X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 10 Mar 2009 22:36:34 -0400 Message-ID: X-Original-Return-Path: Received: from [64.12.143.101] (HELO imo-m13.mail.aol.com) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3541084 for lml@lancaironline.net; Mon, 09 Mar 2009 18:15:49 -0400 Received: from Sky2high@aol.com by imo-m13.mx.aol.com (mail_out_v39.1.) id q.d02.507fd419 (14501) for ; Mon, 9 Mar 2009 18:13:38 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Mon, 9 Mar 2009 18:13:38 EDT Subject: Re: [LML] Re: oil cooling X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1236636818" X-Mailer: AOL 9.1 sub 5003 X-Spam-Flag:NO -------------------------------1236636818 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Randy, My large sharp edged NACA duct is poorly placed on the left rearward side of cowling. It enters a short flexible 3" smooth rubber sleeve (plumber's sleeve) and then to a plenum above the small SW oil cooler mounted to the fire wall. The bottom is open to the lower cowl. I climb at about 135 KIAS and see cylinders occasional reach 400 degrees on a hot day while the oil stays at 180. In cruise in 30-40F temps, I must at least partially close the door between the NACA and the cooler. Recently, in 10C temps, I had to completely close the door to keep the oil temps about 180. In the pattern at 100 KIAS I will see the oil go 190F or even 200F on hot days because of lack of air thru the cooler. It wasn't always that way. When I had high oil temps, I tried a special cooler air exit to assist, no help. Another was to try exiting thru shark gills on the side of the cowl, no help. I temporarily attached a scoop to force more air in the duct, no help. I finally discovered that the air was backed up in the NACA duct plenum (or chamber), thus cutting off air flow. I used Micro to smoothly shape the chamber, thus directing the air into its 3" outlet (no more dead corners) with the results detailed above. Good Luck, Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) In a message dated 3/9/2009 12:41:32 P.M. Central Daylight Time, marv@lancair.net writes: Posted for randy snarr : All, Thanks for the good suggestions on the oil cooler. I flew again today and my oil temps are at 208 F flying in 35 f air. They will be 215 or 220 this summer. I will try a few solutions that do not need to cut the cowl. I will most likely make a duct to carry the exhaust air from the oil cooler down to the lower aft part of the cowl. I have also heard that the aft vertical edge of the naca opening should be shaped like an air foil. Mine is flat and fairly sharp. The easiest way to test will to be construct a piece to give it a little airfoil made from balsa or foam taped in place and flight tested. If that does not work, I will make a duct from the cooler to the low pressure area on the bottom of the cowl and lastly would be a small lip on the bottom of the cowl aft. every producton airplane I have seen with an opening on the bottom of the cowl has 45 deg lip to create a low pressure area. I should have done that before I painted.... I will post my findings when I get them. Randy Snarr N694RS -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! (http://pr.atwola.com/promoclk/100126575x1219671244x1201345076/aol?redir=http:%2F%2Fwww.freecreditreport.com%2Fpm%2Fdefault.aspx%3Fsc%3D668072%26hmpgID %3D62%26bcd%3DfebemailfooterNO62) -------------------------------1236636818 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Randy,
 
My large sharp edged NACA duct is poorly placed on the=20 left rearward side of cowling.  It enters a short flexible 3" smoo= th=20 rubber sleeve (plumber's sleeve) and then to a plenum above the small SW oil= =20 cooler mounted to the fire wall.  The bottom is open to the lower=20 cowl.  I climb at about 135 KIAS and see cylinders occasional reach 400= =20 degrees on a hot day while the oil stays at 180.  In cruise in 30-40F=20 temps, I must at least partially close the door between the NACA and the=20 cooler.  Recently, in 10C temps, I had to completely close the door to=20= keep=20 the oil temps about 180. In the pattern at 100 KIAS I will see the oil go 19= 0F=20 or even 200F on hot days because of lack of air thru the cooler. 
 
It wasn't always that way.
 
When I had high oil temps, I tried a special cooler air exit to=20 assist, no help.
Another was to try exiting thru shark gills on the side of the cowl, no= =20 help.
I temporarily attached a scoop to force more air in the duct, no=20 help.
 
I finally discovered that the air was backed up in the NACA duct plenum= (or=20 chamber), thus cutting off air flow.  I used Micro to smoothly shape th= e=20 chamber, thus directing the air into its 3" outlet (no more dead corners) wi= th=20 the results detailed above.
 
Good Luck,
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)

In a message dated 3/9/2009 12:41:32 P.M. Central Daylight Time,=20 marv@lancair.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
Posted for randy snarr=20 <randylsnarr@yahoo.com>:

 All,
 Thanks for the g= ood=20 suggestions on the oil cooler.
 I flew again today and my oil temp= s=20 are at 208 F flying in 35 f air.
 They will be 215 or 220 this=20 summer.
 I will try a few solutions that do not need to cut the co= wl.=20 I will most
likely make a duct to carry the exhaust air from the oil=20 cooler down to the
lower aft part of the cowl. I have also heard that=20= the=20 aft vertical edge of
the naca opening should be shaped like an air foi= l.=20 Mine is flat and fairly
sharp. The easiest way to test will to be=20 construct a piece to give it a
little airfoil made from balsa or foam=20 taped in place and flight tested. If
that does not work, I will make a= =20 duct from the cooler to the low pressure
area on the bottom of the cow= l=20 and lastly would be a small lip on the bottom
of the cowl=20 aft.
 every producton airplane I have seen with an opening on the=20 bottom of the
cowl has 45 deg lip to create a low pressure area. I sho= uld=20 have done that
before I painted....
 
 
 I wil= l=20 post my findings when I get them.
 
 Randy=20 Snarr
 N694RS
 

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