I have been flying r/c for about 15 yrs. and only recently competed in pattern and IMAC. I'm hooked! I have design my own 2m pattern model in 3D cad around the O.S. 1.60 (economical powr.). I have modeled all parts including an airfoil shape (7% sym.). But, I'm wondering if it would be better to contact a manufacturer and purchase wing cores/panels that would closely fit my planform. I'm thinking this would save me a lot of headache and worry about the performance of my airfoil choices. If interested in commenting on this, there are some low res. images at: INSIGHT pattern ship[img]i/expressions/face-icon-small-confused.gif[/img]

Your design looks smart but is the 7% symmetrical section used on any other successful pattern model? Most of the designs I have looked at ( admittedly in the smaller 40 size or 57 inch span types) have something like a 12 to 15% section. 60 size models also seem similar.
For example the 56inch 40 size ? Sonas? design by Alisdair Sutherland - a free plan in the August 2002 RC Model World (Traplet Publications) -uses a NACA 64A015 root rib tapering to NACA 0012 tip rib. A separate article in the same issue explains why a thinner tip rib is desirable. Basically to avoid tip stall by having a blunter LE at the tip.
The few larger designs I have seen plans for seem to use something that looks like the NACA 64A015 as well.

Check out the airfoil section the experts use for, your first design, unless you want to experiment. Of course unconventional might give you a winner, but can you make it strong enough with such a thin section? Will the wing joiner tubes fit?

Thanks for the advice. I don't know why I typed 7% because it is actually closer to 10% (17" root chord, 1.8" thick at the spar tube. I will try to find a wing core already available to avoid the initial design headache. I think I would like to experiment later though with my own wing panels. It would be alot safer to just get it in the air with a proven wing from another pattern bird.

10% maybe a little thin. Part of the function of the airfoil thickness is to create drag when going down vertically. If you have too thin a wing, there wont be enough drag and the plane will pick up too much speed even at idle. In studying pattern and 3D planes, most have a 12% wing. If you don't mind building wings, you can experiment, build one at 10%, one at 12% and one at 15% then fly all three and see which one gives you the performance you want. It could be a matter of personal taste. I think in pattern they want the plane to fly at a steady speed, even in verticles. It has to be able to not gain speed when going down hill.

Merry Christmas and always land wheels first,
Soj

I am designing about a .91 sized airplane inspired heavily by the Great Planes Venus (the fuselage shape anyway) and the ZNLine Synergy. I am sorta stumped on a wing airfoil for it. I was looking at the Eppler 168, and that looks like it would do good. If that won't work too good, I'll just scale down my airfoild from my Hydeout and use that.

For the tail, I am lost though. Should I use the same airfoil as on the wing for that too? Thank you all very much.