Helicopter Aerodynamics essays

Helicopter Aerodynamics essays Helicopters are the most versatile aircraft today because of their ability to use three-dimensional space. Their flexibility allows them to fly backwards, hover, and rotate in air. This makes helicopters a lot more complicated than other aircraft aerodynamically and from a pilots point of view. A modern helicopters power source comes from a turbo-shaft engine, which does not produce thrust. Instead they create mechanical power to drive a shaft that connects to the main rotor. The shape of the turbine blades determines whether thrust is used to drive a shaft, or if most of the thrust is used to propel the aircraft and send a small amount of drive power to the compressor. In helicopters they are used the drive the shaft. These engines are light, powerful, and economical. To get the power from the turbo-shaft engine to the main rotor, a gearbox transfers the engine power to a transmission. The transmission reduces the revolutions per minute (RPM) from thousands to one-hundreds. This increases the torque so it can be accepted by the rotor system. The transmission gives direct power to the rotors. The tail rotor is powered the same way. Once the main rotor is in motion is acts as a wing to create lift. The rotor wings on a helicopter are shaped the same as an airfoil on an airplane, but a lot narrower so they can spin faster. If the rotor wings are rotated to give a slight angle of attack lift is created. When the helicopter leaves the ground the body will spin with the rotor because there is no counter acting force. This is where the tail rotor comes in. The tail rotor produces sideways thrust that counteracts the engines ability to spin the body. To control the helicopter both rotors have to be adjustable. Symmetrical airfoils have identical upper and lower surfaces. They are suited to helicopters because they have almost no center of pressure travel. Travel remains constant under different angles of attack, a...