<HTML><FONT FACE=arial,helvetica><FONT SIZE=2 FAMILY="SANSSERIF" FACE="Arial" LANG="0">In a message dated 4/15/2003 4:50:59 PM Eastern Daylight Time, d.pappas@kodeos.com writes:<BR>
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<BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Subj:<B>RE: Rudder Turbulator Strips </B><BR>
Date:4/15/2003 4:50:59 PM Eastern Daylight Time<BR>
From:<A HREF="mailto:d.pappas@kodeos.com">d.pappas@kodeos.com</A><BR>
Reply-to:<A HREF="mailto:discussion@nsrca.org">discussion@nsrca.org</A><BR>
To:<A HREF="mailto:discussion@nsrca.org">discussion@nsrca.org</A><BR>
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John, we are on the same page:<BR>
Blunt trailing edges make for torsionally stiffer (read that lighter)<BR>
ailerons and the like. They also soften the neutrals (and the textbooks say so).<BR>
They also reduce the ultimate CL of an airfoil, unless it is designed to work with one.<BR>
Selig worked up one such for the SAE weight-lifting students who wanted to stick with non-composite wings. It gives up "almost nothing" to the razor sharp TEs.<BR>
Somehow the hundredth of a mile per hour that is robbed matters to some people.<BR>
Let's face it, the sharp TEs look sexy, and that probably where the rubber meets the road.<BR>
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as confused as you are,<BR>
Dean<BR>
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Dean,<BR>
This vein reminds of the conversation several years ago on this list, regarding flutter induction of ailerons. It has been suggested by many in the past, including the Dean of Pattern himself, (Don Lowe, for the uninitiated), that thicker TEs reduced the onset of flutter. <BR>
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However, I don't recall anyone really having an answer to whether it's a mechanical issue (thicker TE=stiffer surface) or aerodynamic issue (thinner TE at very low Reynolds Numbers=turbulation and flutter). I suspect both are part answers to the equation, and since we fly at pretty low speeds, making the TE's fatter is not a bad thing<BR>
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One thing is certain: supersonic craft have very thin TE's so at high speed thin TE's=less drag<BR>
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Matt Kebabjian<BR>
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