# Questions tagged [angle-of-attack]

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

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### Pitch of a glider with altitude

I'm designing a high-altitude glider. Just to clarify a few points before my question: The glider will weigh close to 200 grams. It will be using the A18 airfoil. The glider is dropped from 80,000 ...
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### Conundrum about designing a glider relating to coefficient of lift

I'm designing a high-altitude glider. Just to clarify a few points before my question: The glider will weigh close to 200 grams. It will be using the A18 airfoil. The glider is dropped from 80,000 ...
125 views

### How to maximize L/D ratio by design in a high altitude glider? [closed]

EDIT: Some initial confusion with TAS and IAS confused me, I now understand this better, thanks for everyone who helped. I'm designing a high-altitude glider, and I'm wondering how the angle of attack ...
101 views

### How does a glider in steady descent glide with negative AoA? [closed]

EDIT: I now understand relative wind is parallel to the travel of the glider. Ignorance was the basis of my earlier confusion. I looked at some toy and commercial gliders and all of their wings were ...
1 vote
67 views

### Constant Speed Propeller and Angle of Attack

Question regarding the AoA (Angle of Attack) on a Constant speed. The CSU (governor) sets the blade angle based on the desired RPM, and the flyweights keep it from speeding up or slowing down using ...
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### Why does the wing drop prior to a spin?

In the process of understanding the aerodynamics of spins, I'm having a hard time understanding why one wing drops. I understand that the for spins to occur, a stall + a yaw must occur. I also ...
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### Why Critical Angle of attack doesn't change with an increase of IAS/TAS?

I am trying to understand this topic that is not letting me sleep. I am a private pilot and I am studying for the CPL, if someone could give me a simple explanation of this I would be very grateful. ...
1 vote
147 views

### Critical angle of attack at high altitude

I remember hearing somewhere that at very high altitudes, the critical angle of attack for a given airfoil can decrease a bit. Is there any credence to this idea? Thank you
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### Incidence angle in Sailplane

I am determining the shape of the fuselage of a sailplane and I found something that gives me a little conflict, and that is that in most sailplanes it has an inclined tip, I read that this helps ...
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### What is the maximum speed at which thrust vectoring can be used? Thrust Vectoring on the SR-71

The SR-71 is limited to a 45 degree bank turn at speeds in between mach 2.85 to ~3.2. This means the blackbird would take almost 5 1/2 minutes to make a 180 degree turn at mach 3. Would it be possible ...
264 views

### Does AOA become 0 after the aircraft flies in a particular attitude for sometime as the relative airflow has changed and how does it affect Stall AOA?

As AOA is the angle between relative airflow and Chord Line. Then after you increase the angle of attack and fly at that angle of attack for some amount of time and the relative airflow changes ...
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### Why do most light aircraft not have AoA indicators?

Why is an angle of attack indicator not commonly included on small airplanes? Is it too expensive?
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### Why would the tip of a propeller stall if geometric pitch was the same throughout the length of the propeller?

I can't seem to understand this sentence from the FAA PHAK about why propellers are "twisted." "If the blades had the same geometric pitch throughout their lengths, at cruise speed the ...
815 views

### Why does elevator trim hold a given airspeed? [duplicate]

I'm trying to understand a principle described in the book Stick and Rudder by Wolfgang Langewiesche between angle of attack and airspeed in relation to the elevator trim. He states that as angle of ...
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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,...
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### 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?
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### 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 ...
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1 vote
455 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 ...
708 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: <...
2k 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 ...
606 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 ...
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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 ...
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 ...
562 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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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### 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
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### 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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1 vote
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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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### 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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### 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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### 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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### 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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### 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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### 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
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### 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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### 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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### 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
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### 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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### 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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### 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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### 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 ...