View Full Version : Idler wheel tail belt
I have a Belt CP that I have about 70 successful flights on now. I’ve been noticing for a while a high pitched squealing sound every now and then. Everything works fine and it flies well with no vibration. Well last night I finally found the problem. It’s the idler wheel on the tail that supposedly keeps proper tension on the belt. I removed the idler wheel and discovered there is no bearing. The manual does not show a bearing either. Are you kidding me! Even the linkage arms have bearings on this thing and they don’t put one in the idler wheel? Anyway, the idler wheel is worn out pretty bad as is the screw that went through it. I simply removed it and checked the tension of the belt without it. Seemed fine and I've since flew four more battery packs through it. The occasional squealing noise was gone and when I shut the helicopter down the rotors free spin noticeably longer. So for the moment my belt CP seems much happier without this idler wheel. Does anyone see this as a problem by just leaving this idler wheel out? To me it seems to be doing more harm then good.
mnwizard
07-07-2008, 12:05 PM
The idler wheel keeps the belt from contacting the inside of the boom, and keeps the belt aligned with the gear on the tail shaft. The belt will expand (lengthen) a little at high rpm and the idler also helps to keep tension on the expanded belt so it doesn't "skip teeth" on the tail shaft gear.
There is no bearing on the stock idler. I use a little white grease on mine.
Heli Yea!
07-07-2008, 12:41 PM
MNWiz is right, things like the idler wheel are there for a reason. Removing it can put unjust stress/wear on your belt, take it out and check for worn/missing teeth. Leave the wheel in if you must have a bearing get CNC tail upgrades!
nitsuj
07-07-2008, 06:25 PM
There is actually a mod to fix this problem. Replace the aluminum wheel with two EK1-0509 bearings. It works great and looks even better.
Heli Yea!
07-07-2008, 06:41 PM
Got any pics?
sutty
07-07-2008, 07:16 PM
I have been using the two bearing approach for months without issues. It is much smoother and seems to work a treat. The only issue I can see with it is that there is no flange to keep the belt in line which may cause wear on the flange around the rear gear but this has not happened to me. Here is a picture of mine. I hope nitsuj doesn't mind but I had my heli and camera handy so I thought I may as well post.
54139
Hopefully this is clear.
Heli Yea!
07-07-2008, 07:29 PM
Yep!
Thanks guys! I'll give that a try. That looks like a much better deal then putting the aluminum idler wheel back in.