Method for determining the performance of at least one downstream propeller of a turbomachine placed behind an upstream propeller of the same axis creating for said downstream propeller an incident air stream under gyration comprising an axial component (V z) and a tangential component (V θ), said downstream propeller being modeled by a generalized theoretical model (M g) defined, for a plurality of angles of pitch (β) of the propeller, by a set of non-dimensional coefficients including at least one generalized progress coefficient (J g), a generalized power coefficient (CP g) and a generalized traction coefficient (CT g) defined by the following formulas: { J g = ν z u − ν θ C Tg β = T β ρ ⋅ u − ν θ 2 ⋅ D 2 C Pg β = P β ρ ⋅ u − ν θ 3 ⋅ D 2 formulas wherein: - u corresponds to the speed of entrainment of said downstream propeller, - V z corresponds to the axial component of the speed of the incident air stream; - V θ corresponds to the tangential component of the incident air stream, counted positively in the direction of the speed of entrainment u; - ρ corresponds to the density of the air, - D corresponds to the diameter of said downstream propeller; - T corresponds to the traction of said downstream propeller; - P corresponds to the power said downstream propeller; - β corresponds to the angle of pitch of said downstream propeller; method, wherein: - parameterizing, with a physical calculator, the generalized theoretical model (M g) of said downstream propeller with input conditions of the turbomachine including at least the axial component (Vz), the tangential component of the speed of the incident air stream (V θ), the angle of pitch (β) and the drive speed (u) of said downstream propeller; and - deducing from the parameterized generalized theoretical model (M g) with the physical calculator, at least the performance in traction and in power of said downstream propeller; - adjusting, with the physical calculator, the angle of pitch of the upstream propeller or of the downstream propeller, based on at least the deduced performance in traction and in power of said downstream propeller. - u corresponds to the speed of entrainment of said downstream propeller, - V z corresponds to the axial component of the speed of the incident air stream; - V θ corresponds to the tangential component of the incident air stream, counted positively in the direction of the speed of entrainment u; - ρ corresponds to the density of the air, - D corresponds to the diameter of said downstream propeller; - T corresponds to the traction of said downstream propeller; - P corresponds to the power said downstream propeller; - β corresponds to the angle of pitch of said downstream propeller; - parameterizing, with a physical calculator, the generalized theoretical model (M g) of said downstream propeller with input conditions of the turbomachine including at least the axial component (Vz), the tangential component of the speed of the incident air stream (V θ), the angle of pitch (β) and the drive speed (u) of said downstream propeller; and - deducing from the parameterized generalized theoretical model (M g) with the physical calculator, at least the performance in traction and in power of said downstream propeller; - adjusting, with the physical calculator, the angle of pitch of the upstream propeller or of the downstream propeller, based on at least the deduced performance in traction and in power of said downstream propeller.