Blade balance??
11-28-2007, 06:26 PM
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Blade balance??
When I start to spool up I get a lot of wobble but when it get's up to speed it is ok . Do the blades need to be balanced or is it something else I have to do? If it is balance how do I do that ?Any help on this matter would be great.It will make the helicopter start to jump till it stats to spinn up faster.
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11-28-2007, 07:19 PM
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RE: Blade balance??
what kind of heli? CP or COAX or FP?
Some wobble at low speed is normal on startup for blades that can pivot. They need a bit of speed to get correctly in-line.
Some wobble at low speed is normal on startup for blades that can pivot. They need a bit of speed to get correctly in-line.
11-28-2007, 08:00 PM
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RE: Blade balance??
It is a Belt CP I had a blade strike and put in new parts . I am going to replace the feathering shaft tomorrow and see if that helps it . How does that sound?I hope that helps. any other help would be great also.
11-28-2007, 10:25 PM
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RE: Blade balance??
like michael said, at low rpms its normal for alittle wobble because the blades havnt spin up fast enough to get inline, you will know if the spindle/feather shaft needs to be replaced because the blades will track horribly. sometimes you can even look at them and see one blade is bent upward. as long as the wobbie goes away after the low rpm range and the blades are tracking straight, u should be okay.
11-29-2007, 04:17 PM
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RE: Blade balance??
Hey guys found out I had a bent feathering shaft. My wobble was worse then I explained to you guys.Thanks for the response . I am shure I will be back with other problems.
11-29-2007, 04:51 PM
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RE: Blade balance??
For future reference, if you spool up, and the wobble seems to go away at high head speed, then throttle back down. The blades are now as "inline" as they can be. as they spool down, watch for the wobble again. If it does not happen on the wind down, then they were just not inline to begin with but are now. If it still does it on the wind down, then something is bent or out of balance somewhere.
If you watch the center of your head (this is tough in some configurations) you may see a wobble there indicating a bent main.
Often, if its the cross shaft, then if you sight down the length of the entire rotor after it has stopped, but BEFORE touching it, you may see the blades are curved, or have a slight "Boomerang" shape (a degree or two off straight).
If your blade pivots are just tight enough to keep the blades from dropping when you turn the heli on it's side (A good place to start for tightness), you can get a good static balance to see where the problem might be. Assuming you have properly balanced the blades first, this will identify if the cross shaft is not perfectly even, or there is a slight bend in the main.
All the balance stuff assumes that there is not a lot of drag to keep the head from "Falling" to the heavy side. I have been known to pull the main and head out as one piece and put them in another set of bearings I have on hand for just that.
Happy Flying.
If you watch the center of your head (this is tough in some configurations) you may see a wobble there indicating a bent main.
Often, if its the cross shaft, then if you sight down the length of the entire rotor after it has stopped, but BEFORE touching it, you may see the blades are curved, or have a slight "Boomerang" shape (a degree or two off straight).
If your blade pivots are just tight enough to keep the blades from dropping when you turn the heli on it's side (A good place to start for tightness), you can get a good static balance to see where the problem might be. Assuming you have properly balanced the blades first, this will identify if the cross shaft is not perfectly even, or there is a slight bend in the main.
All the balance stuff assumes that there is not a lot of drag to keep the head from "Falling" to the heavy side. I have been known to pull the main and head out as one piece and put them in another set of bearings I have on hand for just that.
Happy Flying.
