own wing design questions

[Tartan81]

so ive got this slec coyotey sitting around with out a wing .i fancy giving a redesign a go. i plan on getting rid of the t tail , add a permanent power pod with a cox engine and fuel tank to it and because i no longer have any wings for it i fancy a re-do of the design . how would one go about redesigning the aerofoil , draw a plan, and figure out wingspan .ive been away from the hobby for a good while now  and been getting my flying fix via realflight and other computer games such as il2 great battles and microsoft flight sim so im a bit rusty at this .

can i buy root and tip aerofoils from a cnc company to use the sandwich method with some ribs. i dont own a printer .i have no idea about how to plot an aerofoil .then there is how to guage the center of gravity once its all fueled up.can i have some hints and tips please gents, any help will be much appreaciated.

[Frank Skilbeck]

Unless you are looking for a specific aerofoil section, you could just freehand draw the root and tip sections and then make root and tip sections in ply and make the ribs using the sandwich method, I have done this in the past and the model flew fine. If you wanted a specific profile then there are websites that give details of these and you could hand plot them out.

 

For the c of g go with 25% of the Mean Aerodynamic Chord, plenty of websites showing you how to calculate this, like this one, and adjust the c of g after the test flights.

[Peter Miller]

As FRank says. a"That looks about right" wing section will work very well.  I would suggest about 14% thick and the maximum thickness.

AS Frank says CG at 25%.My standard location.

For a trainer type model or glider flat bottomed is fine. Makes building a bit easier too. If you want it to be a bit more aerobatic a semi symetrical section would be better.

If you PM me with some more details of planned root and tip chords I could send you a PDF file of one of my plans (Wing only) which any good office supply shop or print shop could print out for you.

[Peter Miller]

Having just looked at Coyote the ideal wing section wold be the good old faithful Clark Y. A perfect section for a glider. Flat bottomed and all.

I once read up on an American competition glider which was a plan in Flying MOdels. 

This glider was winning competitions all over the place and beating the opposition which used fancy Eppler and other highly technical sections.

When the designer was asked what wonder section he was using he just grinned and said "Clark Y" which really sickened the other competitors

It should be easy to find a copy of ClarkY on the internet.

[Peter Miller]

http://airfoiltools.com/airfoil/details?airfoil=clarky-il

 

Here it is

[J D 8]

   As a Coyote flyer I would say leave as is T tail and all, it is just a very good flyer in varied conditions. Mine is electric with nose mounted motor. The only mod is a small rudder, this is used in light soaring conditions to keep it pointing the right way without deploying the ailerons.