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Questions tagged [aerodynamics]

Aerodynamics is the study of how air moves and interacts with solid objects. It is an essential part of aircraft design.

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Could Falcon 9 fairing become glidable / flyable?

Reading and thinking about this and this questions on space exploration stackexchange, I was wondering if the fairing could shape itself, so that it becomes one stable and steerable gliding element ...
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828 views

Why do most GA aircraft not have vortex generators?

It is my understanding that vortex generators produce more favorable aerodynamics by delaying flow separation. If this is the case, why do more GA aircraft not have vortex generators?
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Are there any airplanes with the Centre of Gravity behind the Centre of Pressure?

We are used to seeing a forward CG in all airplanes, from a small Cessna to a large Boeing. I wonder whether any airplane with CG behind wing CP exists in production? Is it even possible? If so, what ...
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1answer
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Why is the 737’s aileron/spoiler authority reduced at low flap settings?

According to the NTSB report on the crash of United Airlines Flight 585, the ability of the 737’s lateral controls (ailerons and flight spoilers) to counteract the rolling forces produced by (say) a ...
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1answer
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Why does the wing root of the A330 have a pronounced twist?

just wondering what the purpose of the pronounced twist on the Airbus A330 wing root is, I've noticed this on the 380 as well.
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0answers
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Air flow over an airfoil

We know that in real viscous flow, boundary layer exists around the airfoil and there will be a separation point which flow starts to separate from the back of the airfoil( velocity gradient equal ...
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2answers
318 views

What is the difference between ground effect for an infinite wing and for a finite wing?

A question about ground effect has just reappeared. I think one needs to differentiate between ground effect for a finite wing (3D flow) and ground effect for an infinite wing (2D flow). What are ...
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2answers
163 views

Why does elevator input move the turn coordinator ball in steep turns?

When practicing steep turns, I'm running into an unusual phenomenon. If the airplane is losing altitude in coordinated flight and I apply aft stick pressure to pitch up and correct, I notice that the ...
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3answers
2k views

How does bank angle differ from roll angle with respect to stability in fixed-wing aircraft?

I would like a clarification on bank angle and how its different from roll angle with respect to to fixed wing aircraft. It is my understanding that the bank angle is a result of rotating the aircraft ...
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1answer
50 views

Where can you find wind tunnel visualization data online?

I was wondering if there was a repository of flow visualization results somewhere online, preferably of wing sections categorised in some manner.
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0answers
44 views

How to calculate the power required during transition from VTOL to fixed wing?

In a VTOL, I have calculated the power required for take off and cruise which was not difficult at all. Between take off and cruise, there is a phase where the VTOL has to transition by tilting the ...
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3answers
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How do elevons work to roll a flying wing?

I have a RC Flying Wing that uses elevons for control. To go up both elevons pitch upwards and the wing climbs. Both go down and the wing falls. I’m OK with this. However, if I want to roll right, ...
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What is subcritical and supercritical boundary layer?

What is subcritical and supercritical boundary layer? What is the difference between them?
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Can the ball on a turn coordinator be to the full right/left while the wings are level?

Can it ever happen in a wings level flight that the Turn and Slip indicator ball is to the full right/left? If so then when and what will be the flight path of such an aircraft? Thanks in advance.
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1answer
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How can I calculate the velocity of air drawn by a pusher configured propeller?

I am attempting to construct a model plane using Custer channel wings. In order to calculate (or at least approximate) the lift generated I need to find the speed of the air through the channel due to ...
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4answers
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Would a propeller extracting air from a cylinder with holes in it be an ideal lift apparatus for a VTOL aircraft?

I am wondering if enough lift can be created for a VTOL aircraft using a propeller that is extracting air from a cylinder which is closed at one end and has holes in the top half of the cylinder. ...
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3answers
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Is there a maximum lift to drag ratio?

If I recall correctly, the best competition gliders have a L/D ratio as high as 60:1. What imposes this limit? Is there a maximum theoretical L/D ratio, or could sufficiently advanced materials allow ...
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Does shrouding a propeller minimize induced drag by equalizing the downwash velocity along its blades?

EDIT: It's not a duplicate of Are ducted fans more efficient? That question and the answers doesn't address the reason for the higher theoretical efficiency, it is more about efficiency in practice (...
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1answer
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What causes the adverse pressure gradient that leads to flow separation?

When reading about flow separation I generally see a diagram like this: imp source: Wikimedia commons This shows that the boundary layer slows as it passes over the wing, eventually creating an ...
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3answers
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Was the Space Shuttle aerodynamically neutral while piggybacking, or did the combination act like a giant biplane?

Trying to investigate this question, I see that 'Ask the Captain' says: The weight of the shuttle is calculated like any payload. The 747 produces enough lift to fly and to carry the weight of ...
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2answers
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What is the most efficient symmetrical airfoil shape?

What is the most efficient symmetrical airfoil shape to make for a covering for a round upright bar that measures 40mm outside diameter? The speed of travel will be 25Kph and I also need a shape to ...
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4answers
2k views

Why does the bottom part of an aircraft nose curve upwards?

As you can see in this picture the bottom of the fuselage curves upwards to form the nose.
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2answers
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Why does the B777 have no winglets? Are there any drawbacks to having winglets?

I have googled and noticed that almost every Boeing 777 is not equipped with winglets. Does anybody know the reasons why Boeing did not equip B777s with winglets? Are there any drawbacks to having ...
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1answer
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How come diverterless supersonic inlets haven't been discovered much earlier?

DSI's seem like such an absolutely elegant solution to a problem that has, so far, been solved in a truly overly complicated way. So, if I'm not missing out on some important small speck of knowledge ...
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How are these parameters derived from readings of sensors in an aircraft: angle of attack, slip angle, and airspeed?

From what I've learned, the reading comes from an angle of attack sensor and a slip angle sensor. Let's call the readings $\hat\alpha$ and $\hat\beta$ respectively. These are of either the ...
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3answers
110 views

Why does an aircraft's nose tend to pitch downward at higher bank angles?

In the usual aircraft configuration, the center of lift is located behind the CG producing negative pitch moment (the horizontal stabilizer counteracts it by producing downforce - positive pitching ...
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2answers
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Is there any evidence that the downwash vortices impact the performance of a wing?

Or is it merely flow separation on the upper surface towards the end of the wing? The assumption seems to be that the air "leaks" from under the wing to low pressure above with sufficient rapidity to ...
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1answer
488 views

Which moments are acting on a flying airplane?

I would like to ask some clarifying questions regarding the moments acting on a flying airplane. My understanding is that there are following force: Weight (pointing down and applied to the CG of ...
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1answer
56 views

Force Balance in Wind Tunnel

I am considering a model wing inside a wind tunnel supported from underneath from its center of mass. Two load cells can be used, when properly oriented, to measure the lift force and the drag force. ...
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0answers
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Wing Shape: Long/Wide Span Wings vs Deep Wings [duplicate]

Planes use wings to generate lift. The wider the span of the wing (looking at the plane from the front) the more lift it generates, however, this is at the expense of more drag. Some planes like the ...
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2answers
178 views

What is a rudder or fin stall?

What is a rudder or fin stall, how will the aircraft behave in that situation, and how should the pilot recognise it? What is the recovery procedure? And what is rudder reversal?
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6answers
296 views

How does Bernoulli's principle contribute in lifting airplane?

I have searched if any explanation that bind Bernoulli's principle in lifting airplane. There is one here which receive many appreciations, but still did not answer the question. So far, it was taught,...
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1answer
233 views

What was the lift equation used by the Wright brothers?

NOTICE: The modern lift equation and the lift equation used by the Wright brothers in 1900 are slightly different. The lift coefficient of the modern equation is referenced to the dynamic pressure ...
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1answer
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Why does the rotor thrust decrease at smaller tip clearance for shrouded rotor?

Consider this system, rotor with shroud: From this research, we see that: at the same rpm, the rotor thrust decreases,the shroud thrust increases as tip clearance decreases. But why does the rotor ...
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1answer
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What are these unsymmetrical parts at the tail of the Tupolev TU-144?

On a recent trip to the Technikmuseum Sinsheim, I noticed that the back of the Tupolev TU-144 is not symmetric. Please take a look at the picture I took to understand what I mean: (Please don't mind ...
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2answers
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Is the Meredith effect utilized in the cowling design of air-cooled engines?

The P-51 is famous for its advanced-for-its-time aerodynamics, the prime example of which is the radiator design under the belly which utilizes the Meredith effect to, in effect, turn it into a mini ...
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0answers
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What elements are required for an airplane to generate lift? [duplicate]

I'm not a scientist but what basic things does a plane need to get lift? Does it have to do with the flow of air produced by the shape of the wing as the plane moves forward on the runway? What would ...
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5answers
312 views

Do swept back wings affect the moment of inertia of an aircraft enough to be relevant for the roll response?

I have studied that swept back wings help in delaying the shock waves formed on the wing, but also to my understanding I feel swept back wings reduce the moment of inertia (like for example a ...
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1answer
84 views

What was the Airfoil of Handley Page P.115?

This extreme sweptback delta was built to test the Concorde wing at low speeds, sources say it had a biconv 6% airfoil, but I failed in finding data about it.
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Would it be more effective to increase the length or chord of a rotor blade for better performance?

Would it be more effective to increase the length or chord of a helicopter rotor blade for better performance? (Say, 10%?)
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2answers
108 views

What is the relationship between drag and sink rate?

I was just brushing up on basic aerodynamics and I have something I want to clarify about flying in the region of reverse command. I went up in my 172 the other day and noticed the following while ...
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0answers
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What is the glide ratio on the CE-S550 Citation S-II?

I couldn't find it in the AFM. Is it different then the square winged citation II?
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2answers
137 views

Does rolling or yawing affect the angle of attack?

If I'm on final in windy conditions and I need excessive rolling and yawing movements to stay on centerline and say, my pitch stays constant - does rolling or yawing change my AOA such that I could ...
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2answers
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What's P-Factor and why does it occur?

Whenever I hear anyone talking about P-Factor, (whether it be single-engine left turning tendencies or multi-engine loss of directional control scenarios), someone always brings up the fact that the ...
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0answers
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How do split winglets reduce bending moment in the wings?

I am doing a study on split winglets and how they are more advantageous than blended winglets . While browsing through the net, I was reading an article about the Boeing 787 Dreamliner and they had ...
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3answers
8k views

Why do low wing aircraft have higher dihedral than high wing aircraft?

I have noticed and read in books that low wing aircraft have higher dihedral than high wing aircraft. Dihedral is design feature for lateral stability so should be needed for both designs. So why is ...
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0answers
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Where am I wrong at aerodynamic center calculation?

I'm currently taking aerodynmics course.In the classical thin airfoil theory. we saw that both for symmetric and non-symmetric airfoils the term $dc_l/d\alpha= 2\pi$. But in the preceding chapter, ...
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4answers
104 views

Aerodynamics moment of a wing

An old flight book that I am reading discusses the aerodynamic moment about a wing and talks about an upper and lower lifts. I can see how the pressure distribution on the top surface produces an ...
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3answers
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Why does the DC-10's horizontal stabilizer have such a pronounced dihedral?

If you look at this picture, you'll see that the horizontal stabilizer has a very pronounced dihedral in comparison to the wings. Could somebody explain in a simple way why? I understand that a ...
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1answer
386 views

What makes the loss of a flap track fairing strongly increase fuel consumption on Airbus planes?

Inspired from this question about the loss of a flap track fairing. In the answer by Thunderstrike, a part of the configuration deviation list of an Airbus A320 is linked. In it, it says: One ...