四发螺旋桨滑流对某运输机气动特性的影响研究

四发螺旋桨飞机滑流影响区较大,需要准确获得滑流引起的升力、阻力和俯仰力矩特性的变化以评估飞机的飞行性能和品质.采用动力模拟风洞实验研究某运输机在滑流影响下的气动力特性,包括升阻特性、俯仰力矩特性和升降舵效率,并采用七孔探针技术测量平尾区的尾流场特性.结果表明:滑流对气流加速的效应使得飞机的升力、阻力均有增加,升阻比在典型巡航和爬升状态下分别降低了6％和20％;滑流随迎角的增加从下至上扫掠过平尾,使得俯仰力矩和升降舵效率出现明显的非线性变化.

The research of the aerodynamic characteristics of a transport aircraft with slipstream effect of four turbo-propeller engines

The slipstream of the aircraft with four turbo propellers affects large area around the aircraft, and the induced variation of lift, drag, and pitching moment must be accurately measured to evaluate flight performance and quality. The aerodynamic force of the aircraft with slipstream effect is investigated quantitatively by powered wind tunnel tests, including the lift, drag, pitching moment and elevator efficiency characteristics. The wake flow field is measured by seven hole probe technique. The research reveals that the lift and drag are increased due to the high speed slipstream, and the lift to drag ratio is reduced by 6% and 20% at typical cruise and climb condition respectively. The wake flow tests reveal that the slipstream sweeps from below the horizontal tail to above it with higher AOA(angle of attack), which causes the strongly non linear variation of pitching moment and elevator efficiency.