Hey all, I have a question about vibe issues. My axe has whacked a few things in the past but I have always put it back in new shape and am pretty decent at hovering tail and side in now. I have the jcs trainer blades on it (plasti-blades). The other day it set down a lil hard and one of the blades just barely caught the tail boom. I didn't even realize it had happened but there is a very small ping in the boom so I know it must have struck it. After that, I am getting a prettty ugly vibration in flight. I see no major wobble of the head during rpm increase and as long as the heli sits on the ground it isn't vibing to bad but increase a bit more to get that 2-3ft hover and once it gets up it starts to vibrate so bad that it actually causes the tail boom to rotate in the frame and you can hear it in flight. I have viewed the blades while running close to hover rpm and can't visually see a major tracking issue. I imagine the blades are slightly out of balance but I don't think I have ever flown with perfectly balanced blades and it usually isn't like this. The training gear balls are pretty worn, is it possible this has something to do with it or should I start replacing rotor parts until I get it with process of elimination?

Da

Sounds like a bent Feathering Spindle, or maybe ruptured 'o' rings in the head behind the blade grips (and also on the feathering spindle). Other possibilitiy is bent FlyBar or FlyBar paddles out of alignment ( should be parallel to main rotor blades at 0 degrees pithc).

Plastic blades from JCS come pretty well balanced from John.

FlyBar paddles out of alignment

HUGE

by twisting the paddles you can get to a no vibration flight, they are REALLY sensitive

Take your drive shaft out and chuck it up in a hand held drill. Spin the drill slowly. If you see any wobble in the shaft then it is bent. All of mine were out .25 inch so that was bad. Having 9 new ones made out of 6mm Stainless Steel Rod from a local MFG CO. I'll let you know how that goes.