Align/Hyper 50

Just finished the strip down on Zaids Hyper 50. Use less thread lock next time buddy

The reason for the strip down was to find the cause of va vibration in the helicopter which I think is effecting the gyro.

One bolt sheared on the engine mounting and that will have to be removed with a bit of heat in the morning.





Here is what I found. The rear bearing is discoulered and feels rough whilst the front bearing whilst looking OK feels even rougher. New bearings will be on order in the morning

Hope this sorts out the problem. The piston and linner look great with very little blow back past the ring. Whenever I strip an engine I always remeber a coinversation I had a few years ago with John Haytree an engine guru from Devon. We talked about bearings and what precautions should be taken when laying up and he finished the conversation by saying "of course bearings in model engines should always be treated as consumables and be changed on a regular basis" I thought at the time that he was trying to drum up bussiness but now I agree.

Glad in a way that they are knackered as that justifies the strip down.


DaveS

PS Mark can we have a spell checker on the forum please.

Dave did you measure the bearings? are they imperial sizes as on the OS 50 aero motor? just curious They certainly were consumables on my OS 50 it got through more bearings than any other motor I've had, it's sitting on my bench up in the loft waiting for, you've guessed it, another set of bearings. I think it's going to wait a long time specially as I don't have a model for it

THe rear bearing is 28mm OD - 15mm ID

DaveS

Might be worth trying ceramics unless they're too expensive or made from "unobtainium"

It looks like that rear bearing has got a bit warm!!!

Andy

bearing damage/corrosion
Wash and rinse with light oil every session
Paul Q

Usually bearing discolouration is not down to corrosion though. Discolouration is usually caused by the bearings getting a bit hot, and the environment they are running in (i.e. fuel and oil and air in this case) causing a build up of residue, possibly down to the lubricant used. The residue build up can then cause stuck balls (oo-err!), excessive friction and therefore excessive wear and "roughness".

The discolouration looks quite even and consistent on that rear bearing. Corrosion is very rarely even and consistent, unless it is severe corrosion, and the whole thing is basically just rust!

I'm pretty certain that Zaidy runs his engines "dry" after use, which would eliminate the majority of the nasty methanol and Nitromethane from the engine, just leaving behind the residual oil that is present in the bearings. This should be enough for a break in flying of a week or so, but perhaps not for a winter layup... That said, perhaps this is an example of needing a dash of afterun oil squirting in the engine after each days flying?

I completely agree about the cheapy bearings though. The fact the front bearing is shot, without being discoloured, would lead me to think that the bearing was either under-specced (in terms of load rating, or speed rating), or has suffered some kind of impact damage. I've actually had a similar experience of some guide roller bearings I specced for a production machine. The supplier charged a fortune, and sent us cheap, no-name chinese tat. Branded Chinese tat, I could live with, but no-name tat?! No chance!

Cheers
Andy

It looks like Andy S & PDQ are setting off on a marathon to see who can write the most useless load of s**te that no one has even the slightest incline to read.

Has Andy finally met his match..!!!

keep up the good work I'm sure one of you will get bored soon enough

I've finished now

Andy

Thanks Rich
You'r absolutely right
It did go on a bit.
Some of us excel at "boring"
PQ

Rich wrote:It looks like Andy S & PDQ are setting off on a marathon to see who can write the most useless load of s**te that no one has even the slightest incline to read.

Has Andy finally met his match..!!!

keep up the good work I'm sure one of you will get bored soon enough

TOP POST! nearly fell of my chair Paul there was no need what so ever to edit your post! Just abit of freindly banter

M

No comment

Like BB says just a heavy bit of banter, makes the boring life a little easier to swallow

"no offence intended"

wish I knew what you all were talking about.Some of us are completly stupid.or at least we feel that way... still can not get a buddy lead to even work

John, Have a word with Tim (Mackay). He has got a DX6i, and I'm sure he has used it as a buddy. If not, I'm sure he'll know about it

Cheers
Andy

Okay I see that Dave, you are a top man for doing it :-) mate.
That engine have never been run lean, if anything its on the rich side, so I can't understand why the bearings are like that.

Regards

Zaidy

Andy Sayle wrote:Usually bearing discolouration is not down to corrosion though. Discolouration is usually caused by the bearings getting a bit hot, and the environment they are running in (i.e. fuel and oil and air in this case) causing a build up of residue, possibly down to the lubricant used. The residue build up can then cause stuck balls (oo-err!), excessive friction and therefore excessive wear and "roughness".

The discolouration looks quite even and consistent on that rear bearing. Corrosion is very rarely even and consistent, unless it is severe corrosion, and the whole thing is basically just rust!

I'm pretty certain that Zaidy runs his engines "dry" after use, which would eliminate the majority of the nasty methanol and Nitromethane from the engine, just leaving behind the residual oil that is present in the bearings. This should be enough for a break in flying of a week or so, but perhaps not for a winter layup... That said, perhaps this is an example of needing a dash of afterun oil squirting in the engine after each days flying?

I completely agree about the cheapy bearings though. The fact the front bearing is shot, without being discoloured, would lead me to think that the bearing was either under-specced (in terms of load rating, or speed rating), or has suffered some kind of impact damage. I've actually had a similar experience of some guide roller bearings I specced for a production machine. The supplier charged a fortune, and sent us cheap, no-name chinese tat. Branded Chinese tat, I could live with, but no-name tat?! No chance!

Cheers
Andy

Andy
You are correct, I do run the engine dry after every flying session. As stated before that engine since starting life have been run, slightly rich (never lean)

Regards
Zaidy

Mark Barnes wrote:

Rich wrote:It looks like Andy S & PDQ are setting off on a marathon to see who can write the most useless load of s**te that no one has even the slightest incline to read.

Has Andy finally met his match..!!!

keep up the good work I'm sure one of you will get bored soon enough

TOP POST! nearly fell of my chair Paul there was no need what so ever to edit your post! Just abit of freindly banter

M

Mark can you please remove the edit option, as I didn't read PDQ post before editing, so I can't understand Rich's comment about the most boring post ? I would like to make my own decision on that

Zaidy
The edited post you didn't see
Perhaps Mark can reinstate it for you from the forum backup file.
Paul Q

Going Electric

Okay thanks Paul.

Zaidy
Your not alone with OS50 Hyper bearing damage

Rear bearing 15X28X7 (S6902 in stainless) 15 ID, 28 OD, 7 Wide
There is also a SS ring ceramic ball version too.
Or 6902 standard.
This is a "light" grade bearing. Also used in 46FX-H, 46VX-M,50SX-H and 55AX
There is negligible axial load but a large radilal one from primary and secondary components.
These increases as the speed squared.

Brian C commented his OS 50 engine had bearing failures
Andy S commented rear bearing looked overheated

Plenty of information about OS50 Hyper bearing problems...
Have a look at
http://runryder.com/helicopter/t513949p1/


and in google
hyper crankshaft modification

Suggestion
Engine rear bearing failed and seized ....(known problem)
followed by
Recovery, crankshaft driven by flywheel stored energy, skidded in locked inner ring

Fact
The stored energy of a 50 engine/flyweheel spinning at 13,000 is massive
The rear and front bearings were damaged
The paddle shaft ends were forced forwards

Suggestion
The rear bearing seized but the stored energy still spun the engine
The speed faltered but then recovered once the shaft slipped in the locked inner ring
(If this did happen, then the shaft will now be undersize at rear bearing)
look for loose fit of shaft in a new bearing... usually a light interference cold when new)
The hesitation and recovery caused the blades to swing forwards

Conclusion
The bent paddle shaft was only a symptom of the main problem

You DID have a very lucky escape

The Cure
Change the Hyper bearings frequently as described on runryder
And maybe get the crank web modified

Zaidy
apparently the crank mod doesn't solve the problem
See this one
http://www.flyinggiants.com/forums/fg227/24515-os-50-hyper-not-runing-good-2.html

One guy (he's an American!) reckons the bearing is undersize (load rating) for this particular engine

Normally bearings are selected to have a "B10" life
This means that, statistically, out of a sample of bearings selected to do a job ....like car wheel bearings
10% will fail within the expected time to failure. Used to be 80,000 miles.
And the rest ? well there will be some superstars.
Bit like fuses really, how do you select a good one ?

Worth choosing a good make to start with and pay a little more.
Fag SKF are OK. OS oriiginal pack OK, Midland Helicopters do stock and sell these.
Beware agents who may, without deliberately trying to rob you, be selling poor quality equivalents.

Thanks for that Paul, will start looking into it

Zaidy
I've edited the 2 posts slightly (bit more info)