helicopter

A helicopter is a rotorcraft that uses one or more horizontal rotors to generate lift and thrust. It can take off and land vertically, hover, and maneuver with precision, capabilities not matched by fixed-wing aircraft.

Key components include the fuselage, main rotor(s), propulsion engine(s), transmission, and a tail or anti-torque device. The main rotor provides lift; the anti-torque system counters the main rotor's torque. The cockpit houses controls such as cyclic, collective, and throttle, with a swashplate transmitting blade pitch changes.

Control: cyclic tilts the rotor disk to steer; collective increases or decreases lift; yaw is managed by adjusting tail-rotor thrust or anti-torque devices. In engine failure, autorotation provides a safe landing.

Configurations vary. Most helicopters use a single main rotor with a tail rotor, but other designs include coaxial rotors, tandem rotors, and intermeshing rotors. Tiltrotor and compound layouts aim to improve speed and efficiency.

Uses span civilian applications such as transport, medical evacuation, firefighting, search and rescue, construction, and law enforcement, as well as military operations, disaster relief, and tourism.

History: early experiments in the early 1900s culminated in Sikorsky's successful VS-300 in 1939, which helped popularize practical helicopters. Earlier attempts included Paul Cornu's 1907 helicopter.

Safety and economics: helicopters are complex and expensive to operate, weather sensitive, and require extensive training and maintenance to mitigate risks.