Airframe - History

History

Modern airframe history began in the United States when a 1903 wood biplane made by Orville and Wilbur Wright showed the potential of fixed-wing designs. Many early developments were spurred by military needs during World War I. Well known aircraft from that era include the Dutch designer Anthony Fokker's combat aircraft for the German Empire's Luftstreitkräfte, and U.S. Curtiss flying boats and the German/Austrian Taube monoplanes. These used hybrid wood and metal structures. During the war, German engineer Hugo Junkers pioneered practical all-metal airframes as early as late 1915 with the Junkers J 1, whose techniques were adopted almost unchanged after the war by both American engineer William Bushnell Stout and Soviet aerospace engineer Andrei Tupolev. Commercial airframe development during the 1920s and 1930s focused on monoplane designs using radial piston engines. Many, such as the Ryan model flown across the Atlantic by Charles Lindbergh in 1927, were produced as single copies or in small quantity. William Stout's designs for the all-metal Ford 4-AT and 5-AT trimotors, Andrei Tupolev's designs in Joseph Stalin's Soviet Union for a series of all-metal aircraft of steadily increasing size, culminating in the enormous, eight-engined Maxim Gorky, and with Donald Douglas' firm's development of the Douglas DC-3 twin-engined airliner, were among the most successful designs to emerge from the era through the use of all-metal airframes. The original Junkers corrugated duralumin-covered airframe philosophy culminated in the 1932-origin Junkers Ju 52 trimotor airliner, used throughout World War II by the Nazi German Luftwaffe for transport and paratroop needs.

During World War II, military needs again dominated airframe designs. Among the best known were the US Douglas C-47, Boeing B-17, North American B-25 and Lockheed P-38, and British Vickers Wellington that used a geodesic construction method, and Avro Lancaster, all revamps of original designs from the 1930s. The wooden composite construction high performance fighter-bomber de Havilland Mosquito was developed during the war. The first jets were produced during the war but not made in large quantity. The Boeing B-29 was designed to be a high altitude bomber, the first with a pressurised fuselage.

Postwar commercial airframe design focused on larger capacities, on turboprop engines, and then on jet (turbojet, later turbofan) engines. The generally higher speeds and stresses of turboprops and jets were major challenges. Newly developed aluminum alloys with copper, magnesium and zinc were critical to these designs. The Lockheed L-188 turboprop, first flown in 1957, used some of these materials and became a costly lesson in controlling vibration and planning around metal fatigue.

The de Havilland Comet was the world's first commercial jet airliner to reach production. It first flew in 1949 and was considered a landmark in British aeronautical design. After introduction into commercial service, early Comet models suffered from catastrophic air frame metal fatigue, causing a string of well-publicised accidents. The Royal Aircraft Establishment investigation at Farnborough, founded the science of aircraft crash reconstruction. Over 3000 cycles of pressurisation later, in a specially constructed pressure chamber, air frame failure was found to be due to stress concentration, a consequence of the square shaped windows. The windows had been engineered to be glued and riveted, but had been punch riveted only. Unlike drill riveting, the imperfect nature of the hole created by punch riveting may cause the start of fatigue cracks around the rivet.

Eventually Boeing in the U.S. and Airbus in Europe became the dominant assemblers of large airframes, known as wide-body aircraft. Numerous manufacturers in Europe, North America and South America took over markets for airframes designed to carry 100 or fewer passengers. Many manufacturers produce airframe components.