氢气球、飞艇等是比空气轻的航空器,它们的飞行原理可以用浮力来解释,这就像木材、泡沫塑料等比水密度小的物体可以浮在水面上一样。鸟和飞机重于空气,鸟靠翅膀不断扑动产生升力来支持它身体的重量而能在天空中自由飞翔,可是飞机的翅膀——机翼,在飞行的时候是静止不动的。那么,它是怎么产生升力的呢?这要从我们身边的空气谈起。 Hydrogen balloons, airships, etc. are lighter than air and their principles of flight can be explained by buoyancy, just as wood, foam, and the like can float on water less than water. Birds and planes are heavier than air. Birds fly by their wings to generate lift to support the weight of their bodies and fly freely in the sky, but the wings of the aircraft, the wings, are stationary while flying. So how does it generate lift? It’s about the air around us.