drag index

例句：

1. 1. The drag index of this model is very low, which means it has excellent performance.
   这个模型的拖曳指数非常低，意味着它性能卓越。
2. 2. In the study of aerodynamics, the drag index is an important factor to consider.
   在空气动力学研究中，拖曳指数是一个需要考虑的重要因素。
3. 3. The drag index of the aircraft was calculated based on its weight and size.
   根据飞机的重量和尺寸计算了飞机的拖曳指数。