X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 13 Feb 2014 11:29:21 -0500 Message-ID: X-Original-Return-Path: Received: from nk11p08mm-asmtp002.mac.com ([17.158.58.247] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTP id 6730863 for lml@lancaironline.net; Thu, 13 Feb 2014 10:07:02 -0500 Received-SPF: pass receiver=logan.com; client-ip=17.158.58.247; envelope-from=gw5@me.com Received: from [192.168.0.7] (cpe-071-077-249-052.ec.res.rr.com [71.77.249.52]) by nk11p08mm-asmtp002.mac.com (Oracle Communications Messaging Server 7u4-27.08(7.0.4.27.7) 64bit (built Aug 22 2013)) with ESMTPSA id <0N0X00DKMWMPNA80@nk11p08mm-asmtp002.mac.com> for lml@lancaironline.net; Thu, 13 Feb 2014 15:06:27 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.11.87,1.0.14,0.0.0000 definitions=2014-02-13_04:2014-02-13,2014-02-13,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1401130000 definitions=main-1402130067 From: George Wehrung Content-type: multipart/alternative; boundary=Apple-Mail-77FF71CD-DDA4-47E1-812B-E5089D9B91B6 Content-transfer-encoding: 7bit MIME-version: 1.0 (1.0) Subject: Re: [LML] Re: Angle of attack X-Original-Message-id: X-Original-Date: Thu, 13 Feb 2014 10:06:26 -0500 References: In-reply-to: X-Original-To: Lancair Mailing List X-Mailer: iPad Mail (11B554a) --Apple-Mail-77FF71CD-DDA4-47E1-812B-E5089D9B91B6 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable I remember in the E-6A Mercury (B707) I flew we had an AOA gauge for a few d= ifferent flight profiles. Of particular usefulness was max endurance and ma= x range. I would love to have max range depicted on an AOA gauge.=20 Sent from my iPad > On Feb 9, 2014, at 20:44, Jeff Edwards wrote: >=20 > How about best glide AOA?=20 >=20 > We used an engine out AOA in the A-6. >=20 > Jeff=20 >=20 > Sent from my iPad >=20 >> 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 ang= les 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 airfra= me=20 >> or airfoil geometry then zero degrees can produce positive lift. To keep= the=20 >> math simple, the zero lift line is used. By definition, when it is at ze= ro=20 >> angle there is zero lift. Any positive angle produces positive lift. Th= is=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 abou= t=20 >> 1.9 degrees - referenced to the zero lift line. >>=20 >> Chris Zavatson >> N91CZ >> 360std >> http://www.n91cz.net/ >>=20 >>=20 --Apple-Mail-77FF71CD-DDA4-47E1-812B-E5089D9B91B6 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
I remember in the E-6A Mercury (B707) I= flew we had an AOA gauge for a few different flight profiles.  Of part= icular usefulness was max endurance and max range. I would love to have max r= ange depicted on an AOA gauge. 

Sent from my iPad

= On Feb 9, 2014, at 20:44, Jeff Edwards <vtailjeff@aol.com> wrote:

=
How about best glide AOA? 

We used an e= ngine out AOA in the A-6.

Jeff 

Sent fr= om my iPad

On Feb 9, 2014, at 3:29 PM, Charles Brown <browncc1@verizon.net> wrote:
I vote with Chris.  I've be= en an aerodynamicist at Boeing and at General Dynamics (now Lockheed Martin)= .  For a whole airplane (not just an airfoil section), to simplify all t= he complexity of wing root incidence, twist/washout and spanwise airfoil var= iations, normally the angle of attack that produces approximately zero lift o= n the whole airframe+wing is arbitrarily chosen as "zero".  And by the w= ay, usually airplanes are designed with the wing tipped up slightly with res= pect to the fuselage (angle of incidence), so that at cruise conditions the f= uselage deck angle (waterline) is approximately zero (level) while the wing i= s tipped up just enough to produce 1g lift (lift=3Dweight).

I'm curious though, what does it matter for an AOA indicator?  = ;Cruise angles of attack are absolutely uninteresting.  Stall warning a= t some angle of attack that's just a little shy of max lift coefficient is t= he only angle that you have to dial in properly, right?

Charl= ey Brown


Posted for 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-77FF71CD-DDA4-47E1-812B-E5089D9B91B6--