Return-Path: Received: from fed1rmmtao06.cox.net ([68.230.241.33] verified) by logan.com (CommuniGate Pro SMTP 4.2b8) with ESMTP id 323098 for flyrotary@lancaironline.net; Fri, 16 Jul 2004 00:14:58 -0400 Received-SPF: error receiver=logan.com; client-ip=68.230.241.33; envelope-from=ALVentures@cox.net Received: from BigAl ([68.107.116.221]) by fed1rmmtao06.cox.net (InterMail vM.6.01.03.02 201-2131-111-104-20040324) with ESMTP id <20040716041425.VQCD26045.fed1rmmtao06.cox.net@BigAl> for ; Fri, 16 Jul 2004 00:14:25 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: New Scoop Date: Thu, 15 Jul 2004 21:14:51 -0700 Message-ID: <000001c46aeb$711a3be0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C46AB0.C4BB63E0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C46AB0.C4BB63E0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Subject: [FlyRotary] Re: New Scoop=20 =20 Al, I don't know exactly how to phrase this question but I'll take a stab at = it. When you decided to place the heat exchangers in the wings how did you estimate the effect(if any) due to impact on the designed airfoil(s)? I think = this is a great place for them in the canard designs. I am thinking about the = spaces in the rear of the strakes for mine. Dean Head Cozy MK4 BKV FL =20 Dean; =20 You probably phrased the question better than I can phrase the answer. =20 Actually; I wasn't very concerned about airfoil effects because on the canards the strake is not a very effective lifting surface because of = the very high Reynold's number. It is designed for neutral angle of attack = at cruise, with essentially all the lift provided by the canard and wings. There is some pressure differential between upper and lower surface = (based on aerodynamic analysis) in the wing rot behind the strake which can = help the flow through the coolers, and the difference is greater at higher = angles of attack, when you need the flow the most. I pushed my strake tops up a = bit during installation increase the effect, as well as give me a bit more = fuel capacity. I guessed - no; ah-h, applied my engineering judgement - that = the amount of flow through the cooler would not significantly impact the = lift. =20 I designed the exit faring like the upper half of an airfoil to retain attached flow to minimize the turbulence generated behind the faring. =20 I really don't know yet how well it is going to work. Is that why they = call these "experimental aircraft"? The only data point we have is Alan = Shaw's oil cooler installation, which apparently worked well even though his approach to the airflow was not as; let's say, "sophisticated" as mine. =20 Al ------=_NextPart_000_0001_01C46AB0.C4BB63E0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Subject: [FlyRotary] Re: New Scoop

 

Al,

I don't know exactly how to phrase this question but I'll take a stab at = it.

When you decided to place the heat exchangers in the wings how did you = estimate

the effect(if any) due to impact on the designed airfoil(s)? I think this is = a

great place for them in the canard designs. I am thinking about the spaces = in

the rear of the strakes for mine.

Dean Head

Cozy MK4

BKV FL

 

Dean;

 <= /font>

You probably = phrased the question better than I can phrase the answer.

 <= /font>

Actually; I = wasn’t very concerned about airfoil effects because on the canards the strake = is not a very effective lifting surface because of the very high Reynold’s = number.  It is designed for neutral angle of attack at cruise, with = essentially all the lift provided by the canard and wings.  There is some = pressure differential between upper and lower surface (based on aerodynamic = analysis) in the wing rot behind the strake which can help the flow through the = coolers, and the difference is greater at higher angles of attack, when you need the = flow the most. I pushed my strake tops up a bit during installation increase = the effect, as well as give me a bit more fuel capacity.  I guessed = – no; ah-h, applied my engineering judgement – that the amount of flow = through the cooler would not significantly impact the lift.

 <= /font>

I designed = the exit faring like the upper half of an airfoil to retain attached flow to minimize = the turbulence generated behind the faring.

 <= /font>

I really = don’t know yet how well it is going to work.  Is that why they call these = “experimental aircraft”?  The only data point we have is Alan Shaw’s = oil cooler installation, which apparently worked well even though his = approach to the airflow was not as; let’s say, “sophisticated” as = mine.

 <= /font>

Al

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