Talk:Flap (aeronautics)

message: Does anyone know anything about the history of flaps?  I was thinking about this on a flight to CDG today - who is credited with first developing them?  When?  I'm pretty sure that the Wright Flyer didn't have any...  Duncan (talk) 20:38, 20 June 2008 (UTC)
replies: text: Seconded. No one wants to address this over 10 years?? --BjKa (talk) 12:01, 12 April 2017 (UTC)
thread_title:  History 

message: I'm concerned that the issue of drag is not well dealt with. For most planes, the initial few degrees of flap extension increase lift and drag while adding full flap  produces mainly drag with little extra lift. To build on this idea, split flaps are mainly drag devices where as Fowler flaps are more efficient lift producers. Would someone like to try to capture these ideas? Cheers MarkC (talk) 23:50, 1 May 2009 (UTC)
replies: text: I've added this a few times.  People keep changing the article and posting their gross over-simplifications instead.  I've given up on re-adding it. Jadias (talk) 05:06, 26 May 2009 (UTC)
replies: text:  This should be re-added, along with mention that flaps extended above certain airspeeds can cause structural damage/failure. 64.148.241.133 (talk) 21:19, 12 September 2009 (UTC)
thread_title:  Drag 

message: The author says, useful side effect of flap deployment is a decrease in aircraft pitch angle resulting from the increase in angle of attack relative to the fuselage. This allows the pilot to lower the nose for better ground visibility. Have I misread this because whenever I have deployed flaps on base leg, the nose has pitched markedly UP and I have to trim forward to rebalance the aircraft before turning onto final? Maybe it should be rewritten that flap deployment allows the pilot to trim the nose down more for the same amount of lift, thus increasing his visibility. —Preceding unsigned comment added by Percussim (talk • contribs) 16:49, 19 September 2009
:Hi Percussim.  You have identified some shortcomings in the article so I have made some amendments.  Hopefully they improve the article.
:The article is referring to the steady-state situation following deployment of flaps, and you are referring to the transient effects.  As wing flaps are extending or retracting the pitching moment is changing.  As wing flaps are extended on a high wing aircraft the increase in downwash onto the horizontal stabilizer is predominant and the aircraft pitches nose-up, requiring the pilot to push on the elevator control or trim nose-down.  Conversely, as wing flaps are extended on a low-wing aircraft the increase in pitching moment coefficient is predominant and the aircraft pitches nose-down, requiring the pilot to pull on the elevator control or trim nose-up.
:Regardless of whether the aircraft pitched nose-up or nose-down, when the aircraft is restored to the trimmed condition after extending flaps the wing will have a lower angle of attack because of the greater camber of the wing with flaps extended.  Consequently, in a conventional aircraft, after flaps are extended for approach and landing the pilot has a better view of the ground ahead because of the lower angle of attack.  Conversely, in an aircraft with leading-edge slats or Krueger flaps the effect appears to be reversed because leading-edge devices allow a much greater angle of attack than is possible without these leading-edge devices.  Aircraft with a clean leading-edge approach to land with a generally nose-down attitude providing a good view of the ground ahead, but aircraft with leading-edge devices extended approach to land with a generally nose-up attitude.
:Delta-wing aircraft such as Concorde, the Fairey Delta 2 and the Mirage are a third case.  They can achieve very high geometric angles of attack without stalling and without the aid of leading-edge devices so they approach to land in a very nose-up attitude with resultant poor view of the ground ahead.  In the cases of Concorde and the Fairey Delta 2 it was so accentuated that the aircraft were equipped with drooping noses. Dolphin51 (talk) 12:03, 20 September 2009 (UTC)
thread_title:  Flap deployment and pitch attitude 

message: I seem to remember hearing about "Junkers flaps" being used on some ultralights, probably the Apollo Fox is one. They seem to be separate from the wing permanently. Is anyone able to document them? Jan olieslagers (talk) 19:43, 7 February 2011 (UTC)
replies: text: Gratitude to NiD.29 for serving me to full satisfaction! Jan olieslagers (talk) 19:16, 18 October 2011 (UTC)
replies: text: My pleasure - I was amazed I found a reference. NiD.29 (talk) 04:08, 19 October 2011 (UTC)
thread_title:  Junkers flaps 

message: The many images on the right mean that the reader cannot see the body of the text without scrolling down. The article is therefore not user-friendly. --TraceyR (talk) 05:45, 27 May 2011 (UTC)
replies: text: Right. So you think the article World War II would be much improved if you could read all of it without scrolling down? --BjKa (talk) 12:03, 12 April 2017 (UTC)
thread_title:  Pretty pictures spoil article at present 

message: The section has been copied from the page it links to word for word - and doesn't make any sense on either. Fluidics appears to be a means of using hydraulic pressure to control components (complete with logic gates) but its application to aviation seems problematic, and the claims (particularly about being faster or more efficient) made for it seem absurd since earlier on the fluidics page, it suggested in was several orders of magnitude slower than electronic systems, and was being phased out in the only application anyone has found for it - namely automatic transmissions. Sounds to me like some badly done corporate advertising rather than a legitimate addition to the flaps page - especially since no other mechanisms used to move flaps are discussed (though perhaps they could be?)
Does someone have an explanation that isn't complete gibberish?NiD.29 (talk) 03:34, 18 October 2011 (UTC)
thread_title:  Fluidics

message: Just came across a mention of the Cosandey flap - it is used on the rear airfoil of a tandem wing aircraft such as the flying flea and deflects up (acting much as an elevator) seemingly allowing a higher angle of attack than normal for a "parachute descent", but I can't find any good paper refs for this - can anyone help?NiD.29 (talk) 05:04, 8 January 2012 (UTC)
thread_title: More flap types

message: Greetings NiD.29, The quoted source doesn't say the blown flap was a British invention nor that first flight tests were in Germany.
It quotes a British test report dated May 1939 (ie before the war) and a German test report dated 1938. It doesn't say when the tests were actually done, nor who invented the blown flap or when.
It says German flight tests were done during the war but it doesn't claim they were the first although they may well have been. It just doesn't mention any others. The report was written in 1955 and I don't suppose the author would have known about tests in the Soviet Union, for example, if there had indeed been any. Best regardsPieter1963 (talk) 23:39, 12 January 2016 (UTC)
thread_title: blown flaps

message: I've often seen flap settings measured in degrees of deployment. The article also talks about "10° of flaps" for takeoff in a Cessna 172S. The definition of this number should be explained in the article. I could for example imagine a ruler laid against the flap, measured against the chord of the original wing profile, or the changed chord measured against a ground surface, or many other ways. So which one is it? --BjKa (talk) 12:10, 12 April 2017 (UTC)
replies: text: Any measurement you can imagine that isn't relative to the airframe would be pointless because the whole aircraft can be retrimmed to other angles other than by the flap - the 10° is relative to the aircraft itself, and is the same whether you choose to use the aircraft's datum line or the camber of the wing, or any other pair of points unless there is a serious structural problem. The flap has rotated 10°, period. - NiD.29 (talk) 14:22, 12 April 2017 (UTC)
thread_title:  Degrees 

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thread_title:  External links modified 

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thread_title:  External links modified (January 2018) 

message: There's an interesting discussion from DarkAero about different types of flap designs.  At 8:56, he's talking about Cd of a split flap and argues that it's not as bad as commonly believed. RoySmith (talk) 23:53, 19 February 2024 (UTC)
thread_title:  Drag of split flaps