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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3
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2answers
103 views

What does “wraparound” mean in the context of flight controls?

In the references regarding the flight control (for example in F-16) I see the word "wraparound". For example "Rudder coil wraparound", "IBU pitch wraparound", "IBU lateral wraparound"or "AMUX bus ...
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4answers
11k 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?
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3answers
3k views

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 ...
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0answers
100 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 ...
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1answer
345 views

In F-16, is rudder used to arrest the adverse yaw effects (by FBW) in direction of roll during an aileron roll? or opposite way?

Is the rudder moving by FBW in direction of roll or in the opposite direction? I understand that the rudder is used due to the ARI system (ailerons - rudder interconnect), but don't have any idea ...
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1answer
66 views

How much force is produced by control surfaces?

Context: For some context, I'm a game developer and I'm building a flight sim game. My goal is to have realistic -- not arcade -- physics. The game is in Unity. Unity handles the actual application ...
12
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1answer
528 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 ...
3
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1answer
193 views

What is the function of activating an individual elevator on the B-1B Lancer?

This B-1B Lancer's picture I captured from this Youtube video. The control axes is from Wikipedia. As we know, the three "conventional" axes are as follows: Roll axis controlled by aileron, Pitch ...
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2answers
1k views

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 ...
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2answers
883 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?
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2answers
223 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?
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1answer
183 views

What are the maximum possible stabilizer and elevator deflections for the A320?

For research purposes I would like to know the maximum deflection angles (in both positive and negative direction) of the A320-200's stabilizer and elevator. I am trying to analyse what flight ...
3
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1answer
392 views

What flight controls should be used to counter asymmetric yaw?

How should the autopilot or pilot handle asymmetric yaw, as with one failed engine on a multi-engine turboprop whose engines are not on the centerline? Should one apply roll control or rudder control?
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2answers
2k 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?
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1answer
100 views

Do all Bombardier jets have manual reversion?

Whatever CRJ 700 or Learjet 35A/45XR. Do these aircraft have full manual reversion? Can you operate the flying surfaces in a hydraulic failure? These aircraft are very small – even ...
3
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1answer
139 views

Does the MU-2 have a crossover airspeed?

Airplanes generally have a crossover airspeed (a minimum airspeed below which directional control of the airplane cannot be maintained in the event of a rudder hardover). This is because, as airspeed ...
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1answer
2k views

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 ...
4
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2answers
71 views

How to calculate the variation of Z force with elevator deflection (Zδe) in Nelson for pitching dynamics?

I have been trying to model the pitching dynamics of a General Aircraft (Nelson, "Flight Stability and Control"). I need to use the Zδe which uses ...
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3answers
2k views

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 ...
2
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2answers
103 views

Surface deflection if loss of hydraulics on combat jet

In a typical combat jet from the 1970ties, at loss of hydraulic pressure, how does the deflection surfaces behave? If it happens on the runway, will the weight of the surfaces make them deflect ...
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1answer
80 views

Where can I find details on the control surfaces of the F-15C?

Me and my team were working on a short animation and I need precise details on the following if you guys can point me to a website or answer them here it'll save hours off my search cause Google isn't ...
7
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3answers
713 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 ...
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1answer
117 views

How does a circulation control helicopter work

This essay describes that this helicopter uses circulation control of the rotor for cyclic and collective control, but not how circulation control works. https://ntrs.nasa.gov/archive/nasa/casi.ntrs....
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3answers
282 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 ...
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0answers
36 views

Effect of Rudder on Velocity Vector

Suppose we have an aircraft flying in steady, level flight at zero angle of attack. In this configuration, the velocity vector $\vec{V}$ is perfectly aligned with the $x$ axis. At some time $t=t_0$, ...
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2answers
791 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 ...
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2answers
158 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 ...
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5answers
5k views

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 ...
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2answers
199 views

What would happen if the elevators were set to opposite angles?

For example left elevator angle = +30 deg, right elevator angle = -30 deg. Would these settings be able to induce a rolling moment on the aircraft? What would happen with the pitch?
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2answers
241 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?
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1answer
271 views

How can an airplane roll, yaw and pitch up and down without control surfaces?

This is a Sprat 103 ultralight, it has no ailerons, and no ruddervator (on its v-tail). How then does it fly controllably?
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1answer
246 views

Is aerodynamic flutter speed dependent?

Is it possible for control surface flutter to occur at low Reynolds and low speed? If yes,why don't Ultralights have counter weights or tail sting mass to immune the control surfaces against flutter ...
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1answer
625 views

Is the 737NG hydraulically controlled or electronically controlled?

I know that the 737NG is not fly-by-wire, but are the control surfaces controlled with hydraulic systems that transfer the input from the pilot to the control surfaces via fluid (hydraulics), or is ...
7
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1answer
456 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 ...
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4answers
405 views

How can larger wingspan decrease the strength of wingtip vortices?

In the last paragraph from the link below, it states that Vortex Strength is inversely proportional to Wingspan. Why is this? http://avstop.com/ac/flighttrainghandbook/wingtipvortices.html EDIT: ...
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2answers
239 views

Is having the tailplane at the wings backwash a design flaw?

Most airliners have their tailplane below or above the backwash of the wings, so is placing the tail control surfaces directly in the backwash of the wing a disadvantage?
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4answers
4k views

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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1answer
324 views

How do I calculate the lift force on an aileron?

How do I calculate the force of lift acting on an aileron with a deflection of 8° and a flight speed of 40km/h?
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2answers
395 views

What is a minimal step angle deflection for flight control surfaces?

If the flight control surfaces (ailerons, elevators, rudder) are controlled digitally by servo motors, yet disregarding the way how the input to the servo motors get generated (manually or autopilot), ...
0
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1answer
343 views

How does the propeller position affect the effectiveness of control surfaces?

I've found several questions about differences between pusher and puller aircraft, but the effectiveness of control surfaces was not discussed in any of them. Consider the following three scenarios: ...
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2answers
1k views

How strong would a servo motor need to be to power the control surfaces of a fixed wing ultralight aircraft?

I'm looking to build an ultralight aircraft. The video above shows a good example of how one is controlled with wires or with metal fulcrums/levers, but I am ...
18
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3answers
3k 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 ...
8
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3answers
2k views

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.
3
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1answer
815 views

How are the dimensions of the empennage determined for jetliners?

How is the height of the vertical and span of the horizontal stabilizers determined for different turbofan aircraft like the Airbus A380 and the Boeing 747-8? What are the maximum forces (in ...
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0answers
209 views

What is the relation between missile fin deflection limit and altitude?

What's the relation between limit of deflection for aerodynamic control surfaces (tail control) and altitude for surface to air missiles? Also how can the fin deflection range (Max/Min) be determined ...
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2answers
2k views

How does hydraulic actuator servo valve feedback work?

The book Aircraft Systems uses the following diagram for a mechanically controlled hydraulic linear actuator (for moving a control surface e.g. an aileron): The following explanation is given about ...
10
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5answers
4k views

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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2answers
957 views

What kind of flaps are used in gliders?

I'm estimating some wing parameters for an imaginary airplane (simple college project). We are allowed to use coefficients for any basic types of flaps (plain/split/slotted/Fowler etc), but since I'm ...
2
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1answer
488 views

Does it make sense to use a canard in combination with a conventional aft elevator control surface?

I am designing a UAV and have settled on a canard design. However, I’m curious whether it would be helpful to have a typical horizontal stabilizer behind the wing as well as a canard wing in front of ...
15
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6answers
3k views

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 ...