X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-iw0-f180.google.com ([209.85.214.180] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4472441 for flyrotary@lancaironline.net; Sun, 19 Sep 2010 09:19:14 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.214.180; envelope-from=msteitle@gmail.com Received: by iwn8 with SMTP id 8so4516709iwn.25 for ; Sun, 19 Sep 2010 06:18:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=1z0gX4I91+zYBVR2dviiSjSApv0Q/VZ38LjnWaFUbe0=; b=tFxja3SPKiMl9W9cBPiwX+fbmHpfd51ws43HxKs4Iu9aoyF/GY5whueGR3pAkc+aYH B/m3x4+1iDgQyPsGI9NRw1QDrLWxcbxCGdT9yOmYYhpUSerNViad9C2R636iCtdv+UEz IPs15SxoBR2LpQCixxzzXbru6gr2xwQJvuDM0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=oaSGCxCRNdNa0Vv1edEeblwkN/iKyR989Xug+IelG5/GZQ7a2G/AosVYHiLYxEIOae SES6s3hzj9/vrZwm7tq41rk/+34lvMuCZG5YxsXTD28mMJoWdh3zek51I6tkmwn3HIPU og1kVbt6qEtYOaQjLfYvpZpoezkHiqUNF6aL4= MIME-Version: 1.0 Received: by 10.231.169.10 with SMTP id w10mr8669369iby.106.1284902318707; Sun, 19 Sep 2010 06:18:38 -0700 (PDT) Received: by 10.231.173.137 with HTTP; Sun, 19 Sep 2010 06:18:38 -0700 (PDT) In-Reply-To: References: Date: Sun, 19 Sep 2010 08:18:38 -0500 Message-ID: Subject: Re: [FlyRotary] Check PSRU Oil Drain-back hose was Re: Watch that psru oil seal From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0016e6d26cc8471abb04909ca293 --0016e6d26cc8471abb04909ca293 Content-Type: text/plain; charset=ISO-8859-1 Ed, You and Lynn may have hit on something regarding the crankcase vent line being too small. It may have been marginally acceptable with the side port engine, but way undersized for the fire-breathing p-port. First time I ran it real hard, out came the seal. I am using the stock vent line, but will go ahead and up-size it while I'm fixing the psru seal. Mark On Sun, Sep 19, 2010 at 8:10 AM, Ed Anderson wrote: > 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 > *Sent:* Sunday, September 19, 2010 8:39 AM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: Watch that psru oil seal > > Lynn, > > 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, > > 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 > > --0016e6d26cc8471abb04909ca293 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Ed,

You and Lynn may have hit on something regarding the= crankcase vent line being too small. =A0It may have been marginally accept= able with the side port engine, but way undersized for the fire-breathing p= -port. =A0First time I ran it real hard, out came the seal. =A0I am using t= he stock vent line, but will go ahead and up-size it while I'm fixing t= he psru seal. =A0

Mark

On Sun, Sep 19, = 2010 at 8:10 AM, Ed Anderson <eanderson@carolina.rr.com> wrote:
Mark, here's another thing to check for - the= oil drain=20 back hose from the PSRU
=A0
The PSRU typically has its oil drain-back to the = oil pan=20 which can be "pressurized" by blow-by of the rotors.=A0 This back= =20 pressure=A0could =A0impede 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.=A0=A0So it basically=20 gravity feed back to the oil pan.=A0=A0=A0I guess the oil pan pressure=20 could get to the point of serioulsy impeding the oil blow - but I would thi= nk=20 that much crank case pressure would have given other indications - such as= =20 blowing your dip stick out {:>)
=A0
Now if the PSRU oil drain-back became=20 plugged/restricted/crimped =A0for some reason then the pressure on the seal= =20 might eventually reach near=A0the 80 psi input mark and that would put=20 considerably force on the seal.=A0 So (as I know you already planned) check= =20 out the drain back hose.
=A0
But, in any case=A0mechanically restraining the s= eal=20 sounds like a smart ideal in any case
=A0
Ed
Edward L. Anderson
Anderson Electro= nic=20 Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com

Sent: Sunday, September 19, 2010 8:39 AM
Subject: [FlyRotary] Re: Watch that psru oil seal

Lynn,=20

=A0=A0Am 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 per= haps=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, Septe= mber=20 19, 2010, 7:14 AM

In a message dated 9/19/2010 5:41:35 A.M. Eastern Standard Tim= e,=20 msteitle@gm= ail.com writes:
Kelly,=A0=20

My custom adapter plate was built on a Bridgeport mill. =A0T= he=20 hole spacing (and sizes) were obtained from a drawing for the act= ual=20 RD-2C plate. =A0Could it be a thou or two oversize? =A0I guess=20 that's possible, but I don't think so. =A0The machinist t= hat did=20 the work is very meticulous. =A0However, before reassembly, I'= ;ll=20 definitely check it to be sure. =A0The bottom line is that there = is=20 90-100 psi trying to push it out of place. =A0So, I feel that a= =20 mechanical fastener is the only real way to guarantee that it sta= ys=20 put 100% of the time. =A0

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=A0 pressed into cavities th= at=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 sea= l 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 t= han=20 from crank case gasses..
=A0
I had a weaver Brothers three section dry sump pump that had t= he=20 pressure section in=A0the 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 o= f=20 minimal size=A0against the Garlock seal pressed into a smooth bore = in=20 the end plate. Each session the seal would be found dancing along t= he=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 week= end=20 was over I did that with a plate and three little screws. I replace= d the=20 single lip seal=A0with 2 half width lip seals and the plate and nev= er=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 low= er=20 pressure area.=A0
=A0
Lip seals are the most freedom loving seals of all. If pressur= ized=20 they turn their lips inside out and leak on you.
=A0
If you persist, they will escape the bore and dump your oil ou= t on=20 the ground. They have been that way since the first day. Thought sh= ould=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 smal= l for=20 operation above about 3500 RPM.
=A0
Lynn E.=20 Hanover

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