RE: Q 500 aerofoil
I will sugested two airfoils mh 18b or naca 66-012 both are good maybe with a naca 66-012 you can get a faster airplane if you have good thumbs, but must be careful with construction to keep the airfoil acurate.
Profili is a very good program to generate airfoil coordinates and can export cor. archives for cnc foam cutting machines.
Marco Vergara