The wings of an airplane are one of its most important components. They provide the aerodynamic lifting force. An airplane wing has several elements. Each of them has its own separate function that allows the wing to work correctly. In the early days of aviation, engineers understood its importance to the aircraft.
With the development in the field, different variants of wings have appeared, which are used for different models of aircraft. Wing shapes and dimensions are important for a passenger airliner or military fighter. The mechanization of an aircraft wing, its design and purpose will be discussed in this article.
The lift force of an airplane wing is created due to the pressure difference. It changes due to the presence of air currents.
The principle of operation is explained and Newton's impact model. Air particles collide with the lower half-plane of the wing, which is located at an angle to the flow, and bounce down, pushing the wing upward.
The structure of an airplane wing.
How many wings does an airplane have? In the classic model there are two of them - one on each side.
There is such a thing as the wing span of an airplane. This is the distance from the top of the left wing to the top of the right. It is measured in a straight line and does not depend on its shape or sweep.
About their device
The totality of all the elements that make up the wing is called its mechanization. This includes flaps, slats, flaperons, spoilers, etc.
It's shared into three main parts. These are the right and left half-planes and the center section. Half-planes are also called consoles. This is the structure of an airplane wing, and more about the structure below.
Airplane wing.
Flaps
The flaps were seen by everyone who sat at the window, near the wings. Few people know that these are flaps. These are deflectable surfaces. Their function is to increase the load-bearing capacity of the wings during landing and flight at low speed.
When they are not extended, they are a continuation of the wing. During their release, they move away from it, forming small gaps.
When taking off or landing an aircraft, the flaps must be extended. Why is this being done? This is necessary to reduce speed and increase aerodynamic drag. There is a third reason - aircraft rebalancing.
The flaps of an airplane wing form one to three slits when releasing them.
Flaperons
They can also carry out the operation of flaps. They are used on ultralight aircraft and radio-controlled models. They have one significant disadvantage - they are as effective as ailerons.
Slats
They are installed in front of the wing. Like flaps, they are deflectable surfaces. When they are released, a gap is also formed. Usually they are managed simultaneously with the first ones, but they can be managed separately.
Exists two types of slats - automatic and adaptive.
Interceptors
Their other name is spoilers. These are wing surfaces that are deflected or released into the flow. Their task is to increase aerodynamic drag and reduce lift.
These are its main parts that ensure its smooth operation.
Types of wings
You can see a photo of the airplane wing above. They vary greatly in their design and structural features.
According to their shape there are straight lines, swept, reverse swept, triangular, trapezoidal, etc.
Swept wings are the most popular. They have many advantages. There is an increase in lift and . It also has disadvantages, but still they are not so significant due to significant advantages.
Airplanes with forward-swept wings - better controlled at low speeds, efficient in terms of aerodynamic properties. One of their disadvantages is that the design requires special materials that would create sufficient wing rigidity.
On Tuesday, the main “black box” of the Tu-154 that crashed in Sochi was delivered to Moscow. The Life publication published a transcript, the authenticity of which was not officially confirmed, but it followed from it that the crew had problems with the flaps. And an Interfax source, in turn, said that the Tu-154 could have crashed due to a “stall” with insufficient wing lift for takeoff.
“According to preliminary data, the flaps on board operated inconsistently, as a result of their failure to release, the lifting force was lost, the speed was not sufficient to gain altitude, and the plane crashed,” said a source at the operational headquarters for work at the scene.
Novaya Gazeta asked experts to comment on the version with flaps.
Andrey Litvinov
1st class pilot, Aeroflot
— Flaps are very critical. We ( pilots — ed.) at the very beginning they assumed that these were flaps - as soon as it became clear that it was not fuel or weather. There were several versions - technical, pilot error. But it can be both. A technical problem resulted in a pilot error.
Flaps are needed only for takeoff and landing - the wing area increases, the lifting force increases, therefore, the plane needs a shorter takeoff distance than without flaps. You take off with the flaps, gain altitude, and the flaps retract. But they may not clean up if something is broken, or they may not clean up synchronously - one is faster, the other is slower. If they don’t clean up at all, it’s not a big deal; the plane flies on and on. He doesn't go into a dive. The commander simply reports to the ground that he has such a technical problem, returns to the airfield and lands - with the flaps extended, as required during a normal landing. And engineers are already figuring out what the problem is.
But if they are removed asynchronously, then the plane crashes, that’s what’s scary. On one plane of the wing the lift force becomes greater than on the second, and the plane begins to roll and, as a result, falls on its side. If the plane falls over, dives, and begins to lower its nose, the crew instinctively begins to pull the yoke towards themselves and increase the engine speed - this is absolutely normal. But the pilot must control the spatial position of the aircraft.
There is a concept - supercritical angle of attack. This is the angle at which air begins to escape from the wing. The wing becomes at a certain angle, its upper part is not flown around by air, and the plane begins to fall, because nothing is holding it in the air.
I flew the TU-154 for 8 years. I had no problems with the flaps, there were minor failures, nothing serious. It was a good reliable plane in its time. But that was 25 years ago. It is a product of its time. Aeroflot has all new planes - we fly Airbuses and Boeings. And the Ministry of Defense flies the TU-154. Yes, you need to make your own planes, yes, but at least let them take a superjet. Modern aircraft have a lot of protection systems; it is actually a flying computer. If some situation happens, the automation prevents the plane from stalling and is very helpful to the pilot. These same planes are all in manual mode, all in manual control. But this does not mean that it should fall, it must be technically sound. It must undergo maintenance. The question for the technicians is why such a serious breakdown occurred on this plane. Anyone can make a mistake. The crew does have experience, but military pilots generally don’t fly much. A military pilot flies 150 hours a year. And civilian - 90 hours per month.
Surprise could also have worked, they did not expect such a development of events, they did not have enough reaction to cope. This does not mean that they are inexperienced. Don't forget that the time was 5 am. Just sleep, the body is relaxed, the reaction is initially inhibited. We have been saying for a long time that we should ban night flights or reduce them to a minimum, we should strive to fly during the day, this is what many European companies do.
You also need to remember that the plane was heavy; the fuel tanks, cargo, and passengers were full. There was little time to make a decision. They didn't have time. This situation, of course, must be worked out. I don’t know how the army trains pilots, but here at Aeroflot it’s being worked on. There is an algorithm of actions for every emergency situation. Everything is endlessly practiced on the simulator. Did this crew go to the simulator when? If you were on the simulator, did you practice specific flap exercises? We are waiting for answers from the investigation.
Source close to the investigation
— Now the entire technical investigation is being conducted by the Ministry of Defense. This is a military aircraft - the Air Force Institute in Lyubertsy is engaged in deciphering the recorders, and all recorders, units, systems were transported to Lyubertsy. Flaps are not a critical situation, but in principle a controlled and manageable situation. There is an algorithm for actions in case of desynchronization or incorrect position of the flaps. Pilots are trained in everything, including in simulators; for every emergency, the flight crew practices how to behave, how to control the aircraft. Each aircraft has its own specifics; algorithms have been developed for the Tu-154. A combination of technical problems and human factors can be assumed, but there is still not enough information.
Vadim Lukashevich
Independent aviation expert, candidate of technical sciences
— Failure to retract the flaps is not a disaster. This is a very unpleasant event, but nothing bad should happen from it. And in my opinion, a combination of circumstances and the actions of the crew led to the disaster in the Black Sea.
The essence of airplane flaps is to increase the lift of the wing at low speeds. How a wing works - the higher the speed, the greater the lift. But when the plane takes off, the speed is still low, the same as during landing. And in order to prevent the lift force from decreasing when the speed drops, the flaps in question are extended. You also need to understand that during takeoff the flaps do not extend as much as during landing. When the aircraft is taxiing on the runway, the flaps are already extended, and at the moment of takeoff, the landing gear is sequentially retracted, braking the aircraft, and after 15-20 seconds the flaps are also retracted, hindering the plane as its speed increases. In addition to lifting force, they also create additional air resistance and an additional diving moment - when the plane “wants” to lower its nose.
What happened at the time of the disaster? A heavy, loaded plane, filled with fuel, takes off, the pilots retract the flaps, but for some reason this does not work. In theory, you can continue the flight normally and in this state, without picking up speed, you can turn around and land to fix the problem. It is possible to land with the flaps in this position, but the landing speed will be higher and it will not be very easy. But obviously there was no such solution here. Perhaps the problem with the flaps was not noticed immediately, and when the plane began to lower its nose, words deciphered from the recorder may have been spoken.
Wing mechanization is an integral part of modern aircraft wings. This includes devices that allow you to change the aerodynamic characteristics of the wing at individual stages of flight (Fig. 3.8).
There are two types of mechanization based on the functions they perform:
- · to improve takeoff and landing characteristics (flaps and slats);
- · for control in flight (spoilers in lift damper mode and in aileron mode).
Aircraft wing mechanization:
1 - flaps; 2 - slats; 3 - spoilers
A simple flap is a section of the tail section of the wing that deviates downward to 45°. To increase the efficiency of the flap, it is made slotted. When the retractable flap is deflected, a profiled gap is formed between its toe and the wing. Modern aircraft use two- or three-slot flaps.
The slats are a part of the wing tip at the leading edge, which deflects downward by an angle of up to 25° and moves forward, forming a profiled gap with the wing. Just like flaps, slats reduce the takeoff and landing speeds of the aircraft, and most importantly, increase the critical angle of attack.
Mechanization means include spoilers (interceptors) used as brake flaps, air brakes, lift dampers, roll controls, etc. When the spoilers are deflected upward, the flow around the wing is disrupted, which leads to a decrease in the lift coefficient. With the help of spoilers, you can change the vertical speed of descent, reduce the length of the landing run due to more effective braking of the landing gear wheels, and increase the efficiency of roll control.
The wing of modern aircraft has mechanization of the front and rear parts. Elements of mechanization of the front part of the wing ensure the elimination of stall on the wing at high angles of attack. Their work is synchronously connected with the work of the mechanization of the rear part - flaps. The most effective and widespread are slotted retractable flaps, which increase the curvature of the wing profile and its area. Shields can be installed in the nose and rear of the wing. Their design is simpler than that of flaps, but their efficiency is less.
Elements of the aircraft's aerodynamic control system: 1 -- nose flaps; 2 -- flaps; 3 -- all-moving keel; 4 -- differential stabilizer; 5 -- interceptors
To reduce the effort on the control levers, all modern aircraft have boosters in the control system - steering actuators. In the 70s, a fly-by-wire control system (EDCS) appeared. On aircraft equipped with such a system, there is no (or redundant) mechanical control wiring, and control signals are transmitted from the levers to the steering gears via electrical communications. The electric control system has a lower mass and allows increasing the reliability of the control system by redundant communication lines. This system can use computers and high-speed actuators to control statically unstable aircraft and reduce stress when maneuvering or flying in turbulent atmospheres.
On subsonic aircraft, to reduce the loads acting on the controls, servo compensators and servo rudders are used - small surfaces connected in the first case with rudders, in the second - with control levers. With their help, the rudders are facilitated or deflected.
Wing mechanization
Extended flaps and slats.
Extended slats.
Wing mechanization- a set of devices on the wing of an aircraft designed to regulate its load-bearing properties. Mechanization includes flaps, slats, spoilers, spoilers, flaperons, active boundary layer control systems, etc.
Flaps
Flaps- deflectable surfaces symmetrically located on the trailing edge of the wing. The flaps in the retracted state are a continuation of the wing surface, while in the extended state they can move away from it with the formation of cracks. They are used to improve the load-bearing capacity of the wing during takeoff, climb, descent and landing, as well as when flying at low speeds. There are a large number of types of flap designs:
The principle of operation of flaps is that when they are extended, the curvature of the profile increases and (in the case of retractable flaps, which are also called Fowler flaps) the surface area of the wing, therefore, the lift force increases. The increased lift allows aircraft to fly without stalling at lower speeds. Thus, extending the flaps is an effective way to reduce takeoff and landing speeds. The second consequence of flap extension is an increase in aerodynamic drag. If during landing the increased drag helps to slow down the aircraft, then during takeoff the additional drag takes away part of the engine thrust. Therefore, during takeoff, the flaps are always extended at a smaller angle than during landing. The third consequence of flap release is longitudinal rebalancing of the aircraft due to the occurrence of additional longitudinal moment. This complicates the control of the aircraft (on many modern aircraft, the diving moment when the flaps are extended is compensated by moving the stabilizer to a certain negative angle). Flaps that form profiled slits during release are called slotted. Flaps can consist of several sections, forming several slits (usually from one to three).
For example, the domestic Tu-154M uses double-slot flaps, and the Tu-154B uses three-slot flaps. The presence of a gap allows the flow to flow from an area of high pressure (the lower surface of the wing) to an area of low pressure (the upper surface of the wing). The slots are profiled so that the stream flowing from them is directed tangentially to the upper surface, and the cross-section of the slot should gradually narrow to increase the flow speed. After passing through the slot, the high-energy jet interacts with the sluggish boundary layer and prevents the formation of vortices and flow separation. This event makes it possible to “push back” the flow stall on the upper surface of the wing to higher angles of attack and higher lift force values.
Flaperons
Flaperons, or “hovering ailerons” - ailerons that can also perform the function of flaps when they are deflected down in phase. Widely used in ultra-light aircraft and radio-controlled model aircraft when flying at low speeds, as well as during takeoff and landing. Sometimes used on heavier aircraft (for example, Su-27). The main advantage of flaperons is their ease of implementation on the basis of existing ailerons and servos.
Slats
Slats- deflectable surfaces installed on the leading edge of the wing. When deflected, they form a gap similar to that of slotted flaps. Slats that do not form a gap are called deflectable leading edges. As a rule, the slats are automatically deflected simultaneously with the flaps, but can also be controlled independently.
In general, the effect of slats is to increase the permissible angle of attack, that is, flow separation from the upper surface of the wing occurs at a higher angle of attack.
In addition to simple ones, there are so-called adaptive slats. Adaptive slats automatically deflect to ensure optimal wing aerodynamic performance throughout the flight. Roll control is also ensured at high angles of attack using asynchronous control of adaptive slats.
Interceptors
Release of the left aileron spoiler when parrying a right roll
Interceptors (spoilers)- surfaces on the upper surface of the wing that are deflected or released into the flow, which increase aerodynamic drag and reduce lift. Therefore, spoilers are also called direct lift control elements.
Depending on the purpose and surface area of the console, its location on the wing, etc., interceptors are divided into:
Aileron spoilers
Aileron spoilers They are an addition to the ailerons and are used mainly for roll control. They deviate asymmetrically. For example, on a Tu-154, when the left aileron is deflected upward by an angle of up to 20°, the aileron-interceptor on the same console automatically deflects upward by an angle of up to 45°. As a result, the lift on the left wing console decreases, and the plane rolls to the left.
For some aircraft, aileron spoilers may be the main (or backup) roll control element.
Spoilers
Spoilers released
Spoilers (multifunctional spoilers)- lift dampers.
The symmetrical activation of spoilers on both wing consoles leads to a sharp decrease in lift and braking of the aircraft. After release, the aircraft balances at a higher angle of attack, begins to slow down due to increased drag, and descends smoothly. It is possible to change the vertical speed without changing the pitch angle. That is, when released simultaneously, the spoilers are used as air brakes.
Interceptors are also actively used to dampen lift after landing or during an aborted takeoff and to increase drag. It should be noted that they do not so much dampen the speed directly as they reduce the lift of the wing, which leads to an increase in the load on the wheels and improved traction of the wheels with the surface. Thanks to this, after releasing the internal spoilers, you can proceed to braking using the wheels.
see also
- Rotary slat - a propulsion device based on a slat
- Vibrating slat - slat-based propulsion
- Ailerons are rudders that control the roll of an aircraft.
- Aerodynamics of the Boeing 737
Notes
Wikimedia Foundation. 2010.
See what “Wing mechanization” is in other dictionaries:
A set of devices in the front and (or) rear parts of the wing to change its aerodynamic characteristics. The operation of all airfoil elements is based on controlling the boundary layer on the wing surface and (or) changing the curvature of the profile. M. k.... ... Encyclopedia of technology
A set of devices that change the lift and drag of an aircraft wing. MK reduces the speed of landing of an aircraft, and during takeoff it facilitates its lifting off the surface of the earth. Depending on the type of M. lifting... ... Great Soviet Encyclopedia
wing mechanization Encyclopedia "Aviation"
wing mechanization- Rice. 1. Scheme of mechanization of the front part of the wing. wing mechanization a set of devices in the front and (or) rear parts of the wing to change its aerodynamic characteristics. The work of all elements of the M.K. is based on the management of the border... ... Encyclopedia "Aviation"
wing mechanization- Rice. 1. Scheme of mechanization of the front part of the wing. wing mechanization a set of devices in the front and (or) rear parts of the wing to change its aerodynamic characteristics. The work of all elements of the M.K. is based on the management of the border... ... Encyclopedia "Aviation"
wing mechanization- Rice. 1. Scheme of mechanization of the front part of the wing. wing mechanization a set of devices in the front and (or) rear parts of the wing to change its aerodynamic characteristics. The work of all elements of the M.K. is based on the management of the border... ... Encyclopedia "Aviation"
Wing mechanization- devices (slats, flaps, flaps, etc.) for changing the aerodynamic characteristics of the wing in order to reduce the landing speed (take-off), take-off run (run), as well as improve the maneuverability of the aircraft in flight, etc.... Glossary of military terms
Encyclopedia "Aviation"
wing power mechanization- Rice. 1. Energy mechanization of the wing. energy mechanization of the wing devices for increasing the lifting force of the wing, the principle of operation of which is based on the use of energy from the aircraft engines or additional... ... Encyclopedia "Aviation"
Devices for increasing wing lift, the operating principle of which is based on the use of energy from aircraft engines or additional power sources. E.m.c. is used to improve the takeoff, landing and maneuvering characteristics of an aircraft,... ... Encyclopedia of technology
