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Questions tagged [flight-controls]

The methods or mechanisms used to control an aircraft's movement in roll, pitch, and yaw.

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36 views

What happens when you apply full cyclic + collective?

Can a helicopter apply full cyclic and then full collective at the same time? Would'nt the blades on one side (opposite of the intended tilt direction) have already maxed their aoa, resulting in a net ...
3
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1answer
96 views

Do fly-by-wire fighter aircraft automatically reverse the direction of control surface deflections during a tailslide?

During a tailslide (a flight regime where the relative airflow over the aircraft is from the tail towards the nose; i.e., an attack angle between 90º and 270º; i.e., the airplane is moving tail-first),...
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2answers
246 views

Why was the 737 main rudder servo valve’s vulnerability to causing uncommanded reversals never discovered in testing?

As was discovered during the NTSB investigation into the crash of USAir Flight 427, the design of the servo valve inside the main rudder power control unit (PCU) formerly used on 737 Original- and ...
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1answer
32 views

Are there any special considerations involved in designing manual flight controls for supersonic/hypersonic aircraft?

What things, if any, might need to be taken into account in the design of manual flight controls for supersonic or hypersonic aircraft that wouldn’t need to be taken into account with manual controls ...
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1answer
105 views

Why didn’t the 757 have manual-reversion capability?

The Boeing 757 was the highest-capacity and latest-designed narrowbody Boeing ever produced (and, in the case of the 757-300, the highest-capacity narrowbody anyone ever produced); it was also the ...
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0answers
28 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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50 views

Why is a stabilator more effective? [duplicate]

As far as I know, a stabilator is an elevator made up of the entire horizontal stabilizer. Why is it more effective?
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2answers
168 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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1answer
117 views

Why is the 737’s aileron/spoiler authority reduced at low flap settings?

According to the NTSB report on the crash of United Airlines Flight 585, the ability of the 737’s lateral controls (ailerons and flight spoilers) to counteract the rolling forces produced by (say) a ...
3
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1answer
165 views

Why are the Convair 880's yokes shaped differently from each other?

Looking at this picture of a Convair 880's flight deck... (Image originally by the San Diego Air & Space Museum at Flickr, via Wikimedia Commons) ...the captain's and first officer's control ...
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2answers
105 views

Can horizontal stabilizer trim be worked independently (each side)?

I notice most jetliners have a big trim wheel on each side of the center console. This wheel is black with white stripes, and notably turns on its own via the autopilot. Two large trim wheels: And ...
4
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1answer
106 views

Can roll be controlled through elevators in a fixed-wing aircraft? [duplicate]

In fixed-wing aircraft, roll is typically controlled through ailerons. But I am wondering if roll could also be controlled through split, independently controllable left/right elevators?
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0answers
75 views

Is there any book like the “Stick and Rudder” about the helicopter?

I have read the Stick and Rudder, that's really a classic book. Now I want to study the flight theory about helicopters, is there any book like this?
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1answer
240 views

Boeing 737-MAX stabilizer control

Various websites have stated that during the 737-MAX crash in Indonesia, the pilots could not pitch up because of a faulty AOA sensor pitching plane down. Stabilizer has a rear fulcrum and front jack ...
2
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2answers
147 views

When is aileron trim used?

There is an aileron trimmer in some Boeings. When and why should it be used? P.S. I'm not a pilot, can you answer with less smart words?
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1answer
3k views

Identification of this control panel for a four-engine plane

While cataloguing a printer's copper plates I came across a control panel image, and I have attached it here in the hope someone can identify what plane it's from. The Lorenz blind-landing instrument ...
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1answer
124 views

What is the meaning of 'stall' in this sentence? [duplicate]

I have no knowledge about aviation. Can somebody tell me what is the meaning of "he ran through a series of stalls" in: He ran through a series of stalls, killed the engine, and brought the plane ...
2
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1answer
219 views

Why didn’t the space shuttle have flight control manual-reversion capability?

The Wikipedia article on STS-1 (the first orbital space shuttle mission), in a discussion of all the problems and malfunctions occurring during the mission, mentions that, due to an unexpected ...
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3answers
229 views

Why don’t large aircraft (larger than ~737-size) have even partial manual-reversion capability?

Essentially all large aircraft1 have flight control surfaces powered, either directly or indirectly, by hydraulic actuators, as do most medium-sized and some small aircraft. Small- to medium-sized ...
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2answers
289 views

Flight physics for a roll [closed]

I am working on a pet project to write a game with flight physics. It will not be a simulator but instead much simpler. What I have done so far I have created winged components that generate lift ...
3
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1answer
152 views

What are some of the fastest UAVs? How do the pilots ensure that their controls are being transmitted to actions?

I would clarify that the drones I refer to are UAVs that were piloted using a control station. I know many military projects include such capabilities but I want to know how pilots work on such ...
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1answer
208 views

Hot helium balloon this way? [closed]

Is it possible to make a helium balloon with a clear side to create lift from the heat from the Sun entering a transparent side like a hybrid hot air/helium blimp? How would the direction of the ...
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3answers
152 views

Do cellphones have the technology to measure altitude through an App [closed]

Do cellphones have the technology to measure altitude through an App as they do speed and GPS.
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0answers
97 views

What are stick position stability and stick force stability?

What are stick position stability and stick force stability? What are the difference between them? How will changing trim of an aircraft affect them?
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0answers
19 views

How to determine maximum loads on control surfaces for supersonic flight

I checked control surface sizing and actuator selection having some estimates, but are largely meant for subsonic flight adhering to FAR regulations which dictate the maximum loads and flight ...
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4answers
215 views

In general, how do aircraft handle differently in inverted flight versus in upright flight?

Inverted flight is flight with a roll angle between 90° and 270° (although it classically referred specifically to flight with a roll angle of 180° - i.e., upside-down). In what ways, in general, ...
5
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1answer
222 views

What sort of control mechanisms (i.e., PID controllers) do modern FBW aircraft use?

It's a well-established fact that aircraft like the Boeing 777, and all Airbus passenger aircraft that were designed after the A300, feature a digital fly-by-wire control system. Considering the ...
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0answers
93 views

Why do so many supersonic aircraft feature delta wings and elevons?

Commercial and military supersonic aircraft constantly favor the delta configuration if they exceed the sound barrier, and also tend to be tailess or twin tail. What is the reason behind such designs? ...
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1answer
127 views

Why does elevator dropdown occur in some loss-of-flight-controls accidents, but not others?

In some instances of an aircraft suffering a catastrophic failure of its primary flight controls, the loss of control force on the elevator allows said elevator to drop down under its own weight, ...
5
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1answer
204 views

Why do some Mach trimmers move the elevator?

A pop-up rod on a the FO's control column on a DC-9 that shows the Mach trim position. (YouTube) Regarding the title, I'm not sure if it's just some or all jetliners (I tried to research it). On the ...
3
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1answer
219 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
105 views

Why does an elevator deflection (step) result in a nonzero short-term-steady-state response in pitch rate?

I know from the simplified Short Period linearized equations (state space with Angle of Attack ($\alpha$) and Pitch Rate ($q$) as states) that the steady-state value of the pitch rate response to ...
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1answer
82 views

Does the FBW system of a passenger aircraft use differential thrust for yawing? [duplicate]

Are there situations where the fly-by-wire system of a commercial passenger aircraft will use differential thrust to yaw? Or is that even possible at all (i.e. do the necessary interfaces exist)? I ...
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1answer
271 views

Fly-by-wire vs hydraulic systems [closed]

So, the great old argument, flyer-by-wire systems vs conventional hydraulics. I was wondering which one was better and why. Which one is safer? Pros and cons in terms of safety? Basically, I just ...
2
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2answers
258 views

Were Airbus planes always fly-by-wire?

So, as most of you know, Airbus has adopted fly-by-wire (fbw) technology. Pretty much every single plane made by Airbus is a fbw plane. So I was wondering, before computers were everywhere, did Airbus ...
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1answer
123 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
139 views

What is the “A/B AUTO EXT” button for in a Falcon 7X?

What is the "A/B AUTO EXT" button in the overhead panel of the Dassault Falcon 7X? I see it's in the Flight Control section but I don't know what is its purpose. (sorry for low quality image)
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1answer
2k views

Is it safe to fly a glider when I can't move the stick fully left and right?

This past Saturday, I started training in a Schweizer 2-33A glider. When I got in the glider for the first time, I found that I couldn't move the control stick fully left and right, because my legs ...
21
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7answers
13k views

How much physical strength is required to control a Cessna 172?

I have heard a number of folks tell me that one needs a certain amount of physical strength to be able to control the Cessna 172. Is that true? I'm flying sims now, just wanted to know.
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1answer
188 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 ...
5
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2answers
342 views

Do any aircraft use throttle steering during normal flight?

If the engine(s) on one side of a multiengine airplane are set to a higher throttle setting than those on the other side, the airplane (all else being equal) will yaw towards the lower-throttle side; ...
5
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1answer
578 views

Why is it not allowed to dispatch an Airbus A320 with an inoperative ELAC 2?

In the case of ELAC 2 failure, ELAC 1 will take over. However, it is not allowed to dispatch an Airbus A320 with an inoperative ELAC 2. Why is that?
5
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1answer
570 views

What are the consequences of attaching an unused extra engine under Boeing 747 wing?

It turns out Boeing 747 can carry an extra engine under its left wing in case there's need to transport an engine somewhere far away. The engine is attached between the body and the left inner engine ...
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1answer
2k views

Why do the A220 cockpit seats have a cutout?

Why do cockpit seats on the A220 have a cutout on the bottom cushion? The answers to Aircraft pilot's seats: what is the notch for? explain that these cutouts allow for easier maneuverability of the ...
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2answers
245 views

What is the average aerodynamic load on a control surface of a commuter-sized airplane?

I'm doing a study about aircraft hydraulic pump sizing. In order to do that, I need to know the size of a flight control actuator, then determine the maximum flow and pressure that the actuator needs. ...
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3answers
521 views

Does “pendulum effect” apply to hang gliders or any aircraft?

In discussion of aircraft roll stability in FAA paragraph on dihedral effect and in keel effect and in Why are high wing aircraft more stable the question of pendulum effect arises. This is usually ...
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1answer
404 views

How can a VTOL aircraft control yaw while hovering? [duplicate]

I watched this video of a F-35B performing a flight-hover-flight transition and was pretty impressed by the fact that it was able not only to control pitch and roll (which could be, I suppose, ...
2
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1answer
232 views

How did the controls work for variable-pitch props?

Variable-pitch propellers date way back to the 1930's and even earlier. I would like to know, what kind of controls they used? Some kind of lever or crank? How heavy were these controls? I'm thinking ...
3
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3answers
888 views

Can you disengage A320 autopilot with stick pressure?

I was recently reading that in most military jets, auto-pilot can disengaged without hitting the button, by applying 5lbs of pressure to sticks. Does this work in commercial airliners such as the ...
2
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2answers
174 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: ...