无人机气动特性改进及风洞试验研究

为延长某无人机的留空时间，加大航程和提高升限，用适当加大机翼展弦比和加装翼尖小翼的办法对原型机的气动特性进行了改进，以期能使该无人机的升阻比有较大提高。在工程估算的基础上，对改进后的气动特性和几十种翼尖小翼的组合方案进行了风洞试验研究和优化分析，得出了可供该无人机使用的气动特性改进的最佳方案。风洞试验结果表明：和原型机相比，改型机的最大升阻比可提高20．6％。

Wind tunnel experimental research on aerodynamic improvement of UAV

The modification requirements of a certain type UAV are ceiling increment,range enlargement and endurance extension. To match these needs,a bigger wing aspect ratio and winglet are adopted as the improvement measures,hopefully the lift-drag ratio of the modified UAV could be increased. Based upon the engineering estimation, tens winglet schemes ( different combinations of winglet height, chord, bank angle, leading edge sweep angle and installation angle) are investigated in the wind tunnel,global optimization analyses of the experimental results are conducted,finally the optimal aerodynamic improvement scheme available for modified UAV is decided. The wind tunnel test results show that the longitudinal static stability change of the whole aircraft is minor, but the directional static stability of the whole aircraft decreases a lot. To restore the directional static stability of the whole aircraft to original level of the UAV prototype, test results show that the simple and easiest way is to enlarge the height of the vertical tailplane. Comparing with original UAV finally,the experimental results show that the maximum lift-drag ratio of the modified UAV increases by 20.6%.