Helicopter Controls and How They Work: Cyclic, Collective, Throttle, and Yaw pedals

Helicopters like this Bell 47 are said to be very difficult to fly. Image by Helen Krasner

Helicopters have the reputation of being extremely difficult to fly.

But in reality, all the pilot has to do is coordinate the four main controls: the cyclic, collective, throttle, and yaw pedals.  So what does each of these do?

The Cyclic or Stick

The cyclic, often called the stick by pilots, is a control positioned vertically in front of the pilot, except on the Robinson R22, R44, and R66 helicopters, where the configuration is slightly different.

It is used to change the attitude and airspeed of the helicopter. The cyclic does this by altering the attitude of what is called the rotor disc, i.e., the hypothetical ‘disc’ the rotors make when they are turning.

Actually, what the cyclic is doing is changing the pitch angle of the rotor blades by different amounts, but the net effect is to tilt the rotor disc. The disc then moves in the direction of tilt, and since the rotors are attached to the helicopter fuselage, the body of the helicopter then follows.  Moving the cyclic forward causes the rotor disc, and the helicopter, to tilt forward.  The helicopter pitches nose down, and also speeds up, due to the effects of gravity.  Moving the cyclic aft has the opposite effect, and moving it sideways causes the aircraft to turn.

The Collective or Lever

The collective is on the pilot’s left side, and looks rather like an old-fashioned handbrake in a car.  It is used to enable the helicopter to climb and descend.  It does this by altering the pitch of the rotor blades together, or ‘collectively’.  Raising the lever increases the rotor pitch and causes the helicopter to climb; lowering it puts the aircraft into a descent.

Engine Throttle

The throttle controls the power of the engine.  Raising the lever and increasing the pitch would cause more drag, so more power is needed for lift to initiate a climb.  The collective and throttle need to be carefully coordinated, or they did in early helicopters.  In most modern ones, there is an electronic governor which senses the position of the collective and adjusts the power accordingly, so throttle control it rarely needed these days – indeed, some say it is becoming a lost art!

Click to Read Page Two – Yaw Pedals

© Copyright 2012 Helen Krasner, All rights Reserved. Written For: Decoded Science

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