Abstract: A deflector for reducing swirling flow spillover occurring when gas flowing hrough curved ducting attempts to exit into a freestream flow. When a gas flows through curved ducting it develops a swirling motion and when it attempts to exit into a freestream it is forced down over the sides of the duct by the strong freestream flow rushing past. The deflector is arcuately shaped and positioned upstream and adjacent the exit end of the curved ducting. As the freestream flow travels over the surface of the deflector, it is turned toward the direction of the flow from the exit of the ducting and draws the exiting flow along with it. The drawn exit flow is straightened and strengthened and is able to penetrate into the freestream flow. Further the ends of the deflector generate vortices which draw along the swirling flow at the sides of the exit end and straighten and strengthen it also. Thus the problem of swirling flow spillover of a gas exiting curved ducting into a freestream flow is substantially eliminated.