<HTML><FONT FACE=arial,helvetica><FONT SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">Bob,<BR>
<BR>
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. <BR>
<BR>
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. <BR>
<BR>
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.<BR>
<BR>
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.<BR>
<BR>
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. <BR>
<BR>
Overall, I prefer the WEBRA approach: Larger bearing all the way around. I expect the bearing to last for years.<BR>
<BR>
Matt Kebabjian<BR>
<BR>
<BR>
<BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Subj:<B>Re: O.S. 1.4 RX bearings </B><BR>
Date:7/4/2003 3:45:17 PM Eastern Daylight Time<BR>
From:<A HREF="mailto:rcaerobob@cox.net">rcaerobob@cox.net</A><BR>
Reply-to:<A HREF="mailto:discussion@nsrca.org">discussion@nsrca.org</A><BR>
To:<A HREF="mailto:discussion@nsrca.org">discussion@nsrca.org</A><BR>
<I>Sent from the Internet </I><BR>
<BR>
<BR>
<BR>
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.</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"> 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. </FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"> That starts plating flaking, and eats things...it could just be coincidence that they rust, too....</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
<BR>
Bob Pastorello, Oklahoma<BR>
NSRCA 199, IMAC 1320, AMA 46373<BR>
<A HREF="mailto:rcaerobob@cox.net">rcaerobob@cox.net</A><BR>
<A HREF="http://www.rcaerobats.net/">www.rcaerobats.net</A><BR>
<BR>
<BR>
</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
<BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">----- Original Message ----- <BR>
<B>From:</B> <A HREF="mailto:mdarr00@comcast.net">mdarr00@comcast.net</A> <BR>
<B>To:</B> <A HREF="mailto:discussion@nsrca.org">discussion@nsrca.org</A> <BR>
<B>Sent:</B> Friday, July 04, 2003 2:43 PM<BR>
<B>Subject:</B> Re: O.S. 1.4 RX bearings<BR>
<BR>
<BR>
Dave, I could not agree with you more!</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
<BR>
</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">Mike Darr</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
<BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">----- Original Message ----- <BR>
<B>From:</B> <A HREF="mailto:dfs@navnet.net">Dave Smith</A> <BR>
<B>To:</B> <A HREF="mailto:discussion@nsrca.org">discussion@nsrca.org</A> <BR>
<B>Sent:</B> Friday, July 04, 2003 3:22 PM<BR>
<B>Subject:</B> Re: O.S. 1.4 RX bearings<BR>
<BR>
<BR>
Verne: Based on my experience with the YS .60 & .61 two strokes,the grease will disappear very soon,even with two seals intact. </FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">I don't think lubrication is the problem,or the cure. The rear bearing is just too small.</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
<BR>
</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">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.</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
<BR>
</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">Good luck,,,,,,,,,,,,,Dave</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=3 FAMILY="SANSSERIF" FACE="Arial" LANG="0"><BR>
</BLOCKQUOTE><BR>
</FONT><FONT COLOR="#000000" style="BACKGROUND-COLOR: #ffffff" SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0"></BLOCKQUOTE><BR>
</BLOCKQUOTE><BR>
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