RE museum - how helicopters manoeuvre


The cyclic pitch column changes the blades' pitch individually as they sweep round. This creates more lift on one side than the other, making the rotor tilt. The craft is propelled in the same direction in which the rotor is tilting.

Takeoff To increase lift, the pitch of all the blades is raised by the collective pitch lever. The throttle usually opens up automatically to provide the extra power needed for takeoff.
Gaining height Applying more engine power increases the collective pitch of the blades and lifts the craft. To move forwards, the rotor is tilted using the cyclic pitch column. The movements are coordinated to make a smooth transition to forward flight.

Stability - Twin rotors are used to prevent the fuselage from turning. On the Chinook , gearing stops the intermeshing rotors hitting one another. The Russian Mil Mi-26  has two rotors on the same axis turning opposite ways. The world's largest helicopter is the 100 ton Mil Mi-12. The overall span of its rotors is only slightly less than a jumbo jet's wingspan.

Flying forwards - Easing the cyclic pitch column forwards gives more lift over the tail of the helicopter. The rotor tilts and propels the craft forwards at a constant altitude.
Hovering - To hover, the pilot adjusts the pitch of all the blades with the collective pitch lever so that the amount of lift just exceeds the weight of the helicopter.

Flying sideways The pilot moves the cyclic pitch column in the direction he wants to go, causing the blades to give more lift on one side than the other. The rotor tilts and propels the helicopter in the chosen direction.
Flying backwards - By easing back the cyclic pitch column, the blades are given more lift as they pass over the front of the craft than over the back, so the rotor tilts backwards enabling the helicopter to reverse.

Read More: Helicopters, how they work or how they fly