Not sure what happened, but 5 minutes in, I landed to check motor temp and noticed that the blades stopped free spinning quickly like something was binding. Took a look and the tail rotor, where the belt wraps the pulley, has grey dust accumilated on it and in the belt pulley in the frame. Tail belt has a little shredding on one side but not all the way around. Got 19 flights on thus far.
What happened?
Does it need some silicone spray on the belt?
Is the belt worn out? Looks fine to me.
Did the belt get a little too loose and try to run up high on the tail rotor pulley?

Probably too tight. Do you get Model Aviation? Ray Stacys article in the last issue addresses the issue of shredding tail belts, mine went at 6 flights and caused a crash.

My belt started to shread after about 20-30 flights i put a new one on and sprayed it with WD-40 i have about the same fight time as before and the belt looks great. The Trex has a problem with there tail belt design and they need to get it fixed.

Someone (i think it was whtbronco) said something about running the MX400 pully or taking the idler out, I cant remember, I'll page him to the discussion.

Yes, I replaced my belt due to shredding on flight 13 and at the same time installed the idler pulley from the MX400. The MX400 pulley has flanges on each side that help to ensure the belt remains centered on the tail drive pulley.

I have not decided on whether to use any belt dressing on my new belt, but it sure won't be WD40. I won't use WD40 for anything. I intend to see how things go with the new pulley and the try something else if that doesn't correct it.

I believe mine ran up on the tail rotor pulley and wore itself out.

Oh Yea!!, I would not use that belt anymore. if you do you'll be asking for a failure IMO.

Hi! My first post... Hope it's helpful.

Did I read that one cause of belt problems was that the tail was not perfectly, uh, aligned... as in: tail pulley shaft perpendicular to the vertical, driven shaft and pulley up front.... resulting in the belt running to one side of the rear pulley. I realize the belt is flipped 90 degrees on installation... just makes it a bit more difficult to adjust.

Not unlike a belt sander where the belt runs over to one side, but can be brought to a centered position with careful adjustment of the belt tension adjusters... which can send the belt running right or left if not tweaked perfectly.
In our case, just loosen the tail clamp and rotate the assembly minutely. Will this lessen the problem?

This is one thing I'll be watching as I'am building mine.

Lee

Thanks for the help guys!!

I tightened the belt and put some silicone on it. Working great now!
Got to get out of the..."if it isn't broke, don't fix it" mode and more towards... "an ounce of prevention, is worth a pound of cure".
...Must keep these "babys" maintained. They sure are "AWESOME" when everything is working right!!

Thanks again!!!

yes read my post further down about titlting the tail i describe it very well there.


todd

I know some say not to use WD 40 but let me say it works . Silicone might do good also.

Ive gone through 3 belts. I have had a bind up at 50'. Good thing they make flex skids. The SE tail is a good thing but they could make a higher flange.50+ flights scince my last shred.

I wouldn't use WD-40 or any such spray onthebelt--can more rapidly cause deterioration. OK for a tiny bit of anti-staticspray.

As for best belt life & effiency--

1. Tighten by the book -- Then a "Hair" looser. It WILL work
2. (Got this clever inspitation from another thread) Check the belt position, on the tail
gear, while running.(Make sure Heli is strapped down- Be careful) If there's a tendency
to pull to one side or the other, loosen the tail
gear case and rotate it very slightly to the Rt or Lt, until belt stayscentered.Remember,
there's 90 deg twist to the belt so there will be a tendency to pull to one side. This slight
adjustment will help correct the problem. No need for a flanged idler & more friction.

Lloyd

My belt also would wear out after 15 to 20 flights. The belt would slowy tear itself up. I was reading a post and found out about silicon spray. I used some on a belt (sprayed inside the boom) and I quickly notice the rpm go up and it also stop some glitching I was having.
It is now 3 months later and over 50 flight and my belt still looks new. Silicon spray is definitly a must for belts. Dosn't work so well on the tail slider. After a while the spray kinda get a little gummy on the slider. But I have heard Tri-Flow is great for bearing and the tail slider. I'll have to get some myself. Try it. It's about $5 a can for Silicon Spray at your local Hardware store.

Silicone spray is the correct fix. Don't waste your time chasing thousands of an inch for alignment.
Silicone also works great on the main gear and all the sliding parts

It also picks up minimal dirt due to the fact that it is a " dry " lube.

Oh yeah........ don't just spray it on directly from the can !!!
Spray some into a cup, then use a cotton swab to apply it. Works great !!

My first belt failure was at 15 flights.

I started using silicone and am at 50 flights with a tail belt that still looks brand new !!!

Anyone know if silicon oil would work aswell? Like the stuff they use for the shocks in the rc buggies? I've got some of that here.

It would probably work, but the carrier oil MAY degrade the belt material.

Pick up a can of the spray silicone. After you apply it the carrier evaporates
leaving just pure silicone on the surface.

Good info. I'll go down to Home Depot today and see if I can find some silicone spray there.

I've noticed, even on my X400, that theres been some minor wear on the belt and i've only had about 8 real flights or so.

I have used Hdoc method above and with the addition of slight silicone to the outside part of the belt not the grooved inside I have manged to get over 50 flights and belt still going 100% not showing any deterioration.

Before this method some lasted 5 to 8 flights but I was over tightening the belt. Trick is slightly less than by the book (as slack as you can but tfat your tail rotor does not slip when you move main rotor) and a little silicone oil on the outside once only.

Yeah WD40 is great for breaking free rusted bolts on a car but I don't really use it on anything else. It really degrades plastics and rubber fast. The silicone spray is tha bomb diggity and the right tool for the job.

I'm just chiming in with another vote of confidence for using silicone spray..... petroleum products will aid in breaking down rubber... As an alternative, I bet Armor All would work pretty well too...

I found a silicone/teflon spray made by DuPont at (I believe) AutoZone. I wasn't sure if any of the WD40 ingredients would attack the belt rubber, so I opted for product.

I have the SE. I had a belt shred after about 4 flights from new. Installed the MX400 grooved idler pulley, a little silicone, replaced the tail pulley and shaft and bent the boom slightly so the belt didn't pull to one side of the pulley. Many folks don't run an idler pulley at all. Bending the boom slightly if you have the aluminum will move the tracking on the pulleys (like the belt sander reference above). I wouldn't get too carried away with this but if the belt is always tracking hard to one side of the pulley a slight bend will cure this. I got a little carried away with this until I decided the main problem was a bad rear pulley (pressed on off center).

The old pulley was plastic and slightly off to the left. I replaced it with the metal Align one. If the gear is slightly off to one side the belt will hit the corner of the housing where it is cut out in front of the pulley (square opening in the housing). This only happens at RPM with centrifugal force arcing the belt into the housing. This cuts the belt.

WD40 is for metal and not very good at that. I use LPS 1 or 2 for metal on bigger things and gun oil with Teflon on models. Silicone is for rubber and plastics.

I wonder if anyone's tried a belt pulley that's slightly raised in the middle. The belt on our Sharp vacumm cleaner uses this method to keep the brush belt centered on the pulleys.