摘要
静稳定的固定翼飞机纵向稳定性与飞行性能对飞机布局的要求往往相矛盾,这个矛盾对飞翼布局飞机的影响尤其显著,这导致飞翼布局的飞行性能一定程度上被降低。针对这个问题,提出了采用螺旋桨动力参与纵向配平的飞翼布局无人机。提出的飞翼布局无人机使用正弯度翼型改善升阻特性,利用外洗和螺旋桨动力实现无人机纵向配平。利用CMARC面元法和粘性阻力修正进行气动力计算和稳定性分析,在失速范围内,其计算结果与风洞实验结果吻合较好。研究了动力系统螺旋桨和电机的匹配,同时考虑到不同任务段功率需求不同,建立了动力系统效率计算模型并融入到总体设计中。基于遗传算法对有无动力配平的飞翼布局无人机总体参数进行了优化,优化结果表明:采用螺旋桨动力配平可以部分地替代升降副翼进行纵向配平,一方面提升了无人机最大可用升力系数,增大了无人机翼载荷,在保持翼展固定的条件下增大了无人机展弦比,另一方面减小采用正弯度翼型飞翼布局无人机的后掠角和外洗,改善无人机展向升力分布,二者共同作用下提高无人机升阻比,提升了无人机的航时。最后探讨了总体参数对螺旋桨动力配平布局无人机性能的影响,为此类无人机设计提供了一定的指导意义。
The existing aircraft configuration cannot satisfy the requirements for the longitudinal stability and flight performance of a static and stable fixed-wing aircraft. This is especially true for a flying wing aircraft, whose flight performance deteriorates in maintaining its static stability. Hence, we propose a new aerodynamic configuration that uses the propeller thrust to trim longitudinally the flying wing of an unmanned aerial vehicle （ UAV） . In the config-uration, the positive cambered airfoil is used to replace the conventional reflex cambered airfoil so as to raise the lift to drag ratio and lift of the UAV, which is longitudinally trimmed by wash-out and propeller thrust. We use the commercial software CMARC and empirical formulate to calculate the aerodynamic force of the UAV and analyse its stability. During its stall, the calculation results are in good agreement with the wind tunnel experimental results. We also study the matching between the propeller of the UAV and its motor and establish the mathematical model to calculate the efficiency of its power system and merge it into the overall design by taking into account the difference in power at different mission stages. We use the genetic algorithm to optimize the overall parameters of the flying wing UAV trimmed and not trimmed with propeller thrust. The optimization results, given in Table 1 and Fig. 9, show preliminarily that：（1） the amounts of wash-out and sweepback of the UAV longitudinally trimmed with pro-peller thrust are reduced and its coefficient of maximum lift available and wing loading increase, thereby reducing the wing area;this leads to a larger aspect ratio when the wingspan is kept constant;（2） because of few elevon de-flections and reduced wash-out, the lift to drag ratio increases during cruise and loitering. Finally, we study the effects of overall parameters on the performance of the UAV trimmed with propeller thrust.
出处
《西北工业大学学报》
EI
CAS
CSCD
北大核心
2014年第2期181-187,共7页
Journal of Northwestern Polytechnical University
关键词
动力配平
飞翼布局
电动无人机
总体参数设计
遗传算法
aerodynamics, aircraft, airfoils, design,lift, lift drag ratio, mathematical models,efficiency, fixed wings, genetic algorithms,optimization, stability, wings, unmanned experiments,aerial vehicles（ UAV）, wind tunnels, aspect ratio
propeller thrust trimming, flying wing, configuration parameter
作者简介
王刚（1988-），西北工业大学博士研究生，主要从事无人机总体设计研究。
