Rudder Turbulator Strips

[Dean Pappas]

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

-----Original Message-----
From: John Ferrell [mailto:johnferrell at earthlink.net]
Sent: Tuesday, April 15, 2003 4:42 PM
To: discussion at nsrca.org
Subject: Re: Rudder Turbulator Strips


There were several who objected that the blunt trailing edge resulted in
more drag than a sharper edge.
I felt that the blunt edge was easier to construct and maintain uniformly
and that drag was not much of
a consideration on this particular model. Somewhere I read that racing
sailboats had blunt training edges
on the rudder to reduce the tendency of the surface to "hunt" under light
loading. I don't have any scientific
evidence to support that but Dave Guerin also liked blunt trailing edges so
we kept the recomendation.

I would not know where to start to find the equations to support either side
of the argument,
If you can't quantify it, you really don't understand it,
Therefore I really don't understand it.
Howerver, I do prefer it!

----- Original Message -----
From: "Dean Pappas" <d.pappas at kodeos.com>
To: <discussion at nsrca.org>
Sent: Tuesday, April 15, 2003 3:00 PM
Subject: RE: Rudder Turbulator Strips


Why?
Dean

-----Original Message-----
From: John Ferrell [mailto:johnferrell at earthlink.net]
Sent: Tuesday, April 15, 2003 2:34 PM
To: discussion at nsrca.org
Subject: Re: Rudder Turbulator Strips


The blunt trailing edges recieved a lot of criticism on the Prophecy.



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