Belt slipped off

[rdlohr]

Luckily I was able to auto it down with no damage. I did notice some black residue on the motor mount and the underneath of the belt looks a bit ratty. Its my original belt so it likely has over a hundred flights on it.

What is your guess:
a) Belt just wore out, completely normal, replace it
b) Belt tension must not have been right and caused it to prematurely wear
c) Something else


Rick

[oliver1071]

D) you fly so badass that the model just couldn't hold up

Man autoed a mini impressive. My belt just snapped because of that damn one way bearings seizing wrapped around the head and fell from the sky.
I need to pick up that Lynx pinion thIs one way is garbage.

[learnedthehardway]

If you're flying really hard I could see the belt wearing out in 100 flights. Think I saw someone mention a roller guide bearing seizing up caused his belt to slip off using the Lynx solid pinion.

Must be a standard length Mini or you're running the solid pinion for the belt to slip off so there must not be a y support??

Owb failure? roller guide seized up, most likely the one close to the pinion?

Other than that tension or wear like you mentioned. I went back to a plastic guide near the pinion when I ditched the y support. Little deeper wall than the aluminum for a little extra piece of mind.

[DominicD]

D) Sloppy wiring ?

[Mikej]

I have hundreds of flights on my mini protos belt. As has been said check the idler by the pinion - I have had these seize which isn't helpful. I would think that if it slipped off then your tension was too loose on one end - you know that you have to set tension at either end separately?

[rdlohr]

Thanks all.

I do have a solid pinion with a lynx A frame. I'll check the rollers.

I'll also check the sloppy wiring Dom.

Rick

[rdlohr]

Rollers seem good. How are you guys adjusting tension?

[learnedthehardway]

I run the tail side a bit snug and use average everyday tension on the motor side. Between 2-3mm deflection

If the pinion is too high it will shred the belt quickly, might be something to check.

[Mikej]

I have the Lynx front roller which allows me to run the motor fairly loose. The tail I have pretty much as I would have done a trex 450

[jrman83]

Not trying to get too far off subject, but I'm not sure if my belt is too tight or not. It's pretty snug at both ends. But what I noticed is I am getting a grind sound if I hit heavy positive pitch. Very similar to what my Oxy did when I first built it but it went away. Only thing I could think of then was the belt was too tight and then as it broke in, it went away as the belt stretched a little. I'm thinking I may loosen some.

This is not a new belt.

[rdlohr]

Thanks. I'll eyeball the pinion height. Its very possible I didn't line it up correctly and that would explain my ratty belt.

Rick

[rdlohr]

Originally Posted by jrman83

Not trying to get too far off subject, but I'm not sure if my belt is too tight or not. It's pretty snug at both ends. But what I noticed is I am getting a grind sound if I hit heavy positive pitch. Very similar to what my Oxy did when I first built it but it went away. Only thing I could think of then was the belt was too tight and then as it broke in, it went away as the belt stretched a little. I'm thinking I may loosen some.

This is not a new belt.

Go off subject all you want.

Rick

[learnedthehardway]

Originally Posted by jrman83

Not trying to get too far off subject, but I'm not sure if my belt is too tight or not. It's pretty snug at both ends. But what I noticed is I am getting a grind sound if I hit heavy positive pitch. Very similar to what my Oxy did when I first built it but it went away. Only thing I could think of then was the belt was too tight and then as it broke in, it went away as the belt stretched a little. I'm thinking I may loosen some.

This is not a new belt.

You can run it fairly loose compared to the Oxy and mine seems to get slack every now n then so I have to retension it.

So far sounds at full positive on my Protos helis tend to be a bearing issue,usually the motor bearings. Slightly imbalanced mains will make them noisy as well, especially at full positive

Maybe check your pinion height plus main shaft and idler bearings as well.

[jrman83]

Originally Posted by learnedthehardway

You can run it fairly loose compared to the Oxy and mine seems to get slack every now n then so I have to retension it.

So far sounds at full positive on my Protos helis tend to be a bearing issue,usually the motor bearings. Slightly imbalanced mains will make them noisy as well, especially at full positive

Maybe check your pinion height plus main shaft and idler bearings as well.

When I put in the pinion, replaced to a Lynx solid type, I thought I put at the same height that was in there but I will check to see what the manual says. Could an overly tight belt be causing stress on the bearings? I didn't recall it doing it until I re-tightened the belt in the tail section, but can't remember if I pushed it too much. I have 16 flights on it now.

[learnedthehardway]

The way the Lynx pinions are cut if they sit too high they shred the belt.

You want the belt to ride in the middle of the part above where the teeth start to flare out.

Put mine just a hair too high and got a buttload off belt dust everywhere in a 2 min test hover.

No idea what the manual says since I've never looked at it but mine's been running great for a while with the belt running in that spot.

[jrman83]

I'll check it out before I take it out next. I remember when I was checking it out when first setting it up that there seemed to be a lot of belt dust all over the y-support (before I removed it) and the motor mount. Maybe that should have clued me to something being off, but I'm sure some dust is normal.

[rdlohr]

Originally Posted by learnedthehardway

If the pinion is too high it will shred the belt quickly, might be something to check.

We have a winner! Good call. My pinion is indeed too high!

Thanks
Rick

[rdlohr]

To lower the pinion, I had to drill it out to allow it to go further onto the shaft. Then the set screws in the pinion started hitting two out of the four motor hold down screws so I removed them. Not too happy holding down the motor with only two screws. Anybody else play this game?

Rick

[learnedthehardway]

Interesting, 16t dropped right in on mine. Pulled off and tossed the bearing eating Y support bracket and the pinion slid on with ease.

[jrman83]

Checked my pinion height...if I look at the pinion and where the grooves start and stop, my belt crosses almost exactly in the middle of that area. This is good, right? The motor shaft sticks up above the pinion about 3mm.