Clicking or popping noise during spool down

[stevehof]

The last couple of times I flew my E7 I noticed a clicking or popping sound during spool down. It was loudest when I lowered the collective after the blades had mostly stopped. I could not see any mechanical interference anywhere when moving the collective up and down. Also, there was no click or pop when the blades were static. So, I called over a friend with 'younger' ears. He said it sounded like carbon fiber. Sure enough when I flexed the blades up and down in the blade grips it sounded like a squeaky door or hinge. I loosed up the blades a bit in the grips and the noise disappeared. I just got done greasing the blade shims and now there is no sound no matter how tight the blades are. I can run the blades at the proper tension without any noise....Just an FYI....

[Matt Botos]

Good tip Steve!

I've also seen tight ball links cause strange sounds.

I am in the process of manufacturing Delrin main blade and tail blade shims as I believe aluminum is a poor choice of material for this application. Aluminum against aluminum will cause galling which will lead to the rotor blades not being able to lead / lag correctly. My temporary solution is the same as Steve's.

Thanks,

Matt

[Darren Lee]

That's awesome Matt!  I've never liked the metal spacers either.

[steffgiguere]

Delrin shims, I'm in

[scotty82]

I found tight ball links on my E7 causing some strange noises. A quick touch up with the Boto sizer and the noise went away.

[Ross Lawton]

Good tip Steve!

I've also seen tight ball links cause strange sounds.

I am in the process of manufacturing Delrin main blade and tail blade shims as I believe aluminum is a poor choice of material for this application. Aluminum against aluminum will cause galling which will lead to the rotor blades not being able to lead / lag correctly. My temporary solution is the same as Steve's.

Thanks,

Matt

Nice one Matt, i have always prefered the delrin/plastic blade shims over the metal ones but they are hard to find.

Cheers,
Ross

[RyanW]

Totally agree with metal to metal comment. I use the old Hirobo ones, but have to stack them up. Matt's solution will be best.

http://www.ronlund.com/rcheli-prod/414388.html

[stevehof]

While we are on this subject of those spacers.  It is hard to get blades installed on my E7. I have to use the handle of some tool to press the 'second' spacer into place. Maybe this is caused somewhat by the galling on the spacers. In any case, then I have to use a tapered center punch to align it with the blade hole. If the tolerances weren't so TIGHT on everything, maybe it wouldn't be such a complicated drill to get a set of blades installed...   BTW, yes Rail blades...

[RyanW]

The easiest way I have found is to take a ball-end hex wrench and line it up from the bottom. Stick the wrench in a little, the blade with spacers and wiggle it. The ball-end usually goes in pretty nice and lines everything up. Then push it back out from the top with the blade bolt and you are done!

-Ryan

[stevehof]

The fit is so tight that there is no way to get the blade and both spacers inside the grip in one motion. One of the spacers is going to be a very tight press fit. One side of the head is worse than the other. I have two E7's and both are like this. I certainly have not over tightened the blade bolts to cause this, and with properly designed blade grips that should not be possible anyway. The blade/spacer fit was very tight when new and after a few hundred flights is even tighter. So, either the galling on the spacers/blade grip is causing this or the top and bottom of the blade grips have gradually moved closer together from the pressure of the blade bolt.

[Chuck Bole]

 I put the blade bolt through the top spacer, then through the blade hole, then the bottom spacer before installing the blade. Then slide the whole group into the grip. Push the bolt up slightly so the shoulder is resting
on the top and bottom of the grip. Then with the blade and spacer assy started in the grip pull the bolt out and slide in the rest of the way. Line up the holes and insert the blade bolt.

Been doing it that way for years..

Delrin spacers will be much better when they are available though..

chuck

[Darren Lee]

+1 Chuck, that's exactly how I do it.