The field of aircraft construction is of interest to many people, especially those who often fly on airplanes. Knowing the structure of airplanes will not only make you more erudite, but also save you from many fears, for example, from the fear of flying. This article will talk about how the aircraft brakes when landing and how to brake on different aircraft.
How airplanes slow down
Not only cars have brakes. Airplanes are also equipped with them, because during landing they can develop quite high speed, and the landing strip has a limit. Therefore, whatever one may say, you cannot do without a brake. There are several types of braking, and all of them are used on different types of aircraft. How do planes slow down when landing?
- Reduced engine power. The pilot simply slows down, and the plane gradually stops without additional help. But this method is only possible on a long landing strip.
- Change in balancing position.
- Braking by increasing drag. Usually it is achieved with the help of spoilers, which are put forward after the command of the pilot.
- Reverse braking. In the engine of the aircraft, reverse thrust is activated, which is directed against the movement of the aircraft.
- With brakes on the chassis. Like cars, they come in several forms: shoe, disc and drum.
- A special parachute can also provide braking during landing.
Types of aircraft
In aviation, two types of aircraft can be distinguished: civilian and military. They are very different in structure, so their braking systems are different. Also, the braking method depends on the weight of the aircraft. Among military aircraft, fighters, interceptors, and bombers can be distinguished. They are light in weight and small, therefore they are most often braked using a parachute, which allows you to quickly stop the aircraft. Additionally, they use brakes on the chassis. Passenger liners usually use brakes on the chassis, as well as reverse engine braking. What it is?
What is reverse thrust
Engine thrust reverse is rarely used on small aircraft: they are mainly equipped with passenger liners. Reverse itself is needed to direct the air stream in the direction in or against the movement of the aircraft. Reverse engine reverse thrust just serves for braking and for emergency reduction. Most often it is used after the plane has landed and touched the surface of the wheels. Sometimes reverse is also used for a reverse stroke, but it is extremely rare. But there are also jet aircraft. How is a jet engine built? If for a reverse in an ordinary airplane it is enough to close the damper so that the air goes in the other direction, then in jet engines there are special bucket doors that redirect the air flow.
Advantages and disadvantages of reverse
Reverse thrust of the aircraft engine has its pros and cons. The advantages include the fact that it allows you to slow down the plane at a time when the brakes on the chassis still do not work. With it, you can not only slow down, but also move in the opposite direction. With the help of a reverse, if necessary, you can quickly turn onto the desired track, turning it on only on one of the engines. On this, all the pluses end. The efficiency of reverse engine reverse is only 30%. Therefore, on passenger aircraft, other braking methods are also often used. Together with them there is a guarantee that the plane will stop exactly: if not using one, then using another device. Yes, and the weight of the device is too large, which is why it is used only on large airliners, which boast good load capacity. The disadvantages of the reverse also include its behavior at low speed aircraft. When it drops to 140 km / h or less, there is a high probability of various debris rising from the air, which can then get into the engines.
How to slow passenger aircraft
In passenger aviation, only one aircraft braking system is rarely used during landing. During the flight, many emergency situations can happen and in order to safely land the device, pilots usually have several braking options. What can we say about passenger liners, where responsibility increases many times. Yes, and the large weight of the aircraft simply does not allow to slow down using only one method. What methods are used in civil aviation?
- Brakes mounted on a wheeled chassis. During landing, the aircraft still has a fairly high speed, so the brakes on the landing gear are never used as the only way to stop. Yes, and you can only use them after the wheels have touched the landing strip, and yet the speed of the aircraft must be started to be reduced even before that. In addition, adhesion to the surface may deteriorate due to weather conditions: wet or icy coating.
- Engine reverse usually complements the first braking method. Only airplanes with a variable pitch propeller can create a reverse. The pilot simply changes the position of the screw and it begins to "pull" in the opposite direction. On jet aircraft, reverse reverse is activated by changing the position of special dampers.
- An auxiliary method of braking on passenger airliners is the use of special spoilers that extend during landing. They create drag, which also helps to dampen the speed of the aircraft.
The problem of braking in modern aviation is quite serious. After all, airplanes have long developed tremendous speeds, and their mass is often very impressive. Therefore, the engineers had to work hard before coming up with how to not only land, but also stop the Boeing or Liner.
Emergency braking
In the modern world, it is not easy to do without international flights, which often take more than one hour. Despite all the progress of civilization, the number of people suffering from aerophobia is only growing. Statistics persuades us not to be afraid of flights, because the risk of getting into a fatal accident is much higher than crashing on an airplane. But fears are rarely justified, so many continue to fly, only after drinking a pre-sedative. But fears can be reduced if you learn better the structure of the aircraft and how everything is arranged in it in case of various unforeseen situations. If for some reason the aircraft has failed one or more braking systems, then there are additional emergency methods that help stop the aircraft even in emergency situations.
For example, in the case of an emergency landing with damaged brakes, heated fuel oil is poured on the runway, which helps to reduce speed. On small airplanes, a brake parachute is used, which is thrown out after landing and allows you to quickly stop it. Another way of braking: braking is still in the air by reducing engine traction and increasing drag. As a rule, aircraft braking does not cause any problems during landing. And all the causes of serious air crashes lie mainly in an unsuccessful combination of several circumstances.
Light aircraft
Aircraft of different categories can quite differ from each other in technical characteristics and device. Therefore, it is not surprising that braking systems on different models are also different. What is the structure of the aircraft and its braking system? Most often, pilots are braked using a hydraulic brake system. The weight of a light-engine aircraft rarely exceeds half a ton, therefore, additional braking means like spoilers are rarely installed on them. Disc brakes are installed on the chassis itself, the design of which is identical to that of automobile brakes. When the brake is applied, the pads are closely pressed against the chassis and create a mechanical obstacle to its further rotation. The pilot’s task is to organize such pressure so as not to damage the surface of the wheel, but at the same time reduce the speed of the aircraft. As a rule, this method of braking is quite enough to stop the aircraft. In some "maize" there is reverse braking, with which the pilot can also control the aircraft on the landing field. At small aerodromes, there are rarely towing cars, so this feature comes in handy.
Fighters
How do military aircraft slow when landing? Fighters and other military aircraft belong to a very special category of aircraft. They are light in weight and capable of developing tremendous speeds. In general, the method of braking fighter aircraft is not much different from other aircraft. They also use spoilers and brakes. Most aircraft have jet engines that have reverse thrust capability, but this feature is rarely used. If you turn it on during the flight, the plane can simply tear to pieces. And after the decline as a whole, it is enough to use only disc brakes and a spoiler. For example, the US F / a-18 fighter uses a spoiler-interceptor as one of the braking systems, which rises above the aircraft body during a descent. Also, for many models, the wings have many moving parts that can change their position and reduce the speed of the aircraft.
But there is one method of braking, which is used for the most part only on military aircraft. A parachute-braking system is usually used when approaching the CDW, at a speed of 180 to 400 km / h. This allows you to sharply increase air resistance, as a result of which the plane slows down. If the parachute flies out at the beginning of the lane, when the speed is still too high, then there is a risk of an accident, therefore it is used after applying other braking methods.
Landing on water
Landing an aircraft on water is considered one of the most favorable landing options in an emergency. With proper action, water softens the blow and helps prevent serious damage. Repeated examples of landing on water are known in the history of aviation, as a result of which hundreds of people were saved. When landing on water, the pilot usually performs the following actions:
- Flaps, landing gear and spoilers are cleaned, as they will only interfere with landing.
- Engines are switched to low revs.
- Speeding at landing is possible at 20 km / h, that is, the speed of the aircraft is about 200 km / h in contact with the surface.
- The nose of the aircraft should be slightly raised.
- When in contact with water, the aircraft should be located as even as possible so that the surface of contact with water is as large as possible.
Thus, when the aircraft lands on water, the pilots do not apply either brakes on the landing gear or reverse. Braking is due to the natural resistance of water.
Information for those who are afraid to fly
If you read this article, but are still afraid to fly, then simple knowledge can help you, which opens the veil of secrecy about flying on an airplane and its internal structure.
- Each passenger plane has several jet engines. Thus, even if one of them fails, you are guaranteed to fly to the nearest airport.
- The flight of each ship is controlled by a dispatching service that monitors not only the weather, but also the airborne route.
- Most people are afraid of the turbulence zone. The so-called "air holes" can cause considerable panic among passengers. But do not worry about the safety of the wings and other parts. They are made with enormous load. The wing of the aircraft can bend very much, but not break.
- All systems have duplicate programs, so the risk of error is minimized. The same braking system has spare options, and this applies to all major parts of the aircraft.
- Most modern civilian liners fly using autopilot. If necessary, the control goes into manual mode, but there is no need to be afraid of the human factor - everything is automated to the limit.
Summary
Landing an airplane is the most difficult part of the flight, which implies a great deal of responsibility. There is no definite answer to the answer on how planes slow down during landing. The pilot needs to do many actions, on which the soft landing will directly depend. Most often, to stop an aircraft, not one, but several aircraft braking systems are used, which are activated sequentially one after another. First, the pilot reduces engine speed, which reduces the speed by almost half. Therefore, the aircraft lands at landing at a speed of 200 km / h. Then flaps are released and brought to the stop. After this comes the turn of the brakes on the chassis, which serve as the main brake. If the runway is too short or there was some kind of emergency situation, then connect the engine reverse or parachute (depending on the type of aircraft). The combination of these measures allows you to stop the aircraft even in adverse conditions.