Helicopter Controls
Helicopter flight is actually very simple when broken down into its parts. I'll begin the explanation by going over the various parts of the helicopter so you'll be able to follow me.
Pilot Side Controls
Helicopters are controlled with three different controls:
Cyclic- this is the "joystick" you see in the cockpit. It controls the forward (fore), backward (aft) pitching, left and right rolling (roll) of the helicopter. It is used by the pilot's right hand.
Collective- this controls the helicopters altitude. It is called collective because (I'm winging it here) it collectively adds pitch to all the rotor blades at once. The collective is used by the pilot's left hand. This will make more sense later.
Pedals- the pedals control the yaw of the helicopter or the left and right pointing of the nose with respect to the horizon. The pedals control the pitch of the tail rotor that counteracts the torque created by the main rotor. They also are used for directional control of the helicopter during hover- a.k.a. where the nose points. They are located at the pilot's feet.
Rotor Side Controls
The rotor side controls translate what the pilot does into something the rotor can do. This is where the swash plate comes in. There are MANY different ways to implement a swash plate. The swash plate physically translates the up and down motion of the controls (non rotating) to a rotating type control. The basic design of all swash plates is the same. The bottom half does not rotate and the top half does. The picture to the right shows the two parts.
The examples you'll see here are from a model helicopter the Kyosho Nexus 30. This swash plate uses a 180 degree swash plate mix (in radio controlled helis we call it swash plate mixing). This means there are two control arms spaced 180 degrees apart. Other mixing options are 120 degrees (three control arms) and 90 degrees (four control arms). Each mix method has advantages and disadvantages. Full size helicopters normally utilize 90 degree mixing because it provides more strenght to the swash plate and is more stable given the weight of full size helicopters.
Yaw and Pitch Control
The swash plate is moved forward, backwards, left right and in some cases up and down to control the helicopter. The pictures here show the different positions of the swash plate and what they will do to the helicopter. The pictures of the swash plate on the left are oriented with the nose of the helicopter to the left.
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Main Rotor Pitch Control
Ok, so we can see how the heli moves around, but how does it go up and down? In these examples, the middle portion of the swash plate (not actually part of the plate in this case) moves up and down to adjust the pitch of the rotors as shown here. The little brass looking cuff and the mess of black on the mast that are pointed out are the collective controls attached to the blades. On this helicopter when the pitch control is all the way up there is no pitch on the blades, when it is all the way down there is full pitch on the blades.
The only part of this system that spins is the upper part. The brass cuff is attached to the control linkage to move it up and down.
On larger helicopters (and in real life...) like my scale EC-135, it uses a 90 degree swash mix to control the four blades. To adjust the pitch on it, the whole swash plate moves up and down for pitch in addition to the other controls on it.
The Tail Rotor
The tail rotor is just a sideways main rotor that is much smaller. Its main purpose in life it to counter-act the torque for the main rotor by pushing against the rotation of the main rotor. It uses the same principals to adjust its pitch. A linkage connects to a swash plate of sorts that adjust its pitch. There are a bunch of different ways that pitch adjustment on real helicopters. Check out the Heli Data area to see some of the ways it's done in the real world. Most notibly is the way the Sikorsky Blackhawk does it.
Ok, so we've covered the swashplate, main and tail rotors. Together these control the helicopter and are the main parts aside from the engine. The next part to understand is why they work the way they do. Click the here to go to that article.