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Questions tagged [flaps]

Surfaces that extend from the wings to increase lift, allowing flight at slower speeds (such as for takeoff and landing).

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Question on a flapped vs non-flapped wings local lift coefficients

I'm developing a workflow in XFLR-5 for adding flaps/control surfaces to a wing design, and I encountered an interesting thing in my data results that I wanted some more insight on. In plotting a ...
Dryden6400's user avatar
1 vote
2 answers
88 views

Effect on Thrust and Power Required Curves of Flaps

I know for a fact that the extension of flaps shifts the thrust required/total drag curve higher. How do I prove mathematically that it also shifts to the left (LDmax with flaps extended occurs at a ...
Terry's user avatar
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3 votes
1 answer
242 views

Is it better for a flap and/or aileron to be an airfoil shape or simply replicating the trailing edge shape of the wing?

I am designing a UAV with the goals, broadly speaking, of a short take-off and high top-speed. I've already selected the airfoil for the wing itself. The wing is going to have a single slotted flap, ...
Postman's user avatar
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0 votes
2 answers
149 views

Are flap track fairings (just the appendages themselves) necessary for wing aerodynamics?

Coming from this answer by Peter Kämpf leaving me a little perplexed about the necessity of flap track fairings. without flap tracks, would we still need them on the wing of any given sub/transonic ...
ageek245's user avatar
5 votes
3 answers
2k views

What drives the mechanical challenges which make trailing-edge flaps an (almost) ubiquitous solution vs leading-edge flaps?

(Apologies for the mouthful of a title.) I was thinking about canard aircraft and how trailing edge flaps (TEF) are actually counterproductive for them. Leading edge flaps (LEF) could theoretically ...
Kenn Sebesta's user avatar
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5 votes
6 answers
622 views

Is it pragmatic to use slats and flaps to maintain position of center of lift?

I am coming to this with an amateur understanding of CL, Cp and their contribution to the overall lift of a wing, so bear with me :) I have been wondering for some time about whether you could design ...
Timothy Cater's user avatar
6 votes
1 answer
201 views

Split flap variant

Reading about this Q&As, how would a split flap behave if it acted like a solid, with no real split, but a thick trailing edge? Mostly wondering what happens between a) and c) and influence of ...
user721108's user avatar
10 votes
3 answers
2k views

Split Flaps and lift?

Do split flaps produce lift? I don't see how, because there is no change in camber. It seems like an upside down speed break, producing only drag
Willaim Aylikci's user avatar
6 votes
5 answers
2k views

Does more lift cause a plane to stall at a lower airspeed?

Does more lift cause a wing to stall later? (By more lift I mean a bigger wing) I was looking and saw this question, but the answers didn’t really address why more lift will help a plane not stall. ...
Wyatt's user avatar
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-1 votes
1 answer
128 views

Thoughts on Idea - AP Disengage, Land Flap Selection

When AP disengages the aircraft goes into a slight roll or the possibility exists for the aircraft to go into a degree of roll. Do you think it would be prudent for airlines to include as an SOP for ...
oshsec's user avatar
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8 votes
1 answer
2k views

Visually see flap settings from passenger window behind wing

I've flown on a lot of Airbus and seen a lot of trip reports on YT and wonder if you can visually see the different flap settings (if you are seated at a window behind the wing), for example Up, Flap ...
DilKent's user avatar
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9 votes
2 answers
2k views

Why such a small Krueger flap on 777-300?

Why is there such a small Krueger flap just inboard of the engine pylon on the Boeing 777-300, when the rest of the wing (including the further-inboard section of the wing) has leading edge slats? I ...
pr1268's user avatar
  • 1,955
0 votes
1 answer
125 views

what is the cross section of an elevator and trailing edge flap?

Is the cross section of both a Trailing edge flap and elevator an aerofoil please or, like i've shwon in in image below? I tried to find a side view of an elevator and TE deflected to see this for ...
SirTimothy's user avatar
1 vote
0 answers
159 views

Is there a known problem with the Airbus A340, fuel, flaps/slats and temperature?

From the press I read that the German minister of foreign affairs stranded with an Airbus A340 in Abu Dhabi, because the flaps or slats would not correctly retract. To return to the airport they had ...
U. Windl's user avatar
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3 votes
1 answer
309 views

What would the effect be of flap deployment on a UAV such as the Reaper or Predator?

I've read answers that said that the climb performance is usually worse with flaps extended, and the pilots would, if they could, just retract them and get into a clean config as soon as possible. ...
Sharva Potdar's user avatar
3 votes
3 answers
3k views

How come deflected flaps cause a nose-up pitching moment in high-wing aircrafts and a nose-down pitching moment in low-wing aircraft?

I imagine that the increased downwash due to the new camber of a high-wing aircraft causes a down-force on the horizontal stabilizer which in turn causes a nose-up pitching moment. However, I read ...
mino's user avatar
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1 vote
0 answers
445 views

Role of Spoilers in Conjunction with Flaps A350

Upon observing the Airbus A350, I have noticed that both the outboard and a few of the inboard spoilers are deployed maybe three quarters of an inch when the flaps are fully extended. I assume this is ...
Eddie's user avatar
  • 150
0 votes
1 answer
145 views

How does a trailing edge flap move on an Airbus A320?

Airbus flaps move in flight direction [link] I don't exactly understand how that works, do they move just 180 degrees (opposite direction) of the flight path or is it something else? And doesn't ...
Aviation Enthusiast's user avatar
-2 votes
1 answer
288 views

Disadvantages of the Fowler trailing edge flap?

I get that the trailing edge plain flap has disadvantages (like tendency to separate flow as I read on a question on here) But what’s so bad with the fowler flap? Aren’t they like really efficient and ...
FlightWatcher's user avatar
3 votes
4 answers
3k views

Which one of these flaps is used on take off and land?

I’m really confused about which one of these flaps is used on take off and land? I didn’t even know there were different types, I thought that the top configuration was the only used one today? Also, ...
FlightWatcher's user avatar
6 votes
3 answers
2k views

Why are trailing edge flaps used for landing? [duplicate]

Why are flaps used when landing? Doesn’t a flap increase lift? Edited: why are there so many different flaps on the back of a wing? Isn’t one just used when taking off and landing? Are the others ...
FlightWatcher's user avatar
1 vote
3 answers
630 views

Why is a level off required for flap retraction after a single engine failure?

In the Airbus A320, why do we need to level-off for flap-retraction after a single engine failure? Even if we maintain a climb, the airspeed will still accelerate and be enough to retract the flaps ...
Sachin Chaudhary's user avatar
1 vote
1 answer
89 views

Trailing edge flap disadvantages

What does ‘high local surface curvature’ mean with respect to trailing edge flaps? I’ve been reading up on them, and that came up as one of their disadvantages?
MikeKnows's user avatar
4 votes
1 answer
245 views

Is there any significance to the flap design on some Cessna citations?

In some business jets, I've noticed that the flaps seem to be split into sections. Here is one example on Cessna citation As you can see, the flaps are split into three sections. The Embraer Phenom ...
Boeing787's user avatar
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1 vote
1 answer
287 views

What is the additional planform area added to an A380 on take-off flaps setting (Flaps 1+F)

I would like to know how I can approximate the additional area added to wing on flaps 1+F: Can someone use other dimensions they know of the A380 wing and approximate what this area would be, we can ...
vLxgic's user avatar
  • 11
0 votes
1 answer
87 views

How does varying camber affects control over an aeroplane? [duplicate]

How does a trailing edge flap actually help an aeroplane? It just changes camber but what does that exactly do that’s beneficial?
Ranulph's user avatar
0 votes
0 answers
61 views

What flaps are used for, if the aircraft has already landed? [duplicate]

When watching the below clip in the final approach sequence we can clearly hear setting flabs to 1, 2 and then to maximum. At 12:05 into the clip, when fully landed ...
trejder's user avatar
  • 4,160
3 votes
1 answer
371 views

Flaps type for Beech Bonanza V-35B

I'm writing a thesis on airplanes' flaps and I was analizing the flaps on the Beech Bonanza V-35B: on the book "The wind and beyond - Volume II" published by NASA on page 375 states that ...
Lollo's user avatar
  • 33
1 vote
2 answers
537 views

What happens to aerofoil downwash with Flaps extended vs retracted and how does it affect the Tail down force?

In my logic: Flaps extended will cause a greater Angle of Attack, to maintain Straight and Level Flight, AoA will be reduced, due to the increased "Surface", this allows to fly at lower ...
Ted Staggs's user avatar
0 votes
1 answer
144 views

How long does it take to complete a partial and full flap overspeed inspection?

I am trying to determine the cost of a flap overspeed inspection. Ignoring the cost of any parts. On average, how long does a flap overspeed inspection take? Or how long would a partial/full flap ...
Pilot Collins's user avatar
1 vote
3 answers
231 views

Can the flap on one wing be used to reduce a left turning tendency?

I fly a single engine Jabiru UL45 and it has a tendency to turn left during straight and level flight. Is it possible, in order to reduce a "Heavy Wing" to slightly increase the degree of ...
Kev's user avatar
  • 21
8 votes
2 answers
2k views

Is a plane stalled during landing rollout?

IMAGE SOURCE: https://pilotinstitute.com/wp-content/uploads/2022/01/Parts-of-a-Wing.jpg As the lift dumpers are extended on landing they cause the air to move away from the wing. Also as the flaps are ...
Aviation Enthusiast's user avatar
6 votes
4 answers
1k views

Why is flap retraction done in stages?

After takeoff and upon achieving positive climb, why is flap retraction done in stages? For example, in the Airbus there are characteristic speeds after which flaps can be retracted (S and F speeds) ...
user avatar
9 votes
1 answer
3k views

Can flaps on Airbus/Boeing airliners be deployed at high speeds during cruise, still?

Brief Background of the Incident Mayday Season 22 Features an Episode "Terror over Michigan" (Episode 6) based on the events of TWA Flight 841. The Episode revolves around a Boeing 727 ...
Atheesh Thirumalairajan's user avatar
1 vote
1 answer
199 views

How do GA aircraft flaps stay in place?

On most small GA aircraft such as the well-known Cessna 172P "Skyhawk", the flaps are electrically actuated. Now - how do they stay at the setting selected by the pilot after extension ? Is ...
TheEagle's user avatar
  • 1,404
1 vote
2 answers
129 views

Is it possible to reduce the angle of fully extended flaps of an aircraft without affecting lift generated?

I think flaps are inspired from eagle feathers which increase the overall wing surface area and help provide the necessary lift at lower speeds. However, fully extended flaps hang lower and cause more ...
lousycoder's user avatar
0 votes
2 answers
142 views

Reasoning for an inboard flap- take off [duplicate]

so Ive been looking into airplane flaps, like the longer one for take off- Is it correct to say that the only reason to have one is for take off, to make it take off easier? And so when they take off, ...
Jonathan Ching's user avatar
0 votes
1 answer
645 views

Elevator or Aileron?

I was just looking at an airplane take off, and when it was taking off, some flaps were facing down at the back of the main wings- Are these Ailerons or elevators please? I did some research but the ...
Jonathan Ching's user avatar
2 votes
1 answer
650 views

How can I calculate 'Max aircraft Load Factor' and 'Max aircraft Speed' when flaps are fully extended on a civil aircraft? [closed]

I am trying to calculate the critical loading conditions for Flaps (in order use them inside my Finite Element Analysis to, determine if the Flaps will be able to bear these critical loads) during the ...
Rameez Ul Haq's user avatar
3 votes
1 answer
266 views

Does use of flaps or ailerons affect the aerodynamic forces distribution on the wing area before them?

Assume I want to use the flaps or ailerons at a specific altitude for some maneuevers on an aircraft. We know that the overall aerodynamic forces like lift and drag on an aircraft wing will change ...
Rameez Ul Haq's user avatar
15 votes
6 answers
7k views

Why aren't takeoff flaps used all the way up to cruise altitude?

In general aviation aircraft such as Diamond star DA-40, flaps to take-off are used until 500ft AGL and speed before retracting flaps is Vy (best ROC speed)-67kts and after retracting flaps is 80kts. ...
Krishna Kanth's user avatar
4 votes
1 answer
655 views

Is all the extra lift from flaps added upstream where the spars sit?

Flaps can significantly increase the lift for a wing, is all that extra lift added upstream where the spars sit? I ask this question because the flaps in airliners seem to be only connected by a few ...
Mridul's user avatar
  • 1,242
2 votes
1 answer
624 views

Does the A220-300 have krueger flaps or are all of its leading-edge highlift devices slats?

They look like slats to me, but I could be wrong. I'm asking because I know the 737, a very similar airplane, has inboard krueger flaps. Also, what number of slats/krueger flaps does it have?
stevederekson555's user avatar
2 votes
1 answer
2k views

What trailing edge flap design does the A350 use? Is it similar to the A380?

Both Airbuses have similar flap deployment based on some YouTube videos I have watched, just wondering if they both have the same flap design being "Single-Slotted Fowler Flaps".
Isaac's user avatar
  • 103
3 votes
1 answer
1k views

How many Krueger flaps does the 737-700 have?

How many Krueger flaps does the 737-700 have? It has inboard krueger flaps, but I'm trying to make out if it has one or two.
stevederekson555's user avatar
7 votes
2 answers
3k views

What flap design does the A380 use? Is it Fowler flaps, slotted flaps or a combination?

I have looked at maintenance manuals, the Airbus website, and Wikipedia but still could not find a definite answer as to what trailing edge flaps the Airbus A380 uses.
Isaac's user avatar
  • 103
2 votes
2 answers
6k views

What are the approach speeds for each flap setting in a Cessna 152?

I am still trying to understand how the approach speeds for different flap speeds work. I cant find it in the handbook but I want to know the different approach speeds for the following flap settings: ...
C.D.Smith's user avatar
4 votes
0 answers
738 views

How can I design a slotted flap?

I have not been able to find satisfactory methods on design of slotted flaps, or flaps in general. Most of the answers are about eyeballing or experience. Can you guide me on what could be good ...
Mridul's user avatar
  • 1,242
2 votes
1 answer
389 views

Why does the Information Manual say "C172S - Flaps 10 (Preferred) for Normal Takeoff", when the models before S-model do not have this note?

Do Flaps 10 really do anything performance-wise other than reducing ground roll and distance over a 50-foot obstacle? If not worried about clearing an obstacle, does a Flaps UP-normal takeoff make ...
Jacob Doore's user avatar
2 votes
1 answer
242 views

Who manufactured the 737 MAX flap track fairings?

I can't seem to find the information online, would anyone of you know where / by who the flap track fairing for the B737 MAX is produced?
Max's user avatar
  • 31