Each wing has a single aileron surface on the trailing edge to control roll and two flaps to control lift and drag.
Once the airplane reaches a high enough altitude, the water freezes, affecting the operation of an aileron control bearing.
Probably due to flutter, an aileron departed the wing and the racer flipped over out of control and smashed into the ground.
It dawned on me the free-play I felt in the flight controls was an aileron gasping for air to push against as I leveled the wings.
There, stretching from the leading edge to the aileron hinge, was a crack in the plywood skin about an eighth of an inch wide.
From a distance, it was easy to see that while the aileron on one side was in alignment, the other aileron was sagging significantly.
Put the palm of your hand against the bottom of the leading edge of the aileron at each hinge and push up.
In order to prevent student pilots from getting into deeps stalls followed by deadly spins, Thieblot created a wing that allowed the ailerons to remain effective in a stall, thus making stall recovery easier.
Contrary to what one might think, the short wings and the four ailerons give only a modest rate of roll.
It sat on the trailing edge of the wings, preventing the ailerons from moving.