Concepts, Plane Aerial Concepts Belgium, Patric Dietvorst, AS3X, Fun Cub, Multiplex, Spektrum
Like any other aircraft, the FunCub must be balanced at a particular point in order to achieve stable flying characteristics. The Centre of Gravity (CG) should be at the position 80 mm aft of the root leading edge, i.e. at the fuselage sides. This is correct, but in fig 30 in the manual, the order of the electronic components is not optimal to achieve this CG.
A better order of the electronic is as follows: From propeller/motor; first the ESC motor controller, than the receiver (RX), and most to the back the battery (3S 2200 mAh). With my battery and this plane, the battery had to be put completely to the back above the air ventilation opening on the bottom of the plane. I have put two horizontal carbon rods so the battery can not move vertically. A piece of Velcro keeps the battery horizontally fixed during flight.
I have glued two small pieces of sanding paper (20mm x 10mm) at the bottom of the plane at centers of gravity about 30cm apart. This makes it easy to put your finger at the Centre of Gravity with sufficient grip to balance the ready to fly this airplane (battery mounted)..