Tests of an N.A.C.A. 23012 Airfoil with a slotted deflector flap
This is a 1939 NACA technical report from the NASA Technical Reports Server, written for aeronautical engineers, testing a 23012 airfoil fitted with a slotted deflector flap in a wind tunnel. Its pictures are engineering line charts and a cross-section drawing; a designer might borrow their clean grid plotting and precise dimensioned profile linework as a restrained technical graphic style.
