What is gyroscopic precession?
This is a counter-intuitive aspect of helicopters, that even many advanced pilots don’t clearly understand. In order to get the helicopter’s rotor disk to tilt (for example) downward at the front, you increase the lift on the right side of the rotor disk and decrease the lift on the left side of the rotor disk. (This is assuming the standard clockwise main rotor rotation.) To see why this is so, consider the following example. If the heli is in a nose-down attitude, the forward moving blade travels downhill, and the aft-moving blade travels uphill. The blades travel level at the front and back. To get a hovering heli to go into a nose-down attitude, you need to encourage the forward-moving blade to start going downhill and the aft-moving blade to start going uphill. Hence, pushing the cyclic stick forward causes lift to be killed on the forward-moving (left) part of the rotor disk and increased on the aft-moving (right) part of the rotor disk.
