X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 12 Mar 2009 10:30:48 -0400 Message-ID: X-Original-Return-Path: Received: from web111415.mail.gq1.yahoo.com ([67.195.15.216] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with SMTP id 3544795 for lml@lancaironline.net; Thu, 12 Mar 2009 00:33:03 -0400 Received-SPF: none receiver=logan.com; client-ip=67.195.15.216; envelope-from=randylsnarr@yahoo.com Received: (qmail 90388 invoked by uid 60001); 12 Mar 2009 04:32:27 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type; b=DxTKU8aL7i0YakSeQc5rf5tcl5LKJwQdxVBX8/e/VnXJfy7RbgtXM+vszyx7SyMqtcXFq2uD5nfE2Pfx+BH2FJr5k8Vc+oIwVozFmMsVRUmCBD6K3/tUeellggcYuqLfi6ZDSO6hRUWBtmXo52ZkzyI14lWBZTuS7NLC7gSQ4fA=; X-Original-Message-ID: <615350.89841.qm@web111415.mail.gq1.yahoo.com> X-YMail-OSG: cavD3QMVM1lgKnoEbAwCoffVOQUKOerPef2PgCZL4PPD2a2CHPsJJ1d3V24BQd4vvaeH0184A6vxRX53UAL1TvR4ioqClvJcTvXIODlhDkWbQSNcnAnAx5daCpJSLx4RQ2dQJ1Kr7kUHWw6W3eyRbTm1SIttQQjqirPq0czQMyPGZ92WbkVlj6AXl4nEb5gpKx6UobNURYHY5hl9W5UV4htNlt7i9ykNRLcYXwPFx0ozNRl7nqRSbeSWxFIcr93ssPrKsNn_sZ5_nVzukxVQKgnhyVpinMn5uMdLRxsQ8egZvtOYbOpj Received: from [76.8.220.18] by web111415.mail.gq1.yahoo.com via HTTP; Wed, 11 Mar 2009 21:32:27 PDT X-Mailer: YahooMailClassic/5.1.19 YahooMailWebService/0.7.289.1 X-Original-Date: Wed, 11 Mar 2009 21:32:27 -0700 (PDT) From: randy snarr Subject: Re: [LML] Re: oil cooling/vernatherm X-Original-To: Lancair Mailing List MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1122244493-1236832347=:89841" --0-1122244493-1236832347=:89841 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Ron, Thanks for the kind words. I really appreciate it. I had someone else say basically the same thing about the oil cooler inlet.= Maybe there is something to that.=20 I will try that and post my results. Randy Snarr --- On Tue, 3/10/09, Ron Laughlin wrote: From: Ron Laughlin Subject: [LML] Re: oil cooling To: lml@lancaironline.net Date: Tuesday, March 10, 2009, 8:36 PM Hi Randy, I read an article once about a Velocity builder (canard pusher) who used NACA ducts behind the cabin to cool his whole engine. As you can imagine, he had some trouble getting adequate air flow through the cowl. He tried many different modifications (short of bonding on some big scoops) but nothing worked. He finally determined that the boundary layer air was just skipping over the NACA ducts and very little was being drawn into the cowl. His solution ended up being very simple. He bonded a small triangular ridge (think similar to a stall strip) on the cowl surface just ahead of the NACA inlet to "trip" the boundary layer so that it would tumble into the duct opening. IIRC, the final shape that worked best for him was a "V" shaped (like a chevron) 3/8" ridge placed about an inch forward of the ducts pointing toward the nose. This might not work in your case but it would be easy to test. Just tape on some balsa strips and go fly. I wish I had a picture for you but I can't remember where I read it. BTW, I'm still very impressed with the unbelievable quality of your work. RonL On Mon, Mar 9, 2009 at 12:41 PM,=A0 wrote: > Posted for randy snarr : > > =A0All, > =A0Thanks for the good suggestions on the oil cooler. > =A0I flew again today and my oil temps are at 208 F flying in 35 f air. > =A0They will be 215 or 220 this summer. > =A0I will try a few solutions that do not need to cut the cowl. I will mo= st > likely make a duct to carry the exhaust air from the oil cooler down to t= he > 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 fair= ly > 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 pressur= e > area on the bottom of the cowl and lastly would be a small lip on the bot= tom > of the cowl aft. > =A0every 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 tha= t > before I painted.... > > > =A0I will post my findings when I get them. > > =A0Randy Snarr > =A0N694RS > > > -- > > For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.ht= ml -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html =0A=0A=0A --0-1122244493-1236832347=:89841 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Ron,
Thanks for the kind words. I really a= ppreciate it.

I had someone else say basically the same thing about = the oil cooler inlet. Maybe there is something to that.
I will try that= and post my results.

Randy Snarr

--- On Tue, 3/10/09, Ron= Laughlin <ronlaughlin@gmail.com> wrote:

From: Ron Laughlin <ronlaughlin@gmail.com>
Subject:= [LML] Re: oil cooling
To: lml@lancaironline.net
Date: Tuesday, March= 10, 2009, 8:36 PM

Hi Randy,
I read an a= rticle once about a Velocity builder (canard pusher) who
used NACA ducts= behind the cabin to cool his whole engine. As you can
imagine, he had s= ome trouble getting adequate air flow through the
cowl. He tried many di= fferent modifications (short of bonding on some
big scoops) but nothing worked.= He finally determined that the
boundary layer air was just skipping ove= r the NACA ducts and very
little was being drawn into the cowl.

H= is solution ended up being very simple. He bonded a small triangular
rid= ge (think similar to a stall strip) on the cowl surface just ahead
of th= e NACA inlet to "trip" the boundary layer so that it would tumble
into t= he duct opening. IIRC, the final shape that worked best for him
was a "V= " shaped (like a chevron) 3/8" ridge placed about an inch
forward of the= ducts pointing toward the nose. This might not work in
your case but it= would be easy to test. Just tape on some balsa strips
and go fly. I wis= h I had a picture for you but I can't remember where
I read it.

B= TW, I'm still very impressed with the unbelievable quality of your work.
RonL



On Mon, Mar 9, 2009 at 12:41 PM,  <marv@lancair.net> wrote:
> Posted for randy snarr = <randylsnarr@yahoo.com>:
>
>  A= ll,
>  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 t= ry a few solutions that do not need to cut the cowl. I will most
> li= kely 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 construc= t 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 bott= om of the
> cowl has 45 deg lip to create a low pressure area. I shou= ld have done that
> before I painted....
>
>
> &nbs= p;I will post my findings when I get them.
>
>  Randy Snar= r
>  N694RS
>
>
> --
>
> For archi= ves and unsub http://mail.lancaironline.net:81/lists/lml/List.html<= /a>

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