User:Dolphin51/Sandbox2

Wing surface area adjuster, typically for shortening take-off and landing From Wikipedia, the free encyclopedia

I found a sentence that was poorly written because another sentence had been inserted into the middle, surrounded by parenthesis and beginning with the abbreviation “e.g.”.

When an English variety's consistent usage has been established in an article, maintain it in the absence of consensus to the contrary. With few exceptions (e.g., when a topic has strong national ties or the change reduces ambiguity), there is no valid reason for changing from one acceptable option to another.

I attempted to improve the paragraph by extracting the contents of the parenthesis and using them to form their own sentence. This had the effect of dividing one very long sentence into two shorter sentences.

When an English variety's consistent usage has been established in an article, maintain it in the absence of consensus to the contrary. With few exceptions, there is no valid reason for changing from one acceptable option to another. One exception is where a topic has strong national ties or the change reduces ambiguity.

reverted my edit, leaving an edit summary saying: It’s certainly not something our Manual of Style proscribes.

is in error saying there is nothing in the MOS to proscribe the problem I was trying to repair. At WP:Manual of Style#Avoid unwarranted use it refers to abbreviations, including e.g., and says Avoid abbreviations when they might confuse the reader, interrupt the flow, or appear informal. Insertion of a bunch of words facilitated by the abbreviation “e.g.” and all surrounded by parenthesis into a perfectly good sentence most definitely interrupts the flow. It most definitely appears informal - in well-written prose, when there is value in adding extra information, it is added carefully either in a sentence of its own or by proper use of punctuation and the rules of English grammar. It isn’t added coarsely by planting parenthesis in the middle of the host sentence, adding the abbreviation e.g or i.e. and then pasting the extra information.

Also, the principles at WP:BOLD encourage Users to be bold in their attempts to improve Wikipedia. There is nothing written anywhere on Wikipedia that supports the notion that Users should only be bold in a manner that removes things that are proscribed. I’m prepared to go out on a limb and say that the millions of incremental improvements that have raised Wikipedia to its present standard are improvements that have nothing to do with what is proscribed, and what isn’t.

I invite interested Users to contribute to this discussion. Considering I initiated this discussion thread, I will restore my version until a consensus has been reached, or at least until the matter has been adequately discussed.

Aircraft design

In aircraft design and aerospace engineering, a high-lift device is a component or mechanism on an aircraft's wing that reduces the stalling speed of the aircraft at a given weight. The device may be a fixed component, or a movable mechanism which is deployed when required. Common movable high-lift devices include wing flaps and slats. Fixed devices include leading-edge slots, leading-edge root extensions, and boundary layer control systems.

Purpose

The size and lifting capacity of a fixed wing is chosen as a compromise between differing requirements. For example, a larger wing and more cambered airfoil section will lift the weight of the aircraft at a slower speed than a smaller wing, and so reduce the distances required for takeoff and landing, but at the expense of higher drag which reduces performance during the cruising portion of flight. The designs of the wings of jet aircraft are optimized for speed and efficiency during the cruising portion of flight, since this is where these aircraft spend the vast majority of their flight time. High-lift devices compensate for this design trade-off by enabling the weight of the aircraft to be lifted at the slower speeds used for takeoff and landing, and allowing the use of a more efficient wing in cruising flight.

Stalling speed

The stall of a fixed-wing aircraft occurs at the angle of attack called the critical angle of attack. The aircraft lift coefficient is a maximum at this critical angle of attack. This lift coefficient is denoted by $C_{L}max$ .

The $C_{L}max$ of an aircraft is strongly influenced by the airfoil sections used in the design of the wing, and the presence of any high-lift devices. When a high-lift device is extended in flight it increases the $C_{L}max$ of the aircraft, and this reduces the stalling speed.

High-lift devices are used to increase the camber of the wing section and increase $C_{L}max$ . For example, if $C_{L}max$ is 1.5 with high-lift devices retracted, deploying those devices might raise it to 2.0 and reduce the stalling speed by 13%.^[1]

Types of device

Flaps

When a flap is extended it re-shapes the airfoil section to give it more camber, or more chord, to reduce the stalling speed and lift the weight of the aircraft at a slower speed.^[2]^[3] The most common high-lift device is the trailing-edge flap. Leading-edge flaps are also used on most high-speed jet aircraft.

There are many different designs of trailing-edge flap:

Simple hinged flaps came into common use in the 1930s, along with the arrival of the monoplane which had higher landing and takeoff speeds than the old biplanes.
In the split flap, the lower surface hinges downwards while the upper surface remains fixed to the remainder of the wing.
Travelling flaps extend backwards to increase the chord when deployed, increasing the wing area. These began to appear just before World War II.
Slotted flaps comprise several separate small airfoils which separate apart, hinge and even slide past each other when deployed. Such complex flap arrangements are found on many modern aircraft.^[4] Some large modern airliners make use of triple-slotted flaps.

Slats and slots

Another common high-lift device is the slat, a small aerofoil shaped device attached just in front of the wing leading edge. The slat re-directs the airflow at the front of the wing, allowing it to flow more smoothly over the upper surface when at a high angle of attack. This allows the wing to be operated effectively at the higher angles of attack required to lift the weight of the aircraft at slower speeds. A slot is the gap between the slat and the wing.^[5] The slat may be fixed in position, with a slot permanently in place behind it, or it may be retractable so that the slot is closed when not required. If it is fixed, then it may appear as a normal part of the leading edge of a wing, with the slot buried in the wing surface immediately behind it.

A slat or slot may be either full-span, or may be placed on only part of the wing (usually outboard), depending on how the lift characteristics need to be modified for good low-speed control. Slots and slats are sometimes used just for the section in front of the ailerons, ensuring that when the rest of the wing stalls, the ailerons remain effective and the airflow upstream of the ailerons remains attached to the wing surface.

The first slats were developed by Gustav Lachmann in 1918 and simultaneously by Handley-Page who received a patent in 1919. By the 1930s automatic slats had been developed, which opened or closed as needed according to the flight conditions. Typically they were operated by airflow pressure against the slat to close it, and small springs to open it at slower speeds when the dynamic pressure reduced, for example when the speed fell or the airflow reached a predetermined angle-of-attack on the wing.

Modern systems, like modern flaps, can be more complex and are typically deployed hydraulically or with servos.^[6]^[7]^[8]

Boundary layer control and blown flaps

Powered high-lift systems generally use airflow from the engine to shape the flow of air over the wing, replacing or modifying the action of the flaps. Blown flaps take "bleed air" from the jet engine's compressor or engine exhaust and blow it over the rear upper surface of the wing and flap, re-energising the boundary layer and allowing the airflow to remain attached at higher angles of attack. A more advanced version of the blown flap is the circulation control wing, a mechanism that ejects air backwards over a specially designed airfoil to create additional lift through the Coandă effect. The Blackburn Buccaneer had a sophisticated boundary layer control (BLC) system which involved compressor air blown onto the wings and tailplane to reduce the stalling speed and facilitate operations from smaller aircraft carriers.

Another approach is to use the airflow from the engines directly, by placing a flap so that it deploys into the path of the exhaust. Such flaps require greater strength due to the power of modern engines and also greater heat resistance to the hot exhaust, but the effect on lift can be significant. Examples include the C-17 Globemaster III.

Leading edge root extensions

More common on modern fighter aircraft but also seen on some civil types, is the leading-edge root extension (LERX), sometimes called just a leading edge extension (LEX). A LERX typically consist of a small triangular fillet attached to the wing leading edge root and to the fuselage. In normal flight the LERX contributes little to the total lift. At higher angles of attack, however, it generates a vortex that is positioned to lie on the upper surface of the main wing. The swirling action of the vortex increases the speed of airflow over the wing, so reducing the pressure and increasing the maximum value of the lift coefficient. LERX systems are notable for the potentially large angles of attack at which they are effective.

Co-Flow Jet

A Co-Flow Jet (CFJ) wing has an upper surface with an injection slot after the leading edge and a suction slot before the trailing edge, to allow the required lift to be available at a higher angle of attack, increase the stall margin and reduce drag. CFJ is promoted by the mechanical and aerospace engineering department of the University of Miami. For a hybrid-electric regional aircraft based on the ATR 72 with the same wing area, size and weight, CFJ improves its cruise lift coefficient for a higher wing loading, allowing more fuel and batteries for longer range.^[9]

[1]
Hurt, H.H. (1960), Aerodynamics for Naval Aviators, pp.37-45, University of Southern California
[2]
Abbott and Von Doenhoff (1949), Theory of Wing Sections, Chapter 8, Dover Publications, New York
[3]
Clancy, L.J. (1975), Aerodynamics, Chapter 6, Pitman International
[4]
Taylor 1990, p. 337.
[5]
Kermode, A.C. Mechanics of flight, 8th Edn., Pitman, 1972
[6]
Taylor 1990, p. 346
[7]
Taylor 1990, p. 399.
[8]
Abzug, Malcomb (2005). Airplane Stability and Control: A History of the Technologies that Made Aviation Possible. 231: Cambridge University Press. p. 416. ISBN 9780521021289.{{cite book}}: CS1 maint: location (link)
[9]
Graham Warwick (Jan 21, 2019). "The Week In Technology, Jan. 21-26, 2019". Aviation Week & Space Technology.

Flaps

Slats and slots

Boundary layer control and blown flaps

Leading edge root extensions

Co-Flow Jet

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