Google is your friend... 
Yes,perhaps I was too brief in my OP. The airfoil on my RW-2 is nearly symetrical but differs from the Google example of semi-symetrical, in that if you use the line of thrust as a datum, the leading edge droops to a position where the airfoil is actually just barley undercambered. But it has 50 hp propelling 505 pounds all up (10.1 #/hp).
To pull 425 pounds with 38 hp (11.2 #/hp) and keep the stall speed under the mandated 27.6 mph I wanted to make certain that the extra 0.2 lift points given on the 36 were real. So a better way to ask might be:
Does anyone disagree with the following: when the lift of an airfoil increases the stall speed ALWAYS decreases...
(Yeah, it gets nastier when it finally comes and there is more adverse yaw, but I'm not asking that.)
