Questions tagged [angle-of-attack]

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

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731 views

Do wingtip vortices cause a decrease in the lift component of aerodynamic force, and do planes need to pull more AoA to compensate?

So, from what I know about wingtip vortices, they shift the angle of the relative airflow to where the effective angle of attack of the airfoil is lowered. Since the aerodynamic force is always ...
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Does wing sweep affect the direction of lift?

Given both a straight and swept wing (identical otherwise), exposed to the same airflow, would the direction of lift be the same? Please see below a crudely drawn example of my thinking. Additionally,...
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Why does stall speed decrease when flaps are deployed?

I've been told that deploying the flaps on approach enables the following: Potentially steeper approach Slows down the plane Lower stall speed It's the last one that confuses me. Given the equation ...
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Spinning wing heat dispersion dynamics for Mach 24 and beyond?

Could a spinning disk dropped from orbit survive speeds faster than conventional aircraft in our atmosphere? Does the rate of spin matter when dispersing heat? Does a spinning disk create stability ...
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What's the pattern of airflow over the airfoil at high angle of attack?

When at high angle of attack the boundary layer tends to: A. stagnate and stop B. loop around the upper camber line C. decrease air pressure along the chord The answer is A, but as I see it, B ...
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How to find trim condition of a sectional airfoil without knowing the angle of attack?

I am using a reflexed airfoil designed for positive pitching moments to achieve a pitching angle matched to the changing of free-stream velocity (Aerodynamically tailored). I ended up with a pitching ...
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1answer
790 views

Does zero-lift angle of attack depend on Reynolds number?

In this post I read that, due to viscous effects, the $C_{l}$ at a given angle of attack increases slightly with the Reynolds number but it seems that it just happens near the stall angle of attack. ...
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How to define pitch angle for a passive variable pitch propeller?

This question is a continuation of the question How to calculate variable pitch propeller parameters? mentioned before. Actually, the theory described as an answer on the question above is the exact ...
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Is induced drag caused because of the tilt of the wing backwards?

In this question: Why is induced drag less on a high span wing? In the answer it was stated that wing tip vortices do not cause induced drag. If this is the case then what causes the induced drag. ...
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How does change in airspeed affect pitching moment?

In aircraft with conventional elevator control, if I increase the speed, the horizontal tail sees higher velocity and hence higher lift. Does it mean that increasing airspeed creates nose down ...
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What is the typical angle of attack aircraft fly at and at what angle of attack do they stall?

At what angles of attack do aircraft typically fly at? How much of a margin is there before aircraft stall due to an increase of an angle attack due to factors such as gusts or rotation of the wing ...
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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 ...
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Can variable incidence wings replace ailerons?

If a wing can change its incidence angle, can aileron be omitted in the design? Since aileron are used to increase lift and decrease it. so is the incidence angle. How would the two solutions ...
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What exactly happened with the Flight Computers on XL Airways Germany Flight 888T?

I recently saw a documentation about XL Airways Germany Flight 888T. This made some questions rising in my mind: Two AOA-Sensors failed (freezed) simultaneously. From Wikipedia: Two out of three ...
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644 views

What happens to the pressure differential of airflow under and over the wing as the critical angle of attack is reached?

I've been doing a research project for mathematics which involves calculating the relationship between lift and angle of attack. While this may seem pretty easy, it's not for a 12th-grade student like ...
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For a flying wing airfoil, which AOA is to consider when selecting Cl?

I'm in the process of designing a flying wing. I'm trying to keep it a small as possible, so the lift coefficient is very crucial for me. I'm currently looking at some airfoils but most of them ...
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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 ...
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How is a sideslip maintained (aerodynamically)?

(Public domain image that I've modified.) The initial rudder deflection to the left creates a side force that points right and yaws the plane to the left. NASA puts it this way: For the vertical ...
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Is this angle of attack animation backwards?

Is this animation of the angle of attack sensor in this video from 25:30 to 25:50 correct? It seems like motion of the sensor is the opposite of what it should be based on the angle of the aircraft. ...
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Is it possible to fly horizontally with zero angle of attack?

If an aircraft has a zero angle of attack and the wing doesn't, is it possible to fly horizontally? Because as the book says, there is no lift in this condition, Is this zero angle of attack of the ...
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994 views

Is it possible to fly a Straight and Level flight at high speed?

The question arise while discussing with some of my student pilot friends that as we have been performing Slow Flight we have to keep increasing the AOA of the aircraft to compensate for every lose in ...
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How does the relative wind on a propeller, strike the blade from behind (the non camber side)?

This may be a stupid or simple question, although any help is appreciated! :) If possible, please answer without mathematical terminology. So I understand the concept of the blade increasing air ...
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How does centre of pressure change with angle of attack?

I've been given the distance of centre of pressure from the leading edge with a certain angle of attack and was wondering if it's possible to calculate the new position when the angle of attack ...
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622 views

Why doesn't the flight path angle increase beyond a certain angle even if the angle of attack is increased?

From level flight, when the angle of attack is increased the flight path angle increases (the aircraft starts to climb). What causes the aircraft to stop to increase its angle of climb (angle between ...
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793 views

Does angle of attack change in a sustained climb?

I saw this question on a closed Facebook group, generating wildly differing answers. So I thought I would ask it here. You're in a C172 flying straight and level at 5000 feet and 100 knots IAS. You ...
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What does it mean when pitch numbers move all over the HUD screen?

In this video from an F-16: You can see pitch angle move out of screen or be on the side at the end.
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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 ...
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Do airliners adjust altitude for latitude?

According to this NASA article, the troposphere extends from about 5 miles at the poles to about 9 miles at the equator. Though the height of the troposphere is defined by the height of the tropopause ...
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What happens during a powered descent?

I was having a discussion with my friend about equilibrium condition in flight: Scenario: While going in straight and level flight, say I reduced my airspeed by 30 mph. At the same time keeping the ...
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What is the significance of stall speed [duplicate]

Irrespective of the stall speed, the only reason aircraft stalls is when its control surface (elevator, aileron) exceeds critical AOA. Then what is the significance of the stall speed? Does the ...
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What are the definitions of elevator angle of attack and critical angle of attack?

Angle of attack is the angle between the chord line of the wing to the direction of relative wind. So angle of attack helps the aircraft climb. Then what is the angle between the chord line of the ...
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Why is angle of attack information not displayed in the cockpit?

Would not it be useful to have the angle of attack information displayed on the flight display? I know that we have shakers that alert pilot when the critical AOA is exceeded, but still we have cases ...
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How accurate are these Stall Diagrams depictions of relative wind?

Why in diagrams of a stall, the relative "wind" comes in horizontally no matter how the airplane is orientated? Doesn't the engine, which produces the thrust for the "wind", stay parallel to the wing ...
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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 ...
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762 views

Which of these is true for a glider flying with constant angle of attack?

I'm trying to answer the following question, but I'm not sure of which one is correct. A glider is gliding with constant angle of attack along its path. We can assume the hypothesis of small angles. ...
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What is the relation between the Lift Coefficient and the Angle of Attack?

I'm trying to understand the relation between the Lift Coefficient and the Angle of Attack using PEP software for the A320 IAE. However, I notice that often for a given Angle of Attack, there could be ...
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How much can falling down due to a stall influence the angle of attack?

I am trying to understand the af447 incident, more precisely, how a professional pilot having an attitude indicator available failed to understand that the angle of attack was too high. Was it that ...
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How did this Boeing 787 perform this near vertical takeoff? [duplicate]

At angles of attack like this an airliner would stall very easily. The 787 wing would stall at an angle of 30 degrees. The plane would have been flying at speeds of around 200mph(more likely less) at ...
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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?
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Why Air France 447 could not reduce angle of attack?

I just finished reading this article and couldn't understand why in 3 minutes and 30 seconds even though there was no reliable speed data, pilot could not level the plane? Isn't the angle of attack ...
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Why do airliners on autopilot climb during cruise?

Several years ago I was a passenger on a near cross-country flight when the pilot came on the PA and announced that we were climbing towards our cruise altitude, on autopilot, and as our fuel load was ...
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How does flight control surface authority change with AOA?

I am working on semi-realistic (let's just call it "believable") flight simulation component set for a game engine. One of the topics that I tried to research but could not find reliable information ...
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How to calculate the Lift Coefficient for the A320?

I'm trying to figure out the lift coefficient of an A320. What I'm doing is the following: during cruise, the lift is equal to the weight of the aircraft ($mg$) so that I used the cruise table taken ...
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What is the wing angle of attack of a Boeing 737 in cruise?

I would like to know the angle of attack that a 737 flies at during cruise. I am specifically interested in the wing angle of attack (if you know the cruise nose-up attitude and the wing incidence ...
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How does an alpha (AoA) vane work?

The alpha vane (also called AoA vane) is an external probe used to measure the angle of attack. I have been trying to understand how exactly it works, but I can't find any clear explanation or ...

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