We present a new system for the generation of rapid, strong flow perturbations in the aerodynamicwind tunnel at École Centrale de Nantes. The system is called the chopper, and it consists of a rotating bar cuttingthrough the inlet of a wind tunnel test section, thus generating an inverse gust that travels downstream. Theflow generated by the chopper is investigated with respect to the rotational frequency using an array equippedwith hot-wires that is traversed downstream in the flow field. It is found that the gust can be described as asuperposition of the mean gust velocity, an underlying gust shape, and additional turbulence. Following thisapproach, the evolution of the mean gust velocity and turbulence intensity are presented, and the evolution ofthe underlying inverse gust shape is explained. The turbulence is shown to be characterized by an integral lengthscale of approximately half the chopper blade width and a turbulence decay according to E(f ) ∝ f −5/3.