poss blade imbalance?

[stevek32]

hi all,
just a little prob, fitted new carbon blades to my 450 and when it started spooling up heli was shaking like mad, but as 50% throttle vibration stopped, i thought id balanced the blades properly but when i removed them and spooled up heli was fine, what are your thoughts blades? or something else?

[Mslater]

You might have them too tight in the grips. The need to be firm but not tight.

[chugga-bug]

Probably weren't straight in the grips that's all. Spool it up then shut down and spool up again. If it still shakes on the second spool up start looking for an imbalance somewhere.

[stevek32]

I thought this too so I loosened them right off and still the same only I haven't done is the tracking would this cause the extreme wobble?

[cjcj1949]

I just had a problem like this. In my case it was one of the dampers not being in straight or faulty. I had just tightened up the feathering shaft bolts. Lots of vibration at start then nothing. It could also have been that the main blade bolt tensions were not the same. Anyway I took it apart and put it back together with new dampers and a bit more care, making sure the dampers were properly seated and the bolt tensions were as close as possible and problem went away.
Standard way of getting rid of faults. Also a good way of introducing one if there wasn't one there in the first place.

[stevek32]

umm its strange because i've studied it with my old glass fibre blades its ok not really any wobble, but with the new carbon fibre on a linear throttle curve bottom stick to 25% very smooth, 25%-50% really bounces and shakes (rotor wobbles) but as soon as 50% upwards its very smooth again any ideas now? ive checked dampers all good could it be the blades somehow? they arn't the cheap ones and i've checked everything i can blade wise and they are identical,

[Dudifiedad]

check your jesus bolt? mine comes loose sometimes and starts to wobble or your headspeed it to low

[stevek32]

jesus bolt? whats that? newbie question sorry, and its a linear curve so i would have to throttle curve it to pos 1 @ 50%? but it would still bounce for a second until its gets to 50%

[Dudifiedad]

Jesus bolt is the bolt that hold the head onto the mainshaft. The bolt that goes through the head. My 450 wobbles when in normal mode but not when in idle up but that's just because I have kbdd damperners