When the ailerons go up the airfoil is reflexed. Reflexing the airfoil reduces the mean camber which lowers the maximum lift coefficient available and decreases the angle of attack at which the reflexed airfoil stalls. The decrease in maximum lift coefficient along the aileron when combined with the unreflexed airfoil of the rest of the wing can only lower the average maximum lift coefficient of the wing. This has the net effect of raising the stalling speed of the wing. The increase in drag of the reflex will slow the plane but not below a higher stalling speed than without reflex. It is for this reason that very, very few full scale planes reflex both ailerons at once. The Minimoa is the only one that comes to mind. When full scale designers want to lower the landing speed, they use flaps and slats to increase the lift coefficient available.

You can't reliably judge the airspeed by just looking at the model. With a radar gun you can only measure the ground speed. It takes special instrumentation to measure the airspeed.