X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 09 Feb 2014 20:44:03 -0500 Message-ID: X-Original-Return-Path: Received: from omr-m10.mx.aol.com ([64.12.143.86] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTPS id 6725304 for lml@lancaironline.net; Sun, 09 Feb 2014 18:22:17 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.143.86; envelope-from=vtailjeff@aol.com Received: from mtaout-mcb01.mx.aol.com (mtaout-mcb01.mx.aol.com [172.26.50.173]) by omr-m10.mx.aol.com (Outbound Mail Relay) with ESMTP id 2C85C70202BC8 for ; Sun, 9 Feb 2014 18:21:42 -0500 (EST) Received: from [10.217.203.33] (unknown [166.147.97.118]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by mtaout-mcb01.mx.aol.com (MUA/Third Party Client Interface) with ESMTPSA id A085D3800009F for ; Sun, 9 Feb 2014 18:21:41 -0500 (EST) From: Jeff Edwards Content-Type: multipart/alternative; boundary=Apple-Mail-5B5AD44A-FEA6-4B3F-8D3F-D7A41EC08592 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) Subject: Re: [LML] Re: Angle of attack X-Original-Message-Id: X-Original-Date: Sun, 9 Feb 2014 17:21:39 -0600 References: In-Reply-To: X-Original-To: Lancair Mailing List X-Mailer: iPad Mail (11B511) x-aol-global-disposition: G x-aol-sid: 3039ac1a32ad52f80d856efe X-AOL-IP: 166.147.97.118 --Apple-Mail-5B5AD44A-FEA6-4B3F-8D3F-D7A41EC08592 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable How about best glide AOA?=20 We used an engine out AOA in the A-6. Jeff=20 Sent from my iPad > On Feb 9, 2014, at 3:29 PM, Charles Brown wrote: >=20 > I vote with Chris. I've been an aerodynamicist at Boeing and at General D= ynamics (now Lockheed Martin). For a whole airplane (not just an airfoil se= ction), to simplify all the complexity of wing root incidence, twist/washout= and spanwise airfoil variations, normally the angle of attack that produces= approximately zero lift on the whole airframe+wing is arbitrarily chosen as= "zero". And by the way, usually airplanes are designed with the wing tippe= d up slightly with respect to the fuselage (angle of incidence), so that at c= ruise conditions the fuselage deck angle (waterline) is approximately zero (= level) while the wing is tipped up just enough to produce 1g lift (lift=3Dwe= ight). >=20 > I'm curious though, what does it matter for an AOA indicator? Cruise angl= es of attack are absolutely uninteresting. Stall warning at some angle of a= ttack that's just a little shy of max lift coefficient is the only angle tha= t you have to dial in properly, right? >=20 > Charley Brown >=20 >=20 > Posted for Chris Zavatson : > =20 > Angle of attack can have a few different definitions. If tied to airfram= e=20 > or airfoil geometry then zero degrees can produce positive lift. To keep t= he=20 > math simple, the zero lift line is used. By definition, when it is at zer= o=20 > angle there is zero lift. Any positive angle produces positive lift. Thi= s=20 > removes all the variables of the physical geometry such as washout and=20 > incidence angles, etc. > Down low and fast the 360 needs a lift coefficient of about 0.19 or about= =20 > 1.9 degrees - referenced to the zero lift line. >=20 > Chris Zavatson > N91CZ > 360std > http://www.n91cz.net/ >=20 >=20 --Apple-Mail-5B5AD44A-FEA6-4B3F-8D3F-D7A41EC08592 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable

How about best glide AOA?

<= div>

We used an engine out AOA in the A-6.

Jeff

Sent from my iPad

On Feb 9, 2014, at 3= :29 PM, Charles Brown <browncc1@v= erizon.net> wrote:

I= vote with Chris. I've been an aerodynamicist at Boeing and at General= Dynamics (now Lockheed Martin). For a whole airplane (not just an air= foil section), to simplify all the complexity of wing root incidence, twist/= washout and spanwise airfoil variations, normally the angle of attack that p= roduces approximately zero lift on the whole airframe+wing is arbitrarily ch= osen as "zero". And by the way, usually airplanes are designed with th= e wing tipped up slightly with respect to the fuselage (angle of incidence),= so that at cruise conditions the fuselage deck angle (waterline) is approxi= mately zero (level) while the wing is tipped up just enough to produce 1g li= ft (lift=3Dweight).

I'm curious though, what does i= t matter for an AOA indicator? Cruise angles of attack are absolutely u= ninteresting. Stall warning at some angle of attack that's just a litt= le shy of max lift coefficient is the only angle that you have to dial in pr= operly, right?

Charley Brown

Posted f= or Chris Zavatson <chris_zavatson@yahoo.com= >:

Angle of attack can have a few different defi= nitions. If tied to airframe
or airfoil geometry then zero degrees can produce positive lift. To keep t= he
math simple, the zero lift line is used. By definition, when it is at zero
angle there is zero lift. Any positive angle produce= s positive lift. This
removes all the variables of the physical geometry such as washout and
incidence angles, etc.
Down low an= d fast the 360 needs a lift coefficient of about 0.19 or about
1.9 degrees - referenced to the zero lift line.

Chris Zavatson
&= nbsp;N91CZ
360std
http:/= /www.n91cz.net/

= --Apple-Mail-5B5AD44A-FEA6-4B3F-8D3F-D7A41EC08592--