减速板对水平尾翼的干扰研究

在ＮＨ－２风洞中对某机放减速板产生较大抬头力矩的机理进行了研究，通过减速板分离涡场的测量和测力试验表明，抬头力矩主要是由减速板分离涡在平尾处产生在的诱导下洗角所致，诱导下洗角涡机身轴线向后逐渐减小，减速板前移可以消除抬头力矩。保持原减速板位置不动时，减速板开孔减小涡强度可以减小抬头力矩，选择适当的减速板开孔率和开孔位置能使抬头力矩减小到可以接受的程度并且保持具有足够的阻力。

On the Research of Interactions of Drag Plate the Tail

The principle of the increase of the nose up pitching moment by opening the drag plate for an airplane has been studied in NH 2 wind tunnel. The measurements of the separated vortex field and forces for drag plate show that the nose up pitching moment is produced due to the large induced downwash angle from the separated vortices of drag plate at the tail. The induced downwash angle is reduced asymptotically along the axis of fuselage. The nose up pitching can be eliminated by moving drag plate forword to suitable location. If the location of drag plate is kept still, making use of the porous drag plate can reduce the vorticity and the nose up pitching moment. The nose up pitching moment can be reduced to acceptable level and enough drag can be kept by the selection of suitable porosity and location of drag plate.