Aerodynamic Development of a Forebody Strake for the V-22 Osprey

During flight testing of the V-22 Osprey tiltrotor aircraft, higher-than-expected buffet loads were measured on the empennage during wind-up turns as Mach number increased. This paper describes the water tunnel and wind tunnel investigations that were conducted in conjunction with CFD analysis to uncover the source of the buffet and to develop a solution. The solution was a set of forebody strakes positioned on top of the cabin aft of the cockpit and in front of the wing that reduced the buffet loads through the operating angle-of-attack range. Flight test results are presented that confirm that, up to the Mach numbers tested to date, the forebody strakes are as effective at full scale as in the wind tunnel.