Flight Dynamics: The Swashplate and Phase-angle

[delta3]

To Chiplight

I quote you:

"Flapping , in a teetering rotor, causes the rotor tip-path plane to tilt away(flap back) from the spin axis and is the result of differing airspeeds on adv/retreating blades."

I would agree with this definition (this are the beta's in my simulator)

If the main rotor axis is not perpendicular to the required tip plane for the given flight path than flapping occurs. Flapping has two effects : the first order is it tries to "do as if the main rotor is tilted". A visualisaton aid is : think of the heli in hover and change the load and balance (aft and back), the cyclic will try to 'replicate' a fixed angle of attack in the horizontal tip path.
However inertia does not like the rotor to go away from the perpendicular so it takes extra effort to get the tip path angle, and thus different angle of attacks (remember centrifugal forces are at least 10 bigger than lift).

A well designed heli (tail wing etc) will probably have the main rotor more or less perpendicular in 'most common' (forward) flight path scenario's (that I found is the case in the R44 at least in my simulator). 50 knots lateral is not a common flight path. As I said I did not simultate this one yet exactly (perhaps spending too much time on this forum..) but it appears unlikely if I saw how much balancing (wings etc) it takes to get this sort of behaviour in forward flight (that I fooled around with a lot so far)

If you are still with me... than this means that more ore less important changes in flapping will occur (this does not mean the rotor is all over the place, just refering to the above definition). It is the changes in these directions that are important, not their steady states. Not anticipating them can/will create brutal blows (and this will create all over the place situations, because the whole heli gets involved). This is quite different from a gradual accelerated lateral flight (mind tail rotor vortices in this case see different thread)

Delta3 trying to make sense...