Help designing flying wing

[Sprat]

Hello!
I'm very new to RC airplane topic so excuse me in advance for my inexperience.
I'm going to build a flying wing:
Wingspan 40" 100cm
Root chord 9.4" 24cm
Tip chord 5.5" 14cm
Sweep 20°
I intend to use PW75 airfoil.
Now, my problem is: I don't know if this measures are good for a somewhat good flying wing and I don't know how big my control surfaces have to be and if they have to be cut out from the airfoil or if they have to be added as a separate part, same for vertical stabilizer I've got no idea on how big those have to be.
Thank you in advance!

Edit: I was planning for it to be a pusher.

[fhhuber]

You can make that work with the correct center of gravity and appropriate control surfaces.

There are all sorts of calculations for doing the vertical stabilizers. Or you can look at models such as the "Zagi" and pretty much copy. https://zagi.com/
More sweep = less vertical stabilizer area needed. Less sweep = more vertical needed.
Mount the wingtip fins aimed a degree or two toward each other. This is to prevent them from accidentally be aimed away from each other which is severely destabilizing.

CG of a flying wing will be appx 15% MAC. That means 15% of the wing area should be ahead and 85% behind the line where it will balance.

The cntrol surfaces are part of the airfoil. If you add them onto some airfoil, you changed the airfoil to a new one. Nothing wrong with that, but its just not the same airfoil.

Too large of a control surface is easier to deal with than too small. You just move the big surface less. About 1/10 of the wing being control surface will work. Less might work.

With the trailing edge sweeping back, leave the center portion of the wing without any control surface. Just have them in the outer half of each wing panel.
Straight trailing edge, full span strip control surface is fine.
Trailing edge sweeping forward, you want separate ailerons in the outer half of the wing panels and elevator surfaces in the center half.
There are interactions of the wing sweep and control surfaces that make the elevator function more or less effective.

Every single seemingly small change you make will have multiple side effects. An airplane is a mass of compromises of effects.


Build a small foam flat plate glider and see if you can make it fly... Test the effects of making assorted changes.... one change at a time.