X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from yw-out-2324.google.com ([74.125.46.31] verified) by logan.com (CommuniGate Pro SMTP 5.2.5) with ESMTP id 3024048 for flyrotary@lancaironline.net; Sun, 13 Jul 2008 11:48:11 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.125.46.31; envelope-from=msteitle@gmail.com Received: by yw-out-2324.google.com with SMTP id 3so2489092ywj.7 for ; Sun, 13 Jul 2008 08:47:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:in-reply-to:mime-version:content-type:references; bh=fXMooz9kjPVqsCb0bC9TAB2dU1amyBLFAzexflR7gCo=; b=YC3RfvJbH2rdws70jcKmY6BdaAoOKq01CjznMi0s4SffdI0mBN3oMDcQUid3gykAzu 7xhotGJygBhLVFoDFvXisa5KvNGvr++hjCRhEKxOvePyHzAxzdtv7VgCs0jXQWDc6Mkb d5RUYT686qMj3KIk+7KtA+3HUohRgykkJo2xQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:in-reply-to:mime-version :content-type:references; b=Zv2wWOwjh1LM1qDtUHSyyDfCOSjn4ck7SFHLJO/9IZoXKGuUIOwYZqh+7kGOPQR4bo c3Yz9kmOLisI24a2NiH3hjdWEPZBxClo3uu9Q7UhKoaDIdx6TU1FsqeTTipfzG8xFHcJ CaToUIZZ0Xb8FClbR+yUvGqRtHFdEjz4Nl1+8= Received: by 10.150.12.3 with SMTP id 3mr18893183ybl.15.1215964051418; Sun, 13 Jul 2008 08:47:31 -0700 (PDT) Received: by 10.150.185.7 with HTTP; Sun, 13 Jul 2008 08:47:31 -0700 (PDT) Message-ID: <5cf132c0807130847w2cbdb8f8yac5161cf9c87052f@mail.gmail.com> Date: Sun, 13 Jul 2008 10:47:31 -0500 From: "Mark Steitle" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] pre-mix; great trip In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_58296_23967191.1215964051414" References: ------=_Part_58296_23967191.1215964051414 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Beautiful picture Al. Good observations on performance. Glad to hear that everything is working well. Mark S. On Sun, Jul 13, 2008 at 10:48 AM, Al Gietzen wrote: > Just returned from about 2500 nm trip. Engine ran great, including > flying over the Rockies west of Denver where I was briefly at about 14,00= 0 > ft with density altitude of 16,500, and still had some throttle to go. > Generally cruising at 165 KTAS, 9.2 =96 9.5 gph, about 5600 rpm. Not bad = for a > 4-place airplane. > > > > OK, now for some technical stuff. You may recall I converted my 20B over > from pan oil injection to using premix. > > > > The main issue is the amount of 2-cycle oil that is ending up in the oil > pan. When mixing 1 oz/gal I found the pan oil level had gone up by abou= t 1 > =BD quarts (from 6 =BD to 8) in about 15 hours of flying; and my nice > clear-amber 15-50 synthetic had become the dark blue-black color of the > SuperTech 2-cycle oil. Doing the math suggests that about 1/3 of the pre-= mix > oil is ending up in the pan. That seems way out of line, and although a > suspect it is not harmful to the engine, I don't think it the best lube f= or > the re-drive. I changed the oil and reduced the amount of pre-mix to =BE= oz > per gallon. I'll be surprised if there isn't still some 2-cycle oil goin= g > into the pan. > > > > So. . ; suggestions? Use different brand 2-cycle? Further reduce pre-mi= x > amount? > > > > I'm wondering if the fact that my cruise coolant temp is now running arou= nd > 150F would result in more of the pre-mix to condense out than if it was > running at maybe 180F. > > > > Another thing I notice is a small amount of fuel is coming out of the fue= l > vent. The only explanation I can come up with is foaming/bubbles forming= in > the return line after the pressure regulator. This goes into the 3-gallo= n > sump tank and up the =BC" vent line. This may have been occurring previo= usly, > and the fuel evaporated as it went back along the surface; but now the bl= ue > 2-cycle oil is left behind to be quite visible at the back of the cowl; b= ut > I suspect the pre-mix is exacerbating the foaming. > > > > I notice the plugs have less carbon than before, and the inside of the > exhaust exit is now very light grey. > > > > Al > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > ------=_Part_58296_23967191.1215964051414 Content-Type: text/html; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Beautiful picture Al.  Good observations on performance.  Glad to= hear that everything is working well. 

Mark S.

On Sun, Jul 13, 2008 at 10:48 AM, Al Gietzen <ALVentures@cox.net> wrote:

Just returned from about 2500 = nm trip. Engine ran great, including flying over the Rockies west of Denver where I w= as briefly at about 14,000 ft with density altitude of 16,500, and still had some throttl= e to go. Generally cruising at 165 KTAS, 9.2 =96 9.5 gph, about 5600 rpm. Not bad for a 4-place airplane.

 

OK, now for some technical stu= ff.  You may r= ecall I converted my 20B over from pan oil injection to using premix.

 

The main issue is the amount o= f 2-cycle oil that is ending up in the oil pan.  When mixing 1 oz/gal I found th= e  pan oil level had gone up by about 1 =BD quarts (from 6 =BD to 8) in about 15 h= ours of flying; and my nice clear-amber 15-50 synthetic had become the dark blue-bl= ack color of the SuperTech 2-cycle oil. Doing the math suggests that about 1/3 = of the pre-mix oil is ending up in the pan.  That seems way out of line, = and although a suspect it is not harmful to the engine, I don't think it the best lube for the re-drive.  I changed the oil and reduced the amount = of pre-mix to =BE oz per gallon.  I'll be surprised if there isn't still some 2-cycle oil going into the pan.

 

So. . ; suggestions?  Use= different brand 2-cycle?  Further reduce pre-mix amount?

 

I'm wondering if the fact that= my cruise coolant temp is now running around 150F would result in more of the pre-mix to condense out than if it was running at maybe 180F.=

 

Another thing I notice is a sm= all amount of fuel is coming out of the fuel vent.  The only explanation I can co= me up with is foaming/bubbles forming in the return line after the pressure regulator.  This goes into the 3-gallon sump tank and up the =BC" vent= line.  This may have been occurring previously, and the fuel evaporated as it went back along the surface; but now the blue 2-cycle oil is left behind to be q= uite visible at the back of the cowl; but I suspect the pre-mix is exacerbating = the foaming.

 

I notice the plugs have less c= arbon than before, and the inside of the exhaust exit is now very light grey.

 

Al


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