Wing (aeronautical)
In aeronautics, wing refers to an aerodynamic body with a very strong and structurally resistant configuration, made up of an aerodynamic profile or wing profile enveloping one or more spars and capable of generating a difference in pressures between its upper face (extrados) and its lower face (intrados) when moving through the air, which produces the upward force of lift that keeps the plane in flight. The typical wing also uses the principle of action and reaction generating a force whose vertical component counteracts the weight. In the particular case of wings for supersonic aircraft, the design is oriented to use only this effect of "reaction" and aerodynamic lift is avoided. The wing will therefore compensate the weight of the aircraft and in turn will generate drag. The aerodynamic lift effect exists due to the pneumatic characteristics of the air, it is its compressibility that makes possible the imbalance between the pressures of the intrados faces and the air. extrados
It is used in various aircraft, it is the reference component of fixed-wing aircraft (airplane for example), but it is not exclusive to them. For example, helicopters such as the AH-64 Apache and gyroplanes are two types of rotary-wing aircraft that, apart from their rotary wings, also have fixed wings that they use to carry weapons; in this case the main function of supporting the aircraft is lost, but it remains an (embryonic) wing whose main function has been exchanged for another.
The aviation pioneers, trying to emulate the flight of birds, built all kinds of devices equipped with articulated wings that generated air currents or built glider devices that, when launched from high places with air currents, offered lift. Only when an engine of sufficient power became available, fixed-wing airplanes were built, which flew through the air instead of moving it self-propelled, was it then possible to fly heavier-than-air machines under their own power and not dependent on gravity, like gliders. It was the Wright brothers in 1903 who achieved the first self-propelled flight; however Alberto Santos Dumont was the first to complete a pre-established circuit, under the official supervision of specialists in the field, journalists and Parisian citizens. On October 23, 1906, he flew about 60 meters at a height of 2 to 3 meters above the ground with his 14-bis, on the Bagatelle field in Paris. Santos Dumont was actually the first person to fly a heavier-than-air aircraft under his own power, as the Wright brothers' Kitty Hawk required the catapult until 1908. Carried out in Paris, France on November 12, 1906 Not only did he have good witnesses present and from the press, but several aviators and authorities also saw him. Also noteworthy are the gliders built by John Joseph Montgomery and Otto Lilienthal that achieved sustained (with wings) and controlled but not self-propelled (that is, they lacked an engine) flight. Although there are wings of all types and shapes, they all obey the same principles explained above and are characterized by an elongated shape (one dimension is much larger than the other dimensions).
In a modern airplane, the wing also fulfills other functions apart from supporting the joint weight of the wings plus that of the rest of the structure, mainly the fuselage and the control surfaces such as the horizontal stabilizer and the rudder. In the functions of the wing, which is also one of the components that has evolved the most since the beginning of aviation, as can be seen in its historical evolution. Being one of the most important parts of the airplane (and perhaps the most studied) to the point that since the 1930s there have been aircraft without a fuselage or independent control surfaces, the so-called flying wings, it turns out that it is possibly the one that uses the most terminology. to distinguish its different parts, with mobile parts, structural parts and geometric parts. Finally, it is interesting to observe how the different planforms have adapted to the different flight regimes.
Functions of the wing
The wing is the main component of an airplane, its main function is to ensure lift, which compensates for weight. This makes the plane able to maintain a stable flight. But being a fairly large structure, the technological evolution of airplanes has made it acquire a series of new functions apart from maintaining flight. The wing is designed based on in-flight performance criteria, that is, design speed, glide ratio, payload, aircraft maneuverability, all of which implies structural design considerations and finally global aircraft design factors (for example, where to put one system or another).
A summary of its main functions would be the following:
- Giving sustainability and keep the flight compensating the weight of the plane.
- Control supplier to the plane in flight. Normally the wing is responsible for the balance control functions, through the disposition of the diero, as well as the control functions around the longitudinal axis through the alloys. In some wings (e.g. wing in delta) it is also responsible for the control of the scalp (normally the horizontal stabilizer (lateral).
- Secure the takeoff and landing capacity of the plane, which is usually done by helping hypersustainer devices, increasing the effective area and the support coefficient.
- In those planes with wing engines, it is the one in charge of fasten the engines and transmit your push to the full plane. As well as the systems necessary for the air drainage of the engine, fuel supply and motor control (cabled, the system that performs the engine control is not normally located in the wing).
- Stay the fuel, with the passage of the years the wing has adapted to carry within its structure the fuel that the plane uses for the flight. This is because the fuel weight is not to alter the position of the gravity center to maintain the aircraft's focused aerodynamic. Fuel is also taken on the lower part of the encastre and on some large transport planes in a rear depot to keep the center. Therefore the internal wing structure should be prepared to contain fuel (chemical protection).
- Lights and signaling. At the ends of the wing usually there are lights that are used for signaling, such as navigation lights, position lights and some fixed wing aircraft installed the landing and reel lights.
- Arms support. In military aircraft, missiles are usually mounted on wing and fuselage.
- External fuel tank support, many aircraft (especially military) carry auxiliary fuel tanks for extended-range missions.
- Landing Train Accommodation, many planes have part or all the landing gear inside the wing.
- Emergency Output Support, being many emergency exits located next to the wing, the wing must be able to hold in a moment of evacuation to the passengers on it.
History and configuration of the wing
The first airplanes were built with the biplane wing configuration where two wings were joined together by braces and stiffeners. The reasons for this configuration were due to structural problems, it was not possible to have a structure strong enough to withstand all the lift that the plane needed using only one wing, it was necessary to minimize the size of the wing (and therefore the structural stresses). and therefore their number needed to be increased to make the plane fly. This configuration was maintained for a long time (there were even some triplane and even multiplane configuration aircraft with more than three wings) until the appearance of monoplane aircraft thanks to advances in the science of materials and structures.
As you can see in the image of the Sopwith Camel, biplanes used external elements (due to the lack of rigidity of the wings) to give the necessary resistance to the wings during flight and, above all, manoeuvres. These elements at first were not aerodynamic (rather blunt bodies and gave great resistance to flight. A great advance was the introduction of the monoplane aircraft and especially the semi-monocoque and monocoque aircraft
Current commercial and transport aircraft configurations are typically single-wing and semi-monocoque configurations. The wing is designed to be able to resist by itself all the forces that can be found during the flight and it performs several functions. This design is the basic one in all configurations flying subsonic although, due to special reasons, some aircraft use different configurations to solve specific problems.
Monoplane aircraft have several possible configurations. They may well have the low wing where the wing goes at the height of the lower fuselage, which facilitates access to the engine but requires a larger landing gear, it is the most used in commercial aircraft of passengers. Another traditional wing is the high wing, where the wing is installed on top of the fuselage, which requires a smaller landing gear but creates problems in the area of the fuselage where the wing is located. wing since the space is smaller. We also have the mid-wing typical of military fighters and the parasol, which is a wing mounted above the fuselage. As a general rule, commercial passenger aircraft tend to have low wings in order to accommodate a greater number of passengers and the landing gear is usually placed on the belly fairing of the wing. plane. Transport aircraft are usually derivatives of commercial aircraft or specific transport aircraft (especially military transport aircraft such as the A400M), these aircraft tend to be of high wing configuration and have their landing gear landing at the bottom of the fuselage, being quite short. This allows more space around for loading and unloading operations.
There are several types of wings for airplanes:
Constant rope rect.
Trapezoidal (record with narrowing).
Elliptical
Arrow
Inverted arrow
Double arrow
Variable arrow
Delta
Delta with timons canard
Delta with rear helms
Double delta
Ojival
The previous models respond to general guidelines of what aircraft are like today, but they clearly depend on the specific aircraft and the mission to be carried out. For example, the Fokker 60 is a high wing airliner with landing gear on the engines.
Currently there are several studies to radically change the shape of the commercial airplane and leave the fuselage-wing structure, moving to a totally integrated structure called flying wing. This structure has the advantage of offering less resistance for the same number of passengers, although today it faces a problem when it comes to responding to the authorities' requests to evacuate the plane (passengers would be in lines of 20- 30 passengers compared to today's maximum of 11). There are various operational aircraft (mostly military) with this configuration, for example the Northrop YB-49 or the B-2 Spirit. Another similar conception (intermediate) is a fusion of the fuselage and wing in a single structure but without becoming a single component although differentiated. It is the so-called integrated fuselage, which is an intermediate step between a current classic monoplane configuration and a flying wing configuration.
All the previous configurations are focused on commercial airplanes, which are mostly subsonic planes, military airplanes (especially fighters) fly supersonic and therefore the wing configuration must respond to this difference. In general, supersonic military aircraft use a delta wing configuration (either with canard variants, double delta...) that better responds to the needs of the mission. These wings have their difficulties and no aircraft today uses a pure hang glider.
Movable geometric parts of the wing
- Wing tip device (1): are geometric shapes installed at the end of the wing, of type wingtip fence In this case, your mission is to reduce the induced resistance of the wing as it avoids the connection between intrados and extrados. The distribution of support along the wing is not uniform and there is a phenomenon of air sweeping towards the tip of the wing, causing the formation of the wing tip vortices, this effect is very accentuated in wings with arrow. This causes the wing to give kinetic energy (in the form of a whirlwind) to the air by consuming energy in this process, because inside the whirlwind a low-pressure zone tends to "jalar" the plane back from the tip of the wing. The winglets or fins reduce this phenomenon, but against it they generate a high moment of the wing encastre. Other wing tip devices are the winglets or sharklets, raked wing tip.
- Alerones: it is responsible for controlling the plane's plane's flight lab movement, by means of an asymmetrical deflection of a portion of the wing closest to the tip and to the flight edge (a wing up and down), by generating a larger ascensional force in the lower portion and a reduction of the substation in the portion that rises, the plane is achieved to rotate on its longitudinal axis. It is this way that the plane performs lateral spins without consuming a high amount of fuel and in a reduced space. There are two wings of commercial aircraft:
- Low-speed or external wing (2): used for spins with the plane below Mach.
- High-speed or internal wing (3): used for spins with the plane to Mach from cruise.
- Hypersustainer devices: are used during takeoff or landing. The mission of these elements is to reduce the minimum speed the plane needs to take off or land. To achieve this there are several techniques: to increase the wing surface, the wing support coefficient, to increase the maximum support coefficient of the wing... this way the total strength of support is increased at a given speed, being able to land at a lower speed. The deflection of these devices increases the aerodynamic resistance of the plane. They can be passive devices (through a geometry modification, increasing the surface and/or curvature of the aerodynamic profile) or active (by injecting energy into the air). Geometrically:
- Carenados de los flaps (4):
- Flap Krueger (5): is a complex passive hypersustainer device.
- Slats (6). These are attack edge devices.
- Flap 3 inner parts (7).
- Flap of 3 outer parts (8).
- Spoiler, disruptor or deflector (9): are elements used to destroy the support of the wing. They are used during landing, once the plane plays ground with the wheels, these devices that prevent the plane from coming back into the air are also used in case of decompression in the cabin, as the plane breaks down rapidly to a flight level where the pressure is the right one. Finally they are used by many planes to get down more quickly (they deflect slightly).
- Spoiler-Aerophics (10).
Strength structure of the wing
The wing is undoubtedly one of the greatest achievements of aeronautical engineering. It combines in a single component an efficient structure, a multifunctional component and an amazing lightness. The current wing architecture is based on semi-monocoque technology based on several components that fulfill a specific function. Nowadays, with the introduction of advanced composite materials, the manufacture of the structure begins to be made of integrated parts (stringers-cladding) but the components (although integrated in one piece) continue to be distinguishable:
- Long-runners: There are usually three lanterns in the root in the wide-running planes. Two form the torsion box and the third ensures the form near the encastre where the wing is larger, and then there are only two larguers (many planes only have 2 larguers). The wing fuel tanks are located between the previous and later sides. The mission of the ridges is to resist the bending of the wing.
- Costs: are structures that give resistance to the wing torsion and the aerodynamic form of the wing. They are interspersed (more or less) perpendicular to the ridges. They are usually emptied to remove material not necessary and lighten weight. Along with the ridges shape the fuel tanks and they must be prepared to chemically resist the fuel.
- Larguerillos: they are small beams (small than the largueeros) that are placed between ribs to avoid the local pandeo of the coating. They can be integrated into the coating itself by forming a single piece (they are only integrated into recent composite planes).
- Revisement: it is the outer part of the wing, whose mission is to resist short efforts and isolate the fuel of the environment. That's what we see as "the skin of the wing."
Apart from all these internal structural components, the wing carries the elements that make up the kinematics of the high-lift devices.
Wing geometry
- Alar Profile: It is the shape of the wing section, that is to say what we would see if we cut it transversally "as in slices". Except in the case of rectangular wings in which all the profiles ("rodajas") are equal, the usual is that the profiles that make a wing are different; they are becoming smaller and narrow towards the ends of the wing.
- Deletion: It is the front edge of the wing, the line that links the previous part of all the profiles that form the wing. It is a geometric, non-physical definition, as it does not match the rowing points of the flight profiles. It is also the most susceptible area to ice formation, so it usually has dehydration or anti-Ice systems.
- Departure or leaking edge: It is the back edge of the wing, that is the line that unites the back of all the wing profiles; or said otherwise: the part of the wing where the air flow disturbed by it, returns to the open current. It is on this edge where part of the hypersustainment components such as flaps are located
- Extrados: Top of the wing between the edges of attack and exit. In this area (in normal flight of the plane) low pressures are formed and the air is accelerated. It's normal to find shock waves in this area.
- Intradós: Lower part of the wing between the edges of attack and exit. In this area (in normal flight of the plane) are formed overpresses. An overpressure in the intrados coupled with a depression in the extrados composes the global support of wing.
- Thickness: Distance between extrados and intrados, which varies along the rope.
- Cuerda: It is the imaginary straight line drawn between the edges of attack and output of each profile.
- Average string: As the wing profiles are not usually equal, they are decreasing towards the ends, the same happens with the strings of each. Therefore, by having each profile a different string, it is normal to talk about the middle rope of the wing. Two types of quarry are defined: the aerodynamic medium string and the geometric medium string.
- Line of 25% of the rope: imaginary line that would be obtained by joining all the points located at a distance of 25% of the length of the string of each profile (measured from the edge of attack), measured distance beginning with the attacking board.
- Healing. From the wing from the edge of attack to the exit. Higher healing refers to that of the upper surface (extrados); lower than that of the lower surface (intrados), and mean curvature to the equidistant to both surfaces. Although it can be given in absolute number, it is normal to express in % of the rope.
- Elong surface: Total surface corresponding to the wing. This term can be confusing, as the wing surface can take into account the wing tip devices or not, giving different surfaces. The elar surface is used as a reference to the time of calculating force coefficients.
- Scope: Distance between the two ends of the wing. By definition, if we multiply the width by the geometric medium string, we must obtain the lengthy surface.
- Alargamiento: Coscent between the width and the middle string. This data tells us the relationship between the length and width of the wing (Envergadura/Cuerda media). For example, if this quotient were 1 we would be facing a square wing of equal length than width. Obviously as this value becomes higher the wing is longer and narrower. This quotient affects the resistance induced so that: to increased lengthening, less induced resistance. Short and wide wings are easy to build and very structurally resistant but generate a lot of resistance; on the contrary the narrow and elongated wings generate little resistance but are more difficult to build and present structural problems. Normally the lengthening is usually between 5:1 and 10:1. or more. Less lengthening, faster speed (less resistance) but also requires more drive or traction (fast aircraft); greater lengthening, less speed but less push or traction required. The extreme is made up of planners whose induced resistance is minimal and its maximum planning coefficient.
- Arrow: Angle that forms the wings (more specifically the line of 25% of the rope) with respect to the transversal axis of the plane. The arrow can be positive (extreme from backward-oriented wings regarding root or encastre, which is usual), neutral, or negative (extremely advanced). To have a more graphic idea, let us put our arms on the cross as if they were wings; in this position they have a null arrow, if we cast them back they have a positive arrow, and if we cast them forward they have a negative arrow.
- Thickening: In a wing, a relationship between the string of the elar profile at the tip of the wing divided by the string of the elar profile of the encastre. (Crowsing=Cuerda of the profile at the wing tip/Cuerda of the encastre profile). That is, the variation of the length of the rope along the wing. A rectangular wing has a narrowing 1 and a triangular wing narrowing 0. Two forms may be narrowed (or both):
- Plant narrowing (planform taper): reduction of the rope and thickness from the encastre to the tip ("conicity").
- Thickening (thickness taper): thickness reduction from the encastre to the tip, but the rope remains constant.
Plantform of the wing
When designing an airplane, the planform will mainly determine the wing load distribution (and therefore the effort in the root), the efficiency of the wing and the resistance of the wing, in addition, it is necessary to take into account when choosing it, factors such as manufacturing cost, space for the systems and the flight conditions of the aircraft.
Due to the plan shapes, the wings can be classified as:
- Rectangular or straight. It is typical of the plane, a wing shaped like a rectangle. Very cheap and easy to build. This wing is installed on low-speed, low-speed, short-flying aircraft that anticipate a cheap aircraft before efficient. Examples of planes with rectangular wing are Piper PA-32, Thorp T-18 or Pilatus PC-6
Ala Recta
Piper PA-32 Cherokee Six
Thorp T-18
Pilatus PC-6 Porter
Fairchild-Republic A-10 Thunderbolt II
- Trapezoidal. Also typical of avionetas, it is a wing that its width from the root to the tip is gradually reduced by giving it a trapezoidal shape. It is more efficient than the right wing giving for a construction difficulty not much greater. It is also possible to find this type of wing in supersonic hunts. Airplanes using this wing are, with a very small wing, the X-3 Stiletto, or F-22 Raptor and X-32 fighters.
Trapezoidal
X-3 Small wing Stiletto
F-22 Raptor hunts with a low wing
X-32, a Boeing hunting prototype
Grob 102 Astir, a single-layer sailboat, appreciates the great lengthening
- Elliptical. Wing that minimizes induced resistance. Typical of some World War II fighters as they did not use wing tip devices. Pretty complicated to build, it's a wing practically disused. Hunts like the Supermarine Spitfire, the Heinkel He 112, some Heinkel He 111 models and the Bäumer Sausewind.
Elliptical
Supermarine Spitfire, famous World War II Hunt
Three Heinkel He-111 in training.
- Arrow. The wing forms a non-right angle with the fuselage, thus it is possible to deceive the air that the plane finds by reducing the number of Mach that actually see the wing profiles. They are typical of high subsonic flight planes, thus reducing the Mach from divergence and therefore to the same engine power can fly faster. They also usually carry this type of wing supersonic hunts when they do not use other configurations. Examples of arrow wing can be found in most of the current passenger transport planes, the B-52 (one of the first series reactors in service), the Su-47 with reverse arrow or the F-14 with variable arrow wing.
Arrow
Inverted arrow
Variable arrow
Double arrow
B-52, plane with wing in arrow.
X-29, experimental plane with wing in reverse arrow.
F-14 Tomcat, variable geometry wing plane, with folded wings (high arrow).
F-14 Tomcat with extended wings (small arrow).
- Delta is the wing generally used for supersonic flight planes, especially in combat fighters. The great advantage of this wing is that it gets the edge of attack of the wing to be delayed regarding the shock wave generated by the tip of the plane. A large majority of hunts have this type of wing like F-106, also using a canard like the Eurofighter typhoon (whose fuselage also meets the area rule)
Delta
Delta with canard
Delta with timons
Double delta
F-106 with canned wing. It also has a fuselage adapted to the area rule
Saab 39 Gripen, plane with wing in delta and canards.
F-16, winged aircraft in delta and timons.
Saab 35 Draken, double-deck wing aircraft.
- Ojival. It is a variation of the wing in the form of delta. The Concorde supersonic plane is a clear example for this type of wing.
Ojival
Concorde, the supersonic commercial plane of the European industry
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