Originally Posted by
dickmct
As crab said, Coriolis Effect is an apparent deviation. The bolt in his example departs in a straight line as there is no force acting on it to change its path; it is on a radial path to the tip plane; the blade tip was in line with it initially. However, by the time it reaches the tip plane the tip has moved so it does not arrive at the tip of the rotor blade but where it was at the moment of departure. A static observer watching from above will see the bolt on this straight, undeviating path. An observer at the rotor hub looking along the blade and rotating with it will see the bolt apparently lag behind the blade and seem to follow a curved route. CE is not a force and no acceleration occurs.
The opposite would happen if an inward-shooting bolt cannon at the blade tip, shoots a bolt initially toward the hub. An observer at the cannon would see the bolt curve forward and to the right, while an outside observer would see it go in a straight line (yet still forward of the blade). This is Coriolis force, and it is a direct result of the conservation of angular momentum. They're not two different things. Check out this video, skip to the 7 minute mark:
Conservation of Angular Momentum is the element that applies to a coning rotor disc and there is a mathematical explanation of it that I am not competent to give. The FAA manual is incorrect; I had some interesting discussions with the trainer on my gyro instructors course as he had based his teaching on that book.
The difference between the free particle that is our inward-shot bolt (or a water droplet in the experiment in the video, or an air parcel on a large scale wind on a rotating planet) vs. a piece of rotor blade in the middle of coning in, is that it's not free but rather rigidly mounted to the rest of the blade. So it pulls the blade forward and RPM goes up.
How does this "apparent" deviation result in an actual force/torque? Seems like a something-for-nothing deal, which we know isn't possible. From an energy budget perspective, we know that angular momentum was conserved: for a free particle, decreased radius converts to a higher angular speed. This can also be put in terms of straight-ahead plain old momentum: Actual speed stays the same, which means that the distance per time stays the same. Which means that the same distance (per time) wrapped around a smaller circle, covers more angle (per time). So the "apparent" path deviation to the right (to an observer rotating to the left with the system) is still a very real angular speed deviation, pulling the rotor forward.