unmanned+helicopter

1) Military: (телеуправляемый) drone helicopter, unmanned helicopter (англ. термин взят из статьи в Wall Street Journal. - 2010. - January 30.)

2) Engineering: pilotless helicopter

SUBJECT AREA: Aerospace

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Cayley was born into a well-to-do Yorkshire family living at Brompton Hall. He was encouraged to study mathematics, navigation and mechanics, particularly by his mother. In 1792 he succeeded to the baronetcy and took over the daunting task of revitalizing the run-down family estate.

The first aeronautical device made by Cayley was a copy of the toy helicopter invented by the Frenchmen Launoy and Bienvenu in 1784. Cayley's version, made in 1796, convinced him that a machine could "rise in the air by mechanical means", as he later wrote. He studied the aerodynamics of flight and broke away from the unsuccessful ornithopters of his predecessors. In 1799 he scratched two sketches on a silver disc: one side of the disc showed the aerodynamic force on a wing resolved into lift and drag, and on the other side he illustrated his idea for a fixed-wing aeroplane; this disc is preserved in the Science Museum in London. In 1804 he tested a small wing on the end of a whirling arm to measure its lifting power. This led to the world's first model glider, which consisted of a simple kite (the wing) mounted on a pole with an adjustable cruciform tail. A full-size glider followed in 1809 and this flew successfully unmanned. By 1809 Cayley had also investigated the lifting properties of cambered wings and produced a low-drag aerofoil section. His aim was to produce a powered aeroplane, but no suitable engines were available. Steam-engines were too heavy, but he experimented with a gunpowder motor and invented the hot-air engine in 1807. He published details of some of his aeronautical researches in 1809–10 and in 1816 he wrote a paper on airships. Then for a period of some twenty-five years he was so busy with other activities that he largely neglected his aeronautical researches. It was not until 1843, at the age of 70, that he really had time to pursue his quest for flight. The Mechanics' Magazine of 8 April 1843 published drawings of "Sir George Cayley's Aerial Carriage", which consisted of a helicopter design with four circular lifting rotors—which could be adjusted to become wings—and two pusher propellers. In 1849 he built a full-size triplane glider which lifted a boy off the ground for a brief hop. Then in 1852 he proposed a monoplane glider which could be launched from a balloon. Late in 1853 Cayley built his "new flyer", another monoplane glider, which carried his coachman as a reluctant passenger across a dale at Brompton, Cayley became involved in public affairs and was MP for Scarborough in 1832. He also took a leading part in local scientific activities and was co-founder of the British Association for the Advancement of Science in 1831 and of the Regent Street Polytechnic Institution in 1838.

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SUBJECT AREA: Aerospace

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Flying kites as a boy aroused Ellehammer's interest in aeronautics, and he developed a kite that could lift him off the ground. After completing an apprenticeship, he started his own manufacturing business, whose products included motor cycles. He experimented with model aircraft as a sideline and used his mo tor-cycle experience to build an aero engine during 1903–4. It had three cylinders radiating from the crankshaft, making it, in all probability, the world's first air-cooled radial engine. Ellehammer built his first full-size aircraft in 1905 and tested it in January 1906. It ran round a circular track, was tethered to a central mast and was unmanned. A more powerful engine was needed, and by September Ellehammer had improved his engine so that it was capable of lifting him for a tethered flight. In 1907 Ellehammer produced a new five-cylinder radial engine and installed it in the first manned tri-plane, which made a number of free-flight hops. Various wing designs were tested and during 1908–9 Ellehammer developed yet another radial engine, which had six cylinders arranged in two rows of three. Ellehammer's engines had a very good power-to-weight ratio, but his aircraft designs lacked an understanding of control; consequently, he never progressed beyond short hops in a straight line. In 1912 he built a helicopter with contra-rotating rotors that was a limited success. Ellehammer turned his attention to his other interests, but if he had concentrated on his excellent engines he might have become a major aero engine manufacturer.

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