Do full-sized helis not require a flybar because their rotor blades have enough mass by themselves to stabilize the heli?
Oops! Sorry, I just realized that I forgot to answer this one the first time.
Well, I read the answer to this question somewhere, but now I don't remember what it is. I believe the main purpose of the flybar is to stabilize the relatively small size of model helicopter rotors. Many scale RC helicopters that do not use flybars - they use "scale heads" that better match the appearance of a full size heli. I have played around with a couple of scale head helis in RealFlight G3.5, and they are basically just a little less stable. I still do not know why full size helis do not use flybars... Who knows, maybe some do, but I've never seen one. Anyone?
Also, the CX flybar is not parallel to or perpendicular to the upper blades, it is at an angle. What effect would changing the angle of the flybar mount have on the flight characteristics?
Another good question. The short answer: I dunno. I'd be interested to find out myself. I'm sure it is related in some way to the fact that the swash plate on the CX/CX2 is actuated 45 degrees from the actual direction you wish to travel. Ever notice that? When you press forward on the cyclic, the swash tilts diagonally forward and to the left. I have been told this characteristic is intrinsic to a coaxial rotor setup. What I'm not sure about is whether the 45 degree flybar causes this effect or is a result of it.