How to choose motor for fix wing plane?

ArduCopter
1

T/O weight : 23kg
wing span: 3.16 m
airfoil: CLARK Y AIRFOIL (clarky-il)
wing area: 9796 cm^2

motor is set up in front

S__22732846
S__227328461920×1080 357 KB

S__22732848
S__227328481920×1080 350 KB

S__22732849
S__227328491920×1080 336 KB

S__22732850
S__227328501920×1080 346 KB

2

Is this a scratch build or from a plan? I’d start with a motor prop combination from a similar wingspan and weight model that is known.

3

CUAV Pixhawk v6x flight controller and 8015 motors ;this aircraft is similar to mine.