The invention refers to a full-flow rocket nozzle having a longitudinal contour essentially corresponding to a parabola. For obtaining a flow separation control and also a side load reduction the invention suggests that the parabola contour shape from the point of 50% expansion ratio onwards or more distant from the throat of the nozzle is changing over into (i) strictly conical shape having an angle to the center line of between 15° and 25°, (ii) a slight outward curvature, i.e. implying a contour shape with positive 2nd derivative of the radius r, or (iii) a slight inward curvature, i.e. with a negative 2nd derivative of r but lying externally of the parabola contour, in the last case the 3rd derivative of r being constantly equal to zero (0).