Here is something else I found..w3mh.co.uk or read this from Collin Mill:
The speed of response of the flybar to commands can be adjusted as follows:
Increasing the weight of the paddles slows it down.
Increasing the area of the paddles speeds it up
Increasing the rotor RPM speeds it up
Increasing the aspect ratio (span/chord) of the paddles speeds it up.
Increasing the length of the flybar speeds it up.
This last point was something that Ken Rudd touched on in W3MH some time ago. However its not obvious why this should be the case so let me just give my reasoning for it. If we take one size and weight of paddles and fit them to a flybar that has been lengthened by say 10%. We :-
1) increase the moment of inertia (the flywheel effect) of the flybar. This means that the flybar will need a greater torque to impose a given rolling or pitching rate on it.
2) However, in putting the paddles further out we have increased the leverage that they have so that, for a given aerodynamic force on the paddles, we have a bigger torque.
3) In addition, by putting the paddles further out we have, for a given head speed, increased the airspeed of the paddles and thus increase the aerodynamic forces they produce.
Now effect 1) acts to slow down the response of the flybar, and it involves a square law so a 10% increase in flybar length increases the torque needed for a given roll rate by about 20%. However, effect 3) also involves a square law so, with the paddles 10% further out they produce 20% more force for a given cyclic pitch. So effects 1) and 3) cancel one another out. This leaves effect 2) which is linear and so a 10% increase in flybar length speeds the flybar up by 10%.