How Helicopters Work

一个helicopter's main rotor is the most important part of the vehicle. It provides the lift that allows the helicopter tofly, as well as the control that allows the helicopter to move laterally, make turns and change altitude. To handle all of these tasks, the rotor must first be incredibly strong. It must also be able to adjust the angle of the rotor blades with each revolution they make. The pilot communicates these adjustments through a device known as theswash plate assembly.

The swash plate assembly consists of two parts — the upper and lower swash plates. Theupper swash plateconnects to themast, orrotor shaft通过特殊的联系。一个s theengineturns the rotor shaft, it also turns the upper swash plate and the rotor blade system. This system includesblade grips, which connect the blades to a hub.Control rodsfrom the upper swash plate have a connection point on the blades, making it possible to transfer movements of the upper swash plate to the blades. And the hub mounts to the mast via theJesus nut, so named because its failure is said to bring a pilot face-to-face with Jesus.

The lower swash plate is fixed and doesn't rotate. Ball bearings lie between the upper and lower swash plates, allowing the upper plate to spin freely on top of the lower plate. Control rods attached to the lower swash plate connect to the cyclic- and collective-pitch levers. When the pilot operates either of those two levers, his or her inputs are transmitted, via the control rods, to the lower swash plate and then, ultimately, to the upper swash plate.

Using this rotor design, a pilot can manipulate the swash plate assembly and control the helicopter's motion. With the cyclic, the swash plate assembly can change the angle of the blades individually as they revolve. This allows the helicopter to move in any direction around a 360-degree circle, including forward, backward, left and right. The collective allows the swash plate assembly to change the angle of all blades simultaneously. Doing this increases or decreases the lift that the main rotor supplies to the vehicle, allowing the helicopter to gain or lose altitude.

Now it's time to see how all these parts work together to get the helicopter airborne.