Have I damaged the motor?

[mkovalcson]

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. 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.

I'm done tweaking my heli. I feel like I did everything I could to build it properly and set it up right. The only thing I may do is slightly adjust my SK-720 parameters as I learn to push my TDR harder and find areas that may need a little adjustment.

My gear puller accident was actually because I wanted to loosen my Castle gear to Umbrella mesh a bit and it turns out I had it right originally.

Sometimes we can be our own worst enemies

[Stolla]

I honestly don't know why you have to shim it, as long add the shaft runs in the counterbearing it will do its job. I've been flying mine without shimming for years, meaning there's a gap and no load on bearings.

[Mercuriell]

Originally Posted by Stolla

I honestly don't know why you have to shim it, as long add the shaft runs in the counterbearing it will do its job. I've been flying mine without shimming for years, meaning there's a gap and no load on bearings.

Glad you said that! - me too, thought I'd missed something big time, i haven't used any shims on the CB and haven't had a Pyro fail n the last 3 years and 100+ flights.

[Groucho_]

Essentially I should have just left it with the gap the was left with .4mm of shims installed...

[jointer]

Maybe you will have different experience when you do 700 flights in 2 years.
I did not had Pyro failure, but i seen bearings damage after 35 flights on stock Pyro.
Bearings damage is not motor failure, the motor will work even with the bearings totally toasted (my past experience), the bearing inner race will just brush the motor shaft.
But i also heard about bearings balls "leaking" into the rotor bell, that was before CB with Pyro 30-12 (mechanically the same like Pyro 700).
That is Pyro failure (but for me, more maintenance failure of the pilot).

My way is working for me, for hundreds of flights without need to replace the bearings, i shared my info and if someone shims here and there without complete understanding of the mechanics (axial forces and heat expansion), of course some damage may occur.

Anyway replacing the bearings is normal maintenance on a heli; the motor bearings are the most weakest spot, because they spins roughly 20000 RPM, fastest spin on the heli. For example the main shaft bearings are spinning max 2000 but they suffer from axial shocks more then the motor bearings...

If my info did not worked for you, i am sorry.

[Mercuriell]

Originally Posted by jointer

If my info did not worked for you, i am sorry.

No apology needed - really good info as ever - you only have to see the tiny sized balls in the Pyro bearing to understand how vulnerable they are, even after KT increased the bearing size from the 30-32

[Groucho_]

Well, I got the Pyro back from Kontronik earlier… Not a bad turnaround time - 11 days from when they received it…

So I mounted the shims and pinion as per the advice on here, and gave it a test in the TDR.

To say that the difference was night and day would be an understatement. Right away, the assembly sounded very different. It seemed to be softer as though it was on lower RPMs than before.

Since I had reset the Helijive, I thought that that could very well be the case, but when I viewed the SK-720 log, the RPMs were identical. Further to that, the vibration readings were ridiculously low…

This leads me to think that I may have had bad bearings in the motor when it was new, as I never had such a smooth-sounding run, and a smooth-looking vibration log…

I did find a 0.1mm of axial play in the intermediate shaft while the motor was in the Kontronik hospital, and took that out, so that will have helped a little bit too I suppose, as did the correct pinion shimming procedure.

So all in all, very happy with Kontronik's service, and even more happy with the motor and TDR now...

(In case anyone cares, the repair cost excluding shipping would have totaled €35.00, but this was done under warrantee.)

[spdntckt]

Slightly off topic question -> which bearings are folks using for the Pyro's as replacements?
eg. i know the sizes, was just curious about which brand/type works best?

i have a pyro black edition which has a ton of flights on it (over 150), the bearings seem fine, but i was thinking i would buy a spare set for when it needs replacement....

[mkovalcson]

Congratulations!!!!!

Now that looks a LOT more like what I'm getting!

1700 rpm should be just under 3G's when you push it, maybe 2.4-2.6 G's.

Originally Posted by Groucho_

[Groucho_]

Originally Posted by mkovalcson

1700 rpm should be just under 3G's when you push it, maybe 2.4-2.6 G's.

Unfortunately, no

The vibes still jump up exponentially over 1550.

[NRPY]

Groucho,
Can you do a motor-only vibration log and post the results? I'm curious about your results.

Your playback log vibe index still looks high for that low of a head speed.

[Groucho_]

Originally Posted by NRPY

Groucho,
Can you do a motor-only vibration log and post the results? I'm curious about your results.

Your playback log vibe index still looks high for that low of a head speed.

I was going to do a motor-only run before everything else, but I used that finned heat sink motor mount this time, and I couldn't move it back far enough to disengage the pinion from the gear, as it was blocked by the esc...

So I skipped it.

Now that I've got everything in place and thread locked, I want to dismantle only if something breaks.

I always had the vibes jump disproportionately though above the 1550 mark. It's a little bit lower than before now. In fact the self-levelling was not deactivated this time. It used to be before...

[mkovalcson]

That still looks a lot higher than what I'm getting.

Is your castle to umbrella pretty tight? My vibrations went up dramatically when I tried to set that mesh too loose.

What bothers me is that the other readings you are getting are about the same as mine up to 1550.

[Groucho_]

Originally Posted by mkovalcson

Is your castle to umbrella pretty tight?

In my very inexperienced opinion, it looks quite tight... However I should point out that the jump in vibes is still there when I remove the boom completely, albeit at a slightly lower level - say down from 7 to 5 (I'm just giving an example here - I can't remember the exact values)

Originally Posted by mkovalcson

What bothers me is that the other readings you are getting are about the same as mine up to 1550.

It bothers you??... I'd say it bothers ME

What I think is that it's an up/down vibration and still motor related - but being amplified somewhere along the train...

[desertstalker]

That has to be something resonating, can you post up a vibration spectrum at that speed?

Actually, would probably be best to post it up in the SK forum, couple of guys there who can look at a log and tell you pretty much exactly where to look...