I talked the problem over with Harry Abbott and John Dee. We flew at speeds ranging from 120 knots down to my minimum airspeed of a gentle pitch bucking 55 knots. We started at 120 and worked the speed down in 10 knot increments. Air flow is straight back on the bottom surface of the wing. Different story up top.
Air flow is reasonably straight at higher speeds.
As you slow up, the deck angle goes up, and with it, the main wing angle of attack. At 90 knots, you can just start to see the yarn begin to turn outboard on both upper wing surfaces. But on the swept Varieze wing, it wants to turn. At 80 knots, the air flow separation occurs well aft of the thickest part of the cord just in front of the aileron. The down aileron is in clean higher pressure air.