Investigation of Aerodynamic Stall Alleviation on a Swept Planform Wing Using Leading Edge Modifications
Final rept. 10 Apr 1980-5 Jan 1981
MICHIGAN UNIV ANN ARBOR AIRCRAFT RESEARCH LAB
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A wind tunnel investigation was conducted to determine the effect of leading edge modifications on the stall characteristics of a swept planform wing. The modifications consisted of openings in the leading edge which generated a vortex pattern over the wing surface. The forcemoment results showed that a 33 percent increase in stall angle of attack could be achieved with the leading edge modifications. A maximum lift coefficient comparable to that of the baseline wing was also achieved with the modifications. Evidence of interference between the modification-generated flow field and the wind tunnel upper surface indicated that these high angle of attack results are a conservative evaluation of the modifications lift enhancement potential. The nose up pitching moment at stall was moderated by the leading edge modifications and no increase in drag occurred below 19 degrees angle of attack. Preliminary flow visualization results indicate that these forcemoment characteristics associated with the leading edge modifications are caused by vortices formed on each side of the modification opening. The test results indicate that the leading edge modifications have the potential for increasing the maneuvering capability and stall margin of airplane flight operations.
- Fluid Mechanics