Abstract: In a mounting structure for mounting a propulsion unit in a fuselage of a model airplane, the propulsion unit having a motor with a fan which motor is fixed to a generally cylindrical cowl by support columns, the cowl at the opening facing the motor has a radial flange extending to the outside of the cowl, a cylindrical sleeve is provided which is inserted in the opening of the cowl, the sleeve also having a radial flange directed to the outside, and wherein between the flange of the cowl and the flange of the sleeve a gap is formed for receiving a round-frame rib of the airplane body for connecting the propulsion unit and the airplane body.