How helicopters main rotor works and how it can change rotor position?

A helicopter rotor is actually a rotating wing. I has an airfoil profile that makes the air to move faster over than under, thus creating a lower pressure on the top of the rotor blade.

The simplest for of the helicopter is the gyrocopter. That craft has no engine power on the rotor but a small propeller behind and as it takes speed on the runway, the big fixed rotor starts spinning. Rudder (yaw) control is via normal rudders but pitch and roll control is via a mechanism that works on the rotor the same way the "weight shifting" principle of the hang glider works.

A helicopter is a gyrocopter but with the main engine on the rotor and rotor blades that are pitch variable. Pitch and roll and then obtained by a change of the pitch either side to side or front to back. The yaw control is then obtained by a second propeller in the tail.

The controls of the helicopter is pretty much like that of a fixed wing craft: a stick for pitch and roll, and pedals for yaw. A difference is that the pilot usually sits on the right hand side and has to his left the controls of both power and pitch of the rotor that is usually pulled or pushed together, hence its name of, collective.

Should the engine of an helicopter fail, it can be landed safely by what is called auto-giration: the rotor turns as for a gyrocopter and prevent a fall. The craft is then tilted slightly on one side or the other to prevent a counter spinning since the tail propeller is not working.

Landing is done with speed forward and a strong pull on the pitch at the last moment.

any informations you want can be found in

www.wikipedia.com

just search for:

helicopters & helicopter rotor

(^_^)