This report describes tests made on a flutter model in the Materiel Division wind tunnel. The object of this report is to report the results of these tests carried out in the 5-foot wind tunnel in order to obtain comprehensive experimental data regarding some of the fundamental factors involved in the flutter of airplane control surfaces. The particular flutter modes studied were those in which oscillations of the rudder interacted with torsional oscillations of the fuselage or bending oscillations of the fin. The model was designed so that comprehensive experimental data could be obtained regarding some of the fundamental factors involved in the flutter of airplane control surfaces. It was found that this model offered an excellent means for studying flutter phenomena.