Balance of rotor at low RPM

[eaglewwit]

When running up the heli (blades off). I noticed that at low RPM's it vibrated quite a bit. Once I was at about 50% throttle the nut on the main shaft just above the chasis appears to move down minutely, and from there to 100% the heli was well balanced with no vibrations. Anyone else experience this.

[tom dubya]

It might not be a good idea to run it that high without the main blades on.

[eaglewwit]

Still does it with blades on. Once past 50% on the throttle it settles and and the vibration is gone, probably just the tolerances on the assembly.

[tom dubya]

Are you sure that the bolt holding the shaft on is tight. Just below the main gear. Can you move the shaft up and down when you pull on the top of the head. Mine has about maybe 1/3 mm of play in it.

But yes there will be some vibrations due to the blades finding there correct positioning as you spool it up. As far as spooling it up without the blades on ,the heads on these things just aren't meant for it at high speeds. Also make sure that your blades are tightened down correctly. Not to tight, not to loose.

[eaglewwit]

Tom, I noticed the play on the main shaft as well. I was thinking about finding a washer to put there to tighten it up. I do run ups all the time without the blades on for safety, and no problems.

[Ber60]

Some pionters :
remove wobble on maingear.
balance the paddles (yes the paddles ) with the flybar
measure the flybar on equal distance in the holder

[Jonnyheli]

Tom, I noticed the play on the main shaft as well. I was thinking about finding a washer to put there to tighten it up. I do run ups all the time without the blades on for safety, and no problems.

To reduce the play. Undo the collar above the bearing on top of the frame. Pull the shaft up and push the collar down, then tighten the collar.

-Jonny

[another_finn]

And, if none of the above works, change to an Align main shaft. That completely eliminated the Belt CP's signature spool-up boogie on mine.