Pressure measurements on twin vertical tails in buffeting flow

Buffeting pressures were measured on the vertical tail surfaces of a 13% F-15 model in a low-speed wind tunnel. Test variables included dynamic pressure, aircraft angle of attack, vertical tail incidence, and rudder deflection. Pressure transducers were flush mounted on rigid and flexible tails. Steady and unsteady pressures were obtained from the transducers at levels as low as 0.1% full scale. The steady pressures were integrated for aerodynamic coefficients and the unsteady pressures were reduced to spectral densities. The pressures are maximum at approximately 22 deg angle of attack and are significantly affected by tail flexibility.