X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 01 Apr 2010 10:01:00 -0400 Message-ID: X-Original-Return-Path: Received: from web57516.mail.re1.yahoo.com ([66.196.101.69] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with SMTP id 4191663 for lml@lancaironline.net; Thu, 01 Apr 2010 07:13:10 -0400 Received-SPF: none receiver=logan.com; client-ip=66.196.101.69; envelope-from=casey.gary@yahoo.com Received: (qmail 53957 invoked by uid 60001); 1 Apr 2010 11:12:34 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=gKHeTGR6QVgrpX0QkFMfpbukGfJdpJDs6I1rKav+VTAP6+DnghJCFRefTTrkY2Eicg+qLcBJWuu0Eep3RyffpuRN5Xo73j0sRvhcne/U5IHkUwSQxudqduU7rwET4xBqOx4QeaarEHs9/QvEftl3hTsZK6qa78FZqKgB2VR5pHc=; X-Original-Message-ID: <707107.53670.qm@web57516.mail.re1.yahoo.com> X-YMail-OSG: JQBJvWwVM1lzaL1hrRLy6XDZxLeVc4mYIwWdA3KqOgVlwm6 1vbKRyRve3c.uv1pc_DebAqKiAAKPn7pNEIfP0PRta_Rzelp6H1yTU0dkr37 fcM_eyPnHsmUWFA9lIQP1Z0a95rTahaOT6BtBGvoiTlemspKTM5ZVviQQtSz xxNkMCJivcWs22EllXj0LcpP9fc3IixU1PCQUdeoy3g7yGkmdksQdBNMOHUF qUjjLa05UjGticGLAF3x5YoeycENufHztvOn4IjcxGHDrJLDAJrdbXIIa6_L 5riZ6WVwZ_cU- Received: from [97.122.178.37] by web57516.mail.re1.yahoo.com via HTTP; Thu, 01 Apr 2010 04:12:34 PDT X-Mailer: YahooMailRC/324.3 YahooMailWebService/0.8.100.260964 References: X-Original-Date: Thu, 1 Apr 2010 04:12:34 -0700 (PDT) From: Gary Casey Subject: Re: Legacy maintenance idea X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-656333845-1270120354=:53670" --0-656333845-1270120354=:53670 Content-Type: text/plain; charset=us-ascii Tom, Ah, interesting idea, but I don't think a row of fasteners on the the trailing edge will do it. The load on that part of the wing is very high. If the wing loading is maybe 20 pounds per sq. ft and the area is, say, between 5 and 10 sq. ft you could have 200 pounds of upward load on that skin, concentrated toward the leading edge. Add 4 G's of load factor and the total force trying to separate that skin from the wing could get as high as 800 pounds. Then take into account the fact that the wing root area accounts for more of the lift than the tips and the load trying to pull that skin off could be as high as 1,000 pounds, a nice round number. I would be tempted to start with #8 screws wherever the skin was intended to be bonded every 2 to 3 inches toward the leading edge, gradually changing to a screw every 6 inches at the trailing edge. Lots of structural screws might, but might not, replace the strength and rigidity imparted to the structure by the wing skin. And the trailing edge "flap gap filler" from the lower skin was not intended to be structural, although in carbon fiber it is probably pretty strong. And then there is the question of the hinge line disrupting laminar flow at the leading edge. If you were going to build a small, race-track-shaped, screwed-on access panel that would only open the areas not accessible from underneath, that would be a different matter. Gary ________________________________ While working on my Legacy kit it occurred to me that once it's flying inspection and maintenance of the main gear would be so much easier if the stub wing skin could be removed. I attached a hinge to the leading edge so that the skin could be opened as shown in the picture. Now I'm trying to decide what sort of fasteners I should use on the trailing edge. Any suggestions? Tom Gourley --0-656333845-1270120354=:53670 Content-Type: text/html; charset=us-ascii

Tom,

Ah, interesting idea, but I don't think a row of fasteners on the the trailing edge will do it. The load on that part of the wing is very high. If the wing loading is maybe 20 pounds per sq. ft and the area is, say, between 5 and 10 sq. ft you could have 200 pounds of upward load on that skin, concentrated toward the leading edge. Add 4 G's of load factor and the total force trying to separate that skin from the wing could get as high as 800 pounds. Then take into account the fact that the wing root area accounts for more of the lift than the tips and the load trying to pull that skin off could be as high as 1,000 pounds, a nice round number. I would be tempted to start with #8 screws wherever the skin was intended to be bonded every 2 to 3 inches toward the leading edge, gradually changing to a screw every 6 inches at the trailing edge. Lots of structural screws might, but might not, replace the strength and rigidity imparted to the structure by the wing skin. And the trailing edge "flap gap filler" from the lower skin was not intended to be structural, although in carbon fiber it is probably pretty strong. And then there is the question of the hinge line disrupting laminar flow at the leading edge. If you were going to build a small, race-track-shaped, screwed-on access panel that would only open the areas not accessible from underneath, that would be a different matter.

Gary

While working on my Legacy kit it occurred to me that once it's flying inspection

and maintenance of the main gear would be so much easier if the stub wing skin

could be removed. I attached a hinge to the leading edge so that the skin could be
opened as shown in the picture. Now I'm trying to decide what sort of fasteners

I should use on the trailing edge. Any suggestions?

Tom Gourley

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