Wind-tunnel investigation of an NACA 23012 airfoil with a slotted flap and three types of auxiliary flap

Wenzinger, Carl J Gauvain, Willikam E
naca-report-679
1939

A test installation was used in which an airfoil of 7-foot span was mounted vertically between the upper and the lower sides of the closed test section so that two-dimensional flow was approximated.

An Adobe Acrobat (PDF) file of the entire report:
http://naca.central.cranfield.ac.uk/reports/1939/naca-report-679.pdf