Logo 500 belt goes loose

[maarset]

This is a logo 500 with CF tail.

Couple days ago when it started getting cooler here I noticed my belt tension was tighter than usual. Usually I have the tension where you can push the belt at the tail and it goes half way across the diameter of the boom.

So I adjusted the belt so it was a little looser and now the belt doesn't stay tight. I would adjust it before a flight and when I land I can push the belt so it almost touches the inner surface of the opposite belt. I hear it when doing tick tocks and flips. It seems to loosen to a point and doesn't get any looser. Boom is all the way into frame and pinned with a screw for ground. I marked the tail case to see if that was moving in flight and it was not. Inspected the belt and it seems fine. Lord knows how many flights I have on it. I just ordered a new belt. Not sure what is going on. Confused

Mike

[bj660raptor]

I think your belt is stretching,i noticed this on mine so i switched to the kevlar belt,i think that's what its made of.

[Blink 182]

Originally Posted by bj660raptor

I think your belt is stretching,i noticed this on mine so i switched to the kevlar belt,i think that's what its made of.

I think its europreprepreprpeprpepene

Something like that

[Kalpazan]

Try to touch the boom when you land. If it is colder than at the time you took off than it might be that the main blades cooled it to the point where it started to shrink. Also, humidity could affect the belt I think.

[maarset]

Thanks guys. Going to inspect belt after each flight. It must be stretching.


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[3D Dave]

Mike, I don't know how many flights you have on that belt but if it's stretching I'd replace it.

[maarset]

Yah I have one on order. Should be here Monday.


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[helirose]

I think this is caused by boom streatching. When you have at home 23°C and then you go to the field where is let's say 13°C your boom become smaller (length) -> belt becomes loose and vice versa (from 20°C -> 30°C -> tighter).

[Andy from Sandy]

I like to get the helicopter at the hotest it is likely to fly at and adjust the belt tension. It will be looser when the temperature drops but I will not have a situation where the belt will be too tight. That happened once and I think it stretched the belt over the small pulley at the back and damaged its structure

[horigan]

When I had this issue with no real temperature swings I solved it by pinning the boom at both ends. No matter how tight I made the tail case bolts it would slip. Not any more with the tail case screwed to the boom.

[maarset]

Originally Posted by horigan

When I had this issue with no real temperature swings I solved it by pinning the boom at both ends. No matter how tight I made the tail case bolts it would slip. Not any more with the tail case screwed to the boom.

Yah the front and back part of the boom is pinned. When I adjusted the case I forgot about the screw I had in the vert fin that pins the boom. It still allowed me to adjust the belt.

Once I removed that screw in the vert fin and adjusted the belt, and re-inserted the screw into a new hole in the boom the belt stayed at the correct tension. Totally operator error.

[shadowmastervn]

Hi
I see that you want to loose the belt tention for smooth auto rotation. I suggest you use some shim which comes along with kit. Place each shim between tail belt gear and under bearing, main gear and tail belt gear. Once you've done that, make the belt tention as much as you can, for sure the rotation will go smoothly.