Questions tagged [stall]

A stall is an aerodynamic condition wherein the angle of attack of a wing increases beyond the "critical angle of attack", causing the wing to cease generating lift.

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What is the explanation for the appearance of airplanes hovering? [duplicate]

A few weeks ago, I saw a plane that appeared to be hovering in the air. It was a large commercial airliner. It was not a windy day, land speeds of 24km/h max that day, about 5km/h at the time I saw it ...
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Why is the definition of $V_{S1}$ vague wrt configuration?

The definition of $V_{S1}$ is the stalling speed or the minimum steady flight speed obtained in a specific configuration from 14 CFR §1.2 Abbreviations and symbols. Why is this vague in terms of the ...
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Why are there two local maximums on some CL vs AOA curves?

I know what a stall is but I don't understand why there are in some cases two local maximums on the $C_L$ vs AOA curve of some airfoils. What is the reason for the mini stall that occurs before the ...
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What is the physical explanation for the pre-stall judder in a Spitfire?

From the book "First Light" by Geoffrey Wellum, where the author describes dog-fight manoeuvres against an Me 109: If you want to shake someone off your tail you have to fly your Spitfire ...
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1answer
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Why are aerodynamic models without stall used in research papers?

Some papers that I'm reading in the Journal of Fluid Mechanics give aerodynamic models in which the lift force appears to not take stall into account -- unless I am misinterpreting the math model, but ...
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Why does stalling increase drag?

I understand (I think) why lift reduces in a stall. What I don't understand is why drag increases. I can see that the ratio of drag to lift would increase, but I'm not sure I understand the mechanism ...
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What’s the difference between an AIRSPEED LOW warning and a STALL warning?

Just an enthusiast here; pardon the dumb question. Im a little confused between the difference of a stall and airspeed low. “An aircraft Stall Warning System is that system which provides the pilot ...
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Why would I want to lower the stall speed?

Why would a cargo pilot for example want to dump fuel to lower the stall speed? I understand that lowering the weight decreases the stall speed, meaning it is "easier" for the plane to reach ...
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What's the difference between an accelerated stall and a dynamic stall?

I am a commercial pilot. I always like to understand everything in detail, so here's my question: What's the difference between an accelerated stall and a dynamic stall? For example, in a high-speed ...
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Does too big an angle of decalage make the horizontal stabilizer to stall?

This styrofoam airplane has two positions for stabilizer. When put in the upper one, the plane flies in a circle. Is the stabilizer now stalled because the decalage angle is very big?What happens with ...
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Vs1, Specified configuration [duplicate]

Vs1 is the stall speed in a specified configuration. What exactly is specified configuration?
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Could an airliner with only one functioning engine recover from a stall?

If a modern commercial airplane such as a Boeing 787 would stall with only one functioning engine, is it possible for the pilots to right it or would it require two functioning engines?
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In this MD-11 stall test video, are we seeing the tail stalling first?

Watching this short stall test video for the MD-11, one can notice obvious buffeting (starting at about 0:04) of the tail section, while at the same time – at least apparently – there doesn't seem to ...
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In this F-104 V-n diagram, why does the stall speed (in terms of IAS) decrease with altitude in some parts of the flight envelope?

(This question has been edited to reflect a change in perspective: based on answers to the related question What is causing these "corners" on this F-104 V-n diagram?, I now believe that the ...
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1answer
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Why did TWA800 not stall?

I believe the NTSB account, but based on this graph, http://twa800.com/lahr/zoom-climb.htm, why did the flight not stall after the nose separated?
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Could leading-edge dynamic stall occur for a tripped airfoil?

As far as I know leading-edge dynamic stall is characterized by the formation of a Leading edge vortex. This leading edge vortex forms due to the 'bursting' of the LSB (Laminar separation bubble). ...
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1answer
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Retreating Blade Stall, P-Factor, and Gyroscopic Precession

Most airplane pilots are aware of P-Factor in propeller driven aircraft and that it tends create a torque in phase with the lift imbalance over the blade disc, resulting in a yaw moment about the ...
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Impact of centre of gravity position on stall recovery

Can somebody explain what is the impact of CoG position on stall recovery. I heard that stall speed is higher with forward CoG comapared to aft CoG, but does it have influence on stall recovery? Is it ...
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Why do tapered wings not stall at the root first?

Why do moderate tapered wings stall first at mid-wing section and high tapered wings stall at tip first? The effective AoA should be always higher close to the root? (considering no geometric or ...
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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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1answer
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Is it possible to stall a stationary helicopter through excessive collective input?

I understand that helicopters can suffer from "retreating blade stall" where the retreating side of the rotor has low airspeed and stalls in a typical way that airplane wings stall. This ...
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2answers
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Can Savannah be stalled with agressive yoke pull?

My friend fly ultra light Savannah, 2 seats plane,wings dont have slats ,it has vortex generators at leading edge. He says that he cant stall plane with agressive yoke pull (I talk about speeds above ...
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What would be the challenges for a pilot taking off into a headwind of just under the clean stall speed?

If a strong and fairly steady headwind was coming down the runway at just under the stall speed for a clean configuration/weight, what challenges would a pilot face? Or would it be fairly easy? Is ...
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Is the vertical flight close to a building possible for GA plane?

Is the vertical flight in GA plane, so close to an actual building, as depicted in 67th second of Microsoft Flight Simulator 2020's official commercial, ever possible: Or is there "at least a ...
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Why do sweptback wings stall at the wingtip first? [duplicate]

Why do sweptback wings stall at the wingtip first? Is it because of ram's horn vortex generation?
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Using XFOIL to find the angle of attack corresponding to buffet onset and stall

I am trying to find the angle of attack that corresponds to the stall point and buffet onset. I understand for stall this occurs at the maximum lift coefficient? However upon plotting a range of ...
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Would a wingtip stall still be bad if there was no aileron there?

If there was no aileron on the wing tip, would a tip stall still be bad compared to a root stall?
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Leading edge or trailing edge stall?

As I wrote last week, I'm doing a Benedek 10355 airfoil performance report. At this point of the work I am analyzing the stall of the profile at a fixed Reynolds number. The Benedek 10355 airfoil has ...
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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 ...
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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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What does the autopilot do if activated in a stall condition?

I was thinking about Air France 447 recently and had a wonder: What would happen if the pilots had re-engaged the autopilot and stopped all stick input? (If that's even possible in a stall condition). ...
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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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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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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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1answer
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Is it possible to increase available take-off distance for a seaplane by turning?

In the video below an A5 had an accident after takeoff. The final cause of the accident seems to be a sharp increase of AOA above stall. Do sea planes have an ...
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What is the impact of camber on CLmax?

I was reading Aerodynamics for Engineering Students by Houghton and saw the following graph: A lot of other sources say that increasing camber increases CLmax, like the graph below. I am a little ...
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Is it practical to intentionally stall an aircraft to execute a fast, controlled descent?

An MD-11 had an onboard fire, but had to request more flying distance at least partly to execute a safe descent (and to dump fuel). It ended in tragedy. In another accident, an A330 descended 30,000 ...
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Should I use rudder to recover from power-on stalls?

I was executing a power-on stall, and upon stalling the nose dropped and the plane rolled hard right. I promptly applied left rudder and released yoke backpressure to recover, and the plane recovered ...
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Helicopter retreating blade stall: Increasing the fwd speed decreases the tip speed on retreating side and angle of attack. So why limit on V_n.e?

On Retreating side: Speed of wind over blade tip = blade rotation speed - forward speed. So, with an increase in forward speed, the speed of the wind over tip is getting reduced. In airflow diagram, ...
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Do adding high thrust in plane prevents it from stalling?

I am convinced that fighter jets (every flying object) do stall. So from quora, Why don't fighter jets stall? But most of the fighters have thrust:Weight ratio > 1 which means that they are not ...
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1answer
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How to find the static stall angle of attack for a given airfoil at given Re?

For vertical axis wind turbines applications I'm wondering how one would find the static stall angle of an airfoil at a given Reynold number? Is it just the critical angle of attach (AoA) where ...
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Are larger airplanes more likely to stall?

Stalls happen when the boundary layer on top of a wing slows so much that it essentially becomes part of the airfoil. My question is, as the wings on larger aircraft present a longer flow path for ...
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Is a "stalled" aircraft free-falling?

If I was in an elevator in a sky-scraper and the cable broke, I would free fall and feel weightless until hitting the ground. When I cause a stall on an airplane (power-ff) and the wings stop ...
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What are the effects of separation at hypersonic rarefied flows?

Shock wave causes an adverse pressure gradient which causes an airfoil to stall. Also because gas density is much lower boundary layer becomes laminar and unable to prevent separation. Correct me if ...
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Would it be frowned upon that with a uncommanded nose up, the pilots just do a full loop?

So what I’m asking is that if a uncommanded nose pitch up happened and was so bad that it reached a pitch angle of 50 degrees, the pilots were unable to stop the pitch up by applying the control ...
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Why does a higher load factor increase stall speed?

I think that’s self explanatory, why does load factor (G) affect stall speed? Why does load factor result reaching the critical angle of attack at higher airspeed?
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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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What plane has the widest range in speed in which it can operate? [duplicate]

What propellor plane, other than planes with vertical takeoff capability, has the largest gap in speed between its slowest stall speed and its maximum airspeed? I am looking for a plane with a short ...
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What is the stall speed of the Antonov An-225?

Under certain circumstances - maximum gross weight, unaccelerated 1G flight, clean configuration (landing gear up and flaps)? Indicated airspeed (KIAS) of course.
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When approaching a stall, is the first priority to apply power or lower nose?

I’ve always wondered. And I’d assume it’s the same regardless of aircraft? But when approaching a stall would the main priority be adding more power? I ask because what if a crew was on final for ...