X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4472416 for flyrotary@lancaironline.net; Sun, 19 Sep 2010 09:11:07 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=88hQlV/VnhrPhhPadeRuWHBNMc0qRjlK2a7+9yZesI4= c=1 sm=0 a=ebwuEJEhqTwA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:17 a=arxwEM4EAAAA:8 a=r1ClD_H3AAAA:8 a=3oc9M9_CAAAA:8 a=Ia-xEzejAAAA:8 a=pGLkceISAAAA:8 a=-ymWafdU5Z_IJOCOuXUA:9 a=1MJjS9z61lvVkCaWKDcA:7 a=f01AfjJhv8MvP6ZaHixlLRRibL8A:4 a=wPNLvfGTeEIA:10 a=U8Ie8EnqySEA:10 a=EzXvWhQp4_cA:10 a=MSl-tDqOz04A:10 a=CjxXgO3LAAAA:8 a=E93lBu2AAAAA:8 a=eztVyQLgPGNATWCFJjIA:9 a=drDzSWgXClm5fJ-lB2AA:7 a=820Q-uRJa5aAjiZcAozSCp7D4EYA:4 a=rC2wZJ5BpNYA:10 a=hO30gm18fF0A:10 a=MpuOTR30KwMA:10 a=FOUTPhXFUAcA:10 a=zgjei8Deq7QA:10 a=NWVoK91CQyQA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.167.5 Received: from [174.110.167.5] ([174.110.167.5:52094] helo=EdPC) by cdptpa-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 78/13-29299-7CB069C4; Sun, 19 Sep 2010 13:10:31 +0000 Message-ID: <2F6FCE7A1F264540862C68A84C04943B@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Check PSRU Oil Drain-back hose was Re: Watch that psru oil seal Date: Sun, 19 Sep 2010 09:10:30 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0028_01CB57DA.821BAD10" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_0028_01CB57DA.821BAD10 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Mark, here's another thing to check for - the oil drain back hose from = the PSRU The PSRU typically has its oil drain-back to the oil pan which can be = "pressurized" by blow-by of the rotors. This back pressure could = impede the flow back of oil from the PSRU because by the time the oil in = the PSRU is ready to drain back it has dropped the oil pressure from its = 80 psi input to practically zero. So it basically gravity feed back to = the oil pan. I guess the oil pan pressure could get to the point of = serioulsy impeding the oil blow - but I would think that much crank case = pressure would have given other indications - such as blowing your dip = stick out {:>) Now if the PSRU oil drain-back became plugged/restricted/crimped for = some reason then the pressure on the seal might eventually reach near = the 80 psi input mark and that would put considerably force on the seal. = So (as I know you already planned) check out the drain back hose. But, in any case mechanically restraining the seal sounds like a smart = ideal in any case Ed Edward L. Anderson Anderson Electronic Enterprises LLC 305 Reefton Road Weddington, NC 28104 http://www.andersonee.com http://www.eicommander.com From: Ben Schneider=20 Sent: Sunday, September 19, 2010 8:39 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Watch that psru oil seal Lynn,=20 Am I reading you right in saying that it it was crankcase = pressure, not oil pressure. And to relieve said pressure, one needs a = larger relief tube than the factory one on the oil fill. (call it = perhaps 3/16" without going to the hanger and measuring) Ben --- On Sun, 9/19/10, Lehanover@aol.com wrote: From: Lehanover@aol.com Subject: [FlyRotary] Re: Watch that psru oil seal To: "Rotary motors in aircraft" Date: Sunday, September 19, 2010, 7:14 AM In a message dated 9/19/2010 5:41:35 A.M. Eastern Standard Time, = msteitle@gmail.com writes: Kelly, =20 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. =20 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..=20 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.=20 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.=20 Lynn E. Hanover=20 ------=_NextPart_000_0028_01CB57DA.821BAD10 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Mark, here's another thing to check for - the = oil drain=20 back hose from the PSRU
 
The PSRU typically has its oil drain-back to the = oil pan=20 which can be "pressurized" by blow-by of the rotors.  This back=20 pressure could  impede the flow back of oil from the PSRU = because by=20 the time the oil in the PSRU is ready to drain back it has dropped the = oil=20 pressure from its 80 psi input to practically zero.  So it = basically=20 gravity feed back to the oil pan.   I guess the oil pan = pressure=20 could get to the point of serioulsy impeding the oil blow - but I would = think=20 that much crank case pressure would have given other indications - such = as=20 blowing your dip stick out {:>)
 
Now if the PSRU oil drain-back became=20 plugged/restricted/crimped  for some reason then the pressure on = the seal=20 might eventually reach near the 80 psi input mark and that would = put=20 considerably force on the seal.  So (as I know you already planned) = check=20 out the drain back hose.
 
But, in any case mechanically restraining = the seal=20 sounds like a smart ideal in any case
 
Ed
Edward L. Anderson
Anderson = Electronic=20 Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com

From: Ben Schneider
Sent: Sunday, September 19, 2010 8:39 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: Watch that psru oil = seal

Lynn,=20

  Am I reading you right in saying that it it was = crankcase=20 pressure, not oil pressure. And to relieve said pressure, one = needs a=20 larger relief tube than the factory one on the oil fill. (call it = perhaps=20 3/16" without going to the hanger and measuring)

Ben

--- On Sun, 9/19/10, Lehanover@aol.com <Lehanover@aol.com>=20 wrote:

From:=20 Lehanover@aol.com <Lehanover@aol.com>
Subject:=20 [FlyRotary] Re: Watch that psru oil seal
To: "Rotary motors = in=20 aircraft" <flyrotary@lancaironline.net>
Date: Sunday, = September=20 19, 2010, 7:14 AM

In a message dated 9/19/2010 5:41:35 A.M. Eastern Standard = Time,=20 msteitle@gmail.com writes:
Kelly, =20

My custom adapter plate was built on a Bridgeport mill. =  The=20 hole spacing (and sizes) were obtained from a drawing for the = actual=20 RD-2C plate.  Could it be a thou or two oversize?  I = guess=20 that's possible, but I don't think so.  The machinist = that did=20 the work is very meticulous.  However, before reassembly, = I'll=20 definitely check it to be sure.  The bottom line is that = there is=20 90-100 psi trying to push it out of place.  So, I feel = that a=20 mechanical fastener is the only real way to guarantee that it = stays=20 put 100% of the time.  

Mark
Anything not positively retained in aircraft, will = eventually fall=20 off. Garlock style lip seals will just barely hold back oil = splash with=20 little to no pressure. You see Garlocks  pressed into = cavities that=20 are cast or formed with retaining lips at the end. Not into = smooth=20 bores. More than a few pounds against a lip seal over heats the = seal and=20 fails the lip allowing a leak. Note the oil drainback paths in = the=20 rotary, so seals see no pressure even beside a main bearing = other than=20 from crank case gasses..
 
I had a weaver Brothers three section dry sump pump that = had the=20 pressure section in the blind end of a casting so no high=20 pressurized oil was exposed to a seal of any kind. The drive = shaft=20 extended from the scavenge pump end, so any pressure pulses = would of=20 minimal size against the Garlock seal pressed into a smooth = bore in=20 the end plate. Each session the seal would be found dancing = along the=20 shaft with oil dripping off of everything. A competitor told me = to=20 retain the seal with a plate of some kind. Once that very long = weekend=20 was over I did that with a plate and three little screws. I = replaced the=20 single lip seal with 2 half width lip seals and the plate = and never=20 had another problem. I also cut a tiny groove from the suction = side of=20 the pump to the center of the shaft cavity. Oil drain-back to a = lower=20 pressure area. 
 
Lip seals are the most freedom loving seals of all. If = pressurized=20 they turn their lips inside out and leak on you.
 
If you persist, they will escape the bore and dump your oil = out on=20 the ground. They have been that way since the first day. Thought = should=20 be expended on the release of crank case gasses. The street = engine has a=20 tiny tube sticking out of the oil filler neck. This is way too = small for=20 operation above about 3500 RPM.
 
Lynn E.=20 Hanover
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