# Lifting capacity of the aircraft

**lifting capacity**- One component of the total aerodynamic force that is perpendicular to the velocity vector of body motion in the flow of liquid or gas, the resulting asymmetry of the flow stream of the body.

Bernoulli empirically found that the static pressure in the flow of liquid or gas flow rate inversely at this point, which means that at the points where the flow rate the higher the pressure - below. In practice, it is easier to understand this expression as an example: when at the entrance to the escalator great pandemonium of people formed at the metro station, there is a crush (front of an escalator), and when you walk on the escalator and begin to climb, then on stage is worth a maximum of 2 man and the speed of your movement above, and m. n. "Overcrowded" (pressure) below.

So "the fluid" in the tube of variable cross section also acts. And now, you can imagine in your head that this pipe was "turned" and laid out on the 2 surface, like the wing of an airplane. One of them (the upper one) has a large curvature (convexity), and the lower one has a smaller convexity (practically equal). Thus, according to the equation of the continuity of the stream of a liquid (or gas) stream, an already understandable physical phenomenon is the difference in pressure on the upper and lower parts of the wing. We get that on the lower surface the flow velocity is lower and the static pressure is higher, and on the upper part the static pressure is lower (because the flow velocity is higher, because of the geometric difference in lengths). This is a simple explanation for the wing of the classical profile and infinitely large scope.

### Calculation of wing lift.Zhukovsky theorem on lift force.

In the life of a wing to make unrealistic. Therefore, we apply the mathematical properties to solve this problem: the final scope, the normal vector to the profile, the profile of the boundary, the magnitude of the pressure, we obtain the following expression:

## Lifting capacity of the aircraft wing

People who start their acquaintance with aviation or it may continue to have mature question, again all all knew, were outstanding and the opening of minds, but the plane was able to fly only 1903 year, what's the deal? And here's the thing: it could make its maiden flight before, but for a long time, scientists were confused how to calculate the lift and what should be the wing of the aircraft, its length?

According to classical physics of Newton and in accordance with the laws of the lift it is proportional to the angle of attack in the second degree, which led to the conclusion that it is impossible to make a small wing span with good load-bearing characteristics. We can imagine the usual parabola, y = x^{2 }and we see that, for example, to lift equal to 2 need to reach an angle of attack in 4, and for a good flight and need to lift in 4, 5, 6 ... sometimes difficult to calculate attack angleAnd if he still will be in the critical zone ...

This confusion continued until the end of the century, 19, already Bernoulli only after many experiments and many other scientists, it was found that this dependence - (!) Straightforward and is already based on these findings could build a small wing span with sufficient lifting power. The first did the Wright brothers.

Avia.pro