Hey guys, I'm no expert, but I'd like to put in my two cents (feel free anyone to correct me if I am wrong)

ARNIE

1... For an aerobatic model you are going in the right direction by starting off with no dihederal. Good one!!

2... As far as wing design, what I have learnt is... Swept back wings with straight trailing edges, such as pattern planes and the Giles 202, make the aircraft fly a lot crisper and produce more axial rolls. Edge 540 wings with the straight leading edge and swept trailing edge are less stable on the roll axis and tend to be better snappers. Extra's are kind of a combination of both.

3... It depends on how aerobatic you want the aircraft. The more unstable the aircraft...technically... the better its aerobatic potential...technically!!! For an aircraft to be more stable in a stall, you want the root of the wing to stall first. If this is what you want, then all you have to do is make the leading edge of the inboard section sharper than the tip and make sure the aspect ratio of the section is thicker too. Having a thicker (higer aspect ratio) tip will make the aircraft want to become more unstable in a stall situation.

UKFlyer

Basically almost all funfly designs use a fully symetrical high aspect ratio wings with no dihedral. Aerodynamically, the same amount of lift is created on the top as on the bottom, making inverted flight easier. Therefore positive lift is created by increasing the angle of attack to the realtive airflow. I hope you are getting this. If not hit me with your questions.

Rule of thumb. The thicker the airfoil (higher aspect ratio wing), the better slow speed performance of the aircraft. I have built a couple of 'wing and boom' type funfly planes and basically used the "that looks about right" method of chosing airfoil section with great success!!!

HOPE THIS HELPS GUYS!!!!