Science 2023

Speed during landing and takeoff of an aircraft are parameters calculated individually for each airliner. There is no standard value that all pilots must adhere to, because aircraft have different weights, dimensions, and aerodynamic characteristics. However, landing speed is important, and failure to comply with the speed limit can result in tragedy for the crew and passengers.

## How is takeoff?

The aerodynamics of any airliner is provided by the configuration of the wing or wings. This configuration is the same for almost all aircraft except for small details. The lower part of the wing is always flat, the upper one is convex. Moreover, the type of aircraft does not depend on this.

The air that passes under the wing when accelerating does not change its properties. However, the air, which at the same time passes through the top of the wing, narrows. Hence,less air passes through the top. This results in a pressure difference under and over the wings of the aircraft. As a result, the pressure above the wing decreases, and under the wing it increases. And it is precisely due to the pressure difference that a lifting force is formed that pushes the wing up, and together with the wing, the aircraft itself. At the moment when the lifting force exceeds the weight of the liner, the aircraft lifts off the ground. This happens with an increase in the speed of the liner (with an increase in speed, the lifting force also increases). The pilot also has the ability to control the flaps on the wing. If the flaps are lowered, the lift under the wing changes vector, and the aircraft rapidly gains altitude.

Interestingly, the smooth horizontal flight of the liner will be ensured if the lifting force is equal to the weight of the aircraft.

So, the lift determines at what speed the plane will take off the ground and start flying. The weight of the liner, its aerodynamic characteristics, and the thrust of the engines also play a role.

## Aircraft takeoff and landing speed

In order for a passenger plane to take off, the pilot needs to develop a speed that will provide the required lift. The higher the acceleration speed, the higher the lifting force will be. Consequently, at a high acceleration speed, the aircraft will take off faster than if it were moving at a low speed. However, the specific speed value is calculated for each liner individually, taking into account its actual weight, degree of loading, weather conditions,runway length, etc.

To broadly summarize, the famous Boeing 737 passenger airliner lifts off the ground when its speed rises to 220 km/h. Another well-known and huge "Boeing-747" with a lot of weight off the ground at a speed of 270 kilometers per hour. But the smaller Yak-40 liner is capable of taking off at a speed of 180 kilometers per hour due to its light weight.

## Types of takeoff

There are different factors that determine the takeoff speed of an airliner:

1. Weather conditions (wind speed and direction, rain, snow).
2. Runway length.
3. Strip cover.

Depending on the conditions, takeoff can be carried out in different ways:

1. Classic speed dial.
2. Off the brakes.
3. Take off with special aids.
4. Vertical climb.

The first method (classic) is used most often. When the runway is long enough, the aircraft can confidently gain the required speed necessary to provide high lift. However, in the case when the runway length is limited, the aircraft may not have enough distance to reach the required speed. Therefore, it stands for some time on the brakes, and the engines gradually gain traction. When the thrust becomes strong, the brakes are released and the aircraft abruptly takes off, quickly picking up speed. Thus, it is possible to shorten the take-off path of the liner.

About vertical takeoffdo not have to speak. It is possible in the presence of special engines. And takeoff with the help of special means is practiced on military aircraft carriers.

## What is the landing speed of the plane?

The liner does not land on the runway immediately. First of all, there is a decrease in the speed of the liner, a decrease in altitude. First, the aircraft touches the runway with the wheels of the landing gear, then it moves at high speed already on the ground, and only then does it slow down. The moment of contact with the GDP is almost always accompanied by shaking in the cabin, which can cause anxiety among passengers. But there is nothing wrong with that.

Airplane landing speed is almost only slightly slower than takeoff speed. A large Boeing 747, when approaching the runway, has an average speed of 260 kilometers per hour. This speed should be at the liner in the air. But, again, the specific speed value is calculated individually for all liners, taking into account their weight, workload, weather conditions. If the aircraft is very large and heavy, then the landing speed should be higher, because during landing it is also necessary to "keep" the required lift. Already after contact with the runway and when moving on the ground, the pilot can brake using the landing gear and flaps on the wings of the aircraft.

## Airspeed

The speed of an airplane landing and taking off is very different from the speed at which an airplane is moving at an altitude of 10 km. Most often, aircraft fly at a speed that is 80% of the maximum. SoThe top speed of the popular Airbus A380 is 1020 km/h. In fact, flying at cruising speed is 850-900 km/h. The popular "Boeing 747" can fly at a speed of 988 km / h, but in fact its speed is also 850-900 km / h. As you can see, the speed of flight is drastically different from the speed of landing.

Note that today Boeing is developing an airliner that can gain flight speed at high altitudes up to 5000 kilometers per hour.

## In closing

Of course, landing speed is an extremely important parameter, which is calculated strictly for each airliner. But it is impossible to name a specific value at which all planes take off. Even identical models (such as Boeing 747s) will take off and land at different speeds due to different circumstances: workload, amount of fuel filled, runway length, runway coverage, presence or absence of wind, etc.

Now you know what is the speed of the plane when landing and when it takes off. Everyone knows the averages.