Now look what you've started!
Imagine two separate simple rotor systems. Both have a central vertically aligned spindle (aka rotor mast) which can be rotated axially and also tilted in any direction by a force acting anywhere at 90 degrees to its axis.
Four lengths of scaffolding tube arms (heavy and NON AERODYNAMIC, simply round in section) are attached to each rotor mast by two different methods.
On the first mast, the arms are held in a rigid steel hub so that the arms stick out horizontally like the spokes of a wheel (or the blades of a helicopter), at 90 degrees to each other. This system is rotated at speed. We now have a crude gyroscope. The system will exhibit the two properties of a gyroscope, namely rigidity (it wants to keep spinning in the same plane) and precession (any force applied to the rotor mast in an attempt to tilt the system will appear to act 90 degrees further round to the direction of application until the plane of rotation of the system aligns with the force and it can no longer act).
In the second system, the arms are suspended from the mast, at 90 degrees to each other, by separate lengths of flexible steel cable. At rest the arms hang down alongside the mast. The system is now spun up to speed. As the mast is rotated, the cables attached to it pull round the arms until they fly out at 90 degrees to the mast and 90 degrees to each other. At this stage, the system looks exactly like the first one. Because the rotating arms have the same mass as the other set, they must also act as a gyroscope and must therefore exhibit the same properties of rigidity and precession. A force is now applied to this rotor mast, as before, in an attempt to change the plane of rotation of the system. Because the mast is only connected to the rotating arms by flexible cable, it cannot transmit the force to them. This time the mast moves very easily in the direction away from the force, but the cables merely flex and the rotating arms maintain their plane of rotation. We have a system where the rotor mast can be easily moved, but there is no control over the rotating arms. If the plane of rotation of the arms were to change, there would be no effect on the rotor mast because the forces could not be transmitted through the cables, which would merely flex.
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In the first instance we have a rigid rotor. It can be controlled but the only way to control it is by applying a force through the rotor mast which must move with the system.
In the second instance we have created a fully articulated rotor. We have no practical way of controlling the plane of rotation of this system because we cannot input a force to cause gyroscopic precession to occur.
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We now stop both systems, dismantle them and replace the rotating scaffolding tubes with properly designed rotor blades of identical size and shape. We retain the original methods of attachment, one system rigid apart from simple pitch change bearings and the second still using flexible cables. We also fit a simple system that allows us to change the cyclic pitch angle of the blades. Both systems are spun up to speed with a neutral pitch angle on the blades.
By adjusting the pitch angle of the blades we find that we can fly them around, up and down, changing the plane of rotation of the rotor systems. The Aerodynamic forces generated by the blades overcome the Gyroscopic forces tending to hold the original plane of rotation.
One very noticeable difference between the two systems is that on the rigid system, while the plane of rototation is changing , the rotor mast moves in sympathy. On the second, cable attached system, the rotor mast says rotating along the same axis.
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Applying these two rotor systems to two simple helicopters we find that we can make them both fly by controlling the plane of rotation of the rotors. This is, as we have shown, done aerodynamically by changing their cyclic pitch. The flying characteristics of the two helicopters are however, a little different. The rigid rotor gives us a very responsive helicopter. This is because as soon as the dics tilts, so must the rotor mast, which is now bolted onto the airframe. The airframe rapidly changes direction as the rotor is flown around.
The articulated rotor still flies but the helicopter is reluctant to change direction in sympathy with the rotor system. This is because there are no forces feeding back through to the rotor mast in order to make it tilt.
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But this is only part of the story...
Right! Someone else please carry on.