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Old Apr 25, 2011, 09:58 PM
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Germantown, WI.
Joined Oct 2007
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1. The term self-stabilizing is often misused to include self-leveling. In any case, FP helis are much more likely to exhibit both of theses characteristics. But, it's strictly because 95% of CP helis currently made are intended to fly 3D, where these traits would be undesirable. There's no reason why a CP couldn't be self-stabilizing and self-leveling. To a large degree, they already possess superior stability due to their higher and more constant headspeed. Some use electronic stabilizations systems that can be dialed down or turned off, for the best of both worlds.

2. Flybarless helis are not self-stabilizing, by themselves. But, they are with a 3 axis gyro or flybarless control system.

3. Quads and other multi head designs use 3 axis gyros and mixing systems. They also use accelerometers. These are what gives them self-leveling properites.

4. Gyroscopic precession dictates that it takes 90 of rotation, from the point where a signal is given, to be acted upon. Which is the reason why flybars are typically 90 from the point where the swashplate linkage connects. 45 offset heads create a leading flybar, 45 offset flybars create a trailing flybar. Both create an out of phase condition that can used to mix with movement hat occurs at the regular 90 interval to affect and damp head movement. Mixing in-phase and out-of-phase conditions is a recurring effect, that has echos. So, the damping effect is multiplied, giving your self-stabilizing effect.

An offset head with an out-of-phase leading flybar will not impede movement; if anything it will enhance. But, may have some rebounding when you attempt to stop. An offset trailing flybar is purely for damping movement.

However, neither of these will make a heli return to level. That requires accelerometers. Self-stabilizing FP helis tend to self level because they have a long vertical CoG (due to the extra linkage and connection points required for self-stabilizing) and a low battery mount right under the main shaft.

I have never got any single rotor heli to hover hands off, nor have I ever attempted to do so. I don't know what point that would serve.
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