Talk:Swept wing

Untitled
It says at the bottom that von Karman discovered the importance of the swept wing; I believe it was Adolf Busemann who first proposed wing sweep with an aim to reducing wave drag. —Preceding unsigned comment added by ‎ 81.101.116.73 (talk) 21:34, 14 December 2006

Models work
In model airplanes, the forward sweep design is awesome. It adds stability and control, and has a very low stall speet. It is also very durable when crashed :-P Basically take the shape of a delta plane, and add on forward swept wings to the existing ones, put the engine in back, but in front of the control surfaces, and you have yourself one awesome flight.

"Discussion" inside body text moved here
I found this discussion inside the body text and moved it here.

!-- this next stuff is so garbled that I have no idea what it means, should it be removed??? -	Probably, Arnero -	.......... -	The real question is now, why would the air see a shorter chord at lower speeds? Especially considering that span wise flow is outwards (for swept back)? -		 -	Looking at the design evolution of the B-52 one can see that chord length and sweep increase, but chord length increases -	more than a rotation of the wing would suggest. Also some experimental aircraft in WWII had swing wings to be operated on the ground, but modern aircraft are designed in the computer and there is no reason for rotation. Sweep and airfoil can be altered independently. And nowhere is said that the chord is not to be measured along the streamlines. Even look at the ribs and engines of the B-52, they are stream-aligned. This whole "fool" stuff is just for "fools", who want an easy misleading explanation. The explanation for the successful experiments and the widespread use is found in the article about the Supercritical airfoil.--


 * Not only was that the wrong place, but the content is simply incorrect. The reason the B-52 gained chord and sweep over its evolution was the captured German data, as explained (and refed) further into the article. I'm not sure what the difference between "head on" and "stream-aligned" is supposed to mean -- when I look at a B-52 head-on, the engines are pointed right at you. That's what I mean by "head on" and I think what you're trying to say with "stream aligned". Finally, I don't understand what the connection is to supercritical airfoil, research from over a decade later. Please, try to explain what you mean in depth. Maury (talk) 18:43, 28 August 2008 (UTC)

ugh
painful physical explanations, muddled with aviation trivia. swept wings mitigate effects of compressibility, not just wave drag. an accurate and concise explanation of swept wing aerodynamics (this wikipedia article is neither): http://www.desktopaero.com/appliedaero/potential3d/sweeptheory.html. the fool explanation implies a swept wing should be equivalent to a straight wing shaped on an airfoil with a stretched chord, definitely false. &amp;#9992; James C. (talk) 07:39, 6 September 2009 (UTC)

Is this sentence complete rubbish!?
This is at the end of the "Subsonic and transonic behavior" section:

"The Starfighter has had a large number of landing accidents caused by its very high landing speed that was needed to keep the wing generating enough lift to fly."

What is the "Starfighter"?? I've never heard of this plane, and can't find information on it anywhere. It may be true but it hasn't got any references...Delete?... —Preceding unsigned comment added by Jez 006 (talk • contribs) 16:35, 21 December 2009 (UTC)

Also the first reference of the article does not work. Jez 006 (talk) 16:45, 21 December 2009 (UTC)


 * Starfighter is the Lockheed F-104 Starfighter. A Wikilink is providing in the preceding sentence.


 * I agree that the first reference in the article is not presently functioning. I have hidden it.  If it resumes its function at some time in the future, or an alternative functioning URL can be located, this Wikilink can be unhidden. Dolphin51 (talk) 03:52, 23 December 2009 (UTC)

Ah, sorry about that, thanks for pointing that out. Still not entirely sure if that sentence is justified though...the only information about landing speed on the F-104 Starfighter page is -

"The small, highly-loaded wing resulted in an unacceptably high landing speed, so a boundary layer control system (BLCS) of blown flaps was incorporated, bleeding engine air over the trailing-edge flaps to improve lift. The system was a boon to safe landings, although it proved to be a maintenance problem in service, and landing without the BLCS could be a harrowing experience."

It would be nice to have a reference to all these "landing accidents" that have taken place due to the landing speed. I just read through the F-104 Starfighter article and it talks about many accidents...but none just caused by "high landing speeds".Jez 006 (talk) 17:49, 23 December 2009 (UTC)


 * I think all references to the F-104 Starfighter are inappropriate in an article dedicated to wing sweep. The Starfighter actually has very little wing sweep!  The high landing speed is due entirely to high wing loading and low maximum lift coefficient, not wing sweep.  I might re-visit the article today and delete some or all of it. Dolphin51 (talk) 21:39, 23 December 2009 (UTC)

Exactly. Thanks for your helpJez 006 (talk) 16:02, 24 December 2009 (UTC)

Definition
How about a definition of what a swept wing is at the start of the article? —Preceding unsigned comment added by ‎ Gebars (talk) 15:09, 8 March 2012

Introduction
In the Introduction section there is a sentence: "The British Supermarine Spitfire used as thin a wing as possible for lower high-speed drag, but later paid a high price for it in a number of aerodynamic problems such as control reversal." It is difficult to see why it is in this article and more importantly, it is rubish. See Supermarine Spitfire Wiki article Talk archive3 section Elliptical Wing to see Kurfürst's failed attempt to spread this misinformation. So the claim is untrue and isn't even appropriate to this article. I suggest that it should be removed.VaidaXX (talk) 19:02, 23 August 2013 (UTC)

No reaction in two weeks, so I deleted the sentence and also the following one ("German design instead opted for thicker wings, accepting the drag for greater strength and increased internal space for landing gear, fuel and weapons."), which was really in error. Neither Bf 109 nor Fw 190 carried any fuel inside their wings, but of Spitfire fighter versions at least Spitfire Mks VII, VIII and XIV had small extra fuel tanks (14 ImpGal per wing) inside the leading edges of their wings saying nothing on the Long Range PR Spitfires which from PR ID onwards carried vast amount of fuel inside their leading edges. And after Bf 109E no production 109 carried any weapon inside their wings but from Spitfire Mk VC onwards Spitfires with C wing had the option of 4 20mm wing cannon which was also the normal armament of Fw 190As. And all three, Spitfire, Bf 109 and Fw 190 had their landing gear retracking inside their wings. Ok I admit that Spitfire had the shortest l/g legs but still.VaidaXX (talk) 17:11, 6 September 2013 (UTC)

Subsonic and transonic behavior[edit]
''As airflow accelerates around curved surfaces, near the speed of sound this can cause the airflow to reach supersonic speeds. When this occurs, an oblique shock wave is generated at the point where the flow slows back to subsonic speed.''

Since this occurs on curved areas, these shock waves are normally associated with the upper surfaces of the wing, the cockpit canopy, and the nose cone of the aircraft, areas with the highest local curvature.

'''The above is I am fairly sure in error. The air does not 'accelerate' around curved objects in the common language use of accelerate as in to speed up. ''' In the case of a wing the air does not 'speed up over the upper surface' with reference to the static air, this is a myth. It actually slows down slightly due to form drag. This is easily seen in wind tunnel smoke stream videos. http://www.cam.ac.uk/research/news/how-wings-really-work

The reason shock waves form as they do and where they do; (such as when the maximum T/C passes or on the reducing taper of a cockpit canopy) is due to a drop in air density as the air turns the corner and rapidly expands to fill the space formerly occupied by the solid object. This rapid lowering of density changes the local speed of sound. If is occurs in the transonic range it can cause part of the aircraft to go supersonic.

This is why supercritical wings are flatter on top and more curved underneath. The very gentle angular change of the local air flow due to the flatter upper wing surface reduces the density drop and weakens the shock wave thereby reducing drag.

The formation of shockwaves varies due to density - in static air caused by temperature. Density (often due to temperature) 5.112.18.148 (talk) 13:57, 21 March 2017 (UTC)

some comments
there are some scientifically wrong words used that is better to be edited: 1- mach number is a dimensionless number that should not use as much speed! 2- critical mach number and drag divergence mach number are different and should not computerized as each other here it is definitions: critical mach number is the mach number when somewhere on the wing section becomes sonic drag divergence is the mach number which drag will rise rapidly rise after that please someone fix do these changes to help other. Regards, an Aerospace engineer.

External links modified (January 2018)
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the swept wing of the Messerschmitt Me 262
was obviously remarkable. I'm no native speaker and working on many other wikipedia 'road works'.

May some fellow wikipedian contribute ? --Neun-x (talk) 19:23, 20 February 2018 (UTC)
 * Not really. Wing sweep was introduced on the Me 262 as much to position the wing root for optimum pilot visibility as anything else. It was too small to have any real aerodynamic significance. The aircraft already has a mention and that is probably enough &mdash; Cheers, Steelpillow (Talk) 20:00, 20 February 2018 (UTC)

Does it not also increase lift because of greater chord length?
And should this not be mentioned in the intro? — Preceding unsigned comment added by 82.68.94.86 (talk) 16:36, 4 March 2018 (UTC)
 * First, please do not top-post. We do not do that on Wikipedia.
 * No, it does not increase lift. As you rotate a given wing back and increase the effective chord, at the same time the span reduces and both the area and loading, which define the lift, remain more or less constant. Alternatively, if you apply a shear transformation to create the sweep while maintaining span, then the chord, area and loading remain unchanged. After that it gets more complicated, so no, this is not a sensible topic to mention in the article lead section. &mdash; Cheers, Steelpillow (Talk) 17:05, 4 March 2018 (UTC)

Template warning
When I try to change a word in the lede I get a Template cite web warning. Why is that? Thanks.Pieter1963 (talk) 21:32, 31 January 2022 (UTC)


 * The explanation appears to be too complicated for me to try to comprehend. I have tried editing the lede with the following results: If I try to edit any place in the article, using the “whole of article EDIT tab” (at the top of the page) I see the template warning you describe; but if I try to edit the lede only, using the EDIT option alongside the title “Swept wing”, the template warning doesn’t appear, so no problem.


 * The option to select the lede or an individual section for editing is an option not available for unregistered editors (using an IP address), but it is available as an option for registered Users. If you don’t have this option visible when you view each article you should activate it. (I think it can be found under your Preferences tab at the top of the page. Let me know if you can’t find it.) Dolphin ( t ) 22:24, 31 January 2022 (UTC)


 * I've always had the edit tab on individual sections. Having just looked at my general option preferences section editting was not enabled altho I always had it. Now it's enabled with no apparent changes. ie I still don't see an option to edit the title line.
 * I transferred the lede to the sandbox led and got the same warning but text updates ok so perhaps it doesn't matter?
 * Also put lede in a sandbox section which does have its own edit option and still get the message.
 * Having done all that it still edits ok.

Pieter1963 (talk) 22:57, 31 January 2022 (UTC)Pieter1963 (talk) 22:53, 31 January 2022 (UTC)

Cylindrical wing
ref 7th para 'subsonic and transonic flight' section : One of the simplest and best explanations of how the swept wing works was offered by Robert T. Jones: "Suppose a cylindrical wing (constant chord, incidence, etc.) is ...

In what way is it cylindrical? Thanks.Pieter1963 (talk) 23:53, 1 February 2022 (UTC)


 * A cylinder is a 3-dimensional figure whose cross-sectional shape is identical at all points along its axis. (My wording.) So round drums, tanks, straight pipes, straight hoses can all be described as “circular cylinders”. An long body extruded through a triangular die could be described as a “triangular cylinder.”


 * A cylindrical wing would be a wing with the same cross-sectional shape at each point along its span - same chord, thickness, airfoil section etc. If the wing is swept it would consist of two cylinders, joined at the fuselage, and each one swept backwards at the same angle relative to the fuselage centreline.


 * It might be an improvement to delete reference to cylindrical and simply say a wing of uniform chord, thickness and airfoil section. Dolphin ( t ) 00:18, 2 February 2022 (UTC)


 * I think so since aircraft don't have such wings. The underlying problem here is that RT Jones wasn't writing for a general audience so quoting him verbatim is out of place in this article even though it is introduced as one of the simplest explanations. Have moved it to Theory section.Pieter1963 (talk) 14:58, 2 February 2022 (UTC)

Pigeonholeing
Wing configuration classifies swept wing and delta separately and there are separate articles Swept wing and Delta wing. However, Swept wing includes delta aircraft and bridges-the-gap/justifies-the-inclusion with the vague "delta is a form of swept wing". Is this ok or shall I take out the delta examples? Thanks.Pieter1963 (talk) 16:46, 2 February 2022 (UTC)