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Aspect ratio (aeronautics) An ASH 31 glider with very high aspect ratio (AR=33.5) and lift-to-drag ratio (L/D=56) In aeronautics, the aspect ratio of a wing is the ratio of its span to its mean chord. It is equal to the square of the wingspan divided by the wing area. Thus, a long, narrow wing has a high aspect ratio, whereas a short, wide wing ...
The Oswald efficiency is defined for the cases where the overall coefficient of drag of the wing or airplane has a constant+quadratic dependence on the aircraft lift coefficient. where. For conventional fixed-wing aircraft with moderate aspect ratio and sweep, Oswald efficiency number with wing flaps retracted is typically between 0.7 and 0.85 ...
This indicates how, for a given wing area, high aspect ratio wings are beneficial to flight efficiency. With being a function of angle of attack, induced drag increases as the angle of attack increases. [4]: Section 5.17 The above equation can be derived using Prandtl's lifting-line theory.
The Lanchester-Prandtl lifting-line theory[1] is a mathematical model in aerodynamics that predicts lift distribution over a three-dimensional wing from the wing's geometry. [2] The theory was expressed independently [3] by Frederick W. Lanchester in 1907, [4] and by Ludwig Prandtl in 1918–1919 [5] after working with Albert Betz and Max Munk.
The ratio of the length (or span) of a rectangular-planform wing to its chord is known as the aspect ratio, an important indicator of the lift-induced drag the wing will create. [7] (For wings with planforms that are not rectangular, the aspect ratio is calculated as the square of the span divided by the wing planform area.)
At the opposite end of the spectrum was the large Convair B-36: its large wings resulted in a low 269 kg/m 2 (55 lb/sq ft) wing loading that could make it sustain tighter turns at high altitude than contemporary jet fighters, while the slightly later Hawker Hunter had a similar wing loading of 344 kg/m 2 (70 lb/sq ft).
A high aspect ratio indicates a long, narrow sail, whereas a low aspect ratio indicates a short, wide sail. [39] For most sails, the length of the chord is not a constant but varies along the wing, so the aspect ratio AR is defined as the square of the sail height b divided by the area A of the sail planform: [3] [30]
Lift (force) When a fluid flows around an object, the fluid exerts a force on the object. Lift is the component of this force that is perpendicular to the oncoming flow direction. [1] It contrasts with the drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to ...