|
Large aircraft pose significant design issues not present in smaller types. These include structural efficiency, flight control response and sufficient power in a reliable and cost-effective installation. Making an aircraft design larger also has advantages, in that the overall fuel efficiency and manhours for transporting a given load improve, while a greater space is available for transporting lightweight cargoes and giving passengers more room to move. The giant airships of the 1930s remain the largest aircraft ever constructed, while the Hughes H-4 "Spruce Goose" of 1947 had the largest wing span of any fixed-wing type. ==History== The first practical aircraft were balloons, used for sport and for military observation. In 1901 the giant balloon ''Preusen'' (Prussia) of rose to a height of . Early airships were little more than elongated balloons with an engine slung underneath. These craft were limited in size because their bodies were non-rigid and could not be made too long. The German Count Ferdinand von Zeppelin realised that a rigid frame could support a much larger volume, and in 1900 the Luftschiff Zeppelin 1 of volume and length took briefly to the air.〔Ege, L,; "Balloons and Airships", Blandford (1973).〕 Early fixed-wing aeroplanes were mostly single-engined. When the Russian Igor Sikorsky designed and flew his Ilya Muromets in 1913 it became not only the first four-engined aircraft but, with a wing span of and laden weight of , by far the largest and heaviest to date. By comparison the LZ 18 airship, which flew the same year, was long (the envelope had a capacity of ) and a empty weight of 20 tonnes. The Beardmore Inflexible of 1928 had a wingspan of and an all up weight of 37,000 lbs. However it was underpowered for such a heavy aircraft. It was structurally advanced for its time, being of all-metal stressed-skin construction.〔''Air Enthusiast International'' March 1974, p.145.〕 The Dornier Do X was the largest, heaviest, and most powerful flying boat in the world when it flew in 1929, having a similar span of 48 m (157 ft 6 in) and a maximum takeoff weight of 56,000 kg (123,459 lb). During the years between the two World Wars, only the Soviet Tupolev ANT-20 ''Maxim Gorki'' landplane of 1934 was larger at 63.00 m (206 ft 9 in) span, but at 53 metric tons maximum takeoff weight it was not as heavy as the Do X's 56 tonnes. The largest airship ever built was the Zeppelin LZ 129 "Hindenburg". First flying in 1936, the Hindenburg had a volume of and a length of . Its maximum payload, of combined passengers and freight, was . Following the Hindenburg's disastrous end, no airships of this scale have since been built. By then, larger aeroplanes - especially long-distance flying boats - had exceeded the Ilya Muromets in scale. Then, during World War II, America foresaw a requirement for a large trans-Pacific cargo carrier able to operate from bases with no prepared landing strip. The giant Hughes H-4 Hercules flying boat was constructed from timber, earning it the name the "Spruce Goose". When finally flown briefly in 1947, its wing span made it the largest plane ever to fly, and it has never been equalled. It required 8 Pratt & Whitney R-4360 Wasp Major radial engines to get it into the air. By then, the landplane had taken over long-distance flight and the H-4 - having made no more than a single mile-long flight less than 100 ft off the water - never flew again. It is today preserved as a museum piece. At the start of the Second World War, Barnes Wallis proposed a "Victory Bomber" of 50 tonnes to carry a 10-tonne bomb but it was discounted by the Air Ministry because of its limited application. As the war progressed the British contemplated very large bomber designs (from 75 to 100 tonnes with bombloads of 25 tonnes and six or more engines) but considered the time required to being them into use, the difficulty of balancing bombload, defensive armament and range, and the success of existing designs (such as the Avro Lancaster) to outweigh any advantages. Some of the work on large aircraft fed into the post-war Bristol Brabazon a 70-m wingspan 130-tonne airliner which would have given its 100 passengers ship-like levels of space and comfort.〔Buttler ''Secret Projects 1935-1950 Fighters and Bombers'' Midland Publishing p128〕 With the arrival of the jet age, airliners continued to increase in size. Wide-body types were introduced and, in 1970, the Boeing 747 "Jumbo jet" entered service. It featured a short second, upper deck to provide increased passenger accommodation. Variants of the 747 remained the largest airliners flying for well over thirty years, some with a "stretched" upper deck, until the arrival of the Airbus A380 series in 2007 featuring a full-length upper deck. Both lines continue to be developed, with ever-larger variants being introduced. The largest is currently (2014) the A380-800, capable of seating up to 853 people. In order to airlift the Buran space shuttle, in 1988 Soviet Union introduced the sole Antonov An-225 Mriya (''dream''). With a (maximum takeoff weight greater than and a wing span of , it was then, and remains, the largest operational aeroplane in the world. Since the conclusion of Buran flights, the Mriya has remained in service as a heavy transport. The largest aircraft of any kind flying today (2014) is the HAV-304 (LEMV) hybrid airship, with an internal capacity of 38,000 cubic metres and a length of 91 m. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「large aircraft」の詳細全文を読む スポンサード リンク
|