X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 28 Mar 2007 09:57:27 -0400 Message-ID: X-Original-Return-Path: Received: from mta10.adelphia.net ([68.168.78.202] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1947692 for lml@lancaironline.net; Wed, 28 Mar 2007 09:36:09 -0400 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.202; envelope-from=glcasey@adelphia.net Received: from [75.82.254.207] by mta10.adelphia.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20070328133519.VTFG375.mta10.adelphia.net@[75.82.254.207]> for ; Wed, 28 Mar 2007 13:35:19 +0000 Mime-Version: 1.0 (Apple Message framework v752.2) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-14--786778917 X-Original-Message-Id: <4AB6841E-2811-4CB1-816D-F99ADE3A64C0@adelphia.net> From: Gary Casey Subject: Re: Lancair IVP Strake X-Original-Date: Wed, 28 Mar 2007 06:35:16 -0700 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.752.2) --Apple-Mail-14--786778917 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed I did the flight test with the strakes taped on with only "100 mph tape", so I elected to do the tests at very low power settings in order to keep the airspeed down. I figured the effects would be similar to those at normal cruise speeds. The indicated airspeed was about 135 (150 kts true as I recall) at about 8,000 ft density altitude. Problem was in doing two consecutive flight tests at exactly the same conditions. The temperature was different and I'm not 100% sure the power setting matched exactly. As long as I kept my rose-colored glasses on I was able to convince myself that the conditions favored the "no-strake" condition and therefore the speed loss wasn't that much. I haven't flown it enough since to get a good feel for the speed loss under normal cruise conditions. If the numbers are accurate the 1.5% speed loss represents an increased power requirement of almost 5%, which I don't think is the case. As I posted earlier, the strakes are 25 degrees from vertical and are parallel. I doubt very much that the natural streamlines at that position are parallel - If I had done a more rigorous job I would have verified the streamlines before installing the part. Gary Casey ES N224SG > From: marv@lancair.net > Date: March 27, 2007 1:23:48 PM PDT > To: lml > Subject: Re: [LML] Re: Lancair IVP Strake > > > Gary, > 1.5% is big. So you are saying around 4 knots? Is that at altitude? > --Apple-Mail-14--786778917 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1
I did the flight test with the strakes taped = on with only "100 mph tape", so I elected to do the tests at very low = power settings in order to keep the airspeed down.=A0 I figured the = effects would be similar to those at normal cruise speeds.=A0 The = indicated airspeed was about 135 (150 kts true as I recall) at about = 8,000 ft density altitude.=A0 Problem was in doing two consecutive = flight tests at exactly the same conditions.=A0 The temperature was = different and I'm not 100% sure the power setting matched exactly. =A0As = long as I kept my rose-colored glasses on I was able to convince myself = that the conditions favored the "no-strake" condition and therefore the = speed loss wasn't that much. =A0I haven't flown it enough since to get a = good feel for the speed loss under normal cruise conditions.=A0 If the = numbers are accurate the 1.5% speed loss represents an increased power = requirement of almost 5%, which I don't think is the case.=A0 As I = posted earlier, the strakes are 25 degrees from vertical and are = parallel.=A0 I doubt very much that the natural streamlines at that = position are parallel - If I had done a more rigorous job I would have = verified the streamlines before installing the part.

Gary Casey
ES = N224SG
Date: March 27, 2007 1:23:48 PM = PDT
To: lml
Subject: Re: [LML] Re: Lancair IVP = Strake


Gary,
1.5% is big. So you are = saying around 4 knots? Is that at altitude?

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