X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-vw0-f52.google.com ([209.85.212.52] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with ESMTP id 4236190 for flyrotary@lancaironline.net; Tue, 27 Apr 2010 14:48:51 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.212.52; envelope-from=rwstracy@gmail.com Received: by vws10 with SMTP id 10so130897vws.25 for ; Tue, 27 Apr 2010 11:48:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:sender:received:date :x-google-sender-auth:message-id:subject:from:to:content-type; bh=rDtzzjwMMjxGNluGijqOH1Txj96QYlAK+OOYG6snJFk=; b=EDtPPKrOp8degkAj+OwDIVjMExeLbX+TZPtlpwRrIvG6zQaJdaH6FAjQJiIt0eqtgQ 6YwAr9aQy6E7oEWFuIOso/hBXpOp92Y2RsDNphwjviTUnzkzsFs46TfJM1rvOtRDv6D2 A2p6FGcNWEO/7KPzro/9Uo8L9O3I7hg2YBg9I= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:date:x-google-sender-auth:message-id:subject :from:to:content-type; b=LddXL299IF1Wr9SEDTr/1R/GQjud3q2Gzf8RofT8O/E+lL9y1CtCdN92kIBIhkFxFf 1feS9QksGBDuJyn3ukX4evyJns8jHtLW8Bx2cEWl9L5XzIfU+XB1o9bbdPjKibZEi2yK VDijxDVHgX26NU9tEN0fxbmOS895atd192Rw4= MIME-Version: 1.0 Received: by 10.220.123.137 with SMTP id p9mr4131282vcr.216.1272394095502; Tue, 27 Apr 2010 11:48:15 -0700 (PDT) Sender: rwstracy@gmail.com Received: by 10.220.97.212 with HTTP; Tue, 27 Apr 2010 11:48:15 -0700 (PDT) Date: Tue, 27 Apr 2010 14:48:15 -0400 X-Google-Sender-Auth: ef393a9657e61355 Message-ID: Subject: Re: 20B RV-8 cooling results From: Tracy Crook To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0016e68def2713a73f04853c561b --0016e68def2713a73f04853c561b Content-Type: text/plain; charset=ISO-8859-1 75% of my cooling problems were solved with the oil cooler change I did but still needed more margin for hot weather climbs. Made the decision to not change or enlarge the cooling outlet (that adds drag) so went ahead and butchered the pretty inlets I made. Ed Anderson's spreadsheet on BTUs & CFM cooling air required was instrumental in deciding to go this way. It showed that without negative pressure on the back side of the rads, there would never be enough cfm to do the job during climb at full throttle. Negative pressure is what I had when I flew without the cowl on but oh what a draggy condition that was. The old inlets were 4.5" diameter for the radiator and 4.125" diameter for oil cooler. New inlets are 5.190" for the rad, and 4.875" dia for the oil. This may not sound like a lot but it represents a 36% increase in inlet area. Results were excellent. Oil temp went down 19 degrees at the test speed (130) and water temp dropped 9 degrees. On 80 degree day and 500 ft msl the oil temp maxed out at 194F at 210 mph which is way faster than I would normally go at this altitude. Temp was around 175 at 130. Oil Temp in climb remained below redline (210) but the temperature lapse rate today made results not very meaningful. OAT was dropping 14 degrees a minute at 3000 fpm climb rate. now back to that nasty composite work to pretty up the inlets again. They look like large stubby pitot tubes now. I hadn't thought of a good name for the RV-8 but a friend in California recently came up with the winning idea which fit it well. "Euphoriac" It's a term from a Sci Fi book (Vintage Season) meaning something which induces euphoria. --0016e68def2713a73f04853c561b Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable 75% of my cooling problems = were solved with the oil cooler change I did but still needed more margin f= or hot weather climbs. =A0 Made the decision to not change or enlarge the c= ooling outlet (that adds drag)=A0 so went ahead and butchered the pretty in= lets I made.=A0
Ed Anderson's spreadsheet on BTUs & CFM cooling air required was in= strumental in deciding to go this way.=A0=A0 It showed that without negativ= e pressure on the back side of the rads, there would never be enough cfm to= do the job during climb at full throttle.=A0 Negative pressure is what I h= ad when I flew without the cowl on but oh what a draggy condition that was.=

The old inlets were 4.5" diameter for the radiator and 4.125"= diameter for oil cooler.
New inlets are=A0=A0=A0=A0=A0=A0=A0 5.190"= ; for the rad,=A0 and =A0 4.875" dia for the oil.

This may not = sound like a lot but it represents a 36% increase in inlet area.

Results were excellent.=A0 Oil temp went down 19 degrees at the test sp= eed (130) and water temp dropped 9 degrees.=A0 On 80 degree day and 500 ft = msl the oil temp maxed out at 194F at 210 mph which is way faster than I wo= uld normally go at this altitude.=A0 Temp was around 175 at 130. =A0=A0 Oil= Temp in climb remained below redline (210) but the temperature lapse rate = today made results not very meaningful.=A0 OAT was dropping 14 degrees a mi= nute at 3000 fpm climb rate.

now back to that nasty composite work to pretty up the inlets again.=A0= They look like large stubby pitot tubes now.

I hadn't thought o= f a good name for the RV-8 but a friend in California recently came up with= the winning idea which fit it well. "<= font face=3D"Times New Roman">Euphoriac"=A0 It's a term from a=A0 Sci Fi book (= Vintage Season)=A0 meaning something which induces euphoria.=A0