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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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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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24 views

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
124 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
141 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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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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68 views

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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1answer
111 views

Did the airfoil choice on the P51D affect its maneuverability? [closed]

Did the wing design on the P51D, which used a laminar airfoil, affect its maneuverability? If so, how? To what extent?
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1answer
121 views

Where can I find complete aircraft blueprints for the purpose of study?

Where can I find aircraft blueprints for the purpose of study? I find that I learn a lot more when I am able to get the big picture of a machine that is used in real life (for example, to understand ...
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1answer
34 views

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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4answers
129 views

Is it reasonable for flight economy to correct banking tendencies with stick and rudder?

An aircraft with side-by-side seating but only one person aboard should fly banked. Banking decreases lift and more elevator is needed than in leveled flight which increases drag. Correcting the ...
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1answer
59 views

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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54 views

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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3answers
79 views

Wing pitching moment decomposition into two terms

Summary: Assuming constant angle of attack $\alpha$, speed $V$, and lift $L$ applied at the center of pressure CP (whose position is $x_{CP}$), the distance $(x_{CP} - x_O)$ between the moment ...
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1answer
20 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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3answers
154 views

How does the power requirement change when weight and speed change?

Suppose I have an airplane with a certain weight M, which uses a certain amount of power P, to fly at a certain speed V. If I use the same airplane, but quadruple the weight (4xM) and double the ...
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1answer
57 views

Where should the support points be for testing a model wing in a wind tunnel?

When testing a certain wing profile inside a wind tunnel where should the model, small scale wing be supported? Should the support be under the center of mass of the wing or under the aerodynamic ...
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2answers
64 views

Pressure Distribution Pattern around Wing

it is clear that the overall integrated pressure on the top of the wing is less than the overall pressure at the bottom of a wing in order to produce a net nonzero lift force. Based on the attached ...
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Could a moving film of gas reduce aerodynamic drag?

https://en.m.wikipedia.org/wiki/File:Coanda_effect_6.jpg In the image linked there is depicted a system which creates, using the Coandă effect, a film of gas traveling along the surface of a body. If ...
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1answer
105 views

Would an F-15 or similar stand in be able to continue flight at high speed if it lost its canopy?

Let's say for whatever reason, miscued ejection system perhaps, a jet in flight at exactly mach 1 blew its canopy but did not eject the pilot. And we can assume the altitude is fairly low (to exclude ...
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1answer
106 views

Aerodynamics and fuel consumption of a powered glider

I want to optimize the flight distance of a powered glider model airplane, without the use of soaring. I've studied some aerodynamics books, but still feel unsure about my conclusions. Please tell me ...
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2answers
63 views

How does wing aspect ratio influence lift and drag?

I know simmilar questions are all over the internet (and this website too), but there's one thing that i just cannot comprehend and none of the articles i read could explain it properly. According to ...
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4answers
147 views

Could an airplane takeoff with a very strong tailwind if its propeller blades are set to a negative pitch? [closed]

Would it be possible for an airplane to accelerate and takeoff with a very strong tailwind if its propeller blades are set to a negative pitch? For example, let's say that a hurricane was approaching ...
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0answers
19 views

Determine “basic lift distribution” over a wing that has a circulation distribution

I don't understand what they mean with basic lift distribution. I have calculated C_L which is 5a (a is alpha in radians). I added the relevant equations here.
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2answers
80 views

How do endplates reduce induced drag?

I have heard the explanation which states that the endplates reduce the tip vortex formation thereby reducing induced drag. From what I understand induced drag is the backwards component of the total ...
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3answers
56 views

Fabric-covered Clark Y Max Coefficient of Lift

I'm looking at the Aeronca C-3 Collegian, which had a Clark Y airfoil, and I'm finding the following: Wing area: 142 ft² Empty weight: 466 lbs Payload: 470 lbs Stall speed: 38 mph When I do the math ...
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1answer
46 views

When calculating lift, using the the NASA lift equation, can any value be increased, ie. velocity or surface area, for increased lift?

I am trying to understand the breakdown of the NASA lift formula, which is written as such $L = C_L \frac{\rho v^2}{2}A$ If I take for example CL=0.87, v=20m/s, ρ=1.22kg/m3, and A=9.02m2, my ...
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1answer
62 views

Does a Stalled Wing Exhibit No Circulation

If a wing is stalled, will the wing not exhibit any circulation as predicted by the Kutta-Joukowski theorem? If so how would this affect the pressure distribution between the top and bottom portions ...
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1answer
77 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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2answers
93 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
146 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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3answers
117 views

Is it possible to make an analogy between a lever and an airplane wing in terms of force applied over distance?

On most aircraft the engine force (thrust) is lower than the weight. Since wings therefore are always capable of generating greater force (lift) than the engine, there is an analogy between an ...
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4answers
91 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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4answers
164 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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4answers
160 views

How does scaling of UAV size impact range?

Lets say you have two autonomous small aircraft, one with a wingspan of 200 cm and one with 400 cm. Both have the same general design. They are both optimized for travel distance on one full tank (gas ...
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2answers
56 views

The sharp leading edge results in a larger pressure peak than airfoils with larger radius leading edge?

I know in the real world the sharp leading edge will results in a larger pressure peak.And there are three types of stall.But I want the explanation in theory.I can't overcome the problem why the ...
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1answer
133 views

What is the exact purpose of the string attached between front fuselage & the tail section of the transport aircraft's? [duplicate]

]2 228]3]3 Usually I got to notice a string attached between front fuselage to rear tail section of the transport aircraft's, what exactly might be the purpose or function of it? But comparatively, I ...
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1answer
187 views

Why is the nose cone of Russian fighters pointing slightly down? [duplicate]

Let's take SU-30 as an example: The nose cone is clearly pointing a bit downwards with respect to the level of the engines and wings. Why is this? How can this kind of a banana even fly properly? ...
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1answer
61 views

What should be the relative positions of a wing's aerodynamic center and center of gravity?

A positively cambered wing with finite length L has its aerodynamic center AC located 25% from the wing's leading edge. What about the CG of the wing itself (not the CG of the whole plane)? Is there ...
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1answer
66 views

What is the first cause of induced drag changes?

What causes induced drag to change with speed: speed itself or angle of attack? I have found in different sources 2 versions: 1). Most cited version according to which, with ↑ speed in straight and ...
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1answer
130 views

What is the cooling air exhaust velocity for the piston engine of a propeller driven aircraft?

Piston engines of propeller driven aircrafts need to be cooled. There are engine cowlings which accomodate the inflow of air to "wash" over the engines within them and which is then exhausted out into ...
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4answers
139 views

What would be a simple aerodynamics simulation software for a student? [closed]

I have a project due 2 weeks from now that demands we make a glider using Styrofoam. I'd like to simulate the results as I plan my glider before I build it. Which simple software, which allows ...
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1answer
140 views

Does a rotating control surface change the wing area?

It might seem like a silly question, but bear with me. I am using the standard formula to calculate the lift force of a wing. L = (1/2) d v2 s CL My question related to the s part of the formula. ...
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1answer
72 views

Model for flutter analysis of Aerofoil

Why is a aerofoil modeled by attached torsional and linear spring in a wing flutter analysis.The model does not even satisfy the boundary condition of zero displacement of wing at point of attachment ...
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1answer
99 views

How does angle of attack vary during climbing flight?

I'm a little confused by the angle of attack of an aircraft during climbing flight. Suppose you have an aircraft in level flight which then rotates to some angle x. Just after rotation, I would assume ...
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1answer
92 views

How widely accepted and used is the International Standard Atmosphere?

Is it used in the US as well for an example, where there is the US Standard Atmosphere. With different standard models, how widely is the International Standard Atmosphere applicable? Or is it only ...
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2answers
370 views

What prevents BFS from becoming unstable when pitching from horizontal to vertical?

In this video from (SpaceX's BFS landing) there is a point where the ship tilts from horizontal « belly first » terminal velocity freefall, to vertical « engine first » landing position. The graph ...
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1answer
162 views

What was the first Russian jet designed with the use of area rule?

What was the first Russian jet designed with the use of area rule? Also, how did the Russians acquire the knowledge of this design method? Was Whitcomb's discovery public?
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7answers
377 views

How does maximum speed vary with altitude?

Question: How does a commercial jetliner's highest possible groundspeed vary with altitude (assuming wind=0) ? My understanding is that drag decreases with altitude, therefore maxspeed increases with ...
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0answers
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How is the inflow velocity distributed of a tilted and trimmed rotor in hover?

I'm wondering of how the inflow velocities per blade look during one revolution of a real-life helicopter in hover (no inflow velocity into the rotor plane) with a tilted rotor plane about 20 deg. Is ...
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4answers
250 views

Why does the aerodynamic center exist?

I am a glider pilot and instructor with a master’s degree in actuarial mathematics. I teach aerodynamics every winter for upcoming glider pilots. As you surely know, the aerodynamic center is the ...