Have I damaged the motor?

[Groucho_]

What happened is, I found a thread about having the counter bearing correctly shimmed, and I adjusted my shims from .4mm to .6mm.

After I did this, I got high up/down vibration readings.

To cut a long story short, I've since gone back to .4mm and now to .5mm, which seems to be a better fit, but the vibrations remain.

Now I've disengaged the motor from the gear, and the up/down vibrations are still there, though around half of what they are when the gear is engaged.

Have I damaged the motor somehow? was the .6mm shim too much stress?

Why don't the vibes go back as they were with the old .4mm shims?

I've not touched anything else at all...

Motor is a Pyro 700-52.

With Gear

Without Gear

[helicraze]

The shim is to line the pinion up, then the set screw it tightened while pushing down on the pinion.

[Groucho_]

Originally Posted by helicraze

The shim is to line the pinion up, then the set screw it tightened while pushing down on the pinion.

I'm not quite sure if that means that I've damaged the motor or not....

[zmooth]

Sounds like those bearings are toasted by running a too thick shim (?). There should be no pressure applied to the pinion/shaft assy when you tighten the 3 motor screws: you should be able to rotate the shim freely. Manual suggests leaving a small gap so there's no axial pressure (manual, bottom of p.23). Busted motor bearings are a very common vibe source: there's a big mass rotating on them at pretty high rpm

[CyprusFlyer]

Agree, I would strip the motor down and check the bearings, cheap fix now rather than an in flight failure (must get those autos practised).
All I did was shim to get the pinion height bang on, grub screw loose, tighten motor bolts then lock up the grub screw with the pinion against the bottom shims, cannot see any other logical complication!

[Groucho_]

Originally Posted by zmooth

Sounds like those bearings are toasted by running a too thick shim (?).

Originally Posted by CyprusFlyer

Agree, I would strip the motor down and check the bearings, cheap fix now rather than an in flight failure

I should have left the thing with those .4mm shims... They were good enough

I've got no idea how to go about checking and replacing motor bearings though.

Wouldn't even know where to begin, or what to order... Maybe I should get it seen to by Kontronik?

[smsodhi]

I think the warranty will be void if you change the bearings yourself. Best to send it back to Kontronik. They may replace under warranty?

[Stolla]

very easy little grub screw on shaft end collar, loosen that then pull motor apart, check out bearings and replace if necessary.

[Mercuriell]

Do the bearings feel notchy ? I dont think a bit of preload would damage your bearings. I personally think people getting too obsessed with vibe data. How does the motor sound ?

Pyro bearings are not hard to change but you need to have some experience or knowledge, cant rememberbthe exact sizes but they're not hard to fnd, something like 6x5x13

Have a look at these Scorpion vids, they give you the general idea but KT do have a very quick service available

[CyprusFlyer]

Talk about obsession, know what you mean, maiden flight on mine is imminent, worry about everything, if it aint broke dont fix it, sod it, must just go and fly the thing. With reasonable precations of course.
Agree with the vibe thing, my 550 gives all sorts of high/extreme vibe warnings from Vbar, however it just flies perfectly!

[abanihani]

Yes, now you guys got my obssessed, I had some difficulty fitting the counterbearing when i build mine and i am sure i pushed it it hard, i may have as well damaged my pyro bearing. In any event i don't hear unusual sounds and had 5 full flights with no drama, but have not checked my vibe analysis yet. I will do that and if it is crazy then back to Kontronik.

[mkovalcson]

I took this note a while back.

Pyro 700 series

Top 6X13X5mm
Bottom 6X15X5mm

[Groucho_]

Thanks everyone for all your help.

I've decided to send it to Kontronik.

I have absolutely no experience in opening up anything of the sort, and wouldn't want to void my warrantee should I need it for something else in the next two years...

Something is definitely not right though - I've compared a few vibe graphs from a month or so ago with those I took today, and you can see the up/down vibes increasing over time. And increasing by double when I added the shim.

I still cannot understand how / believe that the .2mm extra loading made so much difference, and possibly contributed to an acceleration in whatever was wrong with the motor. And all this in a minute or so of testing!

The thing is that even the Pyro manual recommends using a counter-bearing, and as I'm understanding it now, too little shimming is bad, and a .1mm extra shimming is even worse as it will shoot your motor bearings in an instant - At least that what seems to have happened to me...


EDIT -

Mark, what do the figures mean?

Top 6X13X5mm
Bottom 6X15X5mm

[Mercuriell]

Thats the bearing sizes !

[CyprusFlyer]

Groucho, bad luck there, turn this around and see that you may have prevented an incident had you not taken action! Shouldnt take long to sort it out, think marks figs are the bearing dimensions.

See a little trend here, quite a few of us worrying too much and causing damage on the way to perfection, something to be aware of I suppose. One thing I thought about and Jan mentions this, if it holds for the first few hours then its probably good for a long while.
Its the bath tub curve, start with a higher probability of failure at the start of life, then it gets flat with lower probability of failure, extend this with reasonable maintenance. Then end of life the probability of failure goes high again.
Its the reasonable/neccessary maintenance thing to be aware of, every time we tinker we push the curve back up again.

[Groucho_]

Originally Posted by Mercuriell

Thats the bearing sizes !

See! I told you I know nothing about motors

Originally Posted by CyprusFlyer

Groucho, bad luck there, turn this around and see that you may have prevented an incident had you not taken action! Shouldnt take long to sort it out

Very true of course... Tomorrow it goes back to Germany. Kontronik are expecting it...

Originally Posted by CyprusFlyer

See a little trend here, quite a few of us worrying too much and causing damage on the way to perfection, something to be aware of I suppose.

Yes, and I was sure that the CB wasn't shimmed enough - and I'm still sure it wasn't. .5mm seems to be the right fit, but even at .4mm the motor bearing seems to have been wearing itself out.

When it gets back, I still don't know how much I should shim it to not cause damage either way.

[ZuvieleTeile]

I really don't want to contribute to your pain Groucho and other hapless Pyro owners, but . . .

The definition of insanity is, trying the same thing over and over again and expecting different results!

Just have a look at all the threads in HF, Runryder, RC-heli etc. etc.
Tons of post about the Pyro's too small bearings, which requires a counter-bearing, which requires proper shimming and so on and so on.

Did you ever see any thread or post about counter-bearings and their associated problems with X-era or Scorpion motors?????

I know, the child has to put his fingers on the hot plate and get burned in order to believe that it is hot. . . .

The Pyro is a fine motor with one of the best cooling fans on the market, but needs more maintenance and care than others.
If you don't like maintenance or opening up your motor once in a while and check/replace the bearings, then don't buy one of those.

[CyprusFlyer]

Originally Posted by Groucho_

See! I told you I know nothing about motors





Very true of course... Tomorrow it goes back to Germany. Kontronik are expecting it...



Yes, and I was sure that the CB wasn't shimmed enough - and I'm still sure it wasn't. .5mm seems to be the right fit, but even at .4mm the motor bearing seems to have been wearing itself out.

When it gets back, I still don't know how much I should shim it to not cause damage either way.

Do not have the experience to really put forward an argument with this motor set but with my engineering background I cannot see why the correct use of shims has caused a lot of confusion.
I may be wrong and time can only tell and I may be back here reporting tails of woe. But I see the purpose of the shims is to support the pinion at the correct height relative to the plastic gear. Then because there is a small relative downward force, we do not want loads pulling down on the motor bearings.
Therefore with correct amount of shims, motor mount bolts tight THEN pinion grub screw locked with pinion pushed lightly against shims, nothing is under tension and nothing should be able to move against the motor bearings.

There may be mileage in the case where the CB bolts are not tightened carefully enough such that axial loads can be inadvertanly applied without noticing. ie like torquing down a cylinder head, have to be very carefull to do up the bolts gradually in rotation, that could easily damage bearings quickly. Just something to consider.

No expert by any means but just my thoughts.

[jointer]

Not again...
The biggest problem of the Pyro is tight assembly with no wave washer.
So if the motor is pulled down by the gears (for example where there is an unsolved play between pinion and CB), the "top" and smallest motor bearing is easilly damaged by the axial force.
I disassembled Scorpion 4525LE week ago - mine had 2x wave washers under the "top" bearing and one under the locking circlip.
This way the motor have enough space to expand by heat and axial force in any direction could be partially "dampened" by the wave washers.
I will also use CB on it, because bearings in my Pyro lasted 500 flights without major damage when i assembled them as i described before.

[ZuvieleTeile]

Yeah Jointer, the old discussion again. . .

The problem stems partially from Jan's english manual.
He left something out there what would have clarified the issue.
Most guys are under the impression that there should be a small gap between the pinion and the CB. . . because the manual says so.
But when you read the German manual, it explains that this gap will be closed when you tighten the motor screws.
This makes sure, if properly done, that the axial force from the motor being pulled down by the gear, is carried by the CB and not by the smaller bottom bearing inside the motor.
(I know, this bearing is on the top in case of the TDR mounting, but it is still at the bottom of the motor )