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 are modern aircraft wings often pointed instead being more rectangular?
When viewed from the Z axis (above or below), why are modern aircraft wings often pointed as they get towards the wingtips instead of maintaining the same surface area for their entire length?
This ...
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Is the commonly assumed UFO (flying saucer) design aerodynamically efficient? [closed]
Is this design, a circular disc (or flying saucer) slightly humped on the top and bottom aerodynamically efficient? And if, we are able to use it for commercial purposes , would they give a better ...
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Does the Piper PA-28 Cherokee wing have laminar flow behavior?
I've heard (and read) that the PA-28 series has a laminar flow wing:
The Piper had a very thick airfoil that used laminar flow to assure that lift would be lost very slowly up to the stall.
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Why doesn't GE replace all 4 engines for on their flying test bed instead of just 1?
GE (General Electric) flies Boeing 747s equipped with new engines that are being tested. Why can't they equip the test airplane with all 4 of the new engines? Wouldn't the thrust be imbalanced by ...
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How significant is antenna drag on light GA aircraft?
Antennas sticking out of an aircraft obviously increase profile drag, but the folks who design antennas have done a lot to improve aerodynamics: High performance aircraft can have antennas mounted ...
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The stronger the headwind the faster the plane flies if it is in the reverse command regime?
Revision 3. Clarifications, as required by moderators, added. The main reason for asking the question provided.
Regarding the reverse command regime of a plane
Assuming a plane hovers (ground speed $...
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What really causes a low-pressure gradient over the top of an aerofoil? [duplicate]
As air flows over the top of an aerofoil the pressure drops. Compared to the high / normal pressures on the underside, a pressure gradient is formed with higher pressure further above the wing. You ...
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Would turbulence created by two jumbos less than 100ft apart cause both of them to crash?
In a scene from Spider-Man 2 (2014), which you can see in this video, two jumbos almost collided. At the last possible moment, the pilots were able to save their planes, but both planes came to within ...
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How is the climb gradient calculated?
I was part of a discussion about the differences between all engine climb gradients and one engine inoperative (OEI) climb gradients, and a colleague suggested that climb gradient can be calculated as ...
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Is the airspeed different between above and under the wings? [duplicate]
I heard that when an airplane is flying, air speed or air pressure is higher under the wings. Is it true?
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Requirements for Steady Level flight at various speeds [duplicate]
Let an aircraft in a steady level flight be trimmed at certain speed. A level and steady flight at a higher speed can be achieved by changing throttle and elevator together ( and not just by changing ...
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Why isn't the V flight formation being used for commercial purposes?
The V Flight Formationhas been found to be helpful in achieving greater fuel efficiency and range. Though it is currently used mostly for military purposes, what restricts it from being used for ...
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Why do some commercial aircraft have no landing gear cover? [duplicate]
The B737 has no cover on its landing gear, as may be seen in this picture. Doesn't this increase the air drag?
Almost all other airliners have doors that close off the rubber of the wheels, for ...
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Can a steady flow have stagnation points?
I am confused by this idea. If a flow is steady, its streamlines are unchanging. Taking the typical example of an airfoil, there is (at least) one streamline which will hit the leading edge of the ...
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Thought experiment: can an aircraft that is dropped from the sky get into gliding? [duplicate]
Here's a totally hypothetical question that came up in a discussion with friends:
If a commercial aircraft (say, an Airbus A320) was "dropped" from a typical cruising altitude (say, 35,000ft) with a ...
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What is the function of the tail section on a fixed-wing aircraft? [duplicate]
In a generic fixed-wing aircraft like a Cessna, what is the function of the tail section, i.e. the rudder and elevators?
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How do aerodynamic loads explain the Spaceship2 accident?
From the NTSB's preliminary report, we read in the "Findings" section:
Although the copilot made the required 0.8 Mach callout at the correct point in the flight, he incorrectly unlocked the ...
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Stalls: which flight control surface is effective last?
In an aerodynamic stall, which flight control surface (limited to ailerons, elevators and rudder) remains effective for the longest period of time during the stalling condition? In other words, which ...
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Should full flaps be deployed on takeoff?
Are full flaps ever used on takeoff?
One flying book I read strongly discouraged anything more than quarter flaps on most planes due to the amount of drag produced. I was just wondering if there are ...
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What is the typical fatigue life of a helicopter airframe? [duplicate]
For military helicopters such as the Sikorsky UH-60 Black Hawk, what is the typical fatigue life of a helicopter airframe (in cycles and hours) ?
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How does a 'Highly Swept leading-edge' delta wing reduces fuel burn and increases range? [duplicate]
Spike Aerospace claims to have designed an aircraft called S-512, with maximum speed of 1.8 mach and cruise speed of 1.6 mach, speaking about the notable changes in the aircraft, Spike Aerospace says:...
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What is the difference between types of propeller? [closed]
I have been noticing almost every Multirotor vehicle uses a single thin double-bladed propellor on each axis. And yet clearly, there are some that do not fit the norm.
Can someone explain what the ...
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Why does a missile have small wings but better agility than a plane?
An anti air missile has often very small wings but out performs a fighter aircraft, e.g. much higher g-load, since g-load comes from lift which is the area of wing.
Why not designing an aircraft like ...
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Why most of the supersonic or fighter aircraft use all-moving control surfaces?
What are the advantages of using all-moving control surfaces? can someone give explanations based on aerodynamics?
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Would solar panels on the wing of an aircraft increase drag?
If a small scale UAV (wingspan <2 metres) was to be fitted with solar panels on its wings to have more power available, would the addition of these panels cause an increase in the drag coefficient, ...
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How does a wing mounted jet engine on a supersonic airplane prevent the interference in the flow due to Shock? [duplicate]
Wing mounted jet engines face the free stream at Mach number 1 or above, and they work perfectly for Mach numbers below 1 as well, even though the free stream characteristics change a lot after Mach 1....
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Is it possible for an airliner to safely fly with doors open?
From another question asks about the possibility of dropping bombs from converted airliners. My question: is it possible to safely fly aircraft with a door open for the whole flight envelope? Would ...
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What is P-Factor in Propeller Aerodynamics? [duplicate]
What is the P-Factor when we're talking about a Propeller Aerodynamics ?
Thanks
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What is the working principle of trim tabs on the elevators?
Trim tabs are used on the tail's horizontal elevators to adjust its neutral position. What is the working principle behind this? How does this affect the sensitivity (the feel) of the pitch to the ...
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Why don't all wind tunnels use magnets to suspend models?
NASA and the French aerospace agency have conducted research into magnetic suspension and balancing systems (MSBS) to suspend models during wind tunnel tests, like this system in South Korea.
Where ...
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Will wind tunnel modelling ever be completely replaced by computer models? [closed]
With computer-based fluid simulation already being extremely realistic (and likely faster and cheaper than physical wind tunnels), are they, anywhere, completely replacing physical wind tunnels? If ...
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Where does ice collect first on a wing in flight and why?
I've seen some reports that say ice forms on the back half of the wing and on the outside edge of the wing (the part furthest from the body) before it will form anywhere else. I'm wondering if this ...
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What are the opimum values of Cl during descent?
Statistical Analysis of A320 aircraft shows the Cl values to be as under: cl_value. L is assumed to be 0.5*MaximumLandingWeight of A320 as the Aircraft is about to land.
The Units used are: Flight ...
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Why is a control surface that allows two sides of airflow better than those that allow one?
For example, ailerons allow air to flow past both the top and bottom surfaces, which makes it more aerodynamic than speedbrakes. Also, plane rudders have air flowing on both sides, which is apparently ...
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What causes aileron and elevator flutter?
This video shows a Hawker jet with the wing fluttering up and down like it's about to break. What can cause flutter like that? Can it actually cause a wing or stabilizer failure? How can flutter be ...
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Why do some airplanes have vertical strakes?
A lot of different aircraft have vertical or near-vertical fins below the empennage, or above the empennage and attached to the front of the vertical stabilizer.
What purpose do these devices serve?
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How much thrust was provided by a typical Meredith Effect radiator?
The Meredith Effect was used on some aircraft to provide more thrust by channeling air through the radiator such that the air is expanded, heated and then compressed through a constriction, generating ...
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In a slip or skid, how does one wing have a higher angle of attack and more lift?
I've discussed this with my instructor numerous times, and I have the concept memorized, but from an aerodynamic point of view, I can't see how the angle of relative wind to chord line is different ...
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Why can not two modes coincide perfectly for some cases in Flutter phenomena?
I have a question about flutter phenomena. As you know, flutter occurs when two modes (for example, first mode and second mode) coincide (that is, after a specific velocity, the frequencies of two ...
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How are the glide polar and L/D ratio charts related?
We know from other questions and answers that airplanes and gliders in particular can have their performance described in terms of glide polar and Lift-to-Drag ratio.
As it appears from the images in ...
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Minix wingtip vortices mitigation - How does it work?
I stumbled upon this article: Minix wing tip device promises 6% gain in fuel efficiency for airliners.
Such an economy is appealing and I must confess the design is "sexy".
Could someone expand a ...
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How did flight 2574 break up?
My understanding of Continental Express flight 2574 is that a de-icing boot on the horizontal stabilizer of the EMB120 was missing screws and therefore detached, leading to the tail separating.
I ...
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Do the effects of turbulence change when banking/turning compared to level flight?
Are the effects created by turbulence on the aircraft different when the aircraft is banking or in level flight? By logic I'd say yes but I would like some technical and practical explanation.
When ...
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Flying sideways, how is it done? [duplicate]
I assume that the fuselage and tail fin can generate lift when flying sideways with a constant heading and a little pitch up (er, yaw right assuming left wing down) will introduce a vertical component ...
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What is the advantage of increasing an aircraft's horizontal tail surface area?
Most aircraft have horizontal tails. What is the advantage of increasing the horizontal tail surface area?
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What operational differences were there in WWII for constant speed vs. fixed pitch propeller warbirds?
I have read about the operational differences between constant speed and fixed pitch propellers.
Being a World War II buff, I was reminded of reading once about both principles being used in period ...
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Is there always a stall if you exceed a specific angle of attack?
So lets consider that the stall angle (=Cl max) of a B747 is at 16° (in clean configuration). Does this mean, that, at whatever speed you are flying (i.e. 500 knots), you would stall if you go on a ...
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How much lift do planes produce before rotation?
In the takeoff roll, I'm pretty sure planes produce some lift before rotation, but how much? Is it insignificant compared to post-rotation, or is it large compared to the post-rotation lift?
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How can I calculate polar curve?
I recently got the polar curve of an aircraft with the method of Anderson. But this method is too old.
Does someone know a recent method for the polar curve without using CFD?
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Is head-on or trailing wind better?
Does a powered aircraft fly faster when in a head wind or with a trailing wind? The question revolves around the head wind should provide 'better' lift, and trailing winds have very little to 'push' ...
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