X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 18 Apr 2012 13:01:28 -0400 Message-ID: X-Original-Return-Path: Received: from imr-db01.mx.aol.com ([205.188.91.95] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTP id 5487130 for lml@lancaironline.net; Wed, 18 Apr 2012 11:23:09 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.91.95; envelope-from=Sky2high@aol.com Received: from mtaomg-mb02.r1000.mx.aol.com (mtaomg-mb02.r1000.mx.aol.com [172.29.41.73]) by imr-db01.mx.aol.com (8.14.1/8.14.1) with ESMTP id q3IFMOVA026035 for ; Wed, 18 Apr 2012 11:22:24 -0400 Received: from core-mtb001a.r1000.mail.aol.com (core-mtb001.r1000.mail.aol.com [172.29.234.193]) by mtaomg-mb02.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 94ACAE00008C for ; Wed, 18 Apr 2012 11:22:24 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Wed, 18 Apr 2012 11:22:24 -0400 (EDT) Subject: Re: [LML] Re: Fw: L320 flap setting X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_ea36.1fbdae49.3cc03630_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [67.175.156.123] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:456679072:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d29494f8edc3040ad --part1_ea36.1fbdae49.3cc03630_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Chris, Hmmmmmm... Well lazy me ;-} I refuse to go back and read the NASA report again - I am just going to rely on my creaky memory. BUT, my seat of the pants scientific probing makes me believe the drag factor is very significant. Oh drat, I now remember that we are dealing with vehicular drag, not just wing drag. On our slick lawn darts, a little drag has a big effect whilst on those pimply spam cans with wing struts and wheel pants, what's a little more drag? I retire to my quiet padded room now. Scott In a message dated 4/18/2012 10:01:17 A.M. Central Daylight Time, chris_zavatson@yahoo.com writes: Scott, I am dissapointed. :-) Google can fill in the details on Reynolds number. It just relates kinematic viscosity, chord length and velocity. Low Speed is relative. Mach and Reynolds number were right in our range. M 0.3 = ~200 kts Chris Zavatson N91CZ 360std _www.N91CZ.net_ (http://www.n91cz.net/) From: "Sky2high@aol.com" To: lml@lancaironline.net Sent: Tuesday, April 17, 2012 1:54 PM Subject: [LML] Re: Fw: L320 flap setting Chris, Ahh, too bad I can't translate Reynolds numbers into KIAS. I thought the NASA airfoil tests were at slow speeds???? Oh well .. It does match my experience. At high speeds, flap in reflex and nose down trim (on my airplane, small tail, actual TE of elevator is down a bit from neutral) is a very interesting condition to contemplate. After all, the elevator is an upside down wing (slightly cambered on the bottom). Thus, nose down trim is actually with the elevator in reflex. Since the chord of the horizontal stab was positioned with a negative incidence to the longeron (-.5 to -1 degrees, mine is -.8) and at cruise (about 180 - 190 KIAS), the longeron has been measured to be at 0 degrees (hmmm, just like the plane was designed), the horizontal may be at a positive AOA (relative air flow?, think upside down) until one considers the position of the elevator and its trim change on the AOA to a lesser AOA. Thus, less lift (anti lift), less drag. Egads, now my head hurts. Blue Skies, Scott Krueger In a message dated 4/17/2012 8:53:25 A.M. Central Daylight Time, chris_zavatson@yahoo.com writes: I use the attached charts to describe the impact of reflex: Repositioning the drag bucket, a drop of a few drag counts and a huge 3 to 1 change in pitching moment. Chris Zavatson N91CZ 360std _www.N91CZ.net_ (http://www.n91cz.net/) -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html --part1_ea36.1fbdae49.3cc03630_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Chris,
 
Hmmmmmm... Well lazy me ;-}
 
I refuse to go back and read the NASA report again - I am just go= ing=20 to rely on my creaky memory.  BUT, my seat of the pants scientific pro= bing=20 makes me believe the drag factor is very significant.  Oh drat, I now= =20 remember that we are dealing with vehicular drag, not just wing drag. = On=20 our slick lawn darts, a little drag has a big effect whilst on those p= imply=20 spam cans with wing struts and wheel pants, what's a little more drag?
 
I retire to my quiet padded room now.
 
Scott 
 
In a message dated 4/18/2012 10:01:17 A.M. Central Daylight Time,=20 chris_zavatson@yahoo.com writes:
=
Scott,
I am dissapointed.=  =20 :-)
Google can fill in the details on Reyn= olds=20 number.
It just relates ki= nematic=20 viscosity, chord length and velocity.
Low Speed is relat= ive. Mach=20 and Reynolds number were right in our range.
M 0.3 =3D ~20= 0=20 kts
 
Chris Zavatson
N91CZ
360std
www.N91CZ.net

From: "Sky2high@aol.com"=20 <Sky2high@aol.com>
To:=20 lml@lancaironline.net
Sent:=20 Tuesday, April 17, 2012 1:54 PM
Subject: [LML] Re: Fw: L320 flap= =20 setting

Chris,
 
Ahh, too bad I can't translate Reynolds numbers into KIAS.  I= =20 thought the NASA airfoil tests were at slow speeds????
 
Oh well .. It does match my experience.  At high speeds, flap i= n=20 reflex and nose down trim (on my airplane, small tail, actual TE of eleva= tor=20 is down a bit from neutral) is a very interesting condition to= =20 contemplate.  After all, the elevator is an upside down wing (slight= ly=20 cambered on the bottom).  Thus, nose down trim is actually with=20 the elevator in reflex.  Since the chord of the horizontal stab= was=20 positioned with a negative incidence to the longeron (-.5 to -1 degr= ees,=20 mine is -.8) and at cruise (about 180 - 190 KIAS), the longeron = ;has=20 been measured to be at 0 degrees (hmmm, just like the plane=20 was designed), the horizontal may be at a positive AOA (relativ= e air=20 flow?, think upside down) until one considers the position of the elevato= r and=20 its trim change on the AOA to a lesser AOA.  Thus, less lift (a= nti=20 lift), less drag.
 
Egads, now my head hurts.
 
Blue Skies,
 
Scott Krueger 
 
In a message dated 4/17/2012 8:53:25 A.M. Central Daylight Time,=20 chris_zavatson@yahoo.com writes:
I use the attached charts to describe the impact of reflex:  Repositioni= ng the=20 drag bucket, a drop of a few drag counts and a huge 3 to 1 change in=20 pitching moment.
 
Chris Zavatson
N91CZ
360std


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