Questions tagged [angle-of-attack]

Usually refers to the angle between the oncoming air and the wing.

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Will the autopilot raise the AoA above the critical AoA to maintain altitude?

NOTE: This question is regarding commercial airliners (eg: Boeing 737, Airbus A320, etc.. This is for any given configuration of the aircraft) Will the autopilot raise the AoA above the critical AoA ...
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8 votes
4 answers
2k views

Are there wool threads for displaying angle of attack?

Like there is a wool thread on a glider's canopy for showing relative wind on yaw axis. Are there or have there been a wool thread as a long term mean of showing angle of attack? For instance placed ...
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10 votes
2 answers
401 views

Why is this angle of attack sensor tab not symmetrical between the leading and trailing edges?

Here is an Angle of Attack (AoA) sensor I took from here. If you are interested to know the AoA detail, just click the link. You may see what is inside it. But not sure what airplane's AoA sensor it ...
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0 votes
1 answer
115 views

Do critical angles of attack vary from plane to plane? Can a plane have higher or lower critical AoA than the other?

I have done a lot of research and I have found out that different planes have different climb angles. Some look like they are climbing at a higher rate than others. Why is this? Do some aircraft have ...
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7 votes
6 answers
2k views

Can induced drag be negative?

For an aircraft in straight and level flight, lift-induced drag is the horizontal component of the force perpendicular to the wing chord. Positively cambered aerofoils generate lift starting at small ...
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0 votes
0 answers
41 views

What is the relationship between AoA and shock wave position in the transonic regime?

I am sure this is a simple relationship whereby as the AoA increase the shock wave moves forward along the upper surface of the aerofoil however I am struggling to find any studies to validate this, ...
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7 votes
3 answers
275 views

Why do smaller RC helicopters have visible twist in their rotors, and slightly bigger ones do not?

Smaller, cheap, RC helicopters generally have very pronounced twist in their blades, and also vary their chord - slightly larger, slightly more expensive RC helicopters have no visible twist or chord ...
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1 vote
1 answer
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What is meant by the pointing vector and pointing vector magnitude in ECI?

In Siouris's Missile Guidance and Control Systems, it is stated that the angle of attack can be approximated in a 3DoF (degrees of freedom) simulation by the following equation: I know that ECI ...
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2 votes
3 answers
183 views

How the AOA, Pitch and FPA are changing during a flight maneuver

For a steady state flight, there is a equation that FPA + AOA = Pitch, but how these three variables are correlated during a flight maneuver like currently I am in a leveling flight and then I want to ...
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3 votes
2 answers
316 views

Do fighter jets experience angles of attack greater than stall when initiating a zoom climb?

I was just wondering that the fighter jets like F-16, F-35 and Rafale when they are doing a steady flight at a certain airspeed, try to rotate 90 degrees and aim to obtain a vertical motion, so does ...
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2 votes
1 answer
130 views

How to calculate drag of a flat rectangular surface at given area, air density, airspeed and angle of attack?

I'm a complete noob in aerodynamics, and I'm trying to calculate the drag of a rectangular flat area, given the air pressure / density, area, angle of attack and airspeed. I've read this question, but ...
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10 votes
2 answers
1k views

Why doesn't critical angle of attack increase with airspeed? [duplicate]

Critical angle of attack is related to the Coefficient of Lift, which is a function of Reynold's number. Reynold's number depends on the speed of the aircraft. So why doesn't the Critical Angle of ...
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10 votes
6 answers
6k views

Why do planes fly at a high angle of attack when flying slow?

I've noticed that when a plane does slow flight, the pilot increases the angle of attack (AOA). What is the purpose of this? F-18 - Slow Pass
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1 vote
1 answer
181 views

Do redundant angle of attack and sideslip sensors use a voting mechanism, or do they display data directly?

In civil transport aircrafts (featured with dual/triple redundancy), how does airplane's Airflow angle (AoA/AoSS) sensor measurements read by the pilot? By using voter mechanism as used for airspeeds ...
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What are the relations between Angle of attack and Calibrated Airspeed?

I would like to estimate Angle of Attack using trigonometric relations i.e AoA = arctan (w/u) airspeed components (i.e u, v, w). When I am considering body 'x' velocity ('u' component), is it ...
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6 votes
2 answers
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What are those devices sitting on top of instrument panel in this Baron?

On this Baron YT video: what are the two devices sitting on top of the instruments panel, on both sides of the compass? I though at first it is some kind of HUD (Head-...
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0 answers
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Does the airspeed indicator measure speed inaccurately at different angles of attack?

A point of confusion for me has been this: Does the pitot tube measure the airspeed of the plane in the direction of its flight path, or does it measure the speed of the air parallel to the pitot tube ...
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2 votes
3 answers
185 views

Projected Area & AoA - Projected area of the wing is variable (as projected on to a surface that is perpendicular to the relative wind)

Does Wing Area vary with angle ot attack? Edit: why we don't recognize that the projected area of the wing as variable (as projected on to a surface that is perpendicular to the relative wind) Per the ...
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3 votes
3 answers
436 views

Does a wing produce an appreciable amount of lift during the takeoff roll prior to rotation?

I was hoping for some insight on this, perhaps also from pilots who have used AOA indicators. This because I assume that an AOA indicator is the only means to get at least an idea of how much lift is ...
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Getting the cl vs aoa plot from Cp distribution

I am making a CFD simulation where my goal is to calculate the section lift coefficient vs angle of attack plot of an airfoil. From Fundamentals of Aerodynamics (Anderson, 2018), I get the following ...
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Is there any practical benefit of the Boeing-787 to perform near vertical takeoff?

In a promotional video for the Paris 2015 airshow, this video was released promoting the new Boeing 787's near vertical takeoff capability. Whilst highly impressive, I was wondering if there is any ...
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0 votes
2 answers
340 views

In constant speed propeller, if i increase RPM lever from 2300 to 2500, will the Blade AOA decrease?

Assume I am flying straight and level with power setting 21 inches of MAP and 2300 RPM with TAS=100 kts, now I change my Prop lever only (MAP = no change & TAS = no change) from 2300 to 2500, ...
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1 vote
1 answer
129 views

With flight dynamic equations, how do I return to positive alpha if alpha is always negative with negative w?

I'm coding a flight dynamics simulation, but my simulation runs into a problem with negative angles of attack. Once alpha is negative, it is impossible to get back to a state where the plane is ...
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2 votes
1 answer
194 views

What is the reason for this discrepancy regarding the CRJ100/200's stickpusher-activation angle?

The AC646 accident report contains a discrepancy regarding the angle of attack at which the stickpusher of the accident aircraft (a CRJ100, formally a CL-600-2B19, referred to in the aforelinked AAR ...
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2 votes
3 answers
390 views

Is drift and sideslip angle the same in the accompanied figure?

Consider the following figure: Initially aircraft is moving along dotted line. But due to wind, aircraft ground track is changed to solid line but body still pointing parallel to dotted line. I've ...
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3 votes
7 answers
476 views

Is the elevator really an 'angle of attack control' as described in Stick and Rudder?

I've been reading Wolfgang Langewiesche's book Stick and Rudder and am a little confused about the definition of the elevator as the "Angle of Attack Control" or rather, the idea that each ...
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1 vote
3 answers
212 views

How the pitch of a blade must change along the length so that the blade does not stall?

I have to finish an assignment in the next couple of days. One of the questions asks to show how the pitch of the blade must change along the length so that the blade does not stall. I have no idea ...
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7 votes
3 answers
428 views

Could airliners fetch data like AoA and speed from an INS?

If I understood what an inertial navigation system (INS) is, it should be able to calculate speed and orientation of the aircraft. If this is possible, why do airliners solely rely on sensors to ...
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0 votes
0 answers
51 views

How can the flap deflect to higher angles (than the wing) without experiencing loss of lift? [duplicate]

For a simple aircraft wing, assume the stall angle of attack of this wing is 16 degrees. Now, if I use the same airfoil as used in the wing for the flaps, I am able to deflect the flap at quite ...
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2 votes
4 answers
797 views

What's the relationship between AOA and airspeed?

We know that any aircraft will stall at its stall speed (for a specific weight, CG position, etc.) but also, that the same airplane will always stall at the same angle of attack. I´ve read that IAS is ...
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0 votes
2 answers
216 views

How does the aircraft keeps propelling forward when airflow and thrust are not aligned?

Assume an aircraft is flying at an angle of attack of 10 degrees, and that the incidence angle between the aircraft fuselage and the wing as well as the angle between the wing and the engine mount is ...
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3 votes
2 answers
918 views

Deployment of leading or trailing edge flaps - increase or decrease the angle of attack and critical angle of attack?

There are a number of similar questions, but I'd like to clarify the increase or decreases between the angle of attack and critical angle of attack. According to this article, "When the pilot ...
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0 votes
0 answers
60 views

In symmetrical airfoils is the stall angle the same for negative AOAs as for positive ones? [duplicate]

In symmetrical airfoils is the stall angle the same for negative Gs as for positive ones? Let say the stall angle is 17 degrees AOA. Is it the same if you push the nose down?
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3 votes
1 answer
282 views

How does a synchro resolver converter work?

There are Synchro converters or transducers used on aircraft to measure angle of attack using 3 sinusoidal inputs. I could not understand where these 3 inputs come from and what angle information is ...
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19 votes
1 answer
1k views

Why does my wind tunnel experiment give two different stall angles of attack?

When I increase the angle of attack from 0 to 20 the stall begins at 18 deg. When I decrease the angle of attack from 20 to 0 the stall ends at 13 deg. Why the difference and what value (13 or 18 deg) ...
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5 votes
7 answers
3k views

Why angle of attack is always shown against the relative wind parallel to horizon?

I have a question about Stall, which I have difficulty to understand. According to the theory, stall happens when : 1- Speed is slow then a certain limit. 2- Angle of attack is greater than a ...
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0 votes
2 answers
485 views

Why is the critical angle of attack lower in ground effect?

Why is the stalling angle of attack lower in ground effect? Does ground effect more increase pressure on lower side of wing (cushion effect) or more decrease pressure on upper side, or both? So which ...
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-1 votes
1 answer
539 views

How to find the angle of attack?

I'm trying to calculate the angle of attack (AOA) using aircraft some data. From what I understand the AOA is just the angle between the aircraft's forward unit vector (out the nose vector) and the x-...
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4 votes
2 answers
437 views

Do nose cones work well at high angles of attack?

On a lot of fighter jets, I see a heavily slanted intake, such as the F-15. I always thought this is to help ingest air at high angles of attack. However, what about something like the MiG-21? There'...
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5 votes
1 answer
246 views

Is a wingtip vortex strongest at the critical angle of attack?

Generally, wingtip vortices increase in strength as the angle of attack increases. Is the critical angle of attack/Cl Max the peak strength, or do the vortices generally continue to increase in ...
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0 votes
1 answer
476 views

Does thin airfoil theory work at very high angles of attack?

Thin airfoil theory says that lift coefficient is directly proportional to the angle of attack in radians. I haven't been able to find any limit, short of stall, for applying this theory. It would ...
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1 vote
1 answer
91 views

What is the average angle planes wings they need to fly? [duplicate]

The planes I am talking about are everyday passenger plane's, not fighters. Do you know what the angle needs to be for it to create enough lift so the plane can fly?
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2 votes
1 answer
2k views

Why does pitching moment coefficient decrease with an increase in the angle of attack?

Slope of Cm vs alpha graph is negative, why it is so? The attached graph is from https://en.m.wikipedia.org/wiki/Pitching_moment , this graph is for cambered airfoil, as pitching moment is zero for ...
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1 vote
3 answers
445 views

Is it possible to have an angle of incidence for a vertical stabilizer?

horizontal surfaces in airplane have small angle of incidence in general, Is it possible to have an angle of incidence for a vertical stabilizer? Please help me to find it. Thanks!!
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1 vote
1 answer
220 views

Does this web page really correctly depict the angle that is called "incidence" in the French language in the aviation context?

Does this web page really correctly depict the most common usage of the term "incidence" in the French language in the aviation context, in the context of speaking of an entire aircraft and not just ...
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0 votes
1 answer
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A question about the exact meaning of one British usage of the term "Angle of Incidence"

This answer to a related question stated: Most anything can have an angle of attack. If you must be specific, you mention 'angle of attack of ...' ... When we talk about airplane as a whole, ...
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2 votes
2 answers
333 views

Is the lift vector reversed during inverted flight?

Heard a physics professor say that when an aircraft flies inverted, the wing assumes a significant angle of attack (by pushing the stick forward) to continue to generate the necessary "upward" lift ...
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0 votes
5 answers
325 views

Can lift be increased by increasing the angle of incidence of the wing? [closed]

Can the lift of a plane be increased by increasing the Angle of Incidence (angle between the chord line of the main wing and the axis of the fuselage)? Meaning, can more lift be generated while the ...
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4 votes
1 answer
546 views

Finding Angle of Attack/Angle of Sideslip using East/North/Up Coordinates

I've got a set of data that includes: x rate, y rate, z rate (all ENU) which I'll call xd, yd, zd. roll, pitch, yaw (which I'll call ϕ, θ, ψ) roll rates, pitch rates, yaw rates I'm looking at some ...
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  • 131
19 votes
1 answer
3k views

What is the stall AoA for the space shuttle?

Once flying as (fast) glider in order to land, what was the angle of attack it would have stalled? I'm really interested in the angle of attack for such wings and not the speed.
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