Got a toughy question for you guys.

Which model A/C was first to incorporate spoilers into the design of the wing?

I have original plans for the DeBolt Viscount of 1961 which shows how to mount upper and lower spoilers to aide in turns. Used a balsa door, top and bottom, then a cam to lift each open in cooperation with aileron movements.

Was this the first instance? The same aircraft was the first production model to incorporate retracting gear the following year.

Wm.