Questions tagged [flaps]
Surfaces that extend from the wings to increase lift, allowing flight at slower speeds (such as for takeoff and landing).
163
questions
10
votes
1
answer
2k
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 ...
1
vote
1
answer
133
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 ...
- 876
1
vote
2
answers
105
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 ...
- 329
0
votes
2
answers
116
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, ...
0
votes
1
answer
190
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 ...
2
votes
1
answer
132
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 ...
- 319
3
votes
1
answer
107
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 ...
- 319
15
votes
6
answers
6k
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.
...
- 709
0
votes
0
answers
30
views
Typical flaps/slats extension chord ratios?
Fowler flaps for example extend the chord of the airfoil by about 25%. So their chord ratio is C'/C = 1.25.
Does anyone know similar values for other types of flaps, like double/triple slotted Fowler ...
- 672
4
votes
1
answer
455
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 ...
- 910
2
votes
1
answer
189
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?
- 672
2
votes
1
answer
444
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".
- 103
3
votes
1
answer
312
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.
- 672
7
votes
2
answers
2k
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.
- 103
2
votes
2
answers
1k
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:
...
- 31
2
votes
0
answers
116
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 ...
- 910
0
votes
0
answers
100
views
Comparison between Split and Slotted Flaps
Question 4:
As we know, the more complicated design of high lift systems, gives us more maximum lift @ takeoff, such as slotted (single - double) or fowler flaps type.
Beside the point of view of ...
2
votes
1
answer
127
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 ...
- 103
2
votes
1
answer
133
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?
- 31
0
votes
0
answers
95
views
Is pitch-flap coupling an aerodynamic effect or an intrinsic property of a delta 3 offset?
I am modelling a propeller, in particularly the equations of motion of the various pitch/lag/flap angles as the propeller is turning around. The blade includes a $\delta_3$ angle, which provides pitch-...
- 101
9
votes
6
answers
2k
views
Can flaps be used to perform rotation and flare?
TL; DR using flaps to directly control sink/climb rate near ground = simpler and faster response = easy to fly airplane?
Rotating is the pitch up during takeoff that causes the aircraft to leave the ...
- 3,084
2
votes
2
answers
192
views
Is there a cockpit indication if the B737 flap load relief is not working properly?
On a 737, does the pilot get any cockpit indication that his Flap Load Relief is not working properly? Say for instance due to a Flap Lever Position Switch failure?
0
votes
1
answer
962
views
Why does it feel like a plane stops in mid-air during approach?
At some stage while on approach to an airport in a commercial jet, it feels like the plane is almost coming to a complete stop in mid-air. Is this maybe as a result of the flaps engaging or the ...
- 1
7
votes
1
answer
484
views
Is it safe to fly if the flaps won't retract on ground?
The Piper Archer (PA-28) i had this morning had issues returning flaps to normal after being fully extended ON THE GROUND. It required a non trivial amount of push on the air-frame itself to restore ...
- 73
0
votes
1
answer
179
views
Is flap-asymmetry protection on airliners still active even on the ground?
On aircraft with flaps, a general certification requirement is that it must not be possible for the aircraft to suffer a loss of lateral control secondary to an asymmetric-flap condition. This ...
- 26.1k
3
votes
1
answer
231
views
Are overwing exits still useable if the flaps can’t be lowered?
Essentially all narrowbody airliners (except for the very smallest propliners), and many widebodies as well,1 are equipped with one or more overwing exits for use in an emergency evacuation; these ...
- 26.1k
18
votes
1
answer
3k
views
Why is the DC-9-80 ("MD-80") prohibited from taking off with a flap setting between 13 and 15 degrees?
A bit of digging into the 7Z9363 accident investigation has brought up some interesting information regarding the DC-9-80 ("MD-80")'s flap system:
Flaps may be positioned in any of the six ...
- 26.1k
5
votes
1
answer
485
views
Why is there an altitude limitation on operating the slats/flaps on the A320?
As per the FCOM limitations chapter there is an altitude limitation of 20000 feet for operating the flaps/slats on the A320?
Why this specific altitude?
- 1,682
0
votes
1
answer
82
views
What is the temperature of flap linkages during takeoff and landing in passenger and fighter aircraft? [closed]
During takeoff and landing, what is the temperature of flap linkages in passenger or fighter jet aircraft?
0
votes
0
answers
51
views
How can the flap deflect to higher angles (than the wing) without experiencing loss of lift? [duplicate]
For a simple aircraft wing, assume the stall angle of attack of this wing is 16 degrees. Now, if I use the same airfoil as used in the wing for the flaps, I am able to deflect the flap at quite ...
- 319
0
votes
2
answers
355
views
On large aircraft, why do flaperons not run the full length?
This is a 777 flaperon. It looks rather tiny, compared to the flap.
There have been air disasters where the airplane rolled uncontrollably for one reason or the other. It seems to me that a larger ...
- 3,084
0
votes
2
answers
311
views
How do airplane designers determine flap deflection angles for flaps of various % wing chords?
How do airplane designers determine flap deflection angles for flap chords of various % wing chords? E.g. flap chord of 30%, 40% or 50% of wing chord.
I understand most flaps' chords are about 25% of ...
- 889
14
votes
4
answers
7k
views
Why not always take off with 10 degree flaps in a Cessna 172?
10 degree flaps increase our lift, reduce stall speed, reduce ground roll.
Seems like all advantages with no disadvantages.
So why does the Cessna 172 POH say normal take off is 0-10 degree flaps?
Why ...
- 615
0
votes
0
answers
153
views
How can a designer deal with a strict requirement when designing an aircraft?
I'm working on designing an aircraft with some specific requirements (Vstall, Vmax, Ceiling, Payload, Range, RoC, Slanding/takeoff etc).
I'm following Anderson's and Raymer's ways (trying to find the ...
- 25
1
vote
1
answer
184
views
At which point in scale reduction do slats and flaps become unnecessary?
Imagine some Fi-156 Storch, and reduce its scale down gradually to 10cm span. Let's assume full scale Fiesler Storch is 100% efficient at, for example, minimizing stall speed.
During this reduction ...
- 3,913
1
vote
5
answers
1k
views
How does retracting flaps help extend the glide of an aircraft?
As per the video from Smithsonian channel
BA flight 38's captain retracted the flaps of the Boeing 777 by 5 degrees to extend glide, to travel further. Why?
- 148
2
votes
1
answer
688
views
Does the flap settings for the best lift/drag ratio change with speed on the Diamond DA20-A?
As I've recently started time building in DA20, I've noticed the AFM suggests flaps at T/O for a glide. Being very intrigued by this I run across this post. Although I appreciate Peter's reply that ...
- 55
2
votes
4
answers
4k
views
How do slats actually work?
I want to know what is the difference between slats and flaps and the mechanism of the slats
This what I know and researched about flaps:
Flaps are a kind of high-lift device used to reduce the ...
- 148
25
votes
4
answers
5k
views
Why are heavy flaps better than just a bigger wing?
Flaps increase lift during landing and T/O. But when retracted, they do nothing. The space needed to stow the common fowler flaps can't be used for anything else - fuel or structure. Extended flaps ...
- 3,084
3
votes
4
answers
575
views
Why do flaps retract?
Why do flaps retract? I know, it might seem obvious at first, because of drag, but instead of retracting the flaps, can't they just make the flaps flexible enough to get into a reduced drag position, ...
- 722
2
votes
1
answer
199
views
Does leading-edge droop increase or decrease lift, other things being equal?
Consider a conventional subsonic airfoil in level flight. Typically it is cambered and with a small positive incidence, both of which features contribute to lift.
Now droop the leading edge, as with ...
- 6,772
18
votes
7
answers
2k
views
Is lowering V1/VR (and runway length required) the only reason for flaps at take off?
I've read that some aircraft (examples include the Saab 340 and the Fokker 100) can perform flapless take offs, provided there is enough runway available. It's also my understanding that, in terms of ...
user12873
0
votes
2
answers
2k
views
A320 flap settings
Can anyone please explain about the 5 types of A320 flap settings - Up, Flap 1, Flap 2 and FULL. What do these mean? I've read that the A320 gives 2 outputs for the corresponding flap settings. What ...
- 1,643
1
vote
2
answers
1k
views
Do MD-11 pilots ever use flaps 50?
I'm curious if there is ever a purpose to use full flaps like that? Was it a bit of an overkill?
3
votes
5
answers
708
views
Can thrust vectoring be used to enable the use of flaps on tailless delta-winged aircraft?
I'm considering flying wings as well as airplanes with only vertical stabilizer for their compact size, efficiency and high speed.
As I can't find a working example of such scheme, theoretical ...
- 251
4
votes
1
answer
799
views
Why does lift curve slope increase when Fowler Flaps are deployed?
Below is an image for a Fowler Flap:
Notice that as the flap is deployed, both the camber and the area increase. This change in wing shape modifies the lift curve as follows:
(source: Development of ...
- 566
0
votes
1
answer
250
views
What does the lift coefficient take into consideration for flaps?
Angle of attack increases lift for two reasons, Camber and increased flow deflection, What reason does the lift coefficient use? Both?
- 415
4
votes
1
answer
7k
views
What is the difference between an aileron and a flap?
I have already been searching Google for the difference between an aileron and a flap, but I am not much satisfied, so now I am asking here on SE.
What is the difference between an aileron and flap? ...
- 165
5
votes
1
answer
709
views
Why do Boeing planes have more flap settings than Airbus planes? [duplicate]
The Boeing 737 and Airbus A320 are similar in size and performance. They are direct competitors. Boeing seems to have eight flap settings (1, 2, 5, 10, 15, 25, 30, 40) whereas Airbus seems to have ...
- 755
7
votes
2
answers
3k
views
What does "speed checked" mean?
Here is a Scenario:
PF: Flaps one.
PM: Speed Checked, Flaps one.
What does that mean and why do they have to say "speed checked" every time?
- 754