1 WING The wing is the principal structural unit of the airplane. It has several functions beyond that of providing lift. For a wing to produce "lift", it must be oriented at a suitable angle of attack relative to the flow of air past the wing. In aerodynamics, angle of attack (AOA) specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. On larger airplanes the engines are mounted in nacelles either attached to the wing or mounted in the wing. The nacelles also provide a housing for the landing gear when it is retracted. The space within the wing is usually used for fuel storage. The main geometrical features of a wing are its span; the area of the wing; its dihedral angle; its sweepback angle; and the wing section. Dihedral angle is the upward angle of an aircraft's wing, from the wing root to the wing tip. The amount of dihedral determines the amount of inherent stability along the roll axis. Although an increase of dihedral will increase inherent stability, it will also decrease lift, and increase drag. The design of the wing depends on the size, weight, and use of the airplane. Generally, there are two kinds of wing design: cantilever and semi-cantilever. The semi-cantilever usually has one, or perhaps two, supporting wires or struts attached to each wing and the fuselage. As far as the internal structure is concerned, there are three general types of conventional wings: monospar, two-spar, and multispar. Stringers are longitudinal members which are attached to the upper and lower skin to make it stiff. They are used in the design of a wing with stressed skin. Ribs are the basic elements of the wing structure which give the wing section its shape and also transmit the air loads from the skin to the spars. 2 Many of the control functions are provided by special devices built into the wing. Most obvious are the ailerons and landing flaps. Flaps are high lift devices. There are many different types of flaps used, with the specific choice depending on the size, speed and complexity of the aircraft on which they are to be used, as well as the era in which the aircraft was designed. Plain flaps, slotted flaps, and Fowler flaps are the most common. Krueger flaps are positioned on the leading edge of the wings and are used on many jet airliners. The leading edge is the part of the wing that first contacts the air. The leading edge may be equipped with e.g. leading edge extensions, leading edge slats, leading edge slots, vortex generators. The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge rejoins. Essential control surfaces are attached here to redirect the air flow and exert a controlling force by changing its momentum. Such control surfaces include ailerons on the wings for roll control, elevators on the tailplane controlling pitch and the rudder on the fin controlling yaw. Elevators and ailerons may be combined as elevons on tailless aircraft. Other surfaces and equipment that may be attached to the trailing edge of an aircraft's wing or on its control surfaces include: trim tabs, servo tabs, anti-servo tabs, and flaps. Vocabulary structural konstrukční, strukturální to provide poskytovat, vytvářet aerodynamics aerodynamika angle of attack úhel náběhu chord line tětiva atmosphere atmosféra, prostředí to mount montovat, uložit nacelle gondola housing kryt landing gear podvozek to retract zatahovat fuel storage uložení paliva obvious zřejmý, jasný landing flap přistávací klapka aileron křidélko 3 dihedral angle úhel vzepětí sweepback angle úhel šípu wing section profil křídla wing root kořen křídla wing tip špička/konec křídla inherent stability přirozená stabilita roll axis osa klonění weight hmotnost cantilever wing samonosné křídlo semicantilever wing polosamonosné křídlo spar nosník křídla, podélník monospar jednonosníkový multispar vícenosníkový stringer tvarový podélník, podélná výztuha member článek, konstrukční prvek skin potah stiff tuhý stressed skin nosný potah rib žebro to transmit přenášet load zatížení plain flap jednoduchá klapka slotted flap štěrbinová klapka Fowler flap Fowlerova klapka Krueger flap Kruegerova klapka leading edge náběžná hrana trailing edge odtoková hrana, zadní hrana extension nástavec, prodloužení slat slat, náběžná klapka slot slot, štěrbina vortex generator turbulátor, vyvíječ vírů, vířič to rejoin opět se spojit to redirect přesměrovat air flow proud vzduchu to exert vyvinout, projevit, uplatnit momentum hybnost, impuls, kinetická energie aileron křidélko tailplane stabilizační plocha elevon elevon trim tab vyvažovací klapka servo tab pomocná klapka Exercises 1. Read and translate angle: dihedral angle, sweepback angle, aileron angle, angle of attack wing: cantilever wing, delta wing, dihedral wing, upper wing, stressed-skin wing, high-aspect-ratio wing, long chord wing, multispar wing, swept-back wing, fixed wing 4 edge: leading edge, fixed leading edge, movable leading edge, trailing edge, trailing edge flap, tip edge axis: longitudinal axis, axis of symmetry, rudder axis, elevator axis, horizontal axis lift: tail lift, high-lift devices, wing lift, static lift ratio: lift-drag ratio, aspect ratio skin: double skin, stressed skin, upper skin, sandwich skin, fuselage top skin fin: two-spar fin, tapered fin, swept-back fin, fixed fin 2. Fill in The wing has several functions beyond that of ........................lift. On larger airplanes the engines are mounted in .........................either attached to the wing or mounted ....................... it. The nacelles also provide a housing for the landing ............................ when it is ..................................... The ................ within the wing is usually used for fuel ............................... The main geometrical ...................................... of a wing are its ................................; the area of the wing; its dihedral angle; its ....................................angle; and the .........................................section. Dihedral angle is the upward ........................ of an aircraft's wing, from the wing ............................ to the ................................... tip. Generally, there are two kinds of wing design:.....................and ...................... Stringers are longitudinal members which are ................................ to the upper and ............................ skin to make it ............................ Ribs transmit the air loads from the skin to the ........................... There are many different types of flaps used, with the specific choice ......................on the size, ................................ and complexity of the aircraft on which they are to be used. The leading .............................. is the part of the wing that first contacts the air. The trailing edge of a wing is its rear edge, where the ......................... separated .................the leading edge ..................................... Elevators and ailerons may be combined as ………………………on tailless aircraft. 3. Put into plural The leading edge is the front edge of the wing. The airplane is moving around three axes. The horizontal tail consists of a stabilizer and an elevator. On a large airplane the engine is mounted in a nacelle. This type of wing has no stringer. An automatic form of this device is also used. The elevator controls the angle of attack. A fin is fixed and a rudder is movable. 4. Find opposites To retract the landing gear, landing, horizontal, front, leading edge, movable, high, down, small, upper, similar, different, internal, monospar, maximum, conventional, single, civil, obvious, stiff, longitudinal, climb, low-wing, heavier-than-air, generally, assembly, anhedral angle 5 5. Answer 1. What is the main function of the wing? 2. Where are the engines mounted on larger airplanes? 3. What purpose is the space within the wing used for? 4. What are the main geometrical features of a wing? 5. How would you define the term “dihedral angle”? 6. What factors does the design of the wing depend on? 7. How many kinds of wing designs are there? 8. When are stringers used? 9. Which part of the wing structure gives the wing section its shape? 10. What types of flaps do you know? 11. What is the difference between the leading edge and the trailing edge? 12. Explain the term “elevon”. 6. Interpret Another method for increasing lift is to change the curvature, or camber, of the wing. In general, the greater the curvature, the lower the efficiency at higher speeds. The trailing edge flaps provide both high lift and high efficiency by making it possible for the pilot to change the curvature according to the flight conditions. The increase of lift in this way is about 10 percent. 7. Give a short description of a wing Additional materials Elevons are aircraft control surfaces that combine the functions of the elevator (used for pitch control) and the aileron (used for roll control), hence the name. They are frequently used on tailless aircraft. A leading edge slot is a fixed aerodynamic feature of the wing of some aircraft to reduce the stall speed and promote good low-speed handling qualities. A leading edge slot is a span-wise gap in each wing, allowing air to flow from below the wing to its upper surface. Leading edge slats are aerodynamic surfaces on the leading edge of the wings of fixed-wing aircraft which, when deployed, allow the wing to operate at a higher