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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1answer
88 views

In F/A-18, where the servo-loop closure is accomplished?

In the flight control system of F/A-18, where is the servo-loop closed? I mean which of these two scenarios happen: 1-The position of the actuator and servo-valve ram are sent to the flight control ...
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142 views

In an F-18, how do rudders deflect during cross winds and gusts? Can rudders be deflected by different angles?

Deflection of rudders can balance moment about the centre of gravity. I have thought of non-symmetric deflection of rudders so that net sideward force is create to balance the moment about the center ...
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2answers
141 views

Why does the zeppelin NT tail use 3 fins?

I don't if I use the correct vocabulary. By "fin", I mean the control surface at the tail of the airship. As a control surface, it contains a moving part. As airship used to have at least 4 fins at ...
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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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751 views

In simple mechanical stick linkages, is there crosstalk between the aileron and the elevator movement?

The background story: I'm an aviation enthusiast (who has played a lot of sim in his life and will play lots more :D) but I've never actually flown any plane myself, as in, actually used the controls ...
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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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1answer
316 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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When the ailerons on the Airbus A380 are raised to act as spoilers, is roll control power diminished? Plus related questions

All questions pertain to the Airbus A380. 1) At any given airspeed, does the aileron-as-spoiler function reduce the roll torque generated by the aileron surfaces when the joystick is fully deflected ...
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3answers
158 views

What are some common aileron failures?

There are a few parts to the control system for an aileron in a light aircraft, such as the rods, bellcrank, cables, chains etc. What are the main reasons for aileron failures and what parts wear the ...
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1answer
419 views

How do the actuator loads (e.g. for the ailerons) vary between different flight phases?

Assume the hinge moment is given as $HM = 0.5\rho v^2*C_{h\delta} \delta*S*c$ $\rho$ = air density $v$ = air speed $C_{h\delta}$ = Hinge moment coefficient $S$ = Control surface area $c$ = ...
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How is the control surface configuration of predator/reaper for redundancy system?

In commercial aircraft like Airbus or Boeing, there are several control surfaces that work in the same function such as for roll control capability, the control surfaces are aileron and spoiler. Also ...
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How is roll control achieved for the space ship two?

When looking at scaled composite 339 space ship two I fail to see control surfaces on the trailing edge of the wing. For me, it seems that the only moving surface on the wing is the feathering ...
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159 views

What are typical control surface deflections?

How can I tell what a reasonable control surface deflection is? For example, is a 10 deg aileron deflection reasonable? Or a 0.5 degree aileron deflection? Is that too little? Too much? Same ...
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818 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 ...
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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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4answers
231 views

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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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
201 views

How does a delta wing deal with supersonic boundary separation?

The question Why most of the supersonic or fighter aircraft use all-moving control surfaces? emphasis the importance of all moving stabilator for supersonic aircraft. Many supersonic aircrafts ...
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1answer
161 views

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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1answer
416 views

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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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 ...
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4answers
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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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795 views

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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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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1answer
332 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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58 views

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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2answers
231 views

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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1answer
139 views

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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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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1answer
89 views

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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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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2answers
135 views

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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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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3answers
682 views

Why aren't tilting propellers used as an alternative for ailerons or elevators?

I was wondering what are the reasons for not using tilted propellers fixed to ailerons/elevators/elevons? Or even on wings with no control surfaces at all? Wouldn't the 2nd way of thrust vectoring ...
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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?
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1answer
181 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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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 ...
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2answers
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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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1answer
163 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 ...
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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 ...
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 ...
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2answers
4k views

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 ...
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1answer
231 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
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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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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?
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1answer
355 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 ...
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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?
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3answers
605 views

Why are trailing-edge control surfaces usually split?

I've noticed on many military and commercial jets, the trailing edge control surfaces (ailerons and flaps) are separate from each other. Why is this? Can't both serve the same function? It would save ...