X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 29 May 2010 09:30:10 -0400 Message-ID: X-Original-Return-Path: Received: from web57511.mail.re1.yahoo.com ([66.196.100.78] verified) by logan.com (CommuniGate Pro SMTP 5.3.7) with SMTP id 4330048 for lml@lancaironline.net; Sat, 29 May 2010 08:32:31 -0400 Received-SPF: none receiver=logan.com; client-ip=66.196.100.78; envelope-from=casey.gary@yahoo.com Received: (qmail 31661 invoked by uid 60001); 29 May 2010 12:31:54 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=V1Z1SkSZ1Edm7kAfAO/Z2Qpp03rl1NU8isW93ARdRbkO4Z/U0nOyMwRdApB2+wuxy3g5LOcRc23A1qo5VPqIc25a+nPDY3Dus/zcJDfQl298mLH/GRVYjRlNV+l7k+BnjjyeVMArTW+fsjvWaxzxzyGAFLQnJ1kctVox0BHeNi0=; X-Original-Message-ID: <898438.29267.qm@web57511.mail.re1.yahoo.com> X-YMail-OSG: 72FtqJ0VM1kwfpptGHLWyHOR8H8KsXMF54i96Ucq_VLOkoT b13a88gCefRuy0b8HM5FnOx1V05AHbMSupIOQsaBqgIRJGV3_ZrmV_HpbC1b b.EnLxZI0.ZFHznavUe3UQI8LMyqv1Q0NGpH79JY6tSfsgK2deGg.JG__tx0 _BYa54jKPB6JB6uR.D3D4JbiFQTdlxojAb42tHAwhHgAcDS1on4eSpofL0QF lZyt2Yf0mo83Q8_tbp88wNHTo2G5Rark01EdUvJ2KXPCSnqXdx21.gLFmTwo _Ot7.SblVKW0- Received: from [97.122.190.119] by web57511.mail.re1.yahoo.com via HTTP; Sat, 29 May 2010 05:31:54 PDT X-Mailer: YahooMailRC/374.4 YahooMailWebService/0.8.103.269680 References: X-Original-Date: Sat, 29 May 2010 05:31:54 -0700 (PDT) From: Gary Casey Subject: Re: cowl flap cooling drag reduction X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-827088020-1275136314=:29267" --0-827088020-1275136314=:29267 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable I added cowl flaps to my ES and I think it was worth it.=A0 I reshaped to c= owl and front fuselage to make for a more rectangular outlet.=A0 I also red= uced the inlet area about 20%, adding a diffuser section.=A0 The outlet are= a was reduced to about half of the original, depending on what kind of bulg= es on the bottom are assumed to be "standard."=A0 The cooling is marginal, = but adequate - on hot days climb speeds have to be increased and cruise is = done with the flaps open.=A0 This is to keep the CHT's below 400 and oil be= low 220.=A0 Closing the relatively small cowl flaps increases the speed by = 2 to 4 knots.=A0 Would I do it again?=A0 Yes, but I think I would figure ou= t a way to increase the cowl flap area.=0AGary Casey=0AES #157, Lycoming en= gine=0A=0AHas anyone on the LNC2 group experimented with using a cowl flap = instead of reducing cooling inlet area?=0AIf so, what drag reduction/airspe= ed increase, if any,=A0 did they find?=0A=0ATerrence=0AL235/320=0AN211AL=0A= =0A=0A --0-827088020-1275136314=:29267 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable

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I added cowl flaps to my ES and I think it was worth it. I resha= ped to cowl and front fuselage to make for a more rectangular outlet. = I also reduced the inlet area about 20%, adding a diffuser section. = The outlet area was reduced to about half of the original, depending on wha= t kind of bulges on the bottom are assumed to be "standard." The cool= ing is marginal, but adequate - on hot days climb speeds have to be increas= ed and cruise is done with the flaps open. This is to keep the CHT's = below 400 and oil below 220. Closing the relatively small cowl flaps = increases the speed by 2 to 4 knots. Would I do it again? Yes, = but I think I would figure out a way to increase the cowl flap area.

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Gary Casey

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ES #157, Lycoming engine

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Has anyone on the = LNC2 group experimented with using a cowl flap instead of reducing cooling = inlet area?
If so, what drag reduction/airspeed increase, if any, = did they find?

Terrence
L235/320
N211AL

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