An assessment of upper surface blowing for the reduction of tilt rotor download

A study evaluating the use of upper-surface blowing to reduce the wing download on a V-22 tilt rotor aircraft has been completed. The study assesses the penalties associated with the upper-surface blowing system (compressor weight, compressor power, etc.), and the reduction in wing download, for a wide range of blowing slot heights and blowing pressure ratios. Three wing configurations were investigated: blowing at both leading and trailing edges with no change in wing planform relative to the V-22 tilt rotor aircraft, blowing at both leading and trailing edges with a 25% reduction in wing chord, and blowing at the leading edge only with the flap deflected 75 deg. Predicted download is presented for all of these configurations, and is compared with the download of the baseline V-22 tilt rotor aircraft configuration. The optimum configuration had 15% less net download than the baseline V-22 configuration.