RE: Multi-Blade Setups
This is what I can tell you from my multiblade experience, in most respects I felt that response around the centering of the cyclic seems more sensitive compared to a flybarred head, yet that's where it ends, meaning that after you bank or pitch a few degrees from center the fast response ends, the machine had more of a "float" feeling compared to a flybar head, and dissimetry of lift (retreating blade stall) is more noticeable, not that it is something that does not happens to the flybar head, but the flybar will compensate for that making you feel like it does not happen. Same goes for the "ballooning", some flybar heads still exhibit this tendency, yet in most it is compensated properly by the flybar, so I guess it all goes back to really understanding how a heli flies and applying this understanding to the way you fly.
Aside from what a flybar stabilization mechanism will do, everything else is the same. A stabilization system provides the same correction ability of a flybar by reducing dissimetry of lift and balloning, but if you understand how the machine flies and learn how to adjust there is no need for them. A mixer allows you to change swash timming, below you'll see you can do that in your computer radio with no need for an external mixer. What a mixer does provide is the ability of mixing a gyro output to three controls, that is important ONLY if you want to have stabilization on a CCPM system where all comands are shared by all three head servos as opposed to a single servo collective where elevator is one servo and aileron is one as well.
Most issues related to multi blade set-ups are related to swashplate phasing, there are two reasons:
1)The more blades you have, the less space is available on the rotorhead and swashplate to accomodate the required 90 degress from swash control ball to blade holder control ball, this happens on rotorheads with 5 blades or more. This can be corrected by swash mixing to compensate for where your pushrod will be located in relation to the machine's centerline on fore/aft lor left/right orientation in order to compensate for the required amount of degrees to reach 90. In a 5 blade head you only have 72 degrees between each blade, so in order to have all pushrods perfectly vertical to avoid binding and non-linear response, you cannot achieve the 90 degrees required between the swash ball and the blade holder ball, but by properly mixing aileron to elevator and elevator to aileron you can "rotate" the swash timing so that a command happens 18 degrees later (or earlier) from the centerline of the fuselage. If it has to happen earlier or later depends on wether you have a leading edge or trailing edge controled blade holder and your rotor's rotation direction (CW or CC). Any computer radio can do this, there is no need for an external mixer.
2)Tendency to run head at a lower RPM than required to stabilize, every head/blade combination is different and the minimum specific RPM required to achieve stability on the system has to be reached before the head will respond to the inputs on the 90 degress due to gyroscopic precession . This RPM/phasing issue does not happen on flybar heads because your swashplate does not directly control the blades, the flybar does, the flybar is mechanicaly positioned at 180 degrees to the main blades(up/down travel of a paddle will always be at 90 degress from a main blade) and is controled aerodynamically, meaning that AIR FLOW controls it, so there is no gyroscopic precession de-phasing, PLUS, there is stability added by the flybar, meaning that control input will always affect it in the correct phasing, try to picture it and you'll see what I mean. If the rotor head would have responded to an input with a 45 degree lag due to low RPM(you give forward cyclic but head goes forward and left) the fly bar would give a "right" correction to the blades, but no correction to the "forward", left and right would cancel each other and you would only get a forward response.
Makes sense????