Tri planes are tough too much gong on. The bottom wing should stall last and with the tripe the center wing could be the last to stall. If the wing that has the center of lift forward of the CG stalls last the plane goes tail heavy and will flop backwards. If the top wing wing stalls first the nose will drop and hopefully help gaining airspeed. It is tough luck it only has one set of ailerons on the top. The problem too is you want to see the onset of the stall so it would be nice that the wings stall in stages to keep the surprise down.