OWB failures

[dsduani]

I'm having OWB problems with my stretched Protos. I went through two 13T pinions in the last 2 weeks due to OWB failure.
After replacing the pinion last week the new one failed after the first real flight (an easy shakedown flight went normally).
Both times it occurred while going inverted (probably a coincidence). I don't do hard 3D but do push it hard at times on funnels, flips, clumsy tic-tocs, etc.
Rotor speeds are 2200,2300,2450 with Govenor Store on YEG ESC
I previously installed the long motor shaft and 3rd bearing pinion support on the otherwise stock Scorpion motor.
I do not lubricate the motor shaft or OWB.
The belt looks fine but there was some wear on the motor shaft under the pinion.
Any thoughts? Thanks.

[DoubleCH]

I found stock long motor shaft pretty soft such that it got worn out by my 13T OWBs pretty quick. I ended up making my own 13T adaptor and noticed shaft didn't get worn out nearly as fast. Of course now I'm running custom steel pinion without OWBs so I'm running 6mm shaft adaptor for 15T+.

[Dr. M]

You're not lubing the OWB, are you? The Protos OWB comes pre-lubed from the factory and any additional grease/oil will cause it to slip, thus damaging the motor shaft and the OWB.

[dsduani]

Originally Posted by Dr. M

You're not lubing the OWB, are you?

No lube on shaft or bearing

[dsduani]

OK - this is getting frustrating.
Put in a new long motor shaft and new 13T pinion. Made sure the 3rd bearing pinion support was properly in place and the belt not too tight.
OWB fails after about 5 flghts. Belt looks ok.
Fortunately I knew what to look for and didn't crash.
Any thoughts? Conjectures? Wild guesses? Help!

[kavic5150]

Bad batch of OWBs from the factory maybe?

Just guessing here. I've never worn out an OWB on my protos, just the pinion teeth. Mostly from having the belt a bit loose.

Are you ordering from the same vendor each time or different ones?

[dsduani]

Originally Posted by kavic5150

Bad batch of OWBs from the factory maybe?

Just guessing here. I've never worn out an OWB on my protos, just the pinion teeth. Mostly from having the belt a bit loose.

Are you ordering from the same vendor each time or different ones?

Last 4 pinions all from the same vendor.
I'll see what I can find out from them. Thanks

[kavic5150]

I put a drop of tri-flow on the top bearing above the OWB about every 5 to 10 flights or so, same with every bearing on the whole heli including the ones on the FB head. I guess it doesnt make a difference at 1700 to 2100 RPM on a non-stretch.

Dsduani how tight do you have your belt? Also did you spin the rotor head and check for any variance in tightness as the belt makes its rounds?

I know its probably review for you but just covering all the bases.

[dsduani]

The pinion bearings were new with each new pinion so I don't think that's part of the problem. I don't think the belt was that tight but I'll loosen it a bit when the new pinion arrives.
Thanks for the suggestions. I've got this heli back in the air!

[JustPlaneChris]

Looks like the same battle we've been fighting for months with the Mini Protos:

https://www.helifreak.com/showthread.php?t=617512

[dsduani]

Originally Posted by JustPlaneChris

Looks like the same battle we've been fighting for months with the Mini Protos:

https://www.helifreak.com/showthread.php?t=617512

Just finished reading through it. 245 posts on that one topic! Seems that lots of us are having pinion issues.
Looks like some people have no problems with the pinions and others have had a lot of problems. Maybe a problem with quality control/manufacturing of different batches?
I'm going to try a do a "perfect" setup and some easy flights and see how the pinion holds up.

[DoubleCH]

I started with 14T for my stretch and it started to slip especially when the long Scorpion motor shaft started to wear out. I changed to 13T and 4mm shaft adapter with short Scorpion motor shaft so no slip for some time but the 4mm shaft adapter started to wear out and OWB started to slip. Changed to custom 4mm shaft adapter and another 13T and it never slipped again. Next problem to fix was the soft aluminum pinion wearing out which then wear out the belt which slipped. I'm now running my home-made steel pinion with NO OWB plus my double-idler mod. Absolutely zero problem with slipping or wearing out even running belt loose after 110+ flights. By this amount of flights the stock soft aluminum pinion would've worn to the point the belt would start to slip even with more conservative flying than the harder flying style I do now.

[dsduani]

Some time has gone by and I thought I’d post a follow-up to my OWB problems.
I’ve had over 25 flights without a pinion/OWB failure.
It can be hard to really determine the cause of a problem when several variables are involved.
Maybe using a new pinion (the 5th one) made the difference – possibly another batch.
I did find two problems that I suspect may have been the cause – or at least contributed to it.
1) The bearing in the stretch 3rd bearing pinion support showed some wear in the inside that allowed for some slop between the bearing and the long motor shaft. I replaced the bearing and put a very small amount of blue Loctite on the end of the shaft to prevent the inside of the bearing to spin on the shaft.
2) The long motor shaft showed wear from the pinion pretty quickly after it was replaced. I switched back to the short motor shaft + pinion adapter (for 13T pinion) and have noticed very little wear. I think the long shaft may be softer metal than the short one (it’s also a lot easier to replace than the long shaft). This may have prevented the OWB from grabbing the shaft securely – may have also caused overheating of the metal.
I’d be interested to hear if anyone else has had a similar problem.
Anyway, it’s great to be back in the air without any mechanicals. Love that Protos!

[Jomaba4308]

Corrado is about to release an updated pinion.
https://www.helifreak.com/showthread.php?t=656056

[DoubleCH]

Originally Posted by dsduani

2) The long motor shaft showed wear from the pinion pretty quickly after it was replaced. I switched back to the short motor shaft + pinion adapter (for 13T pinion) and have noticed very little wear. I think the long shaft may be softer metal than the short one (it’s also a lot easier to replace than the long shaft). This may have prevented the OWB from grabbing the shaft securely – may have also caused overheating of the metal.
I’d be interested to hear if anyone else has had a similar problem.
Anyway, it’s great to be back in the air without any mechanicals. Love that Protos!

I've already mentioned it TWICE on this thread the long shaft is soft, short shaft adapter is a bit harder, my own shaft adapter insert is even harder but in the end steel pinion plus no OWBs and more worries.

[dsduani]

It was your observation about the long shaft that got me to check out mine.
Thanks

[kavic5150]

Stainless steel pinions with built in one way bearings. Nice.

[DoubleCH]

Originally Posted by dsduani

It was your observation about the long shaft that got me to check out mine.
Thanks

Oh ok! I thought you missed my comments.

[01ws666]

Any idea if corrado is gonna come out with a harder long motor shaft also? The one in my pic had about 400 flights on it and a new pinion wouldn't hold anymore.

[HighFreq]

Wow, that is pretty impressive wear you have.

I'll check the shafts we have in our warehouse. Those are hardened and shouldn't wear to that point.
400 flights are not few flights but still shouldn't wear to that point.


All people that have probs with oneways are using 13T and 14T or having probs even on 15T with bigger oneway?

Corrado