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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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Aerodynamics of Flight Control Surfaces

From what it appears to me, flight control surfaces seem to be taken for granted. In terms of how they actually work and what kind of physical outputs they give in terms of forces and such. Take for ...
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Where is the control loop of the actuator closed?

When electro-hydraulic servo-actuators are used for the actuation of control surfaces in aircraft, linear variable differential transformers (LVDTs) are used for position or velocity feedback. There ...
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Are there roll control devices other than ailerons?

With the little that I've learnt about aeroplanes, I know that the aileron is the control surface that a pilot use to roll the plane by decreasing the lift of one wing and increasing the lift of the ...
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Why would engine fire cause loss of control?

I was wondering why engine fire would cause of loss of control or crash. There is loss of power and even drag. But could some expert please expand on the troubles of a engine fire?
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what are the no load rates of f-16 control surfaces?

What are the no-load rates for the control surfaces of f-16 like flaperon,leading edge flap and horizontal and vertical stabs?
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Did the Wright brothers discover the three-axis control system for airplanes/gliders and the adverse yaw?

1) Various sites like this one: Orville and Wilbur Wright, The Inventors of the 3-axis Flight Control System, 9 Months before their powered flight at Kitty Hawk say that the two brothers invented the ...
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What hardware standards should the flight control computer pass?

There are some standards for each part of the aircraft like actuators, sensors,... I could not find one for the flight control computer hardware. For example what are the environmental tests, or any ...
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322 views

Why were trim tabs invented?

I understand the need for a trimming mechanism, but why use a secondary control surface placed on top of the first, when you could just adjust the resting position of the aileron/elevator/rudder ...
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Does the SAS (stability augmentation system) actuators of f-14 use jet-pipe or flapper-nozzle technology?

F-14 uses electrohydraulic servo actuators for its SAS. What type of hydraulic amplification is used in F-14? jet-pipe, flapper-nozzle or something else?
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How many actuators does the F-35 have for each primary control surface?

How many actuators does the F-35 have for each primary control surface like rudder, stabilator or aileron? And is it active/active or active/standby?
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What factors should be considered to select jet-pipe or flapper-nozzle technology for a primary control surface?

How is the servovalve mechanism chosen between these two mechanisms? what are their advantages and drawbacks?
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How is the bandwidth of an actuator selected for a primary flight control surface?

How the bandwidth of an actuator is selected for a primary flight control surface? Is there any standard? Based on what factors this decision is made?
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How should the maximum output force of the actuator be chosen?

If the hinge moments of the control surfaces of an aircraft are given, how should the maximum output force of the actuator be chosen? Is there any standard or reference?
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How do A320 pilots trim?

So, I am very familiar with the 737NG, and there is a trim switch on the yoke for vertical trim. However, I can't seem to locate this trim switch in the A320. Is there a trim switch on the joystick in ...
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Is there a general standard for servo actuators?

It is said in the standard AS94900 that the standard ARP490 should be considered for the actuators of the control surfaces in the aircraft. However, this standard is on servo valves and not servo ...
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2answers
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Does every control surface need to have a counterweight?

Is it not a good idea to balance all control surfaces, no matter what they weigh? I am building a small plane, with small control surfaces. There are many of the same type of plane flying. Most have ...
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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?
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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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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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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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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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In F-16 the pilot or FLCS , use the rudder to address the adverse yaw effects 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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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 ...
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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 ...
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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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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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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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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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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 ...
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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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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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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 ...
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1answer
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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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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 ...
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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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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 ...
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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
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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 ...
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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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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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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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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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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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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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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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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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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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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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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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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 ...