Most passengers who use air transport to travel have fears associated with aircraft takeoff. Today we will finally dispel these fears.

I started writing this article because of a message from one of the readers, who provided me with a link to several airliner takeoffs from Kurumoch Airport, which is in the city of Samara. In the videos I received, a very curious passenger was filming from the plane.

Now we will try to figure it out!

Experienced passengers who travel by air quite often know about the old tradition that was introduced when flying on domestic aircraft. Before taking off, entering the take-off runway, the plane would stop for a few minutes, as if the pilots were giving the passengers the opportunity to pray. At the same time, the pilots of the airliner also prayed, as they called this time, during which they studied the flight map and determined control points along the route. After this time, the plane actively rushed along the runway, while there was a roar and the entire apparatus was felt trembling. At this moment, whether you like it or not, you will begin to be baptized. After this, the pilots released the brakes, which further pressed passengers into their seats and created horror. With all this, shelves with luggage often began to come off, and something fell from the flight attendants.

How the plane takes off, video from the cockpit.

During lift-off it becomes a little quieter and calmer, but after lift-off the plane gradually begins to fall down!

Nevertheless, the pilots manage to level the device; the engines may also fail a couple of times when gaining the required altitude, and only then everything becomes normal. Flight attendants with indifferent faces offer drinks, and those who pray poorly are offered an oxygen mask. But only then comes the moment for which passengers use air transport - food is distributed.

Looks like you've indicated everything? This is exactly the impression a person should get after reading reviews on non-core forums.

We need to figure it out.

As they say, let’s dot all the i’s about the reasons for the plane stopping on the runway before takeoff. Is this moment necessary before takeoff or is it a quirk of the pilots?

In this case, it must be said that both take-off options are correct. Modern take-off training states that stopping before take-off is optional, but can be done if absolutely necessary. Such needs may be:

• When the controller is thinking, release the plane or hold it a little for the purpose of takeoff safety.
• With limited runway length.

The first reason, I think, is clear to everyone.

As for the second reason, with the limited length of the take-off surface, a stop is necessary in case the aircraft is overloaded. The mass may be just right for taking off from such a length. To do this, every meter of lane is saved, and stopping allows the engine speed to be increased to higher operating modes, while the car is held on to the brakes. Very often, this procedure is carried out even by pilots on light aircraft, as they say, just in case.

Also, such a separation is possible in difficult geographical conditions, for example, takeoff from Chambery. It is necessary to stop and accelerate the engines, which will help to quickly break away from the runway, since a mountain range begins behind its end. In addition, almost all devices are heavy.

However, in most cases, with the permission of the dispatcher and the normal length of the lane, the stop is not carried out. After the taxiway, the airliners do not stop, but immediately begin their takeoff run; after making sure that they are moving in a straight line, the pilots will only add engine speed.
Stop!
But what to do with prayer? After all, at first it was about some checking of control points and studying the flight map.

It is customary not to read out the B737 until you receive permission from the controller to occupy the runway, and even more so before you receive permission to take off. That is why, when I receive both the runway clearance and the takeoff clearance, I am absolutely ready to take off. It only seems to passengers that I am in a hurry, but this is not at all the case, since I am already ready.

There are also advantages to taking off without stopping:

• First of all, taking off without stopping allows the airport to increase its aircraft capacity. This can be explained very easily: the less time the plane spends on the runway, the more airliners the airport can send or receive.
• Also, taking off without stopping allows you to save fuel, since the engines do not stop and accelerate, which burns a lot of fuel.
• The third advantage is security, at first glance you might think that this is a strange advantage. Still, the less time an aircraft with working engines spends on the runway, the less likely it is that foreign objects will enter the turbines, which can lead to surge and engine failure.

Let's fly further!

Why do pilots lift up the nose of the car so much during takeoff? When taking off domestic equipment, this process was done slowly and more smoothly... Such a takeoff can lead to an accident!

The reason for this is simple aerodynamics and the implementation of take-off technology. Foreign-made aircraft generally weakly deflect the entire wing mechanism during takeoff. In turn, this provides the following advantages:

• The angle of climb becomes larger.
• Due to the large lift-off angle, the noise effect in the surrounding area is significantly reduced.
• It also allows you to encounter obstacles if one of the engines fails.

Modern passenger airliners have very powerful engines that even if one of them fails, a safe landing can be made. Nevertheless, in some situations it is recommended to turn on the full thrust of the engines; if the vehicle is lightly loaded, this can turn it into a rocket.

The maximum thrust of the engines provides some discomfort to passengers in the cabin, of course, this is the case when you don’t particularly like to fly with your legs up. But this situation during takeoff does not last long.

“Almost fell after takeoff”

Above in the article I wrote that after liftoff and takeoff, the plane seems to begin to fall down. This situation is very noticeable when flying on a Tu-154 type aircraft; it takes off quite heavily at a large opening angle of the flaps, after which they become in a state of horizontal flight. When the flap position changes, a decrease in altitude is felt as the nose of the car lowers. It should be noted that if the flaps are closed very quickly, the plane can actually lose altitude, but for this you need to be a completely inexperienced pilot, especially since there are two of them in the cockpit.

Also, the feeling of the aircraft stalling is noticeable when changing the climb angle to a flatter one, but these are only sensations; in reality, the plane is controlled and does not fall.

“During the flight, the engine turbines were turned off several times”

It is precisely situations like these that airplane passengers write about most often. These statements can only compete for primacy with stories about how pilots were able to land the plane on the runway only on the fifth attempt. Most of these stories are about airliners such as Tu-134 or Tu-154. In fact, the engines are located in the rear part of the vehicle and are practically inaudible in the passenger compartment, except in situations where they operate at maximum speed.

It is in the noise from the engines that the problem with the supposed “engine shutdown” is hidden. In fact, everything is very simple and clear. During takeoff and climb, aircraft engines actually operate at high speeds, which is accompanied by a high-pitched sound effect. Often, pilots receive commands from air traffic controllers to stop raising their aircraft in order to avoid other aircraft in the air. At the same time, the airliner is transferred to horizontal flight mode; in order not to become a supersonic aircraft, it is necessary to reduce the engine thrust. At the same time, the noise level in the aircraft cabin is reduced, due to this passengers think that the engines are turned off.

Often, watching a plane flying in the sky, we wonder how the plane gets into the air. How does it fly? After all, an airplane is much heavier than air.

Why does the airship rise

We know that balloons and airships are lifted into the air Archimedes' force . Archimedes' law for gases states: " Nand a body immersed in gas experiences a buoyancy force equal to the force of gravity of the gas displaced by this body.” . This force is opposite in direction to gravity. That is, Archimedes' force is directed upward.

If the force of gravity is equal to the force of Archimedes, then the body is in equilibrium. If the force of Archimedes is greater than the force of gravity, then the body rises in the air. Since the cylinders of balloons and airships are filled with gas, which is lighter than air, the Archimedes force pushes them upward. Thus, the Archimedes force is the lifting force for lighter-than-air aircraft.

But the gravity of the aircraft significantly exceeds the force of Archimedes. Therefore, she cannot lift the plane into the air. So why does it still take off?

Airplane wing lift

The occurrence of lift is often explained by the difference in static pressures of air flows on the upper and lower surfaces of the aircraft wing.

Let's consider a simplified version of the appearance of the lifting force of a wing, which is located parallel to the air flow. The design of the wing is such that the upper part of its profile has a convex shape. The air flow flowing around the wing is divided into two: upper and lower. The speed of the bottom flow remains almost unchanged. But the speed of the top one increases due to the fact that it must cover a greater distance in the same time. According to Bernoulli's law, the higher the flow speed, the lower the pressure in it. Consequently, the pressure above the wing becomes lower. Due to the difference in these pressures, lift, which pushes the wing up, and with it the plane rises. And the greater this difference, the greater the lifting force.

But in this case, it is impossible to explain why lift appears when the wing profile has a concave-convex or biconvex symmetrical shape. After all, here the air flows travel the same distance, and there is no pressure difference.

In practice, the profile of an airplane wing is located at an angle to the air flow. This angle is called angle of attack . And the air flow, colliding with the lower surface of such a wing, is beveled and begins to move downward. According to law of conservation of momentum the wing will be acted upon by a force directed in the opposite direction, that is, upward.

But this model, which describes the occurrence of lift, does not take into account the flow around the upper surface of the wing profile. Therefore, in this case, the magnitude of the lifting force is underestimated.

In reality, everything is much more complicated. The lift of an airplane wing does not exist as an independent quantity. This is one of the aerodynamic forces.

The oncoming air flow acts on the wing with a force called total aerodynamic force . And lifting force is one of the components of this force. The second component is drag force. The total aerodynamic force vector is the sum of the lift and drag force vectors. The lift vector is directed perpendicular to the velocity vector of the incoming air flow. And the drag force vector is parallel.

The total aerodynamic force is defined as the integral of the pressure around the contour of the wing profile:

Y – lifting force

R – traction

dΩ – profile boundary

R – the amount of pressure around the contour of the wing profile

n – normal to profile

Zhukovsky's theorem

How the lifting force of a wing is formed was first explained by the Russian scientist Nikolai Egorovich Zhukovsky, who is called the father of Russian aviation. In 1904, he formulated a theorem on the lifting force of a body flowing around a plane-parallel flow of an ideal liquid or gas.

Zhukovsky introduced the concept of flow velocity circulation, which made it possible to take into account the flow slope and obtain a more accurate value of the lift force.

The lift of a wing of infinite span is equal to the product of gas (liquid) density, gas (liquid) velocity, circulation flow velocity and the length of a selected section of the wing. The direction of action of the lifting force is obtained by rotating the oncoming flow velocity vector at a right angle against the circulation.

Lifting force

Medium density

Flow velocity at infinity

Flow velocity circulation (the vector is directed perpendicular to the profile plane, the direction of the vector depends on the direction of circulation),

Length of the wing segment (perpendicular to the profile plane).

The amount of lift depends on many factors: angle of attack, air flow density and speed, wing geometry, etc.

Zhukovsky's theorem forms the basis of modern wing theory.

An airplane can only take off if the lift force is greater than its weight. It develops speed with the help of engines. As speed increases, lift also increases. And the plane rises up.

If the lift and weight of an airplane are equal, then it flies horizontally. Airplane engines create thrust - a force whose direction coincides with the direction of movement of the aircraft and is opposite to the direction of drag. Thrust pushes the plane through the air. In horizontal flight at a constant speed, thrust and drag are balanced. If you increase thrust, the plane will begin to accelerate. But drag will also increase. And soon they will balance again. And the plane will fly at a constant, but higher speed.

If the speed decreases, then the lift force becomes less, and the plane begins to descend.

The energetic takeoff of the Airbus A319. Photo: Manuel Mueller

Denis Okan (Boeing 737 instructor pilot): We continue to unveil the secrets of civil aviation. Today we will dispel the fears of air passengers about the takeoff of a modern airliner.

I was prompted to write an opus now by one of the readers who sent links to a couple of takeoffs from Kurumoch airport (Samara), filmed by curious passengers from inside the plane.

These videos attracted comments. Well, here they are:

Video 1:

Comments to it:

Video 2:

And comments

Both cases have one thing in common - the pilots “immediately took off!”

It's a nightmare, isn't it?!!

Let's find out!

Passengers with experience probably remember the ritual that is repeated in almost every takeoff of a Soviet airliner - the plane stops at the beginning of the runway, then stands for some time - the pilots allow the passengers to pray .. but what to hide - they themselves were “praying” at that time - that’s what they jokingly call reading the checklist. After which the engines suddenly begin to roar loudly, the plane begins to tremble, passengers cross themselves... the pilot releases the brakes and an unknown force begins to press the silent passengers into their seats. Everything shakes, shelves open, something falls from the conductors...

And suddenly, of course, completely by accident, the plane takes off. It becomes a little quieter, you can take a breath... But suddenly the plane begins to fall down!

At the last moment, pilots usually “level the plane”, after which the turbines “turn off” a couple more times while climbing, and then everything becomes normal. Flight attendants with stony faces carry juices and waters, and for those who have not prayed well, an oxygen mask. And then the main thing begins, for which passengers fly - delivering food.

Did you miss anything? It seems that I have read such reviews about flights more than once on non-core forums.

Let's figure it out.

Let’s straight away dot the t’s regarding stopping the airliner on the runway before takeoff. What should pilots do anyway – stop or not?

The answer is that both ways are correct. Modern takeoff technique recommends NOT stopping on the runway unless there is a compelling reason to do so. The following reasons may be hidden:

a) The dispatcher is still thinking about whether to let you out or hold you a little longer
b) The strip has a limited length.

Regarding point A, I think everything is clear.

Regarding point B, I will say the following - if the runway (strip) is really very short, and the plane is loaded so that only just the mass passes for this length - in this case it makes sense to save a few tens of meters and put the engine in high mode, holding the plane on the brakes . Or the runway is simply very unusually short, even if the plane is light. In this case, the pilot will also do this “just in case.”

For example, we use this takeoff in Chambery. There is only a two-kilometer runway, and there are mountains ahead. I want to get off the ground as quickly as possible and fly higher. And usually the mass there is close to the maximum possible for take-off conditions.

In the vast majority of cases, if the controller allows us to take off at the same time as occupying the runway, we will not stop. We will taxi to the center line (and, perhaps, already with acceleration), make sure that the plane is moving in a stable, straight line, and after that we will “push on the gas.”

Stop!

What about “praying”? After all, it’s written above about a certain “card of control checks!”

Calendar of low prices for air tickets:

Humanity has long been interested in the question of how it is that a multi-ton aircraft can easily rise to the skies. How does take-off happen and how do planes fly? When an airliner moves at high speed along the runway, lift is generated at the wings and works from the bottom up.

When an aircraft moves, a difference in pressure is generated on the lower and upper sides of the wing, resulting in a lifting force that keeps the aircraft in the air. Those. High air pressure from below pushes the wing upward, while low air pressure from above pulls the wing towards itself. As a result, the wing rises.

For an airliner to take off, it needs a sufficient runway. The lift of the wings increases as the speed increases, which must exceed the takeoff limit. Then pilot increases takeoff angle, taking the helm to himself. The nose of the airliner rises up and the car rises into the air.

Then landing gear and exhaust lights are retracted. In order to reduce the lift of the wing, the pilot gradually retracts the mechanization. When the airliner reaches the required level, the pilot sets standard pressure, and engines - nominal mode. To see how the plane takes off, we suggest watching the video at the end of the article.

The aircraft takes off at an angle. From a practical point of view, this can be explained as follows. The elevator is a movable surface, by controlling which you can cause the aircraft to deflect in pitch.

The elevator can control the pitch angle, i.e. change the rate of gain or loss of altitude. This occurs due to changes in the angle of attack and lift force. By increasing the engine speed, the propeller begins to spin faster and lifts the airliner upward. Conversely, by pointing the elevators down, the nose of the aircraft moves down, and the engine speed should be reduced.

Tail section of an airliner equipped with a rudder and brakes on both sides of the wheels.

How airliners fly

When answering the question why planes fly, we should remember the law of physics. The pressure difference affects the lift of the wing.

The flow rate will be greater if the air pressure is low and vice versa.

Therefore, if the speed of an airliner is high, then its wings acquire a lifting force that pushes the aircraft.

The lifting force of an airliner wing is also influenced by several circumstances: angle of attack, speed and density of air flow, area, profile and shape of the wing.

Modern airliners have minimum speed from 180 to 250 km/h, during which the takeoff takes place, plans in the skies and does not fall.

Flight altitude

What is the maximum and safe flight altitude for an aircraft?

Not all ships have the same altitude, the “air ceiling” can fluctuate at altitude from 5000 to 12100 meters. At high altitudes, air density is minimal, and the airliner achieves the lowest air resistance.

The airliner engine requires a fixed volume of air for combustion, because the engine will not create the required thrust. Also, when flying at high altitudes, the aircraft saves fuel up to 80%, in contrast to altitudes up to a kilometer.

What keeps a plane in the air?

To answer why airplanes fly, it is necessary to examine one by one the principles of its movement in the air. A jet airliner with passengers on board reaches several tons, but at the same time, it easily takes off and carries out a thousand-kilometer flight.

The movement in the air is also influenced by the dynamic properties of the device and the design of the units that form the flight configuration.

Forces affecting the movement of an aircraft in the air

The operation of an airliner begins with the engine starting. Small ships run on piston engines that turn propellers, which generate thrust to help propel the aircraft through the air.

Large airliners are powered by jet engines, which emit a lot of air as they operate, and the jet force propels the aircraft forward.

Why does the plane take off and stay in the air for a long time? Because the shape of the wings has a different configuration: round at the top and flat at the bottom, then the air flow on both sides is not the same. The air on top of the wings glides and becomes rarefied, and its pressure is less than the air below the wing. Therefore, due to uneven air pressure and the shape of the wings, a force arises that leads to the aircraft taking off upward.

But in order for an airliner to easily take off from the ground, it needs to take off at high speed along the runway.

It follows from this that in order for an airliner to fly unhindered, it needs moving air, which the wings cut and creates lift.

Airplane takeoff and speed

Many passengers are interested in the question: what speed does the plane reach during takeoff? There is a misconception that the takeoff speed is the same for every aircraft. To answer the question, what is the speed of the aircraft during takeoff, you should pay attention to important factors.

1. An airliner does not have a strictly fixed speed. The lifting force of an airliner depends on its mass and the length of the wings. Takeoff occurs when a lifting force is created in the oncoming flow, which is much greater than the mass of the aircraft. Therefore, the takeoff and speed of the aircraft depends on wind direction, atmospheric pressure, humidity, precipitation, length and condition of the runway.
2. To create lift and successfully lift off the ground, the aircraft needs reach maximum takeoff speed and sufficient takeoff run. This requires long runways. The larger the aircraft, the longer the runway is required.
3. Each aircraft has its own takeoff speed scale, because they all have their own purpose: passenger, sport, cargo. The lighter the aircraft, the significantly lower the takeoff speed and vice versa.

Boeing 737 passenger jet take off

• The take-off run of an airliner on the runway begins when the engine will reach 800 rpm per minute, the pilot slowly releases the brakes and holds the control lever at a neutral level. The plane then continues on three wheels;
• Before leaving the ground the speed of the airliner should reach 180 km per hour. The pilot then pulls the lever, which causes the flaps to deflect and raise the nose of the aircraft. Further acceleration is carried out on two wheels;
• After, with the bow raised, the airliner accelerates on two wheels to 220 km per hour, and then lifts off the ground.

Therefore, if you want to learn more about how a plane takes off, to what altitude and at what speed, we offer you this information in our article. We hope that you will enjoy your air travel greatly.

An airplane is a heavier-than-air aircraft. This means that its flight requires certain conditions, a combination of precisely calculated factors. The flight of an aircraft is the result of the lifting force that occurs when air flows move towards the wing. It is turned at a precisely calculated angle and has an aerodynamic shape, thanks to which at a certain speed it begins to strive upward, as the pilots say - “stands up in the air.”

The engines accelerate the plane and maintain its speed. Jet engines push the plane forward due to the combustion of kerosene and the flow of gases escaping from the nozzle with great force. Propeller engines “pull” the aircraft along with them.

The wing of modern aircraft is a static structure and cannot independently generate lift on its own. The ability to lift a multi-ton vehicle into the air arises only after the forward movement (acceleration) of the aircraft using a power plant. In this case, the wing, placed at an acute angle to the direction of the air flow, creates different pressure: above the iron plate it will be less, and below the product it will be more. It is the pressure difference that leads to the emergence of an aerodynamic force that contributes to the climb.