There is a saying in the aviation community that helicopters are a thousand moving parts going in generally the same direction. There is some truth to this. How does the helicopter change direction? Black magic? Pure, unadulterated evil? A mechanical linkage that changes the pitch and path of the blades, creating a higher lift region opposed by a lower lift region allowing the aircraft to move towards the lower lift region? Most likely, it’s a combination of all three.
The swashplate is what makes it all possible. It consists of a fixed outer ring where inputs from the pilot are received and a rotating inner ring that transmits those inputs to the rotor blades. As the pilot moves the stick, he actuates the pitch and roll linkages causing the ‘copter to move in the direction of the lowered actuator. As the pilot moves the collective, he raises and lowers the swashplate which changes the angle of the blade and increases or decreases how much lift they generate.
Here’s an excellent video demonstrating how this devilish system works.
[Ed. Reader TheTokenGreek mentioned this in a comment a while back, and The Professor brought it to my attention. Why am I telling you this? I'm not sure, but I thought they deserved some recognition.]
[Image Credit: Guido Brüscher]