Abstract: A spray gun including a turbine mechanism for reducing the turbulence of fanning air to more effectively control the shaping of a conical spray pattern. A spiral flow of fanning air is created by the turbine mechanism. The amount of pressurized air flowing through the turbine mechanism is controlled by a valve mechanism to provide a greater or lesser amount of fanning air. The improved spray gun is particularly useful in paint spray systems wherein air having a flow rate in excess of 5 CFM and a delivery pressure of less than 15 psi over atmospheric is communicated to the spray head of the spray gun. In one embodiment, the turbine and valve mechanisms include first and second sets of circumferentially-spaced inclined vanes, respectively, which cooperate to create the spiral flow of air. The valve mechanism includes an annular valve member which supports the second set of vanes. The turbine mechanism includes a turbine member which supports the first set of vanes.