EXPERIMENTAL RESEARCH OF THE CONFIGURATION OF WING－TIP DRAG REDUCTION FOR LIGHT AIRCRAFT

hree kinds of devices of drag reduction are presented swept wingtip,stage by stage swept wingtip and downbend wingtip. The effects of changing geometryparameters of the swept wingtip on the drag reducing are also presented. Wind-tunnelexperiment results indicate that a properly designed swept wingtip results in an incre-ment in induced efficiency of 4%～ 7% and that swept wingtip can increase longitudinalstatic-stability. Water-tunnel experiment results indicate that the reason for drag re-ducing of swept wingtip is that when the angle of attack is not zero, the strong end vor-tex of the wing is weakened by the combined effect of the leading edge and trailing edgevortices of the swept wingtip.

轻型飞机翼梢减阻外形的风洞实验研究

介绍了三种翼梢减阻装置：后掠翼梢、分段后掠机翼和下弯翼梢。重点给出改变后掠翼梢的几何参数对减阻效果的影响。风洞实验表明，经优化设计的后掠翼梢可使诱导效率ｅ提高４％～７％。后掠翼梢使飞机纵向静稳定性增大。水洞实验表明，后掠翼梢减阻的原因主要是在有迎角时，翼梢前缘涡和后缘涡共问作用削弱了翼梢涡，从而减小了飞机的诱导阻力。