These airfoils are quite thin- that was the why the foil gag.
We just got through using Mother Nature's wind tunnel to test some stuff-
One model a Mini 3D with AUW of 7 ozs and that included a 2 oz EFlite 370 outrunner motor -on a 9x 4.7
this was really a bad combo - the torque reaction and propblast simply twisted it abut 15 degrees upon application of power.
acceleration tho was spectacular.
I just retired the 370 from that setup---
what was really interesting tho -was a Knuffler design - with a tiny rewound CD Rom motor - the model -in still air - flies just like a very good 1.20 pattern design.
smooth- perfect slow rolls - nice straight pulls n pushes .
All this and no "airfoil" most would recognize - just 3mm thick, flat foam sheet .
The hard part is making it all free from excessive flex.
This is really fun stuff.