Reynald's number
Maybe the guy wants to reduce lift by increasing drag?
Amusing?
I did it on a couple of models and it worked very well
I could have used speed brakes (ala Douglas Dauntless) but he flaps had a manifold use
I could couple em with the elevator and change lift without changing angle of fuselage and I could short field land by really dropping them.
Once upon a time -I made split rudders to slow vertical down lines - Itwas a lousy choice-
The amount of coupled up stuff required to hold the line as the rudder split , was just too much .
The pitch up with application of splitting rudder was quite profound.