Full-scale Wind-tunnel and Flight Test of a Fairchild 22 Airplane Equipped with a Zap Flap and Zap Ailerons (1937)
NASA Technical Reports Server (NTRS) · leaf 24
Figure 11.- Scale effect on the minimum drag coefficient of the Fairchild 22 airplane with flaps up. Propeller and horizontal tail surfaces removed; results corrected for wind-tunnel effects.
NASA Technical Reports Server (NTRS)
Internet Archive · NASA Technical Reports · Public domain (US government work). Free to use for anything.