X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 01 Aug 2007 16:35:46 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-banded.atl.sa.earthlink.net ([209.86.89.70] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2225062 for lml@lancaironline.net; Wed, 01 Aug 2007 13:46:16 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.70; envelope-from=douglasbrunner@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=oB5KE/3wAF8DnbW5hpDX7804UpyOX2zchR4+pP/u+x6LwhRdCsTIdTgwJTHEovpK; h=Received:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE:X-ELNK-Trace:X-Originating-IP; Received: from [74.93.196.177] (helo=DFWK3391) by elasmtp-banded.atl.sa.earthlink.net with asmtp (Exim 4.34) id 1IGIGQ-0005FC-0M for lml@lancaironline.net; Wed, 01 Aug 2007 13:45:38 -0400 X-Original-Message-ID: <003401c7d463$c050a570$1bd0a60a@DFWK3391> From: "Douglas Brunner" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] Template of Leading Edges X-Original-Date: Wed, 1 Aug 2007 13:45:29 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0031_01C7D442.38FC5720" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 X-ELNK-Trace: ad85a799c4f5de37c2eb1477c196d22294f5150ab1c16ac0c864d17e3813b99a080de0ad26a77cca109fe0568c44001c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 74.93.196.177 This is a multi-part message in MIME format. ------=_NextPart_000_0031_01C7D442.38FC5720 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Craig, Thanks for the info. Looks like you are way ahead of me. What I plan/hope to do is to get templates about every 2 feet apart for = the wing, h. stab and (?) rudder. Get the contour right at these points, then = long board in between. Hadn't even thought about the incidence and washout - not sure what I = can do about them anyway. Doug ----- Original Message -----=20 From: Craig Berland=20 To: lml@lancaironline.net=20 Sent: Tuesday, July 31, 2007 6:12 PM Subject: [LML] Template of Leading Edges a.. How close are we to the designed airfoil? =20 I have a IV-P, not a Legacy but my airfoils are very close to design = intent.=20 I CNC machined three templates that are accurate to design intent = within .001". I made one template for the root, one for the = flap/aileron split and one for the winglet split. I did not use feeler = gages, but it was hard to see light under the 3/4" wide templates. I = feel the three locations were within .03" of design intent and the = leading edge was much closer than that. a.. Is it possible that we may have squeezed the wing too tight and = made it too narrow or added too much micro and made it too blunt?=20 b.. Can we get the correct airfoil by hand sanding? =20 I used a very long "long board". Three strips of sand paper long.=20 a.. How do we know what the correct airfoil is - by eyeball?=20 b.. Is there a better way? =20 I am thinking of "templating" my leading edges - getting a template = that is the correct airfoil and attempting to get the leading edges as = close to design as possible. a.. Does this make sense?=20 b.. Am I wasting my time chasing 1 or 2 knots?=20 c.. What is the best method of getting the correct airfoil?=20 d.. Has anyone else done this?=20 While the airfoil shape is very close, I was able to measure incidence = with the templates as well. The incidence was not as good as I would = have liked. Here are my actual incidence inspection results: RH LH Spec BL26.25 -1.764 -1.9705 -1.6 BL104 -.8033 -1.178 -.777 BL171 +.397 +.145 +.342 Washout 2.143 2.115 1.942 Results were obtained with a precision level .0005/ft and a sine bar. = Therefore I'm pretty confident of the numbers.=20 By the way, I did the same thing for the horizontal. The top of the = horizontal is not per design but the bottom is. The horizontal is = actually an inverted wing rather than a symmetrical surface. I'm not = smart enough to know what total effect this has. Craig Berland D. Brunner N241DB 90% done 30% to go ------=_NextPart_000_0031_01C7D442.38FC5720 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Craig,
 
Thanks for the info.  Looks like = you are way=20 ahead of me.
 
What I plan/hope to do is to get = templates about=20 every 2 feet apart for the wing,
h. stab and (?) rudder.  Get the = contour right=20 at these points, then long board
in between.
 
Hadn't even thought about the incidence = and washout=20 - not sure what I can
do about them anyway.
 
Doug
----- Original Message -----
From:=20 Craig=20 Berland
Sent: Tuesday, July 31, 2007 = 6:12=20 PM
Subject: [LML] Template of = Leading=20 Edges

  • How close are we to the designed=20 airfoil?  
I=20 have a IV-P, not a Legacy but my airfoils are very close to design intent.
I CNC machined three templates that are = accurate to=20 design intent within .001".  I made one template for the root,=20 one for the flap/aileron split and one for the winglet=20 split.  I did not use feeler gages, but it was hard to see = light=20 under the 3/4" wide templates.  I feel the three locations were = within=20 .03"  of design intent = and the=20 leading edge was much = closer than=20 that.
  • Is it possible that we may have=20 squeezed the wing too tight and made it too narrow or = added=20 too much micro and made it too blunt?=20
  • Can we get the correct airfoil by = hand=20 sanding?  
I=20 used a very long "long board".  Three strips of sand paper=20 long. 
  • How do we know what the correct = airfoil is - by=20 eyeball?=20
  • Is there a better way?  
I am thinking of "templating" my = leading edges -=20 getting a template that is the correct airfoil and attempting to get = the=20 leading edges as close to design as possible.
  • Does this make sense?=20
  • Am I wasting my time chasing 1 or 2=20 knots?=20
  • What is the best method of getting = the correct=20 airfoil?=20
  • Has anyone else done = this? 
While the airfoil shape is very close, I = was able to=20 measure incidence with the templates as well.  The incidence was = not as=20 good as I would have liked.

Here are my = actual  incidence  inspection=20 results:

       &nbs= p;           =20 RH        &nbs= p;    =20 LH        &nbs= p;   =20 Spec

BL26.25     = -1.764        =20 -1.9705        =20 -1.6

BL104        =20 -.8033        =20 -1.178        =20 -.777

BL171        =20 +.397        =20  +.145        &nbs= p; +.342

Washout      = 2.143        &nbs= p;=20 2.115        &nbs= p;=20 1.942

Results = were obtained=20 with a precision level .0005/ft and a sine bar. Therefore I'm pretty = confident=20 of the numbers. 

By the way, I did the same thing for the=20 horizontal.  The top of the horizontal is not per design but the = bottom=20 is.  The horizontal is actually an inverted wing rather = than a=20 symmetrical surface.  I'm not smart enough to know what total = effect this=20 has.

Craig Berland
 
D. Brunner
N241DB
90% done 30% to go
 
 
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