Questions tagged [control-surfaces]

Aircraft flight control surfaces allow a pilot to adjust and control the aircraft's flight attitude. Development of an effective set of flight controls was a critical advance in the development of aircraft. Early efforts at fixed-wing aircraft design succeeded in generating sufficient lift to get the aircraft off the ground, but once aloft, the aircraft proved uncontrollable, often with disastrous results.

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34
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4answers
12k views

Why do military jets sometimes have elevators in a depressed position when parked?

Why do they have elevators in such a position as if the joystick is pushed forward, even though there's nobody inside the cockpit?
31
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5answers
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In the early days of flight, were there any cockpit control schemes other than the modern one?

Back in the early days, what kind of control schemes were invented for aircraft, other than the modern one? (pedals to yaw, yoke to pitch and roll). I'm only interested in control schemes that can be ...
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3answers
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Why is the Tu-144 the only commercial airplane with canard configuration?

I understand the delta wing was chosen because of the supersonic cruise (like the Concorde), and canards were added to reduce the approach/landing speed. But canards may be used without delta wing (e....
19
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2answers
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What is the purpose of these odd “control surfaces” on the BAE Taranis?

I was looking at a video of the BAE Taranis, and noticed these weird control surfaces: There is a matching pair on the underside. They don't seem to move at all throughout the video, even on landing, ...
18
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3answers
4k views

How do elevons work to roll a flying wing?

I have an RC Flying Wing that uses elevons for control. To go up both elevons move upwards and the wing pitches up. Both go down and the wing pitches down. I’m OK with this. However, if I want to ...
17
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5answers
9k views

How are cruise missiles different from ballistic missiles?

Cruise missiles and ballistic missiles are used by many nations as offensive and defensive technology. How do cruise missiles and ballistic missiles maneuver, and what are the differences between the ...
15
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6answers
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Can an airplane fly with on-off control surfaces?

I understand that, at least for remote-controlled model planes, the control surfaces can point to a range of angles, say, from $-30^\circ$ degrees to $30^\circ$. My questions are: Would the same ...
15
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1answer
2k views

What is the purpose of this aileron trailing edge strip?

See the following photos of the LH aileron of a Beechcraft King Air B200: Source: own work Source: own work As seen in the above photos, the Beechcraft King Air B200 has what I would describe as a ...
13
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3answers
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Do jackscrews suffer from blowdown?

With hydraulic control surfaces, at high airspeeds, there is a point where aerodynamic loads exceed the capability of the actuators. This limits control authority and can result in the control surface ...
12
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2answers
1k views

How does flight control surface authority change with AOA?

I am working on semi-realistic (let's just call it "believable") flight simulation component set for a game engine. One of the topics that I tried to research but could not find reliable information ...
12
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1answer
825 views

Does the B-1B Lancer have controllable canards?

These three pictures shows the B-1B Lancer's canards and its elevators. I am not sure to call that feature a canard as the jet also has elevators. In my limited understanding, canard and elevator are ...
12
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3answers
1k views

Why do aircraft have a crossover airspeed, and why does it increase at higher vertical load factors?

According to the NTSB accident report on the crash of USAir Flight 427, all commercial aircraft have a crossover speed (the speed at which the maximum rolling force from the aircraft’s ailerons and ...
11
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3answers
1k views

Can the MH-60 helicopter fly without one or all of the stabilators?

The MH-60R helicopter has a horizontal Stabilator that consists of three subassemblies, RH Stabilator, LH Stabilator, and Center Stabilator. Can the aircraft fly without the RH Stabilator? Can the ...
11
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1answer
731 views

What aircraft had the first pilot-assisted controls?

This question about regulations regarding hydraulic flight controls got me thinking about the history of hydraulic or pilot-assisted controls. As aircraft get larger the control surfaces must grow ...
10
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5answers
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Can an aircraft be turned without rudder input?

Is it possible for pilots to make a right or left turn, using just the ailerons and without rudder input in all airliners? If not why so, for what reason?
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1answer
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Is the location of an aircraft spoiler really that vital?

I was wondering that spoilers in most of the aircraft are always placed aft (towards the tail) the CG location. Why aren't they placed ahead of the wings or near the nose of the aircraft? The same is ...
10
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2answers
976 views

Why do gliders have bungee cords in the control systems and what do they do? Are they on all control surfaces? What about ultralights?

Why do gliders have bungee cords in the control systems and what do they do? Are they on all control surfaces? Why don't ultralights have them?
10
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2answers
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How is pitch controlled in a flying wing?

How do delta wing or flying wing aircraft maintain their pitch attitude in the absence of an elevator? I understand that the ailerons on the wings do control the banking/roll, but they are ...
10
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2answers
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Will control surfaces on a plane be less efficient at a higher altitude?

I may be wrong but I learned that control surfaces depends on the air flow to work properly, and that airliners have a higher cruise altitude because of the less dense atmosphere, improving the fuel ...
10
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1answer
5k views

What are the pros and cons of having canard control surfaces versus a horizontal tail control surface?

For a normal civil aviation aircraft, what are the pros and cons of having Canard control surfaces or horizontal tail control surface?
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2answers
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How does trim work on an A320?

In the very interesting answer from Jan Hudec to a question about the various flight control computers on Airbus planes, two different means to trim the aircraft are mentioned: The stabiliser and the ...
9
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2answers
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Are the functions of ailerons and rudder similar?

The ailerons help the plane to bank left/right by increasing lift to one wing and decreasing in another. Likewise, the rudder also helps in turning the plane by yawing and deflecting the nose right/...
9
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4answers
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Is a monobloc variable incidence wing viable (updated)?

Could this be a viable way to control roll on an aerobatic airplane, using some sort of tab to control a monobloc variable incidence wing? Both wings are mechanically linked together in order to only ...
9
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3answers
727 views

Has anyone researched or built an aircraft that controls pitch and roll by pumping liquid within the airframe?

I am confident I have seen an article couple years ago about a "static surface aircraft" (or at least a concept of it) with no control surfaces, which uses a "wet mass" to adjust its roll and pitch. ...
8
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3answers
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Do fighter jets use elevators as ailerons?

I saw jets in game using elevators to roll right and left, but I never saw them doing in real life. I was wondering if fighter jets actually use elevator to roll like they do in game.
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2answers
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How are flaps controlled?

I can understand what function(s) the flaps serve, but how are they controlled from an internal perspective? Does flipping the switch send signals to an electrical servo? Or is it hydraulics? How are ...
8
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3answers
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Why is the tail group of virtually every airplane swept instead of straight?

Even low performance airplanes like ultralights have their tail group (vertical and horizontal stabilizer with rudder and elevator) swept backwards knowing fully well that a straight tail group will ...
8
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3answers
747 views

Has the Boeing 737 MAX MCAS system successfully prevented a stall or approach to stall condition outside testing?

The Boeing 737 MAX MCAS system has been in the press a lot as it has been implicated as a possible cause of 2 fatal crashes. The MCAS system was put in to prevent a wing stall caused by excessive ...
8
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2answers
719 views

What are advantages and disadvantages of flaperons?

What are some advantages and disadvantages of flaperons? Do they cause some issues or are they top-notch reliable?
8
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1answer
209 views

Why were the ailerons of the Fokker Dr. I (Red Baron) located on the top wing?

Photos' source are here: Fokker Dr. I (Red Baron), and here: a Sopwith triplane. They are probably not the actual airplane but only (claimed) authentic models. It makes sense to me that the Sopwith ...
8
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2answers
193 views

How long does it take on average for a control surface to deflect by one degree?

I know this should vary quite a bit (because of aircraft size / use / build / actuation / control surface weight), but I was wondering if anyone here could ball-park some numbers on how long it would ...
7
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5answers
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Why don't commercial aircraft use all-movable tail surfaces like my RC plane? [duplicate]

Many conventional RC planes use control surfaces at the tail just like the image below: You can see there is a part in front of each surface control that never moves and only the surface control ...
7
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2answers
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What does it mean to move a single flight control to its full deflection?

It is the speed below which you can move a single flight control one time, to its full deflection, for one axis of airplane rotation only This is part of the explanation of maneuvering speed. What ...
7
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2answers
1k views

How do X-shaped control surfaces work?

I watched this video of the Raytheon SDB II and noticed that it seems to have no control surfaces on its wings, just the four fins on the tail. How do these fins work to alter the attitude of the SDB ...
7
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2answers
8k views

What are the advantages and disadvantages of ruddervators?

Can someone clearly explain the advantages and disadvantages of ruddervators? I cannot find the answer anywhere else.
7
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3answers
290 views

If all control surfaces were disabled, could a passenger plane be controlled by distribution of the passengers?

Let's assume that a large military plane has its control surfaces disabled in combat. The engine(s) can still be controlled. There is a substantial number of ground forces being transported. In ...
7
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2answers
633 views

Do modern airplane controls provide force feedback of external forces on the control surfaces?

As I was sitting inside the cockpit of an old AN-26 at the aviation museum, long grounded and no longer flightworthy, sudden gusts of wind outside would sometimes move the control surfaces and make ...
7
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1answer
520 views

Do airliner spoilers really “spoil” lift?

The two illustrations below show the typical spoiler location and the lift distribution of a wing. For comparison a third picture shows the location of spoilers on a glider. It appears the airliner ...
7
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1answer
246 views

What would the “wings level” button most likely do if activated in the event of a flat spin?

If an aircraft equipped with a wings level button (such as the TBM 930) entered a flat spin, would pressing it accomplish anything productive? I am aware that the purpose of the button is to return ...
7
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1answer
1k views

Are Aircraft yokes self centering in non-auto pilot mode?

In a typical car steering wheel if you release it while the car is in motion, it will return to its center, neutral position. What's the corresponding situation in an airplane? Is a yoke self ...
6
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4answers
2k views

Why don't airliners have rudders on the winglets?

There are a couple airplanes out there that use the winglet as the rudder, but why doesn't the winglet have a rudder on it to increase the turn of the aircraft?
6
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2answers
3k views

What kind of horizontal stabilizer does a Boeing 737 have?

Does this plane have fixed horizontal stabilizers and elevators or has it been fixed with stabilators instead?
6
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2answers
2k views

Is there a parameter that links the areas of the fuselage and control surfaces? [closed]

Do aircraft designers look at the ratio of how much fuselage surface area can be loaded onto a given unit of wing and tail surface area including elevator, aileron, rudder etc? (Possibly, the surfaces ...
6
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2answers
2k views

What is the difference between a trim tab and a servo tab?

They both seem very similar but can someone please explain their main differences and principle of operation?
6
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3answers
7k views

How do pilots adjust trim on the B777, where the control forces are simulated?

I know that pilots of small airplanes (e.g. Cessna 172) use force to trim, i.e. they hold the required attitude using the yoke, then trim the aircraft until no force is required to hold the yoke in ...
6
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1answer
1k views

How does the canard plan of the Dassault Rafale work?

I'm quite puzzled after seeing some videos of the Dassault Rafale. When pulling the stick, the canard plan should move as in this video (low speed, high angle of attack, stick pulled backward on ...
6
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2answers
331 views

How do you know the maximum load a control surface can withstand?

source This is a separate strength testing (load testing) of the elevator of an airplane, how was the load determined? How did the engineers determine the maximum elevator load?
6
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1answer
483 views

How does a flight control computer deal with control surface disengagement?

What action does the flight control computer take (under normal law) when it realizes, for instance, Inboard actuator of aileron/elevator disengaged or There is a disconnect between the LVDT and ...
6
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2answers
671 views

How does a self-centering rudder affect left-turning tendency?

In this answer to a question about controls, Peter Kämpf mentions the Klemm 35: ...the rudder has two narrow strips which are deflected slightly to the left and the right, respectively. This ...
6
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1answer
1k views

How do canard flaps work?

Before examining this XB-70 picture I thought that all canard were one single flight control surface (as seen on many fighters such as the Eurofighter Typhoon), and that there functionning were ...