Flutter induced by aerodynamic interference between wing and tail

Several authors have mentioned that aerodynamic interference between horizontal tail and wing could cause flutter. The unsteady aerodynamic forces pose the problem in analysis and have become available only recently. Naturally, the importance of interaction between two lifting-surface increases when both spans are of comparable magnitude. Several advanced aircraft feature this concept. A flutter analysis based on a variable-geometry airplane at highly swept condition is performed. The unsteady loads resulting from aerodynamic interference are introduced. They were determined with a lifting-surf ace method previously formulated by the coauthor. Destructive flutter was discovered resulting entirely from interference not predictable by applying conventional three-dimensional coefficients for the separate surfaces only. This verified a flutter case of a preceding experiment. The investigation is extended to include different vertical and aft positions of the horizontal tail at several Mach numbers to obtain an understanding of dominating influences.