Two main gears in one day?

[Astronobaldo]

Hi all,

Yesterday I gone two main gears broken on the same day. The Pinion Gear is ok, no bends or anything wrong that I can see with it.

After the first one is gone, I though that was caused by the main shaft bended. So I replaced the main shaft, put another main gear and start flying again. Then after few minutes another main gear gone! Same issue as before. And again nothing wrong with the Pinion gear.

Now I'm worried about get another main gear broken.

I've noticed the Pinion Gear was a little bit loose with the main gear ... was not really tight. could that be the cause of this issue?

Any thoughts?

Here is the video from my helmet cam of the two main gears issue:

[ame]http://www.youtube.com/watch?v=YaWUK5Jv_V8[/ame]

Cheers,
Abner

[Ade_Law]

can you get a good pic of the gear?

is it just the tops of the teeth missing or is the gear almost smooth?

if just the tops of the teeth are missing then the gear mesh was loose.

Ade

[Smoothound]

Possibly your mesh is too loose.

Should be able to get a piece of 100gsm paper between the gears at their tightest point.

Always set the mesh at the tightest point. I always run a strip of paper between them, hold tight then tighten the motor in it's mount then recheck to be sure.

Do it at the tightest point so you don't lessen your flight time or kill your bearings because the gears are "overmeshing" in flight. The loosest point should still be quite close together, if that is too far apart try a new gear

[Astronobaldo]

can you get a good pic of the gear?

is it just the tops of the teeth missing or is the gear almost smooth?

if just the tops of the teeth are missing then the gear mesh was loose.

Ade

Thanks mate ... here are two pics from one of the gears (the other is already in the bin ) Sorry for the pic quality.



I suppose that would be the gear loose then? Right?

Cheers

[mattydred]

Thanks mate ... here are two pics from one of the gears (the other is already in the bin ) Sorry for the pic quality.



I suppose that would be the gear loose then? Right?

Cheers

the bearing in/near the middle of the gear looks nowhere near the middle to me???

cheers

matty

[Smoothound]

the bearing in/near the middle of the gear looks nowhere near the middle to me???

cheers

matty

Certainly looks a bit odd

[mattydred]

Certainly looks a bit odd

yep it does - looks like its got hot and melted at some point aswell.

would a trex 450 main gear fit in the b400?

cheers

matty

[Smoothound]

I think the gearing is different

[Astronobaldo]

the bearing in/near the middle of the gear looks nowhere near the middle to me???

cheers

matty

It was in the middle indeed ... it just looks like odd because I tried to remove the one-way using a hammer but I didn't get much luck and I did a mess with the gear. (Now I gave up and ordered a one-way removal tool )

Cheers !

[Ade_Law]

defo looks like the mesh was very loose.

what i do is push the motor back till there is no slack between the main gear and the pinion. Then move the motor out just a fraction til there is just the smallest amount of movement between the maingear and the pinion.

Ade