Rudder Turbulator Strips

[Rcmaster199 at aol.com]

In a message dated 4/15/2003 4:50:59 PM Eastern Daylight Time, 
d.pappas at kodeos.com writes:


> Subj:RE: Rudder Turbulator Strips 
> Date:4/15/2003 4:50:59 PM Eastern Daylight Time
> From:<A HREF="mailto:d.pappas at kodeos.com">d.pappas at kodeos.com</A>
> Reply-to:<A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A>
> To:<A HREF="mailto:discussion at nsrca.org">discussion at nsrca.org</A>
> Sent from the Internet 
> 
> 
> 
> John, we are on the same page:
> Blunt trailing edges make for torsionally stiffer (read that lighter)
> ailerons and the like. They also soften the neutrals (and the textbooks say 
> so).
> They also reduce the ultimate CL of an airfoil, unless it is designed to 
> work with one.
> 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.
> Somehow the hundredth of a mile per hour that is robbed matters to some 
> people.
> Let's face it, the sharp TEs look sexy, and that probably where the rubber 
> meets the road.
> 
> as confused as you are,
>     Dean
> 
Dean,
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. 

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

One thing is certain: supersonic craft have very thin TE's so at high speed 
thin TE's=less drag

Matt Kebabjian

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