two blades rotor teeter hinge position

[paco]

It's why some people only lurk these days.

phil

[Birdy2]

Teetering and undersling are unrelated.
Teetering allows each blade to compensate equally for the difference in airspeed while traveling horisontaly.
No horisontal travel, no movement on the teeter hinge.
Undersling simply places the teetering hinge in the center of lift/drag, cancelling out the 2per that would be present without it as you add horisontal airflow.

Any increase in teetering angle wont change the cone angle.
Any increase in cone amgle wont change the teetering angle.
The degree of teetering angle is proportinal to airspeed differential.
The degree of cone angle is proportinal to AOA, or load.

[whoknows idont]

Originally Posted by grayzhu

Yes. I am trying to design a rotor head for small Coaxial helicopter.
I have made one. It can fly but I think it's not very well.

Fascinating! Care sharing some pictures and details?

[grayzhu]

I made some calculations.The results are not satisfactory.
I choice the undersling let left and right blade CG distances are equal:
If flap angle is 10 degree,blade CG distance moved 13.2 mm.
I do not think it can work well without lag hinges.

ps:some data I use for calculation.
e=794; blade CG distance from blade root (mm)
x=41.555; undersling (mm)
b=80; blade root distance from rotor head center (mm)
a=3; pre cone angle (degree)


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