Questions tagged [angle-of-attack]

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

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0 answers
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Why are there no protection symbols (=) for high AOA protection on Airbus aircraft?

Green protection symbols (=) are displayed for many protections on Airbus aircraft, such as for bank, pitch, and high speed protection. However, there is no such symbol for high AOA protection. Rather,...
2 votes
1 answer
164 views

Did the F-16 have an AoA limiter since the very first variant?

Did the F-16 have an AoA limiter since the very first variant or was it added later?
4 votes
3 answers
150 views

Where to find out the correct values of AOA of Boeing 737 during different phases of flight?

We can say that practically there are minor differences in AOA for each flight (in the same range of weight). But is there any document that states what flight angle is recommended for each of the ...
1 vote
1 answer
70 views

How does camber affect on critical aoa?

i am pretty clear about why a higher camber would increase Clmax, but critical aoa. one of the resources i read the graphic shows a greater chamber near the leading edge will increase Cl at different ...
2 votes
5 answers
270 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 ...
0 votes
1 answer
119 views

How to choose an attack angle?

I'm writing a little piece of code for preliminary design that can calculate the ideal wing area for a given load, cruise speed and aspect ratio or span. It seemingly works well on the A380 data: <...
7 votes
4 answers
596 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 ...
3 votes
3 answers
533 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 ...
79 votes
7 answers
35k views

Why does the B-52 take off without rotating?

In the answer to this question it is noted that the B-52 takes off without rotating and climbs out in a nose-down attitude. Why was it designed this way?
4 votes
2 answers
475 views

Which wing stalls first in a level coordinated turn?

I was told that in a level coordinated turn the inside wing stalls first because it has a higher angle of attack (AoA). Now, I have always thought that in a level coordinated turn, the wings must have ...
2 votes
1 answer
96 views

Variable-pitch propeller blade design (AOA)

For a variable pitch propeller where the angle of attack can be adjusted during flight, are the individual blades similar in design to standard propellers, with a low angle of attack at the edge of ...
8 votes
2 answers
1k views

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 ...
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 ...
10 votes
2 answers
435 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 ...
3 votes
1 answer
293 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 ...
0 votes
1 answer
157 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 ...
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 ...
0 votes
0 answers
56 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, ...
2 votes
3 answers
252 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 ...
1 vote
1 answer
82 views

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 ...
13 votes
4 answers
3k views

Can a taildragger land tail first?

Inspired by this question... How does a taildragger take off? Does it rotate? I imagine if a taildragger has to land front wheels first it has a very limited range of Angle of Attack (if the pilot ...
1 vote
3 answers
223 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 ...
3 votes
2 answers
452 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 ...
2 votes
1 answer
218 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 ...
10 votes
2 answers
2k 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 ...
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
6 votes
9 answers
785 views

Could the stick position be used as a Angle of Attack indicator?

True or False: The stick determines elevator position and elevator position determines angle of attack. When the critical angle of attack is exceeded, the wing stalls. So, given a design with enough ...
1 vote
1 answer
204 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 ...
1 vote
2 answers
154 views

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 ...
6 votes
2 answers
2k views

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-...
1 vote
2 answers
434 views

What happens to the high pressure below an airfoil when the angle of attack increases?

I recently came across this question in a principles of flight exam: When the angle of attack of an airfoil increases the high pressure below the airfoil increases, the induced drag increases the ...
2 votes
0 answers
87 views

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 ...
5 votes
5 answers
6k views

How does the angle of attack vary in turns?

I read somewhere that when the aircraft banks to turn, its angle of attack increases.Since angle of attack is the angle between the relative wind and chord line, how does turning increase it? Is it ...
5 votes
5 answers
3k views

Are we changing the angle of attack by changing the pitch of an aircraft?

For example: if I pitch the airplane up, but also increase power and am able to maintain the same speed, then no, the AoA hasn’t changed, although it may have varied in the transition between one ...
5 votes
1 answer
260 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 ...
8 votes
2 answers
3k views

Does airspeed affect the critical angle of attack on an airfoil?

I understand that the critical angle of attack is mostly affected by the shape of the airfoil. However does the airspeed of the airfoil or the density of the air affect the critical angle of attack? ...
0 votes
2 answers
203 views

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 ...
6 votes
1 answer
474 views

Is it possible to get into a spin situation while coordinated?

Is there any possibility of spinning while coordinated? Of course, any CFI would tell you no, but I wonder if the the following situation could result in a spin while coordinated: Slow level flight ...
0 votes
2 answers
412 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, ...
1 vote
1 answer
153 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 ...
10 votes
1 answer
10k views

Does lift coefficient vary with the wind velocity for a given angle of attack?

I have this question in my mind. I have been trying to look for this in different books about aerodynamics and I couldn't find the answer. I know I could check the answer experimentally, if I had a ...
3 votes
7 answers
599 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 ...
2 votes
1 answer
225 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 ...
5 votes
1 answer
879 views

What's the theoretical background of the critical angle of attack?

The critical angle of attack seems to be at all (most?) airfoils around 15-20°. Why is that? Why is it in this range and not lower or higher? Is it just the result of optimizing airfoils? Or is it ...
-1 votes
1 answer
705 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-...
2 votes
3 answers
525 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 ...
7 votes
3 answers
439 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 ...
3 votes
2 answers
10k views

What are the differences between symmetrical and cambered airfoils?

I have seen images of cambered and symmetrical wings but apart from that what are the major differences between them? I have also read that symmetric wings don't produce any lift at 0° AOA whereas ...
4 votes
3 answers
8k views

Is there a simple relationship between angle of attack and lift coefficient?

Is there an equation relating AoA to lift coefficient? I have been searching for a while: there are plenty of discussions about the relation between AoA and Lift, but few of them give an equation ...
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 ...