Helicopter wiki:
icopter is an aircraft which is lifted and propelled by one or more horizontal rotors (propellers). Helicopters are classified as rotary-wing aircraft to distinguish them from conventional fixed-wing aircraft. The word helicopter is derived from the Greek words helix (spiral) and pteron (wing). The engine-driven helicopter was invented by the Slovak inventor Jan Bahyl. The first stable, fully-controllable helicopter placed in production was invented by Igor Sikorsky.
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Aviation wiki:
[ion or Air transport refers to the activities surrounding mechanical flight and the aircraft industry. Aircraft, include fixed wing (airplane) and rotary wing (helicopter/autogyro) types, as well as lighter-than-air craft such as balloons and airships (also known as dirigibles.)There are two major categories of aviation:Civil aviationMilitary aviationCivil aviation includes both scheduled air transport and general aviation.
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