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Date: Sun, 18 Jul 2004 18:29:33 -0500
From: msteitle@mail.utexas.edu
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] TES orings
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Ken, 
Yes, TES for oil and water.  Don't have the p/n's handy.  I'll have to dig them
out of the arcives, but I'll post them when I have found them.  

Mark


Quoting kenpowell@comcast.net:

> 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