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From: Lehanover@aol.com
Message-ID: <e66be.69323839.39c7589c@aol.com>
Date: Sun, 19 Sep 2010 08:14:20 EDT
Subject: Re: [FlyRotary] Re: Watch that psru oil seal
To: flyrotary@lancaironline.net
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In a message dated 9/19/2010 5:41:35 A.M. Eastern Standard Time,  
msteitle@gmail.com writes:

Kelly,   


My custom adapter plate was built on a Bridgeport mill.  The hole  spacing 
(and sizes) were obtained from a drawing for the actual RD-2C plate.  Could 
it be a thou or two oversize?  I guess that's possible, but I  don't think 
so.  The machinist that did the work is very meticulous.  However, before 
reassembly, I'll definitely check it to be sure.  The bottom line is that there 
is 90-100 psi trying to push it out of  place.  So, I feel that a 
mechanical fastener is the only real way to  guarantee that it stays put 100% of the 
time.  


Mark


Anything not positively retained in aircraft, will eventually fall off.  
Garlock style lip seals will just barely hold back oil splash with little to 
no  pressure. You see Garlocks  pressed into cavities that are cast or formed 
 with retaining lips at the end. Not into smooth bores. More than a few 
pounds  against a lip seal over heats the seal and fails the lip allowing a 
leak. Note  the oil drainback paths in the rotary, so seals see no pressure 
even beside a  main bearing other than from crank case gasses.. 
 
I had a weaver Brothers three section dry sump pump that had the pressure  
section in the blind end of a casting so no high pressurized oil was  
exposed to a seal of any kind. The drive shaft extended from the scavenge pump  
end, so any pressure pulses would of minimal size against the Garlock seal  
pressed into a smooth bore in the end plate. Each session the seal would be  
found dancing along the shaft with oil dripping off of everything. A 
competitor  told me to retain the seal with a plate of some kind. Once that very 
long  weekend was over I did that with a plate and three little screws. I 
replaced the  single lip seal with 2 half width lip seals and the plate and never 
had  another problem. I also cut a tiny groove from the suction side of the 
pump to  the center of the shaft cavity. Oil drain-back to a lower pressure 
 area. 
 
Lip seals are the most freedom loving seals of all. If pressurized they  
turn their lips inside out and leak on you.
 
If you persist, they will escape the bore and dump your oil out on the  
ground. They have been that way since the first day. Thought should be expended 
 on the release of crank case gasses. The street engine has a tiny tube 
sticking  out of the oil filler neck. This is way too small for operation above 
about 3500  RPM. 
 
Lynn E. Hanover

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<DIV>
<DIV>In a message dated 9/19/2010 5:41:35 A.M. Eastern Standard Time,=20
msteitle@gmail.com writes:</DIV>
<BLOCKQUOTE  style=3D"BORDER-LEFT: blue 2px solid; PADDING-LEFT: 5px; MARG=
IN-LEFT: 5px"><FONT    style=3D"BACKGROUND-COLOR: transparent" color=3D#00=
0000 size=3D2    face=3DArial>Kelly,&nbsp;=20
  <DIV><BR></DIV>
  <DIV>My custom adapter plate was built on a Bridgeport mill. &nbsp;The=
 hole=20
  spacing (and sizes) were obtained from a drawing for the actual RD-2C pl=
ate.=20
  &nbsp;Could it be a thou or two oversize? &nbsp;I guess that's possible,=
 but I=20
  don't think so. &nbsp;The machinist that did the work is very meticulous=
.=20
  &nbsp;However, before reassembly, I'll definitely check it to be sure.=
=20
  &nbsp;The bottom line is that there is 90-100 psi trying to push it out=
 of=20
  place. &nbsp;So, I feel that a mechanical fastener is the only real way=
 to=20
  guarantee that it stays put 100% of the time. &nbsp;</DIV>
  <DIV><BR></DIV>
  <DIV>Mark<BR></DIV></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Anything not positively retained in aircraft, will eventually fall of=
f.=20
Garlock style lip seals will just barely hold back oil splash with little=
 to no=20
pressure. You see Garlocks&nbsp; pressed into cavities that are cast or fo=
rmed=20
with retaining lips at the end. Not into smooth bores. More than a few pou=
nds=20
against a lip seal over heats the seal and fails the lip allowing a leak.=
 Note=20
the oil drainback paths in the rotary, so seals see no pressure even besid=
e a=20
main bearing other than from crank case gasses.. </DIV>
<DIV>&nbsp;</DIV>
<DIV>I had a weaver Brothers three section dry sump pump that had the pres=
sure=20
section in&nbsp;the blind end of a casting so no high pressurized oil was=
=20
exposed to a seal of any kind. The drive shaft extended from the scavenge=
 pump=20
end, so any pressure pulses would of minimal size&nbsp;against the Garlock=
 seal=20
pressed into a smooth bore in the end plate. Each session the seal would=
 be=20
found dancing along the shaft with oil dripping off of everything. A compe=
titor=20
told me to retain the seal with a plate of some kind. Once that very long=
=20
weekend was over I did that with a plate and three little screws. I replac=
ed the=20
single lip seal&nbsp;with 2 half width lip seals and the plate and never=
 had=20
another problem. I also cut a tiny groove from the suction side of the pum=
p to=20
the center of the shaft cavity. Oil drain-back to a lower pressure=20
area.&nbsp;</DIV>
<DIV>&nbsp;</DIV>
<DIV>Lip seals are the most freedom loving seals of all. If pressurized th=
ey=20
turn their lips inside out and leak on you.</DIV>
<DIV>&nbsp;</DIV>
<DIV>If you persist, they will escape the bore and dump your oil out on th=
e=20
ground. They have been that way since the first day. Thought should be exp=
ended=20
on the release of crank case gasses. The street engine has a tiny tube sti=
cking=20
out of the oil filler neck. This is way too small for operation above abou=
t 3500=20
RPM. </DIV>
<DIV>&nbsp;</DIV>
<DIV>Lynn E. Hanover</DIV></FONT></BODY></HTML>

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