This makes sense. The standard recommendation on power planes is to leave
the TEs square and NOT round them off; rounding them is said to produce
flutter (the TE being an aileron).
--Bill
>From: Oleg Golovidov <[EMAIL PROTECTED]>
>Reply-To: Oleg Golovidov <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED], [EMAIL PROTECTED]
>Subject: [RCSE] Re: beefing up an airfoil
>Date: Mon, 16 Jul 2001 09:51:37 -0400 (EDT)
>
>Forwarding Mark Drela's reply to everybody. Mark forgot to CC the list when
>replying.
>
>Thanks a lot, Mark.
>One more comment/question. If the chop-off method is acceptable, it is much
>easier to implement. Just plot the same airfoil for a larger chord.
>The method with opening the arches requires doing some preprocessing of the
>airfoil coordinates, right? Do you just use a spreadsheet to multiply the
>y-coord by the fraction of the x-coord (distance from LE)? Actually, one
>would
>need to add/subtract the correction factor of say 0.005*x, correct?
>Did you try to imply that if one chops off a good bit of the airfoil's tail
>it's
>no longer close to the original flow?
>Oleg.
>
>
>------------- Begin Forwarded Message -------------
>From: Mark Drela <[EMAIL PROTECTED]>
>
>
>Oleg,
>
>The "chop-off" method is usually OK, but on airfoils with
>very thin rear ends like most of the new HLG stuff you'd
>have to chop off quite a bit to get 1% thickness. I like
>the other way better.
>
> >if you MUST have a thick trailing edge, do NOT round
> >it, leave it square.
>
>Yes, absolutely. On a lifting airfoil, the bottom-surface
>corner in particular should be sharp, otherwise the BL
>might stick partway around the curve and turn the flow
>upward and reduce lift. Of course if you -want- a
>lower CL this might help, but reducing camber is
>a far better way to do this.
>
>The rounding is deleterious only when the radius is
>a significant fraction of the bottom BL thickness,
>so this is less of a problem at smallish Re's.
>Still, I don't see a good reason to round off the edge
>in any case.
>
>- Mark
>
>------------- End Forwarded Message -------------
>
>
>______________________________________________________________________
>
> Oleg Golovidov
> Engineous Software Inc.
> www.engineous.com
> (919)677-6700 x107
>
>RCSE-List facilities provided by Model Airplane News. Send "subscribe" and
>"unsubscribe" requests to [EMAIL PROTECTED]
_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com
RCSE-List facilities provided by Model Airplane News. Send "subscribe" and
"unsubscribe" requests to [EMAIL PROTECTED]
