The running condition would be deteriorated and at last the parts of the engine would be damaged if the revolution were reduced too low . the propeller must be redesigned or be modified in this situation . people usually modify the propeller rather than change the propeller because it will be more easily and economical 此时若要更换新的螺旋桨必然造成经济上过重的负担，较方便可行的方法是对原来的螺旋桨采取切边修改的方法，减少螺旋桨的直径、盘面积或螺距，使螺旋桨的扭矩减小，螺桨变“轻” 。
