Vibrations at mid rpm?

[arne997]

I get Vibrations and the heli shakes at spool up and spool down at approx 50% of full rotor speed. At normal headspeed when flying, it is perfectly smooth.

The main wooden blades are ballanced and in track.

Could it be the tailrotor or the flybar?
Is this normal?

Thanks

[Cralis]

I've seen that. A know a fix could be to tighten the main and tail blades. Worth a bash.

[Vinger]

This vibration is normal on helis, even full size ones and is called dynamic imbalance. It occurs because the blades and head are causing a resonance through the airframe and this causes the whole heli to shake. The Hurricane is more suseptable to this but can be minimised with belt tension adjustment, blade tighting etc.

Try all the cures mentioned in this forum and then just live with it when you have it minimised.:shock:

[michael88997]

yea just tighten the blades until you can hold it sideways and they dont move... if it still does it then just bring it a little above midstick and hit throttle hold...

[Phoinix]

Try spooling up with 0° collective pitch and cyclic centered.

[istandalone]

the hurri is very particular about how it's belt is. try tightening it up a bit more then you'd expect to have to.

[Madedon]

This vibration is normal on helis, even full size ones and is called dynamic imbalance. It occurs because the blades and head are causing a resonance through the airframe and this causes the whole heli to shake. The Hurricane is more suseptable to this but can be minimised with belt tension adjustment, blade tighting etc.

Try all the cures mentioned in this forum and then just live with it when you have it minimised.:shock:

Very true what Vinger wrote above. I have also experience that sometimes is worst when defective bearing are on the heli. In my opinion also examine all the bearings in order to minimise posible vibresions.

[Phoinix]

With 0° pitch on the collective, cyclic centered (no cyclic trim) and no wind, there should be no vibration. If there is still some, than you can blame it on the bearings or dynamic imbalance.

[phunk]

I had a wicked resonance when I first spooled up my h550, it started to dance around on the 4 corners of the skids and almost toppled. I tightened the belt and it is nearly gone, there is a little shudder near half throttle & 0 pitch but it passes quickly.

[mjdee14]

I don't have the vibs yet but i was surprised tonight when I grabbed the tail shaft it has play in the bearings....I wonder how many are caused by either the bearings moving in the plastic frame case or the loosness of the shaft. if I develop a bad vib thats the first place I'll be looking on mine.

I'm surprised with how loose it is i don't have a problem......now watch my next flight :arggg: