S.S.Bearing- What to Do about it??

[WHIP23 at aol.com]

In a message dated 8/5/03 4:18:50 AM Pacific Daylight Time, rcaerobob at cox.net 
writes:

> 
> Assuming that OS doesn't offer a solution to lubrication of the rear bearing 
> on the 1.40, what other options are available?
>     What mods could be made to the crankcase to permit more oil flow back 
> there?
>     Would increasing oil content of fuel make any difference?
>   
> If the real core problem is undersizing of the bearing for the load 
> application the motor endures, then a real fix would be a redesign of the crankcase 
> to use a larger and wider bearing.  Pretty unlikely that would happen, I would 
> guess.
>     So what's the solution besides keeping the bearing suppliers 
> well-funded??
>  
> Bob Pastorello, Oklahoma
> NSRCA 199, AMA 46373
> <A HREF="mailto:rcaerobob at cox.net">rcaerobob at cox.net</A>
> <A HREF="http://www.rcaerobats.net/">www.rcaerobats.net</A>
>   
> 

Continued - A larger bearing is a double edged sword, larger bearing means 
larger balls and larger diameter races and thus higher surface speed, between 
the balls and races at a given RPM.  I'm not enough of a mechanical engineer to 
say where the trade off is, but I know in other engines larger bearings have 
not solved the problem (OS .61).  The solution is a tapered/timpkin bearing, 
I've tried to find a match, but no success, the problem is that we are using a 
ball bearing in the wrong application, auto manufactures tried this for years 
on wheel bearings, tapered bearings solved the problem.  I can get roller 
bearings that fit, but they will not stand the thrust load.  Again, stainless has 
worked for me, several different engines and I have a lot of data/experience, 
many thousands of flights on mine and others engines, most recently the OS 140 
and believe me I've tried all the "fixes"  Interestingly I just changed the 
bearing in a new OS 140 RX, just because it had 140 flights and I was planning 
to go to a contest this weekend, bearing seemed fine.  Turns out that it is a 
stainless bearing, with the seals removed (I've never found a stainless without 
seals).  The bearing was fine, no corrosion, I jumped the gun.  No for the 
rest of the story I had this engine apart for other reasons and it was a year or 
so back so it's possible that I just changed the bearing because I was in 
there, but I think I would remember and I keep pretty good records so that is a 
doubtful answer.  It will be interesting to see it the new engines start 
showing up with stainless bearings or if this was a fluke, maybe they were out of 
bearings at the factory and used the bearing from the EFI or...

Bob 

Bob
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