What is the usefullness to have balls?

[quadrirotor]

Is someone able to give a rationnal explanation for those balls?

[hiphop]

Is someone able to give a rational explanation for those balls?

They are stops that release as the centripetal acceleration (also called centrifugal force) swings the balls up as the rotor RPM increases. I cannot tell from the photo what kind of stops they are, but basically they swing out of the way as the rotor speed increases.

Ken Wallis has a similar pair on his gyros to keep the rotor from teetering until the RPM is high enough.

--G

[DennisFetters]

Actually, they are called Chinese weights, and are tuned to it's rotor system to help absorb and dampen certain vibrations.

[quadrirotor]

Thanks Dennis, that's what i knew, i wanted more details...When i google "Chinese ball", i get sex toys!!!