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#937062

23-416: A rocket-powered small aircraft with straight, constant- chord wings, the aircraft was to be towed or carried aloft by another aircraft and released when near enemy bombers. Igniting a Schmidding 533 solid-fuel rocket engine, it was to make a first attacking pass using the 14 nose-mounted R4M 55 mm rockets, before attempting to ram the enemy bomber's wings or tail. The aircraft was expected to survive

46-403: A constant-chord wing of chord c and span b , the aspect ratio is given by: If the wing is swept, c is measured parallel to the direction of forward flight. For most wings 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 wingspan b divided by the wing area S . In symbols, For such a wing with varying chord,

69-428: A high-aspect-ratio wing. However, as the flow becomes transonic and then supersonic, the shock wave first generated along the wing's upper surface causes wave drag on the aircraft, and this drag is proportional to the span of the wing. Thus a long span, valuable at low speeds, causes excessive drag at transonic and supersonic speeds. By varying the sweep the wing can be optimised for the current flight speed. However,

92-434: A large cylinder of air, and a small wingspan affects a small cylinder of air. A small air cylinder must be pushed down with a greater power (energy change per unit time) than a large cylinder in order to produce an equal upward force (momentum change per unit time). This is because giving the same momentum change to a smaller mass of air requires giving it a greater velocity change, and a much greater energy change because energy

115-478: A long, narrow wing with a high aspect ratio has aerodynamic advantages like better lift-to-drag-ratio (see also details below), there are several reasons why not all aircraft have high aspect-ratio wings: Aircraft which approach or exceed the speed of sound sometimes incorporate variable-sweep wings . These wings give a high aspect ratio when unswept and a low aspect ratio at maximum sweep. In subsonic flow, steeply swept and narrow wings are inefficient compared to

138-400: Is also applied to the width of wing flaps , ailerons and rudder on an aircraft. The term is also applied to compressor and turbine aerofoils in gas turbine engines such as turbojet , turboprop , or turbofan engines for aircraft propulsion. Many wings are not rectangular, so they have different chords at different positions. Usually, the chord length is greatest where the wing joins

161-455: Is defined as wing area divided by wing span: where S is the wing area and b is the span of the wing. Thus, the SMC is the chord of a rectangular wing with the same area and span as those of the given wing. This is a purely geometric figure and is rarely used in aerodynamics . Mean aerodynamic chord (MAC) is defined as: where y is the coordinate along the wing span and c is the chord at

184-533: Is most significant at low airspeeds. This is why gliders have long slender wings. Knowing the area (S w ), taper ratio ( λ {\displaystyle \lambda } ) and the span (b) of the wing, the chord at any position on the span can be calculated by the formula: where λ = C T i p C R o o t {\displaystyle \lambda ={\frac {C_{\rm {Tip}}}{C_{\rm {Root}}}}} Aspect ratio (wing) In aeronautics ,

207-416: Is proportional to the square of the velocity while momentum is only linearly proportional to the velocity. The aft-leaning component of this change in velocity is proportional to the induced drag , which is the force needed to take up that power at that airspeed. It is important to keep in mind that this is a drastic oversimplification, and an airplane wing affects a very large area around itself. Although

230-467: Is usually measured relative to the MAC, as the percentage of the distance from the leading edge of MAC to CG with respect to MAC itself. Note that the figure to the right implies that the MAC occurs at a point where leading or trailing edge sweep changes. That is just a coincidence. In general, this is not the case. Any shape other than a simple trapezoid requires evaluation of the above integral. The ratio of

253-436: 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 has a low aspect ratio. Aspect ratio and other features of the planform are often used to predict the aerodynamic efficiency of a wing because the lift-to-drag ratio increases with aspect ratio, improving

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276-415: The fuel economy in powered airplanes and the gliding angle of sailplanes. The aspect ratio AR {\displaystyle {\text{AR}}} is the ratio of the square of the wingspan b {\displaystyle b} to the projected wing area S {\displaystyle S} , which is equal to the ratio of the wingspan b {\displaystyle b} to

299-467: The standard mean chord SMC is defined as The performance of aspect ratio AR related to the lift-to-drag-ratio and wingtip vortices is illustrated in the formula used to calculate the drag coefficient of an aircraft C d {\displaystyle C_{d}\;} where The wetted aspect ratio considers the whole wetted surface area of the airframe, S w {\displaystyle S_{w}} , rather than just

322-454: The aircraft's fuselage (called the root chord ) and decreases along the wing toward the wing's tip (the tip chord ). Most jet aircraft use a tapered swept wing design. To provide a characteristic figure that can be compared among various wing shapes, the mean aerodynamic chord (abbreviated MAC ) is used, although it is complex to calculate. The mean aerodynamic chord is used for calculating pitching moments. Standard mean chord (SMC)

345-408: The coordinate y . Other terms are as for SMC. The MAC is a two-dimensional representation of the whole wing. The pressure distribution over the entire wing can be reduced to a single lift force on and a moment around the aerodynamic center of the MAC. Therefore, not only the length but also the position of MAC is often important. In particular, the position of center of gravity (CG) of an aircraft

368-491: The extra weight and complexity of a moveable wing mean that such a system is not included in many designs. The aspect ratios of birds' and bats' wings vary considerably. Birds that fly long distances or spend long periods soaring such as albatrosses and eagles often have wings of high aspect ratio. By contrast, birds which require good maneuverability, such as the Eurasian sparrowhawk , have wings of low aspect ratio. For

391-451: The leading edge. The point on the leading edge used to define the chord may be the surface point of minimum radius. For a turbine aerofoil the chord may be defined by the line between points where the front and rear of a 2-dimensional blade section would touch a flat surface when laid convex-side up. The wing , horizontal stabilizer , vertical stabilizer and propeller /rotor blades of an aircraft are all based on aerofoil sections, and

414-426: 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. (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.) Wings with higher aspect ratios will have less induced drag than wings with lower aspect ratios. Induced drag

437-455: The ramming of the bomber, owing to the strength of its wing which had a steel leading edge. It would have landed on a retractable skid. Owing to the high risk for the pilot inherent in its operation this aircraft is sometimes referred to as a suicide weapon , however it was originally not intended as such. After January 1945 an order for sixteen prototypes was placed but the Zeppelin factory

460-430: The standard mean chord SMC {\displaystyle {\text{SMC}}} : AR ≡ b 2 S = b SMC {\displaystyle {\text{AR}}\equiv {\frac {b^{2}}{S}}={\frac {b}{\text{SMC}}}} As a useful simplification, an airplane in flight can be imagined to affect a cylinder of air with a diameter equal to the wingspan. A large wingspan affects

483-402: 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 measured in the direction of airflow.) The term chord

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506-511: The wing. It is a better measure of the aerodynamic efficiency of an aircraft than the wing aspect ratio . It is defined as: where b {\displaystyle b} is span and S w {\displaystyle S_{w}} is the wetted surface . Illustrative examples are provided by the Boeing B-47 and Avro Vulcan . Both aircraft have very similar performance although they are radically different. The B-47 has

529-403: Was subsequently destroyed by bombers, ending all work on the project. Aircraft of comparable role, configuration, and era Related lists Chord (aircraft) In aeronautics , the chord is an imaginary straight line joining the leading edge and trailing edge of an aerofoil . The chord length is the distance between the trailing edge and the point where the chord intersects

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