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The Epic Interactive Encyclopedia 1998
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Epic Interactive Encyclopedia, The - 1998 Edition (1998)(Epic Marketing).iso
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Helicopter
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INFOTEXT
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1992-09-04
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21 lines
A helicopter is a powered aircraft that
achieves both lift and propulsion by means of
a rotary wing, or rotor, on top of the
fuselage. It can take off and land
vertically, move in any direction, or remain
stationary in the air. It can be powered by
piston or jet engine. The rotor of a
helicopter has two or more blades of aerofoil
cross-section like an aeroplane's wings. Lift
and propulsion are achieved by angling the
blades as they rotate. Twin-rotor
helicopters, like the Boeing Chinook, have
their rotors turning in opposite directions
to prevent the body from spinning.
Helicopters are now widely used in passenger
service, rescue missions on land and sea,
police pursuits and traffic control,
firefighting, and agriculture.
Subject by: Andrew Row