X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 31 Jul 2007 18:12:05 -0400 Message-ID: X-Original-Return-Path: Received: from [68.98.211.24] (HELO systems3.net) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2222518 for lml@lancaironline.net; Tue, 31 Jul 2007 11:55:08 -0400 Received-SPF: none receiver=logan.com; client-ip=68.98.211.24; envelope-from=cberland@systems3.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C7D38B.143F2024" Subject: [LML] Template of Leading Edges Content-class: urn:content-classes:message X-MimeOLE: Produced By Microsoft Exchange V6.5 X-Original-Date: Tue, 31 Jul 2007 08:54:28 -0700 X-Original-Message-ID: <87C33F695961494D886EB3B6C8A4765138CBA1@s3server.Systems3.local> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] Template of Leading Edges Thread-Index: AcfTV/HIEiyC9oO3QEuKUHqnfLNZSgAJ0Q6A From: "Craig Berland" X-Original-To: "Lancair Mail List" This is a multi-part message in MIME format. ------_=_NextPart_001_01C7D38B.143F2024 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable * 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. * 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 * Can we get the correct airfoil by hand sanding? =20 I used a very long "long board". Three strips of sand paper long.=20 * How do we know what the correct airfoil is - by eyeball?=20 * 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. * Does this make sense?=20 * Am I wasting my time chasing 1 or 2 knots?=20 * What is the best method of getting the correct airfoil?=20 * 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 =20 D. Brunner N241DB 90% done 30% to go =20 =20 ------_=_NextPart_001_01C7D38B.143F2024 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

How close are we to the designed=20 airfoil?

I have=20 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, = one for=20 the flap/aileron split and one for the winglet split. = I=20 did not use feeler gages, but it was hard to see light under the 3/4" = wide=20 templates. I feel the three locations were within .03" of design intent and the leading = edge=20 was much closer than=20 that.

Is it possible that we may have = squeezed the=20 wing too tight and made it too narrow or added too much = micro and=20 made it too blunt?=20
Can we get the correct airfoil by hand = sanding?

I used=20 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 = leading=20 edges as close to design as possible.

Does this make sense?=20
Am I wasting my time chasing 1 or 2 = 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 with=20 a precision level .0005/ft and a sine bar. Therefore I'm pretty = confident of the=20 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 = 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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