Return-Path: Received: from sccrmhc12.comcast.net ([204.127.202.56] verified) by logan.com (CommuniGate Pro SMTP 4.2b8) with ESMTP id 325570 for flyrotary@lancaironline.net; Sun, 18 Jul 2004 12:48:33 -0400 Received-SPF: error receiver=logan.com; client-ip=204.127.202.56; envelope-from=kenpowell@comcast.net Received: from 204.127.205.147 ([204.127.205.147]) by comcast.net (sccrmhc12) with SMTP id <2004071816480301200fq3u9e>; Sun, 18 Jul 2004 16:48:03 +0000 Received: from [68.51.44.162] by 204.127.205.147; Sun, 18 Jul 2004 16:48:02 +0000 From: kenpowell@comcast.net To: "Rotary motors in aircraft" Subject: TES orings Date: Sun, 18 Jul 2004 16:48:02 +0000 Message-Id: <071820041648.29708.40FAA9C20001B01A0000740C220076219404040A99019F020A05@comcast.net> X-Mailer: AT&T Message Center Version 1 (Jun 24 2004) X-Authenticated-Sender: a2VucG93ZWxsQGNvbWNhc3QubmV0 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_29708_1090169282_0" --NextPart_Webmail_9m3u9jl4l_29708_1090169282_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit Mark, Do you have TES orings on the rotor oil seals? If so, where did you get them and what were the part numbers? Thanks, Ken Powell -------------- Original message -------------- > Dale, > If I can put my 2 cents worth in here. Keep in mind that we're measuring the > oil temps as it leaves the cooler and is about to re-enter the engine, so the > oil gets considerably hotter as it goes through the galleys and is sprayed into > the rotors. So, 210 degrees is the starting point and the temps go up from > there until the oil finally reaches the cooler again. Is anyone measuring the > oil temp leaving the engine? > > Mark S. > (20B with TES o-rings) > > Quoting Dale Smith : > > > Ed Anderson wrote: > > > > > Dale , the problem with oil temps in the rotary is that the oil might > > > be able to stand considerably higher temps (particularly the synthetic > > > oil as you point out), but the engine suffers. > > > > > > At least with the older and earlier 13B blocks, overheating could > > > and did cause damage at a temperature range far below where you would > > > have to worry about the oil decomposing. Overheating apparently caused > > > the seals to "chatter" against the housing as well as reportedly > > > "shrinkage" of the aluminum rotor housings. The guidelines were a > > > maximum of 210F after the oil cooler for the oil and 180F out of the > > > engine block for the coolant. Now, we have found that at least with > > > the new blocks the engines will apparently handle higher temps without > > > adverse effects. Apparently short excursions as high as 240F on the > > > oil and 220-230F with the coolant can be tolerated without damage - > > > but, the feeling is that extended operations at those temps is risking > > > damage. > > > > > > The newer blocks seem to be considerably more tolerant of somewhat > > > higher temps reportedly due to changes in the castings, but I and > > > others have found to our dismay that exceeding that magic number > > > (whatever it may be) you do at risk. So that is why you will see more > > > concern with oil and coolant temps with the rotary at a lower > > > temperature than would normally cause concern with a reciprocating engine. > > > > > > Ed > > > > > > > > > Ed Anderson > > > RV-6A N494BW Rotary Powered > > > Matthews, NC > > > > > > Steve ... re: the above underlined. > > > > > > I would say that what you have is just fine regarding your oil > > > temp. Remember that the "delta T" between where you are running > > > and the temperature at where it quits working is quite high. > > > Especially if you are using synthetic oil. Molbil I keeps > > > lubricating quite well up past 400 degrees and beyond. Thus, if > > > you are running temps near 200 degrees you have near a 200 degree > > > temp spread (delta T) between what the oil can take away and what > > > it IS taking away in BTU's of heat dissipation in a stable > > > system. That is a pretty fat safety margin, when you figure you > > > can run 100 degrees hotter than what you are now and still have > > > 100 degrees left before lubrication failure is imminent. > > > Obviously, lower is better. > > > > > > Water cooling now is a different story. operating coolant at > > > temps near 200 while water boils at 212 ... gives you a delta T of > > > just 12 degrees to play with. I know you can kick it up by > > > anti-freeze, pressure on the system, etc. etc. but the bottom > > > line is that you have a lot narrower delta T range to deal with, > > > and you are always working the system a lot closer to near it's > > > maximum potential for heat dissipation. > > > > > > Just a thought, > > > > > > Dale Smith > > > > > Thanks Ed, I value your insights. > > > > I know that seal chatter was an early development problem with the > > wankel, but thought that Mazda had pretty much made it a thing of the > > past with modern materials, geometry, and springs. I did not realize > > that this was a temperature dependent problem, that we still had to deal > > with. > > > > Also, not quite sure what you mean re: "shrinkage of the aluminum rotor > > housings"? It can't shrink with heat. By this do you mean that, that > > having exceeded some elasticity limit, the aluminum cannot return to > > it's original specs upon shutdown once it has been overheated? > > Wouldn't it thus be oversize? Please explain ... this sure sounds like > > an "engine killer". > > > > Thanks, > > > > Dale Smith > > > > > > > >> Homepage: http://www.flyrotary.com/ > >> Archive: http://lancaironline.net/lists/flyrotary/List.html --NextPart_Webmail_9m3u9jl4l_29708_1090169282_0 Content-Type: text/html Content-Transfer-Encoding: 8bit

Mark,

Do you have TES orings on the rotor oil seals?  If so, where did you get them and what were the part numbers?

Thanks,  Ken Powell

-------------- Original message --------------

> Dale,
> If I can put my 2 cents worth in here. Keep in mind that we're measuring the
> oil temps as it leaves the cooler and is about to re-enter the engine, so the
> oil gets considerably hotter as it goes through the galleys and is sprayed into
> the rotors. So, 210 degrees is the starting point and the temps go up from
> there until the oil finally reaches the cooler again. Is anyone measuring the
> oil temp leaving the engine?
>
> Mark S.
> (20B with TES o-rings)
>
> Quoting Dale Smith :
>
> > Ed Anderson wrote:
> >
> > > Dale , the problem with oil temps in the rotary is that the oil might
> > > be able to stand considerably higher temps (particularly the synthetic
> > > oil as you point out), but the engine suffers.
> > >
> > > At least with the older and earlier 13B blocks, overheating could
> > > and did cause damage at a temperature range far below where you would
> > > have to worry about the oil decomposing. Overheating apparently caused
> > > the seals to "chatter" against the housing as well as reportedly
> > > "shrinkage" of the aluminum rotor housings. The guidelines were a
> > > maximum of 210F after the oil cooler for the oil and 180F out of the
> > > engine block for the coolant. Now, we have found that at least with
> > > the new blocks the engines will apparently handle higher temps without
> > > adverse effects. Apparently short excursions as high as 240F on the
> > > oil and 220-230F with the coolant can be tolerated without damage -
> > > but, the feeling is that extended operations at those temps is risking
> > > damage.
> > >
> > > The newer blocks seem to be considerably more tolerant of somewhat
> > > higher temps reportedly due to changes in the castings, but I and
> > > others have found to our dismay that exceeding that magic number
> > > (whatever it may be) you do at risk. So that is why you will see more
> > > concern with oil and coolant temps with the rotary at a lower
> > > temperature than would normally cause concern with a reciprocating engine.
> > >
> > > Ed
> > >
> > >
> > > Ed Anderson
> > > RV-6A N494BW Rotary Powered
> > > Matthews, NC
> > >
> > > Steve ... re: the above underlined.
> > >
> > > I would say that what you have is just fine regarding your oil
> > > temp. Remember that the "delta T" between where you are running
> > > and the temperature at where it quits working is quite high.
> > > Especially if you are using synthetic oil. Molbil I keeps
> > > lubricating quite well up past 400 degrees and beyond. Thus, if
> > > you are running temps near 200 degrees you have near a 200 degree
> > > temp spread (delta T) between what the oil can take away and what
> > > it IS taking away in BTU's of heat dissipation in a stable
> > > system. That is a pretty fat safety margin, when you figure you
> > > can run 100 degrees hotter than what you are now and still have
> > > 100 degrees left before lubrication failure is imminent.
> > > Obviously, lower is better.
> > >
> > > Water cooling now is a different story. operating coolant at
> > > temps near 200 while water boils at 212 ... gives you a delta T of
> > > just 12 degrees to play with. I know you can kick it up by
> > > anti-freeze, pressure on the system, etc. etc. but the bottom
> > > line is that you have a lot narrower delta T range to deal with,
> > > and you are always working the system a lot closer to near it's
> > > maximum potential for heat dissipation.
> > >
> > > Just a thought,
> > >
> > > Dale Smith
> > >
> > Thanks Ed, I value your insights.
> >
> > I know that seal chatter was an early development problem with the
> > wankel, but thought that Mazda had pretty much made it a thing of the
> > past with modern materials, geometry, and springs. I did not realize
> > that this was a temperature dependent problem, that we still had to deal
> > with.
> >
> > Also, not quite sure what you mean re: "shrinkage of the aluminum rotor
> > housings"? It can't shrink with heat. By this do you mean that, that
> > having exceeded some elasticity limit, the aluminum cannot return to
> > it's original specs upon shutdown once it has been overheated?
> > Wouldn't it thus be oversize? Please explain ... this sure sounds like
> > an "engine killer".
> >
> > Thanks,
> >
> > Dale Smith
> >
>
>
>
>
> >> Homepage: http://www.flyrotary.com/
> >> Archive: http://lancaironline.net/lists/flyrotary/List.html
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