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Old Oct 01, 2012, 04:12 PM
Registered User
Gloucester Ma
Joined Dec 2002
1,037 Posts
Discussion
adjusting airfoil for blunt trailing edge

I am venturing into hot wiring some cores and have a question or two.

What is the best way to adjust a particular airfoil to arrive at the correct cord with a square TE of about .090" (2.25mm). Is it okay to just scale the whole foil up and trim the cut foam, which will increase the intended thickness %. Or is it better to decrease the thickness in the original airfoil program ( I use Profili-2) to get the original thickness at the intended cord once the form is trimmed.
Also, and a little more complicated, how do you adjust an airfoil for .2"(6mm) ailerons if the airfoil is a lot thicker where they meet. On this last question so far my ideas are to make built-up depron ailerons,or reduce their size to where they match the airfoil and increase the throes.
Thanks, Alex
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Old Oct 01, 2012, 04:41 PM
Deniable plausibility
Shedofdread's Avatar
Derbyshire, UK
Joined Aug 2008
2,316 Posts
Get yourself XFLR - it's freeware and it lets you modify TE thickness. Doesn't get much better, eh?
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Old Oct 06, 2012, 02:12 AM
find me @samotage
samotage's Avatar
Melbourne Australia
Joined Jul 2005
8,362 Posts
Why not Just sand the TE back after the glass/carbon/wood etc is done?
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Old Oct 06, 2012, 02:14 AM
find me @samotage
samotage's Avatar
Melbourne Australia
Joined Jul 2005
8,362 Posts
Also if your foam is blocked properly, this will not be a problem. Just exacto to trim. And FWIW if you aren't NC machining a mold, it will be lucky to be within 10% of the designed shape when it leaves the hill for the first time
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Old Oct 08, 2012, 12:32 PM
Registered User
illinois
Joined Jun 2001
597 Posts
I think Profili has the optoin to adjust / modify the arifoil with XFLR which should allow you to adjust the T.E. thickness. Many times I've just scaled the airfoil to get the required T.E. thickness - change in section thickness usually is not critical.

Could you describe the model your working on and requirements for the finished plane ?
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Last edited by wim5150; Oct 08, 2012 at 12:45 PM.
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Old Oct 12, 2012, 11:01 PM
No fuse too fat
slopeiron's Avatar
USA, CA, Redondo Beach
Joined Apr 2002
3,886 Posts
Yes, do tell. Cuz you are in the slope forum and most of us here like thin airfoils with razor sharp TE's. Now you have me curious too. What are you building? I see you mentioned depron so, must be something pretty light?
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