to remain within the subsonic air flow contained within the shock cone that forms around a supersonic airplane. These advantages were first enunciated by a young German aerodynamicist, Adolf Busemann, in an Italian conference in 1935. Ignored at the time by all but Germany, the high-speed, swept wing was independently rediscovered by Robert Jones, working at the NACA’s Langley laboratory in Virginia in 1944. Though Germany had many swept-wing projects on the drawing boards, it did not field a true swept-wing aircraft. (The Me 262 was, like the Douglas DC-3, basically a straight-wing aircraft with pronounced leading edge taper, and the rocket-powered Me 163, which used a swept wing for both stability and high-speed flight, had such abysmal flying qualities that it could not take advantage of its wings’ sweep). The XP-86 gave to the world the first truly transonic swept wing, the iconic shape of the Jet Age.
W. Green, The Jet Aircraft of the World;
Adolf Busemann, “Aerodynamische Auftrieb bei Überschallgeschwindigkeit,” Luftfahrtforschung, vol. 12, no. 6 (3 Oct. 1935);
Robert T. Jones, “Wing Planforms for High-Speed Flight,” NACA Technical Note 1033 (1946) [23 June 1945];
Richard P. Hallion, “Lippisch, Gluhareff, and Jones: The Emergence of the Delta Planform and the Origins of the Sweptwing in the United States,” Aerospace Historian, vol. 26, no. 1 (March 1979).
13. Bell XS-1
Conceived to make up for shortfalls in wind tunnel design (existing tunnels could not accurately test models at transonic speeds), the rocket-powered Bell XS-1 became the world’s first supersonic airplane, demonstrating the transonic benefits of a thin, low-aspect-ratio wing (essentially, one that is short and broad, like the wing of a Piper Cherokee) coupled with a streamlined, bullet-shaped body and an adjustable horizontal stabilizer for greater longitudinal (pitch) control efficiency as an airplane approached the speed of sound. It likewise validated the concept of the fully instrumented research airplane that used the sky essentially as a laboratory. Remembered best for its most famous flight—to Mach 1.06 (700 mph) at 43,000 feet, flown by Charles E. “Chuck” Yeager on October 14, 1947—the XS-1 family consisted of three aircraft. Though the third was lost before powered flight testing, the first two flew for years on a variety of transonic and supersonic research missions. It was, effectively, the aircraft that opened the door through the sonic wall, giving aeronautical science its first full look at the tangles and traps of the transonic and supersonic frontier, and it led to the bigger and faster advanced X-1 family that, in the early 1950s, flew beyond Mach 2 and 90,000 feet, to the edge of the atmosphere.
U.S. Air Force, Air Force Supersonic Research Airplane XS-1 Report No. 1 (Wright-Patterson Air Force Base, 9 Jan. 1948);
Richard P. Hallion, Supersonic Flight (Macmillan/Smithsonian, 1972)
14. Boeing 367-80
With its podded engines and low-placed swept wing, Boeing’s “Dash 80” of 1954 gave to the world the generic configuration of the medium- and long-range jetliner. Though other variations would appear, such as aft-mounted engines and T-tails, the basic configuration of the jetliner was set by this remarkable design, which ensured that U.S. air transport would remain dominant in the global marketplace for another quarter-century, until challenged by the rise of Airbus. The Dash 80 was conceived to serve as two types of aircraft: a fast tanker to refuel the Strategic Air Command’s swept-wing B-47 and forthcoming B-52 bombers—also products of the Boeing stable—and a military transport. The Dash 80 is best remembered as the progenitor of the civil 707, which revolutionized air transport across the north Atlantic. From 1958 onward, thanks to the jet airliner revolution, air transportation increasingly became more democratic and less elite. The introduction of the wide-body “jumbo,” beginning with the Boeing 747, was the logical outgrowth of the 367-80 program. Today, the 367-80 is in the collection of the National Air and Space Museum, and most 707s have been reduced to coffee pots. But the direct outgrowth of the Dash 80—the KC-135 family and its own derivatives—still serve in large numbers with the Department of Defense and will do so for decades to come, at least through the first third of this century.