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<DIV><FONT face=Arial size=2>Matt: I just changed the rear bearing
after 80 flights. I was curious as to its' condition. No after run oil was
used at all,and the bearing was in apparently good shape.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I found it interesting that the replacement bearing
(from O.S.) had nary a number or letter on it. Also it was packed
with grease,and either the seals had been removed,or never installed in the
first place,as the outer race was recessed for seals. A friend found
the same when he bought a replacement bearing.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>A commercial industrial bearing supply house might
be able to produce a bearing with larger balls,and thinner races,as per your
suggestion.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards,,,,,,,,,,,,,Dave</FONT></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Rcmaster199@aol.com
href="mailto:Rcmaster199@aol.com">Rcmaster199@aol.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, July 04, 2003 7:32 PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: O.S. 1.4 RX bearings</DIV>
<DIV><BR></DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial size=2
FAMILY="SANSSERIF">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
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px"
TYPE="CITE">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 lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=3
FAMILY="SANSSERIF"><BR></FONT><FONT lang=0 style="BACKGROUND-COLOR: #ffffff"
face=Arial color=#000000 size=2 FAMILY="SANSSERIF"> 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 lang=0 style="BACKGROUND-COLOR: #ffffff"
face=Arial color=#000000 size=3 FAMILY="SANSSERIF"><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=2
FAMILY="SANSSERIF"> That starts plating flaking, and eats
things...it could just be coincidence that they rust, too....</FONT><FONT
lang=0 style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=3
FAMILY="SANSSERIF"><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
lang=0 style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=2
FAMILY="SANSSERIF"><BR>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px"
TYPE="CITE">----- 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 lang=0 style="BACKGROUND-COLOR: #ffffff" face=Arial
color=#000000 size=3 FAMILY="SANSSERIF"><BR><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=2
FAMILY="SANSSERIF">Mike Darr</FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=3
FAMILY="SANSSERIF"><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=2
FAMILY="SANSSERIF"><BR>
<BLOCKQUOTE
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TYPE="CITE">----- 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 lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=3
FAMILY="SANSSERIF"><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=2
FAMILY="SANSSERIF">I don't think lubrication is the problem,or the
cure. The rear bearing is just too small.</FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=3
FAMILY="SANSSERIF"><BR><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=2
FAMILY="SANSSERIF">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 lang=0 style="BACKGROUND-COLOR: #ffffff" face=Arial
color=#000000 size=3 FAMILY="SANSSERIF"><BR><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=2
FAMILY="SANSSERIF">Good luck,,,,,,,,,,,,,Dave</FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=3
FAMILY="SANSSERIF"><BR></BLOCKQUOTE><BR></FONT><FONT lang=0
style="BACKGROUND-COLOR: #ffffff" face=Arial color=#000000 size=2
FAMILY="SANSSERIF"></BLOCKQUOTE><BR></BLOCKQUOTE><BR><BR></BLOCKQUOTE></FONT></FONT></BODY></HTML>