Helicopter wallpaper

Helicopter, aircraft that can take off and land vertically and can also hover motionless in the air. Helicopters are known as rotary-wing aircraft, as opposed to fixed-wing aircraft such as airplanes. A helicopter produces thrust by means of the blades of a main rotor as they rotate above the fuselage, or body, of the aircraft. As the blades rotate, an airflow is created over them, resulting in lift, which raises the helicopter skyward. The same rotor blades can be controlled to make the helicopter travel forward, backward, or sideways. Some helicopters can achieve forward flight at speeds of over 320 km/h (200 mph).

Helicopters vary in design, but all must provide a means ...

Helicopter, aircraft that can take off and land vertically and can also hover motionless in the air. Helicopters are known as rotary-wing aircraft, as opposed to fixed-wing aircraft such as airplanes. A helicopter produces thrust by means of the blades of a main rotor as they rotate above the fuselage, or body, of the aircraft. As the blades rotate, an airflow is created over them, resulting in lift, which raises the helicopter skyward. The same rotor blades can be controlled to make the helicopter travel forward, backward, or sideways. Some helicopters can achieve forward flight at speeds of over 320 km/h (200 mph).

Helicopters vary in design, but all must provide a means of counteracting the torque, or rotational force, produced on the shaft that turns the main rotor. Otherwise, the main rotor would rotate in one direction while the fuselage would rotate in the other. One common solution is to use a tail rotor. A small tail rotor is mounted vertically at the rear of the helicopter and produces a side thrust, preventing the fuselage from rotating. By increasing or decreasing the thrust produced by the tail rotor, the pilot can steer the helicopter to the left or right. Another solution is to use tandem rotors, that is, two main rotors turning in opposite directions. Since each rotor cancels the torque produced by the other, a tandem-rotor helicopter does not need a tail rotor.

Helicopters have both advantages and disadvantages compared to fixed-wing aircraft. The helicopter¡¯s ability to maneuver in and out of hard-to-reach areas and to hover efficiently for long periods of time makes it valuable for operating in places where airplanes cannot land. Helicopters can perform important military tasks such as ferrying troops directly into combat areas or quickly transporting wounded soldiers to hospitals. However, helicopters use more fuel than airplanes and cannot fly as fast. This is because the helicopter rotor must produce both lift, which raises the craft into the sky, and thrust, which enables it to move about. In an airplane, the wings create lift and the engine produces thrust. Despite its poor cruising performance, the helicopter is the obvious choice for tasks where vertical flight is necessary.