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0

Well, both. Lift can be described as a moving wing colliding with air molecules at an angle, the result of the collision is the wing moves one way and the air mass the other, as per momentum physics. Moving the trailing edge, or the entire surface, increases the angle of attack, resulting in more lift at a given speed $V$: $Lift$ = 1/2 × Lift Coefficient ...


5

Thankfully, aerodynamics in the usual flight range is linear. Therefore, there is a gradient of lift over angle of attack and another one over the flap deflection angle. Both are constant over a range of maybe ±15° and can be combined. The angle of attack is referenced to the fixed part of the flight surface and the deflection angle to the moving part ...


2

A trailing-edge control surface, when it deflects, changes the camber of the overall airfoil. More camber means more lift, in whatever direction that airfoil is mounted. In your example, adding up elevator increases the horizontal stabilizer's camber, which increases the downward force it applies. Philosophically, "why" it does this is just, well, that's ...


4

Different aircraft and manufacturers take very different approaches. 1. Boeing 777 The B777 has three Primary Flight Computers (PFC) that are responsible for flight control laws computation and four Actuator Control Units (ACE) that are responsible for the closed-loop control of their responsible flight control surfaces. The ACE is primarily an analog ...


2

Just to add some more insight here. The question of aerodynamics and size keeps being asked. It is for the most part not relevant. Balloons move slow, at the speed of the wind near the equator basically. They relatively quickly get up to speed. During events like this it may appear to be chaos to you from one photo, but it is not, the crews are ...


2

Electromechanical Actuators are used in many aircraft, and in many applications. Applications vary from controlling doors, trims, control surfaces, flaps and air inlets to moving your business class seat to the most comfortable position. For quite a range of examples see the product website of this manufacturer. Or this video of an aileron application


2

Angle of attack is the angle between the relative wind and the chord of the wing. Pitch is the angle between the longitudinal axis of the aircraft and the horizon. They are related, (and both are controlled with the elevator) but independent of each other. In high speed straight and level flight they are probably the closest to being equal, but generally ...


0

I'd say yes, it's possible. I read about a late pilot testing modifications in his Velocity Canard; in flight, one of the propeller blades was lost, no thrust; instead of pushing the stick, the pilot pull, with the result of airplane entering a flat high speed fall into the ground, impossible to revert. This is also a caution about the not 100% true belief ...


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The reference of pitch is the horizontal. The reference of AoA is the direction of the relative wind.


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I've worked with control loading systems quite a bit. What you describe is a reversible system, where the flight crew feels the aerodynamic forces acting on the primary control surfaces (elevator, ailerons, rudder). In the aircraft, the pilot pulls on the flying control, which is connected via a steel cable to the control surface, which then deflects. ...


3

In reality, in a strongly- deflected stuck-rudder situation, the pilot would be best advised to forget about the doors and just land the plane, selecting a runway with a strong crosswind component if at all possible. After all, when landing with a strong crosswind, it's not that uncommon to hold the rudder at close to full deflection in the "downwind" ...


3

From publicly available sources, the first motive of the MCAS was to satisfy the stick force per G requirements, or maneuvering stability (not static longitudinal stability, which deals with speed stability). This is confusingly captured in 14 CFR 25.255(b) and (c) under Out-of-Trim Characteristics, but also applies broadly to buffet characterization at mid/...


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Yes, it is generally more efficient to enter a turn by using ailerons and rudder together than by using rudder alone, even if the poor performance of the aircraft requires the bank angle to be kept rather shallow in order to maintain altitude.


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Yes ailerons would help turn more efficiently, although likely not enough to help with an airplane with such marginal power it can't get out of ground effect. To the extent that it does bank, an airplane loses altitude because of the bank, and it doesn't matter how the bank was induced. When it banks the lift vector tilted means the vertical vector is ...


2

I would first check to see if the car in the background was actually pulling him along in 1908, or maybe the aircraft engine was a bit better. Banking does indeed reduce lift, but not as much as we may think: If vertical lift at 0 degrees bank was 1000 lbs, a 20 degree bank at the same AOA and speed still produces: $$cosine 20 degrees × 1000 = 940 lbs$$ of ...


0

if he lost altitude on turn is probably because the rudder would slow down the plane before sliding it into a turn. I believe he flew very close to stall speed. if he used ailerons as we know them, then given the already prestall speed, I believe the first effect would be to slow the plane down, followed by a bank angle. I guess a bank stall would have been ...


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The Boeing 737 MAX MCAS system is there ONLY to meet the FAA longitudinal stability requirements as specified in FAR Section 25.173, and in particular part (c) which mandates "stick force vs speed curve:, and also FAR Section 25.203 — "Stall characteristics". FEDERAL AVIATION REGULATIONS Sec. 25.173 — Static longitudinal stability. Sec. 25.173 — Static ...


2

The MAX feels like the NG, which feels like the Classic, which feels like the -200. The flight control artificial forces are identical across the different versions, which share a type rating. No need for MCAS there. Also, the MAX is longitudinally stable. MCAS was implemented for tackling some situations in extreme corners of the flight envelope, as ...


3

Many accidents have shown over and over that once the handling becomes muscle memory, the cue that having to pull harder means you are losing speed is easily missed anyway, so it's not as important as it seems. So the artificial neutral stability instead decouples the controls: stick for flight path angle, thrust levers or A/T for speed. Nice and easy and ...


6

Of course the airlines knew about MCAS. Do you think the maintenance manuals, maintenance program documents, tech training, wiring diagrams, and all that stuff was left out so it was totally top secret? There would be a controller, wiring and software on board even though there were no cockpit indications or controls, so certainly the techs who might have ...


1

In the US for commercial aircraft, SAE-ITC provides recommended design standards in ARINC Characteristic 701-1 Flight Control Computer System (FCCS). The recommended environmental standards are in Attachment 6 of ARINC 701. This references environmental categories defined in RTCA DO-160. The issue is that ARINC 701 references an earlier version of DO-160 ...


0

You need to look up MIL-PRF-38535J which specifies electronics performance requirements. Toward the late 90s/early 00s the "performance standard" or PRF, replaced MIL-SPEC for the manufacture of ICs and microprocessors, and production of components built to MIL-SPEC (which specifies physical construction requirements) was discontinued. MIL-PRF doesn't ...


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As mentioned in this answer: stick forces are designed into the control feel. The best feedback for the pilots on how large their control input is, is haptic feedback: push/pull force as detected by the force transducers in our hands. While looking out of a cockpit window, we don't exactly know where our hands are, but we don't have to look at our hands to ...


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No because if stick force per G is too low, when maneuvering it becomes too easy to pull a lot of G and that's bad. It's like having power brakes in your car that don't build up more resistance in the pedal the harder you brake; it becomes difficult to regulate braking effort and too easy to lock the brakes (assuming no ABS). Like with brakes, it's ...


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