O.S. 1.4 RX bearings

[Rcmaster199 at aol.com]

Bob,

 RPM and load are the killers of bearings, all else being equal. Larger props 
turning lower rpm should help the problem but the greater load does not. 

I think dave hit it on the head: The OS bearing was intended for a smaller 
engine designed to turn a smaller load at the same rpm. 

The 140 should be using a larger bearing with proportionately larger ball 
bearings
. These in turn, would spin at proportionately slower rates when the engine 
is at speed, and their larger size would distribute the load better.

In the meantime, I recommend that someone out there who uses the engine 
should try to find a bearing that uses thinner races and larger ball bearings. It's 
the smallish ball bearings turning too fast due to their small diameter, in 
the standard bearing, that wear out under the load of the 140.

Another approach is what 3M Mintors have: two main bearings that look the 
same as the OS 140 bearing (but I have not actually measured these). The idea is 
better load distribution, but nothing is really being done about the rpm the 
balls are turning. 

Overall, I prefer the WEBRA approach: Larger bearing all the way around. I 
expect the bearing to last for years.

Matt Kebabjian


> Subj:Re: O.S. 1.4 RX bearings 
> Date:7/4/2003 3:45:17 PM Eastern Daylight Time
> From:<A HREF="mailto:rcaerobob at cox.net">rcaerobob at cox.net</A>
> Reply-to:<A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A>
> To:<A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A>
> Sent from the Internet 
> 
> 
> 
> Those of us who ran the old OS 61 RF's, pumped or not, remember when 
> bearings lasted forever....UNTIL we started putting high pitch, high diameter props 
> on the beasts.
>     Now, we've just added more pitch and diameter over the years, and my 
> experience has been that bearing life relates directly to those factors.  Of 
> course lubrication, and moisture, certainly contribute, but most bearings I've 
> dissassembled have had the balls and races brinnelled and beaten to death.  
>     That starts plating flaking, and eats things...it could just be 
> coincidence that they rust, too....
> 
> Bob Pastorello, Oklahoma
> NSRCA 199, IMAC 1320, AMA 46373
> <A HREF="mailto:rcaerobob at cox.net">rcaerobob at cox.net</A>
> <A HREF="http://www.rcaerobats.net/">www.rcaerobats.net</A>
>  
>  
> 
> >> ----- Original Message ----- 
>> From: <A HREF="mailto:mdarr00 at comcast.net">mdarr00 at comcast.net</A> 
>> To: <A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A> 
>> Sent: Friday, July 04, 2003 2:43 PM
>> Subject: Re: O.S. 1.4 RX bearings
>> 
>> 
>>     Dave, I could not agree with you more!
>>  
>> Mike Darr
>> 
>> >>> ----- Original Message ----- 
>>> From: <A HREF="mailto:dfs at navnet.net">Dave Smith</A> 
>>> To: <A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A> 
>>> Sent: Friday, July 04, 2003 3:22 PM
>>> Subject: Re: O.S. 1.4 RX bearings
>>> 
>>> 
>>> Verne:   Based on my experience with the YS .60 & .61 two strokes,the 
>>> grease will disappear very soon,even with two seals intact. 
>>> I don't think lubrication is the problem,or the cure.  The rear bearing is 
>>> just too small.
>>>  
>>> It seems this size bearing started out in life as the bearing for the 
>>> 1.08.   It makes no sense to me that a bearing for a rather mild 1.08 would 
>>> stand up to the rigors of a 1.40.
>>>  
>>> Good luck,,,,,,,,,,,,,Dave
>>> 
>> 
> 

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