Abstract: A mixing nozzle for an aircraft turbine engine having an improved aerodynamic stiffening ring secured to the lobes of the mixer. Aircraft turbine engines having a rearwardly discharging nozzle are often provided with a mixer having a generally circular forward end adapted to be attached to an engine and axially deepening corrugations leading to a multi-lobed aft end surrounding the nozzle. This mixer mixes ambient cool air with the hot gases exiting the engine thus suppressing engine sound. The lobes are generally unsupported and subject to vibration and excessive deflections in use. A circumferential stiffening ring is secured to the aft end of the mixer to reduce or prevent the vibration while simultaneously enhancing the mixing of cool ambient air with the hot engine exhaust. The stiffening ring preferably has an airfoil cross-section for lowest drag combined with the ability to direct flow past the ring in a selected optimum direction.