X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from an-out-0708.google.com ([209.85.132.249] verified) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2093899 for flyrotary@lancaironline.net; Sat, 09 Jun 2007 19:54:21 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.132.249; envelope-from=msteitle@gmail.com Received: by an-out-0708.google.com with SMTP id b2so233476ana for ; Sat, 09 Jun 2007 16:53:45 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=ZZgYLrVvruEu/4xUHwQD0E63/I5eRo0Q5daQSWxq39OtKoMarfEfHY3Zp2CCA4HgxraB0LpGEMXuV3Vg33E7J4DyEYYh6ofFYoEYMzc/ax8azHbmN2f9wH2C5vueFGjQ43fBFiUApKko2uSxZUoPzSqZIGW6TphhVoQ870akE1M= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=KqiTr9fzZrpBzFYRE+adyudh5u3NEcL3MHpkU9ghsxzFPlWaXNsvhqeanfB8OiOmxfljjwjIJ2jiabMnYmH/LyqiS0u2xOjA3UQGq5BWfC4whg6a84FRsffeiq6QJo4k/HUiVUrVMiBF/Dg2yvo75w1ctNMIwH/xA2bTU+B+Sh8= Received: by 10.100.254.10 with SMTP id b10mr2529735ani.1181433225033; Sat, 09 Jun 2007 16:53:45 -0700 (PDT) Received: by 10.100.38.20 with HTTP; Sat, 9 Jun 2007 16:53:44 -0700 (PDT) Message-ID: <5cf132c0706091653n185e14d7jee4fdb19d49ee24@mail.gmail.com> Date: Sat, 9 Jun 2007 18:53:45 -0500 From: "Mark Steitle" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: Oil temp limit In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_86353_10562077.1181433224999" References: ------=_Part_86353_10562077.1181433224999 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Lynn, Can you address the oil pressure limits too please. My 20B runs in the 90'= s (warm). Will this hurt anything. In order to check/modify the relief valve, I would have to remove the oil pan which means removing the engine from the airframe. If I'm ok running in this range, I will leave it as is. I would like to hear your take on this. Thanks, Mark S. On 6/9/07, Lehanover@aol.com wrote: > > In a message dated 6/9/2007 12:56:28 P.M. Eastern Daylight Time, > ALVentures@cox.net writes: > > I guess we've had this discussion before but to me it still seems like a > grey area. > > > > The limit has to do with temperature, time, and limiting component. > > > > At typical cruise conditions I have coolant temps of 160-170F and oil > temps about 20 degrees higher. Short term climb out (1000 =96 2000') I s= ee > oil getting up 215 -220 and coolant around 200. If I continue climb, I n= eed > to reduce power to keep them at those levels; which means climb rates of > 500-700 FPM with OAT of 65F, and maybe a bit less if OAT is higher. I do= n't > like being limited to that climb rate when I have power for considerably > more; but the real question is: Is that temp level an issue if sustained = for > 10-15 minutes? And what is it affecting? > > > > I expect to make some modification to improve airflow through the cooler, > just deciding if it is urgent or if it can wait for another 10 -20 hrs of > flying. Anytime I go east from my airport I have to climb from 1400' to > about 7000' to clear high terrain. > > > > Thanks, > > > > Al > > The object of controlling oil temperature is that temps above 160 degree= s > begins to reduce power as rotor face temps begin to limit cylinder fillin= g. > > Second, > The oil temperatures in the wedge will be very much higher than the > temperature being reported on the gage. The bearing area is way over size= d > for the stress levels involved and at the low RPM in aviation use, the > bearings will not fail from stress. > > However the soft overlay on the bearing face has a low melting point. Oil > moving off the bearing carries away the heat from wedge oil. In racing th= e > higher oil pressures used, helps perform this function. > > Some racers just machine off the overlay and run on the copper. Good > bearing material, and a high melting point. Extra clearance allows more o= il > flow for a given pressure. > > The rotor face can run as high as 400 degrees, and the oil is removing > most of that. > By the time you get to 230 degrees in the sump you are walking on thin > ice, as far as rotor bearings is concerned. You could go higher with less > throttle (stress from wedge heat) but in the end I think you need more oi= l > cooling. > > The race car needs 90 water tops and 190 oil tops. At 100 PSI. > > Lynn E Hanover > > > > > > ------------------------------ > See what's free at AOL.com . > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > ------=_Part_86353_10562077.1181433224999 Content-Type: text/html; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline
Lynn,
 
Can you address the oil pressure limits too please.  My 20B runs = in the 90's (warm).  Will this hurt anything.  In order to ch= eck/modify the relief valve, I would have to remove the oil pan which means= removing the engine from the airframe.  If I'm ok running in this= range, I will leave it as is.  I would like to hear your take on this= .=20
 
Thanks,
Mark S.

 
On 6/9/07, <= a href=3D"mailto:Lehanover@aol.com">Lehanover@aol.com <Lehanover@aol.com> wrote:
In a message dated 6/9/2007 12:56:28 P.M. Eastern Daylight Time, ALVentures@cox.net writes:

I guess we've had this discussion before but to me it still= seems like a grey area.

 

The limit has to do with temperature, time, and limiting co= mponent.

 

At typical cruise conditions I have coolant temps of 160-17= 0F and oil temps about 20 degrees higher.  Short term climb out (1000 = =96 2000') I see oil getting up 215 -220 and coolant around 200.  If I= continue climb, I need to reduce power to keep them at those levels; which= means climb rates of 500-700 FPM with OAT of 65F, and maybe a bit less if = OAT is higher.  I don't like being limited to that climb rate when I h= ave power for considerably more; but the real question is: Is that temp lev= el an issue if sustained for 10-15 minutes? And what is it affecting?

 

I expect to make some modification to improve airflow throu= gh the cooler, just deciding if it is urgent or if it can wait for another = 10 -20 hrs of flying. Anytime I go east from my airport I have to climb fro= m 1400' to about 7000' to clear high terrain.

 

Thanks,

 

 Al

The object of controlling oil temperature is that temps above 160 degr= ees begins to reduce power as rotor face temps begin to limit cylinder fill= ing.
 
Second,
The oil temperatures in the wedge will be very much higher than the te= mperature being reported on the gage. The bearing area is way over sized fo= r the stress levels involved and at the low RPM in aviation use, the bearin= gs will not fail from stress.=20
 
However the soft overlay on the bearing face has a low melting point. = Oil moving off the bearing carries away the heat from wedge oil. In racing = the higher oil pressures used, helps perform this function.
 
Some racers just machine off the overlay and run on the copper. Good b= earing material, and a high melting point. Extra clearance allows more oil = flow for a given pressure.
 
The rotor face can run as high as 400 degrees, and the oil is removing= most of that.  
By the time you get to 230 degrees in the sump you are walking on thin= ice, as far as rotor bearings is concerned. You could go higher with less = throttle (stress from wedge heat) but in the end I think you need more oil = cooling.=20
 
The race car needs 90 water tops and 190 oil tops. At 100 PSI.
 
Lynn E Hanover 
 
 



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