An experimental study of the interaction between two airfoils, corresponding to a T-tail aircraft configuration, is implemented in a wind tunnel for a range of medium Reynolds numbers. Measurement of aerodynamic forces is carried out by strain gauges and the velocity field is obtained by particle image velocimetry. The study focuses on large angles-of-attack configurations, corresponding to detached flows on the airfoils and the presence of a downstream vortex shedding. Phase averages of the velocity fields are made building the flow time development. A lift modulation depending on geometric parameters and resulting from different pathlines of the shedding vortices, is discussed.