What is the main reason why airplanes can fly in the sky?

With the rapid development of life technology, our travel mode has undergone drastic changes, from the beginning of the bicycle and motorcycle, to the current car, high-speed rail planes, etc., it is not an exaggeration to say that the world has been turned upside down.

In fact, airplanes mainly rely on four forces to fly in the sky, which are lift, gravity, thrust and drag. Oh my God, the force that keeps us on Earth is gravity, also known as gravity.

It is the force of attraction between objects that have mass. Will the plane also be subject to gravity? Of course, all objects on Earth are attracted to the Earth. So, everybody has gravity. Everyone has gravity, so why can't I fly when the plane can fly?

This is related to the other three forces, the most relevant of which is lift, which is the force that makes the plane rise. Actually, it's the air near the plane that lifts the plane. The wing of the aircraft.

Isn't it like wings, this special shape of the wing makes the plane start to move. The pressure produced by the air below is greater than the pressure produced by the air above. In this way, the lift force is formed.

And the faster the plane, the more lift the air generates. So, when the plane is taxiing on the runway, as long as it reaches a certain speed, it will definitely be able to fly.

You can recall that when you take off the plane, at the moment when the plane takes off, it is not necessary to produce a very fast speed, and the ears will be uncomfortable, this is because the plane has to rely on thrust to produce a very fast speed to fly, it must be the thrust of the aircraft given by the engine, the engine of the aircraft is much more powerful than that of the car, their power is greater, and the technology used is also different. For example, sometimes jet engines are used in airplanes.

It can propel an airplane forward by spraying high-velocity gas.

The last force is drag, and resistance is the force you encounter as you move forward in the air that makes you retreat. Is the force of retreat the force of pulling back legs? Because when you move forward in the air, you hit gas molecules, and they will stop you from moving forward, just like going backwards in **.

The plane must have encountered a lot of resistance when it was going so fast. Therefore, one of the main tasks of aeronautical engineers is to design something that can reduce air resistance.

of the aircraft.

The first main reason is that the airplane has a unique flying device, and the second reason is that the airplane has a balance system, so it can fly around in the sky, which is the research when making the airplane, and the main process is to fly like a bird, which is mainly to study the balance of the bird.

The main reason why an airplane can fly in the sky is that the engine jet propels the aircraft, and under the propulsion of the engine, it relies on the physical principle of relative speed, so that the aircraft can fly into the sky.

Airplanes are able to fly in the sky because their own engines generate kinetic energy, which then generates lift through the wings, so that they can fly in the sky.

Mainly because the wings of the aircraft, propelled by the engine, can generate lift and fly.

Airplanes are heavier-than-air aircraft, so they need to expend their own power to gain lift. And the ** of lift is the effect of air on the wing in flight.

The upper surface of the wing is curved and the lower surface is flat, so when the wing is in relative motion to the air, the air flowing through the upper surface travels a distance (s1) in the same time (t) than the air flowing through the lower surface (s2), so the relative velocity of the air on the upper surface is faster than the air on the lower surface (v1 = s1 t> v2 = s2 t1). According to Panulli's theorem – "The pressure exerted by a fluid on the surrounding matter is inversely proportional to the relative velocity of the fluid." ", so the air on the upper surface exerts pressure on the wing.

f1 is smaller than the lower surface.

f2f1、f2

The resultant force must be upward, which creates a lifting force.

From the principle of the wing, we can also understand how the propeller works. The propeller is like a vertical wing, with the bump facing forward and the smooth facing backward. The resultant force of the pressure as it rotates forward, pushing the propeller forward, thus driving the aircraft forward.

Of course, the propeller is not simply raised and smooth, but has a complex curved surface structure. Older propellers were fixed shapes, while later designs were designed with relative angles that could be changed to improve propeller performance.

Flying requires power to move the aircraft forward, and more importantly, for the aircraft to gain lift. Early airplanes were usually powered by piston engines, and four-stroke piston engines were the mainstay. The principle of this type of engine is shown in the figure, which is mainly to inhale air, ignite and expand after mixing with fuel, drive the piston to reciprocate, and then convert it into the rotary output of the drive shaft

The plane is big and heavy, what does it fly in the sky on? Is it the same as we think?

Why can the machine fly? Despite the fit of the individual components, the main thing is that the aircraft has a pair of wings with a special cross-sectional shape.

Wing profiles are also known as airfoils. A typical airfoil is convex at the top and flat at the bottom, and is often referred to as streamlined. According to the continuity of the fluid and Bernoulli's theorem, the air flow through the upper surface is squeezed compared to the air far ahead, and the flow velocity accelerates and the pressure decreases, and even suction (negative pressure) is formed, and the flow velocity of the air flowing through the lower surface slows down.

As a result, a pressure difference is formed between the upper and lower wing surfaces. This pressure difference is aerodynamic. According to the law of force decomposition, it is broken down along the direction of flight into upward lift and backward resistance.

The drag is overcome by the thrust provided by the engine. The lift is just enough to overcome its own gravity and lift the aircraft into the air. That's why airplanes fly.