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250 Class Electric Helicopters 250 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


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Old 02-28-2009, 08:50 PM   #1
Thrashaero
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Many of you have noticed that the belt tends to shed string material, along the sides.
>>This is not the only problem.<<

I noticed a tiny clump of string sitting between a couple of teeth. thinking this was just a clump of small string debris that got stuck onto the teeth like i had rubbed off once earlier, trying to remove it I saw it was actually still attached to the belt, between a pair of teeth. Since the string's purpose is to keep the belts tension firm and strength backbone, I tried stretching in that area and sure enough saw the teeth spread quite a bit and the backside of the belt narrow. >>The whole set of fibers that run through the belt were completely snapped in this one area, leaving only the rubber to keep it together.<< Other areas there is no stretching of course.
This could definitely result in a snapped belt and might even get caught in the gears (or knotted up inside the tailboom) from the snap. Either way, not pretty.

So those of you who keep trying to pull the boom back because the belt isn't staying tight, might want to check this before you stretch it to the point it will snap even easier.
How the inner surface was broken and the whole set of fibers were severed at once, is something that should be looked into as this isn't just an inconvenience but a catastrophic failure.

I wonder if any of the hard 3D pros have ever ran into this or they just have the luck of it working 100% perfect all the time. My luck with belts in general is terrible. especially the damn teeth!

Last edited by Thrashaero; 03-01-2009 at 01:57 AM.. Reason: clarification
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Old 02-28-2009, 09:45 PM   #2
gixxerjeff
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You should have a look at your belt as it exits the tail shaft housing.there is a rectangular shaped hole that can have burrs that catch the belt sides.I cleaned up mine with a needle file.No more strings.My previous belts would seperate like your describing......
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Old 03-01-2009, 12:46 AM   #3
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I hope TMP makes or gets ahold of those Maverik belts like they had for the 450, those truly are the best belts for the 450 and they would work fantastic for the 250 as they are a semi yeloow rubberish compound and do not shred and they do certainly last!
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Old 03-01-2009, 01:36 AM   #4
Thrashaero
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Quote:
Originally Posted by gixxerjeff View Post
You should have a look at your belt as it exits the tail shaft housing.there is a rectangular shaped hole that can have burrs that catch the belt sides.I cleaned up mine with a needle file.No more strings.My previous belts would seperate like your describing......
well i'm not sure if you're talking about the same thing. I edited my post to basically say the following; i was mentioning the typical problem of fibers coming out the sides of the belt (where the housing would scrape with burrs) though this is not the particular problem I'm referencing but to just say it's not the only belt problem. I was also going to file down the housing as I read your post about that earlier. But I was just in the process of removing that side-fibers problem when I happened to look at the teeth..there was an exit of fibers between a pair of teeth. it seems the whole set of fibers through the width of the belt were snapped and poked through somehow. this would be more along the lines of perhaps a sharp tooth on the gear cogs (or maybe a scrape of the tail blades on the ground, causing a fast stretch or cause the cogs to dig deeper perhaps). but i'm using plastic gears. really a strange problem and can cause a huge problem if i never thought to look there.
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Old 03-01-2009, 08:40 AM   #5
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Quote:
i was mentioning the typical problem of fibers coming out the sides of the belt
there is screws in the tail that can rub the side of the belt too.

That's odd the belt is snapped on the inside..
It would be hard to check if your pulley teeth were sharp.

Whatever you do,
don't pull the fibers out of the belts. Just leave them. Don't burn them off either. And make sure it is well lubed.
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Old 03-01-2009, 10:01 AM   #6
PlaneHeli
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Quote:
Originally Posted by Thrashaero View Post
Many of you have noticed that the belt tends to shed string material, along the sides.
>>This is not the only problem.<<

I noticed a tiny clump of string sitting between a couple of teeth.
I had the same thing after only 35 flights.

No hard 3D.

Im not sure if it was due to the belt being Too Tight or Too Loose.
Some said they thought is was caused by a loose belt. It appears the belt 'teeth' look OK though. So I wondered if it could be caused by the belt too tight. (IE: The tip of the pinion rubbing the threads).

I mentioned it here in this thread.

See my post #17.

Is this what you have

http://www.helifreak.com/showthread....70#post1129670
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Old 03-01-2009, 11:11 AM   #7
Kam Arrow
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I have had the same thing on my first belt, kept pulling the boom out to tighten it and never got any tighter.
I had heard there was a burr on the tail drive pulley that was causing the side to fray and I cleaned that up but this was inside the belt like the OP.

Bill
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Old 03-01-2009, 12:02 PM   #8
Thrashaero
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Quote:
Originally Posted by PlaneHeli View Post
I had the same thing after only 35 flights.

No hard 3D.

Im not sure if it was due to the belt being Too Tight or Too Loose.
Some said they thought is was caused by a loose belt. It appears the belt 'teeth' look OK though. So I wondered if it could be caused by the belt too tight. (IE: The tip of the pinion rubbing the threads).

I mentioned it here in this thread.

See my post #17.

Is this what you have

http://www.helifreak.com/showthread....70#post1129670
Yes planeheli that's exactly what I've got going on.
Though in that post you say tension is ok, however for me the tension is completely gone in that area, very stretchy and gets real thin in that short area. i forgot to think about pics.
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Old 03-01-2009, 06:39 PM   #9
PlaneHeli
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Thrashaero

My belt tension was OK. It may be hard to see in the photo, but all the belt teeth still looked OK. If the belt was loose I would expect the teeth to be worn or stripped in places.

I still dont know what caused it.
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Old 03-01-2009, 08:15 PM   #10
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If you consider how fast that tiny belt is turning (higher than any other Align heli -pretty darn fast), I'm actually kind of impressed with the belt. It's certianly light years ahead of the 450's stock belt.

FWIW, I run no lube and don't have belt issues. The tension has to be spot on. If you ave to adjust your belt more than 3 times, I'd say that's over tighening it causing it.

If your boom is slipping then shave each half of the block and shorted the auminum spacers for a tighter squeeze.
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Old 03-01-2009, 08:53 PM   #11
PlaneHeli
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heli-on,

Yes, Im trying not to overtighten it this time and see how it goes.

Thrashaero,

If the belt tension is gone, maybe that indicates the threads inside the belt have completely worn through. I assume without those threads inside the belt, it would stretch significantly, as the belt is a very thin strip of rubber.
Just a guess though.
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Old 03-06-2009, 08:21 AM   #12
mickeyjohnston
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Last weekend my belt snapped. The tail spun hard and I was able to level off the heli. Once I did that I hit throttle hold and down she came. Atleast now I can say I tried a auto with a 250 at 25ft. I ended up breaking the gear.

Keep an eye on these belts. I probably had 50 flights on it.
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Old 03-06-2009, 08:19 PM   #13
helidude3
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I don't tighten mine very much, I can turn it about 1/8th w/o the main gear moving.
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Old 03-06-2009, 09:31 PM   #14
cbrian4
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Well during a second pack two days ago the tail was acting funny. Then i tried to tighten it but it kept stretching, then i found huge clumps of threads. Good thing i caught it before it snaps.
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Old 05-05-2009, 01:33 PM   #15
nitronuts
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Quote:
Originally Posted by Thrashaero View Post
Many of you have noticed that the belt tends to shed string material, along the sides.
>>This is not the only problem.<<

I noticed a tiny clump of string sitting between a couple of teeth. thinking this was just a clump of small string debris that got stuck onto the teeth like i had rubbed off once earlier, trying to remove it I saw it was actually still attached to the belt, between a pair of teeth. Since the string's purpose is to keep the belts tension firm and strength backbone, I tried stretching in that area and sure enough saw the teeth spread quite a bit and the backside of the belt narrow. >>The whole set of fibers that run through the belt were completely snapped in this one area, leaving only the rubber to keep it together.<< Other areas there is no stretching of course.
This could definitely result in a snapped belt and might even get caught in the gears (or knotted up inside the tailboom) from the snap. Either way, not pretty.

So those of you who keep trying to pull the boom back because the belt isn't staying tight, might want to check this before you stretch it to the point it will snap even easier.
How the inner surface was broken and the whole set of fibers were severed at once, is something that should be looked into as this isn't just an inconvenience but a catastrophic failure.

I wonder if any of the hard 3D pros have ever ran into this or they just have the luck of it working 100% perfect all the time. My luck with belts in general is terrible. especially the damn teeth!

Thats exactly what happended to mine today I only have about 25 flights, mostly indoor hovering and only a few outside. I noticed the tail was twitching on my last flight, flying figure-eights around the yard. The first thing checked was the belt and it was really loose. I tried tightening it but the boom would come all the way out of the holder, so the belt was streching like a rubber band.

Is there an aftermarket belt yet for this heli?
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Old 05-05-2009, 06:52 PM   #16
specialk
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are there burrs on the plastic tail boom holder or the metal one as well? I am wondering if going to the metal one will help the issue. I am running a plastic front pulley, metal tail pulley, plastic tail boom block and no lube with no issues to date
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Old 05-05-2009, 07:16 PM   #17
helidirect
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Quote:
Originally Posted by nitronuts View Post
Thats exactly what happended to mine today I only have about 25 flights, mostly indoor hovering and only a few outside. I noticed the tail was twitching on my last flight, flying figure-eights around the yard. The first thing checked was the belt and it was really loose. I tried tightening it but the boom would come all the way out of the holder, so the belt was streching like a rubber band.

Is there an aftermarket belt yet for this heli?
We have some new belts coming for test now.

www.helidirect.com
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Old 05-05-2009, 09:46 PM   #18
helidirect
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here is the one that made from Japan very high quality, we will test soon.

559T
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Old 05-06-2009, 01:40 PM   #19
heli400
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Helidirect,

Let us know how those belts turn out

I'm interested in getting some of those belts.

Rick
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Old 05-06-2009, 02:25 PM   #20
nitronuts
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Quote:
Originally Posted by helidirect View Post
here is the one that made from Japan very high quality, we will test soon.

559T
Nice, Ill be the first in line for those Really disappointed in the quality of the align belts
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