Heavier than air, how can they fly?

Abstract

Advancing our knowledge of the atmosphere was not done by just observing it from the ground: it had to be crisscrossed and probed with the appropriate vehicles, such as the planes or weather balloons used by the meteorological authorities. The observation of birds and insects proved that it was indeed possible to make ponderous objects fly, without having them fall like rocks. That said, since the dream of Icarus and the first attempts of Leonardo da Vinci, what efforts were not required to first understand how an object heavier than air could fly and then to construct the marvels of technology that are modern airplanes? Let us first focus on analyzing the origin of this force called lift, which seems capable of vanquishing weight. Next, because we shall discuss airplanes, helicopters, and wind turbines, we will also attempt to explain the origin of one of their major drawbacks: the sometimes deafening noise that they emit. Finally, we shall try to understand how and why the diffuse noise from a flying airplane can generate such deafening shockwaves when it flies at supersonic speeds, which will bring us to question the reality of the sound barrier, which is often evoked by pilots.

The wings quivered under the evening breeze With its song the engine rocked the sleeping soul The Sun brushed us with its pale color.

(Antoine de Saint Exupéry, Wind, Sand, and Starts)