67november
Newbie
Have any of you made/used them for your gyroplanes, not your models
I would like to see your comments.
thx, newbe gyro person
I would like to see your comments.
thx, newbe gyro person
CHEAP is always the owner way when it comes to their a/c costs.
I would think a semi ridig rotor system would werk on a four bladed system but thats just a guess on my part.
First off, criss-crossed teetering rotors need a scissors hinge. In the presence of cyclic flapping, the blades don’t maintain their 90º spacing; if they could flap all the way down, they’d be parallel; tips moving along the path of an orange peel or the longitude lines on a globe.
The most serious problem is resonance. A single see-saw rotor with an anvil bolted to the rotorhead resonates at near 1/rev with the usual hub bar arrangement. This destroys blades in a hurry. The second rotor being the equivalent of an anvil in terms of mass.
The Bell 4-blade rotor is a soft in-plane system, meaning the in-plane resonant frequency is ~60% of rotational rpm. This avoids resonant excitation by the periodic air forces but in most cases, is high enough to avoid ground resonance.
When it comes to rotors, life is never simple.
I can manage Euler's equations and know about coupled oscillating systems and so on. But it gives me the creeps to realize the complexity of forces and the havoc they can wreak when you design rotors. I'm glad there are some people around who can tell what works from what doesn't by other means than having someone try it out.
I guess that's the difference between applied engineering coupled with experience in the field and a nuclear physicist
It's great to have you on the forum, Chuck!
-- Chris.