Helicopter

A helicopter 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.

External links

• {{US patent|1848389}} : "Aircraft, especially aircraft of the direct lift amphibian type and means of construction and operating the same"
• History of helicopters
• Page containing an image of a Chinese flying top
• Helicopter development in the early 20th century
• Description of a helicopter
• Homepage about helicopter with pictures and videos.

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