helikopteri

A helikopteri, or helicopter, is a rotorcraft that achieves lift primarily through one or more horizontal rotors. The main rotor provides vertical lift and, together with its propulsion, drives the aircraft forward. A secondary anti-torque system, typically a tail rotor, counteracts the torque produced by the main rotor and helps control yaw. Flight is controlled with cyclic pitch to tilt the rotor disk, collective pitch to vary overall lift, and pedals to steer around the vertical axis. Some designs use alternative rotor configurations to balance stability and performance.

Most modern helicopters use a single main rotor and a tail rotor powered by a turbine or piston engine through a complex transmission. Other configurations include tandem rotors, which place two large rotors in line (as in some military and heavy-lift models), coaxial rotors mounted one above the other (as in several Russian designs), and intermeshing rotors where two blades overlap in a small space. These configurations offer different advantages in lift, stability, and control in confined spaces.

The history of helicopters includes early experiments in the early 20th century, with Paul Cornu achieving an early powered flight in 1907 and Igor Sikorsky developing the practical, controllable helicopter in the 1930s and 1940s. Since then, helicopters have become essential for civil and military use, including transport, search and rescue, medical evacuation, firefighting, offshore support, and military operations.

Operations are regulated by aviation authorities and require certification, maintenance, and trained personnel. Helicopters are sensitive to weather conditions and require specialized piloting skills and ongoing safety procedures.