Another belt failure!

[Cralis]

Yesterday, in between Raptor flights, In put my Trex 450SE up a few time, and all was great. I flew 3 batteries out, and on the forth, I took off, and things didn't seem 100% right with the tail. Seemed to be a bit delayed in what it was trying to do. Yawwing left and right resulted in it over turning, then correcting. So I thought my gain might not be right. But as it was, so I brought it down, and as I turned the tail towards me (I still land tail in only), it started to spin around, so I set it down pretty quick. All OK...

BUT.. noticed the tail wasn't spinning!

Checked and as I though, the belt had snapped! Again! That's 2 in 2 weeks!

Pulled the belt out, and it's a clean snap. I then noticed that ALL the teeth on the belt are loose! If you push one, it lifts on one side, if you know what I mean. So if you drag your thumb along them, along the belt.. they all lift. Only attached on one side of the tooth.

What am I doing wrong?? Surely belts should last?? OK, I am now flying more fff and stuff, and it's since I started that, I've been breaking belts.

So, I have just put a new belt on... I HATE THAT JOB! The tail is so small, and hard to hoild together to get the belt over the cog! Hate it...

Anyway, it's on now, but.. maybe my tension has been wrong? The thinbg is, the tighter I pull it, it seems to add some type of force to the main rotors. If I spin the main blades by hand, I only get 1, maybe 2 revolutions and it stops...

Is that normal? How free should the main blades spin?

[Ashley Davis]

450SE belts should be run pretty loose, they don't need to be tight like a rubber band.

[moyesboy]

Ive been through 6 tail booms loads of blades and never damaged a belt.
Be sure you don't have double twist so the belt rubs on itself.
Check the pulleys for damaged teeth.
Therre shold only ever be a very slight amount of black powder inside your canopy. If you get a lot of that its your belt getting damaged.

[Cralis]

Mines not tight... I can squeeze the two belt sides together next to the driving gear on the heli. Well, if I push one side with my finger, I can't get it to touch th other belt. It gets close, but doesn't touch. Does that sound right?

[Cralis]

Thanks Moyesboy.. I'll clean the canopy and check. Just not sure if I am getting the tension on the belt right.

[Britflyer]

I kept snapping belts too.

Bob J mentioned abut using abit of WD40 on the belt, not had one go since.

Paul

[Ashley Davis]

Mr Sheen is a bit less corrosive than WD40 but does the same thing.

[edarter]

You haven't got a bit of moulding flashing on either the front or rear drive gear have you ? I've heard of this before and it cuts through the belt.... worth a check ??

Ed

[Cralis]

Thanks Ed.. What exactly do I check? Mould on the gears?

[Sao]

Well if you have left your heli in a garage or shed or even on a window ledge there is a chance that the main gear can get the dreaded tail belt rotting mould.
Nasty stuff, greenish in colour, sort of fuzzy like penicilin.
You'll need to go to the heli doctors and get a dose of antibiotics, if it doesn't clear up in a week they might have to operate.




In all seriousness, Ed just means check the main gear to make sure it has been made well and that there are no little sharp protrusions from the manufacturing process that could cut into / damage the belt as it passes over the main gear.

[Cralis]

Aha!!
I was looking for mould!! hehe!
Right, will do. Thing is, it's a different main gear...
Will check the wee gear that spins the tail rotor.
Thanks.
And where do I put this Mr Sheen? Spray the belt while I turn it?

[edarter]

blimey - Sao had me going there for a mo ! yeah - check both small gears (front and back) as there have been reports of this before apparently.

Spraying the belt - well there seems to be 2 schools of thought on that one, some people like to do it and think it makes a big difference, others don't bother because they think it actually attracts dirt and grit etc. I haven't bothered with mine because the whole system seems to freewheel nicely without it, but if you do then yes, spray the belt as you spin the rotors...

[marktigere1]

Aha!!
And where do I put this Mr Sheen? Spray the belt while I turn it?

Thats what I do. Turn the main rotors and give a quick squirt of the old sheen. You'll even feel the difference as you turn the main blades.

Works a treat, self cleans the heli and smells nice too

What more could you want?

[Cralis]

See, this is my worry currently. When I spin the main blades, they have a bit of resistance, as opposed to when the tail belt is off, and it spins freely.

When the tail is off, the tail rotors also spins freely for ages.

Attach the belt, and things change. As I have never seen another 450, I am not sure what is right and what is wrong. If I spin the main blades with the belt on, there is some resistance. The tighter I make the belt, the more the resistance.

So, before the 2nd belt snap, I had the belt, what I would say is loose. I could put my fingers in the frame, and push one belt against the other. Not a lot of force... just a gentle push.

With the belt like that, the blades spun freely.

BUT... the belt spanned, and as I mentioned, on examining the belt, I noticed that the vast majority, if not all the teeth on the belt, were lifted on one side. There was a split, from one side of the belt to the other, betweem the tooth and the belt, on the one side of the tooth, as if it had been bent backwards. Not sure if I am describing it well enough.

Anyways, just before the snap, the heli was yawing strangly when I added rudder. Luckily I decided to land, and as I was coming down, it started spinning, but I was low enough not to break anything.

So, I have now replaced the belt, but this time, it's tight! I could squeeze the belts together now, but it's not easy. As it's a new belt, I assume it will resize it's self, so may require tightening again soon.

But the blades don't spin freely anymore. More resistance. Flight duration is the same though... 7 minutes with >20% reported remaining on the CellPro.

I'm just scared now of another belt snap, because I am running out of lives.

[Cralis]

Maybe Mr Sheen will assist with the resistance, and I'll have the perfect tail ?

Well, I do already, although my wife says.