Main rotor grips.

[longdog67]

Hi chaps,
How tight should the main rotor bolts be done up?
Should they be done up tight to limit movement? or do they need to allow free movement of the main blades?

[J-S-Q]

Generally the blades shouldn't be loose enough to move very easily but they shouldn't be so tight that they're unable to move. A good guide is that if you take the helicopter and tilt it on it's side the blades shouldn't fall under their own weight but if you give it a bit of a shake they should move.

[coptermanic]

Some debate on that one. Yes it is how I check the blade tightness on my 600, but I, and I know others, like their blades much tighter with the 450. I find the head has fewer minor vibes, and of course there is a benefit for auto performance for the smaller helis with less inertia in their main rotors.

[heliward0]

small helis need loose grips
larger helis need tight grips

[coptermanic]

small helis need loose grips
larger helis need tight grips

Just intrigued, cos I'd have thought the opposite. Would you explain why please?

[debrooker]

On the bigger helis, there is a danger of boom strike if the blades are too lose.

[coptermanic]

Mine 600 blades are not loose. They certainly don't drop when you tip the heli on its side - that hi-tech 21st century technique!! But my 450 blades are a lot tighter, almost locked in position. If you try an auto on a 450 with "loose blades", almost guaranteed not to work!! Or better put, it will work much better with stiffly held blades.

[Sesame]

When I started out I used the same method, Hold it on its side and give it a tap.

But as ive gone on I seam to have tightened them up, mainly because in an auto they can swing away from centre, which can cause problems

[Dedcalm]

what about tail blades?

[sacko]

what about tail blades?

So they can freely move in the grips, wit some very gentle persuasion.

Saves TT gears then.

[coptermanic]

When I started out I used the same method, Hold it on its side and give it a tap.

But as ive gone on I seam to have tightened them up, mainly because in an auto they can swing away from centre, which can cause problems

.....

......which is more likely with a smaller heli. So you really want the smaller heli blades tighter; the bigger helis blades have more inertia and centrifugal force to keep them in position so need not be as tight.

[POLAR BEAR]

On the bigger helis, there is a danger of boom strike if the blades are too lose.

Any size heli can boom strike!