RunRyder RC
WATCH
 1 page 1096 views POST REPLY
HomeMy Site✈️Aircraft🚁HelicopterHelicopter Main Discussion › Belt Failure Question
04-03-2013 12:32 AM  6 years ago
Topic Vote0Post 1
Scott1115

rrElite Veteran

Greenwich, CT

MyPosts All Forum Topic
Belt Failure Question
Based on a discussion on the Miniature Aircraft thread, this question came up:

Why does the belt on the Furion 6/Fury 55 fail more than others?

I do not know if this is true or false. I love my Furion 6 but have had two belt failures. Admittedly, I do not hear much about belt failures in the Logo or 7HV or Goblins. I know the 7HV and goblin have self tensioning devices, perhaps that is part of it.

PLEASE, without bashing one brand or another, can we discuss why it appears this belt seems to have a higher failure rate?

Could it be a tension issue?
Could it be a materials issue?
Could it be a size of belt issue?
Etc....

Thanks folks!
Compass 7HV, Trex 550E
RCRCC
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
04-03-2013 01:39 AM  6 years ago
hootowl

rrProfessor

Garnet Valley, Pa.

MyPosts All Forum Topic
I'm thinking possibly the belt itself. I have never had a belt failure on my 4 year old trex 600N. Those belts are of a different manufacture. They seem cheaper but it just might be something about their construction that is the difference. Maybe they don't have the same cord construction and rubber chemistry which might cause heating along the edges in the MA machine... leading to cord separation.

Another observation is the design of the belt systems that use the large main drive gear and the two idler pulleys to get the belt to fit in the tube. You've got those flanges rubbing the sides of the belt along with the tail gear sides. The 600N only has the front and back pulley. Less chance of heat buildup. Also, everytime you induce a bend, you generate some heat. Big front pulley design has three tight bends.
Wolves don't lose sleep over the opinions of sheep
SHARE  PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
04-03-2013 03:56 AM  6 years ago
steve9534

rrKey Veteran

yakima, wa.

MyPosts All Forum Topic
Belt failure
The Furion design fails on a couple of counts. The tail pulley is too small, forcing the belt to bend too tightly as it wraps around the pulley, and having too few teeth in contact with the belt. The idler bearing is placed forward of the pulley thus pushing the upper and lower runs of the belt too close to each other and risking interference between them. The idler bearing needs to be positioned so that it keeps the belt in contact with the pulley. If you look at Mikado's design, the idler is directly above the pulley and close enough that the belt can't skip teeth. The Goblin has a much larger diameter tail pulley that has many more teeth engaged and doesn't force the belt to bend as tightly. Also, the design is such that the belt speed will be higher, but with considerably less force on the belt.
Everyone will have a different experience, but the Trex 600 is not an especially stellar design either, and suffers from some of the same failures. My belt started to fray at ~6 flights and by 20 flights was destroyed. I'm not a particularly adept flier, but do a lot of backwards and sideways flight that really loads up the tail. Hope this helps. steve.
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
04-03-2013 04:30 AM  6 years ago
JKos

rrProfessor

Redondo Beach, CA

MyPosts All Forum Topic
Excellent question and discussion. I consider Hirobo to be an example of excellent tail belt performance. One pulley at each end and it simply works without the belt being super tight.

With respect to the large front pulley and two idler pullies, the Protos doesn't seem to have trouble nor the good 'ol Raptor 30/50.

- John
RR rules!
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
04-03-2013 04:34 AM  6 years ago
jschenck

rrProfessor

La Vista, NE.

MyPosts All Forum Topic
My experience with belt failures says setup has more to do with it than the brand of heli. I had a belt on a Raptor last for years, another Raptor that shredded a belt in a few flights. Same story with the Trex-450 SE's. On the Raptor it boiled down to the angle that the boom goes into the frame. Before tightening down the frame I'd lift the tail up a bit to give it some tension up or at least relieve the tension down from the weight of the tail. Never really had any problems with the Raptor belt using that technique.

With the Trex 450SE, I did remove the idler pulley from the tail but I think the #1 issue with getting the belt to work without shredding was to set the tension so it was as loose as you could get it without it slipping at all. Basically with a little pressure the belt would almost touch across where you can see it in front of the boom, between the frames. Test tension with a screw driver or some similar tool.
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
04-03-2013 05:56 AM  6 years ago
steve9534

rrKey Veteran

yakima, wa.

MyPosts All Forum Topic
Belts
Much of the problem hinges on how hard the heli is flown. I had the belts slip on my Hirobo helis. The Tsurugi uses a relatively high T/R "gear" ratio of about 5:1 and lessens the load on the T/R drive by doing so. It took me a while, but it eventually started to skip teeth also.
I had endless troubles with the Raptor 50. If I'd tighten the belt too much, the T/R housing would break, and even then, the belt slipped some. If I loosened the belt enough that the T/R housing didn't fail, it was always slipping. In addition, the Raptor 30/50 T/R blade grips have no thrust bearings, and I threw the T/R blade/grip combination on a couple of occasions when the radial bearings failed. steve.
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
04-03-2013 12:00 PM  6 years ago
hootowl

rrProfessor

Garnet Valley, Pa.

MyPosts All Forum Topic
The idler bearing is placed forward of the pulley thus pushing the upper and lower runs of the belt too close to each other and risking interference between them. The idler bearing needs to be positioned so that it keeps the belt in contact with the pulley. If you look at Mikado's design, the idler is directly above the pulley and close enough that the belt can't skip teeth.
My Fury 55 that idler back there barely touches the belt... not like you describe, it is just a little forward of the tail pulley and does not bare down on the belt. Looks to only help keep the belt from skipping. It doesn't push on the belt at all.

Maybe we should check and see if the belt gets warm as soon as we land.
Wolves don't lose sleep over the opinions of sheep
SHARE  PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
04-03-2013 03:59 PM  6 years ago
steve9534

rrKey Veteran

yakima, wa.

MyPosts All Forum Topic
Mike
Maybe I misinterpreted what I'm seeing. I don't have a Fury or Furion and was going by what I thought I saw in the previous thread on this subject. If the idler barely touches the belt, then I'm thinking it's not doing much. In order to do the job, it really needs to be in a position where the belt is trapped between it and the pulley, and is so close to the pulley that the belt can't jump the teeth. Sorry for the misinformation if it's not what it seemed to be in those pics. If you look at Mikado Helis, I think you'll see what I mean. I don't own a Mikado and probably never will, but good design is what it is, and I give them credit where it's due.
A helpful trick is to hold the main rotor head and try to turn the t/r. You can easily see the belt starting to climb the rear pulley on most Helis when you do this, and if you continue to turn, eventually the belt starts jumping the teeth. From what I've seen, 100% of the time this happens at the rear pulley. Mikado stops this by placing the idler bearing where the belt can't possibly jump the teeth, whereas most others have the idler far enough away from the pulley that it's essentially useless. Hope this helps. Steve.
SHARE  PM  EMAIL  GALLERY  Attn:RR  Quote
04-04-2013 01:36 AM  6 years ago
ThumbBumper

rrVeteran

A little to the right and down!

MyPosts All Forum Topic
It could just be the materials used.

Harley Davidson as been using belt drives for years, and they hold up really well. They use a Kevlar (I believe) cord in them and one strand of the fiber can hold up the entire dead weight of the bike.
If it ain't broke, go fly some more!
http://facebook.com/groups/TORCHS/
SHARE  PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
04-04-2013 03:05 AM  6 years ago
RCHSF

rrKey Veteran

NC

MyPosts All Forum Topic
I think sometimes the little tension pulleys get tight, and are not spinning as freely as the supposed to and cause friction on the belt and that heats up till it snaps the belt, or a piece of fiber gets tore out and snags somewhere else to finish the job. I have noticed a few pulleys nearly locked up, or turn a little and freeze. All kinds of factors can cause belts to want to quit work and just lay down on the job so to speak. Belts and pulleys, idlers, all need to be running true, and free. Everything straight. No Wobbling, or funky tube geometry. Not to much tension. Just enough. Then a new belt should get many dozens of flight before needs to be replaced. When the edges start rounding off on top sides, and fibers showing splitting out time to change I guess. Thats about all I can know. Right now at this moment in time.
SHARE  PM  EMAIL  Attn:RR  Quote
04-04-2013 03:46 AM  6 years ago
stubbs

rrApprentice

Tuscon, AZ

MyPosts All Forum Topic
Wow, guess my lowly Blade 450X has it goin' on in the belt department. Simple, low parts count and durable as heck. No idler or tensioner pulleys. 250+ hard flights on mine and the original belt still looks like new.
SHARE  PM  EMAIL  Attn:RR  Quote
04-04-2013 09:37 AM  6 years ago
RCHSF

rrKey Veteran

NC

MyPosts All Forum Topic
Yep Pretty much any bird with straight belt is going to out last the others.

I was thinking why not make a serpentine belt, like on a car for a heli. Maybe with a narrow row of teeth down the middle just for little more traction so not to run as tight. The design is stronger. I believe.
SHARE  PM  EMAIL  Attn:RR  Quote
04-04-2013 03:31 PM  6 years ago
stubbs

rrApprentice

Tuscon, AZ

MyPosts All Forum Topic
Yep Pretty much any bird with straight belt is going to out last the others.
My first heli was a Hirobo Shuttle that had a horrible tail drive design with a huge pulley (tail RPM reduction done at the rear) on the tail rotor drive shaft since the front pulley spun insanely fast as it was a direct take-off from the top of the clutch bell/engine shaft versus the main gear. Because of that, it had an idler pulley on the top of the tail box that caused a large bend in the belt to go up and around that huge pulley. Caused a lot of drag, but I never had a belt failure that wasn't directly attributed to crash damage and I flew the piss out of that thing for 2 years. It did have a different type of belt, though. It wasn't black rubber. It was orangeish and semi-clear where you could see parallel strands of something inside it. Kevlar, I'm guessing. It was a very stiff belt, which added to even more drag. You'd think it would have run hot, but it never did.
SHARE  PM  EMAIL  Attn:RR  Quote
WATCH
 1 page 1096 views POST REPLY
HomeMy Site✈️Aircraft🚁HelicopterHelicopter Main Discussion › Belt Failure Question
 Print TOPIC  Make Suggestion 

 5  Topic Subscribe

Saturday, July 20 - 4:41 pm - Copyright © 2000-2019 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online