Experimental Studies of a 70-Degree Delta Wing with Vortex Flaps

Force, surface pressure, and e owe eld measurements were made on a 0.5-m root chord, 70-deg delta wing model with leading-edge vortex e aps at the National Aerospace Laboratory, Japan. The main objective of the experiment is to investigate the effect of the wing sweepback angle upon the vortex e ap performance. Improvements in the lift/drag ratio were observed in a 70-deg delta wing by dee ecting the tapered vortex e aps. Comparisons between the previously measured 60-deg delta wing results and the present results were made. The improvements in the lift/drag ratio of the 70-deg delta wing were attained over a narrower lift coefe cient range than for the 60-deg delta wing. The results also showed that the maximum lift/drag ratio for the 70-deg delta wing is attained when the spanwise length of the separated region formed on the vortex e ap surface almost coincides with the e ap span.