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Showing posts from March 2, 2019

Trailing edge

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Cross section of an aerodynamic surface with the trailing edge emphasised An American Aviation AA-1 Yankee showing its wing trailing edge with aileron (deployed downwards) and flap while being refuelled The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge rejoins. [1] Essential flight control surfaces are attached here to control the direction of the departing air flow, and exert a controlling force on the aircraft. 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. The shape of the trailing edge is of prime importance in the aerodynamic function of any aerodynamic surface. George Batchelor has written about: “ ... the remarkable controlling influence exerted by the sharp trailing edge of an aerofoil on the circulation.” ...

Chord (aeronautics)

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Chord of an aerofoil section. Chords on a swept-wing In aeronautics, a chord is the imaginary straight line joining the leading and trailing edges of an aerofoil. The chord length is the distance between the trailing edge and the point on the leading edge where the chord intersects the leading edge. [1] [2] The point on the leading edge that is used to define the chord can be defined as either the surface point of minimum radius, [2] or the surface point that will yield maximum chord length [ citation needed ] . The wing, horizontal stabilizer, vertical stabilizer and propeller of an aircraft are all based on aerofoil sections, and the term chord or chord length is also used to describe their width. The chord of a wing, stabilizer and propeller is determined by measuring the distance between leading and trailing edges in the direction of the airflow. (If a wing has a rectangular planform, rather than tapered or swept, then the chord is simply the width of the wing...

Dihedral (aeronautics)

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For other uses, see Dihedral. The upward tilt of the wings and tailplane of an aircraft, as seen on this Boeing 737, is called dihedral angle. Dihedral angle is the upward angle from horizontal of the wings or tailplane of a fixed-wing aircraft. "Anhedral angle" is the name given to negative dihedral angle, that is, when there is a downward angle from horizontal of the wings or tailplane of a fixed-wing aircraft. Schematic of dihedral and anhedral angle of an aircraft wing Dihedral angle (or anhedral angle) has a strong influence on dihedral effect , which is named after it. Dihedral effect is the amount of roll moment in a direction produced by the amount of side slip in the opposite direction. Dihedral effect is a critical factor in the stability of an aircraft about the roll axis (the spiral mode). It is also pertinent to the nature of an aircraft's Dutch roll oscillation and to maneuverability about the roll axis. Measuring the dihedral angle Lo...

Spar (aeronautics)

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Main spar of a de Havilland DH.60 Moth In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles (or thereabouts depending on wing sweep) to the fuselage. The spar carries flight loads and the weight of the wings while on the ground. Other structural and forming members such as ribs may be attached to the spar or spars, with stressed skin construction also sharing the loads where it is used. There may be more than one spar in a wing or none at all. However, where a single spar carries the majority of the forces on it, it is known as the main spar. [1] Spars are also used in other aircraft aerofoil surfaces such as the tailplane and fin and serve a similar function, although the loads transmitted may be different from those of a wing spar. Contents 1 Spar loads 1.1 Forces 2 Materials and construction 2.1 Wooden construction 2.2 Metal spars 2.3 Tubular metal spars 2.4 Geodesic constru...

Aircraft fabric covering

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Fabric covering of a de Havilland Tiger Moth showing rib stitching and inspection rings. Aircraft fabric covering is a term used for both the material used and the process of covering aircraft open structures. It is also used for reinforcing closed plywood structures, the de Havilland Mosquito being an example of this technique, and on the pioneering all-wood monocoque fuselages of certain World War I German aircraft like the LFG Roland C.II, in its wrapped Wickelrumpf plywood strip and fabric covering. Early aircraft used organic materials such as cotton and cellulose nitrate dope, modern fabric-covered designs usually use synthetic materials such as Dacron and butyrate dope for adhesive, this method is often used in the restoration of older types that were originally covered using traditional methods. Contents 1 Purpose/requirements 2 Early use 3 WWI/Post WWI 4 WWII 5 Introduction of modern materials 6 Covering processes 6.1 Traditional me...