The paper presents an investigation on the dynamic equilibrium of a pneumatic motor vane. The investigation was based on an analysis of the vane's free body diagram. In particular, a model was formulated for determining the contact forces between vane, rotor and stator and the contact configuration from the known motor geometry, friction coefficients and chamber pressures. In addition, the paper presents experimental measurements of friction coefficients in vane-rotor and vane-stator contact together with a validation of the model through comparison with a FEM model.