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 supersonic flow get faster along an aerofoil?
why is it that subsonic flow gets slower (after point of max thickness of an aerofoil) and supersonic flow gets quicker?
I thought the adverse pressure gradient would slow it down?
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Why do shockwaves move aft with camber/trailing edge deflection?
Why does a shockwave move further towards the trailing edge with increasing camber?
Also, is the shockwave the thing above the aerofoil or behind it?
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What is the typical drag percentage of air intakes on a commercial airliner
I see several questions on the NACA ducts found on airliners Example 1, Example 2, Example 3 and I was wondering how much drag is normally generated by these inlets?
As they take in air, I imagine ...
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Can someone help me understand this aerofoil?
I came across this morphing aerofoil, but don’t understand how it works please?
Can someone explain also what the components are, like that box in the left?
I looked into that reference, but it’s a ...
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How can you tell that the aerofoil has an unsymemetrical section only by looking at Lift to drag ratio against AOA? [closed]
I am doing a wind tunnel experiment on a NACA2412 airfoil with a plain flap where ($P_(ambient)= 1013 mbar, T_(ambient)=15°C, Velocity=33m/s$) and got these graphs
I want to know how can the section ...
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Trailing edge flaps use [duplicate]
Why is it that trailing edge flaps are only used at lower speeds?
Can they be used at higher speeds too?
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How to approximate the drag for rectangular vertical flat panel placed along the wind and inclined?
So on the top is the view from the top, below it is the side view.
If the angle is zero it is similar to simple flat airfoil.
So I calculated the Cl and Cd in xfoil and
got the Cl = 0 and Cd = 0.02398 ...
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Is there an aerodynamic benefit of covering the underside of wings?
What is the nature and extent to the benefit of covering up the bottom of an airfoil?
It seems like all the early airplanes just had ribs and spars that were wrapped only on top, but then pretty soon ...
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Aircraft spoilers (flight spoilers, GLD)
Wondering if anyone has any examples on how a spoiler affects the Cl and Cd of an airfoil.
For example, Xfoil has plenty of data on plain flaps up to 45 degrees deflection but nothing about spoilers. ...
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How does increasing camber increase lift coefficient?
How does increasing the camber of an airfoil (like the NACA 0018) increase its coefficient of lift?
You're just curving the airfoil; I don't see how that increases lift for a given angle of attack?
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Aircraft progress: Evolution or design? [closed]
This video of a Curtiss Pusher is stunning. Had I been around when it was new, I would have stopped there!
Question: What processes led to the aircraft of today?
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Trailing edge flap disadvantages
What does ‘high local surface curvature’ mean with respect to trailing edge flaps?
I’ve been reading up on them, and that came up as one of their disadvantages?
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Why does this site allow misleading answers to remain, and stay at the top of the stack? [migrated]
In searching for some relevant photos for a lecture I am writing, I came across a question "Does lift equal weight in a climb?". The first answer, with most upvotes, is not only very ...
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Why do autopilot controllers use $\theta$ as the input signal rather than $\gamma$?
In particular, referencing how the Matlab/Simulink controller here uses $\theta$ (absolute pitch angle), rather than $\gamma$ (flight path angle). (Autopilot controller starts at 59:26)
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Will the V280 operate with only one engine?
Can the newly contracted Bell V280 Valor operate on one engine?
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A shock propagates in to stationary air at M. Find the speed of the air (fixed frame reference) after the shock has passed [migrated]
The speed of sound prior to completion of the shock is $M_1 * a$, where a is the speed of sound at that point.
The solution is then that the speed of the air after the shock has propagated is $(M_1 * ...
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Why isnt the structure of the aircraft affected by high true air speeds or high ground speeds?
Let's suppose that in Cruise flight I exceed the VNE in TAS or in ground speed, why isn't the structure of the aircraft affected by the high speeds?
I am sorry for my english, I am not a native ...
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What is the additional planform area added to an A380 on take-off flaps setting (Flaps 1+F)
I would like to know how I can approximate the additional area added to wing on flaps 1+F:
Can someone use other dimensions they know of the A380 wing and approximate what this area would be, we can ...
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Can I identify wingtip stall by looking at the lift distribution?
I'm projecting a wing in XFLR5. The lift at the tip of the wing looks like it's dropping very quickly close to the stall angle, so I think there may be wingtip stall, however, is there any way I can ...
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Why does elevator trim hold a given airspeed? [duplicate]
I'm trying to understand a principle described in the book Stick and Rudder by Wolfgang Langewiesche between angle of attack and airspeed in relation to the elevator trim. He states that as angle of ...
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How does propeller length, pitch, and airspeed affect efficiency? [closed]
tl;dr: trying to find propeller efficiency with thrust, velocity and power and see which propeller length to pitch ratio is efficient.
Hello, I'm a high school student working on an extended essay for ...
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Center of Gravity, Aerodynamic Center and Center of Pressure, how do they connect?
I read an article that described static margin by taking the aerodynamic center and the center of gravity. It explained why the center of gravity has to be in front of the aerodynamic center for a ...
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How does varying camber affects control over an aeroplane? [duplicate]
How does a trailing edge flap actually help an aeroplane?
It just changes camber but what does that exactly do that’s beneficial?
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Mathematically calculate Mach number using CAS and PA WITHOUT flight computer
I am just wondering how to calculate the Mach number from CAS and Pressure Altitude WITHOUT the use of a flight calculator.
E.g Given FL300 (30000ft) and 325kt CAS find and Mach number.
I have always ...
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Is this method to calculate a biplane's center of gravity using 57% of the biplane's gap and 23% of each wing's MAC correct?
Once you have the MAC for both wings and the CG balance point as a percentage of the MAC. connect the two CG positions with a line. Measure up between the wing Gap distance and place your center of ...
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Maximum Rotary Lift Altitude
Given that all factors are optimal, What is the physical maximum absolute ceiling altitude of a rotary wing aircraft?
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What should be the ideal distance between wings in a multi-winged air plane?
What is multi-wing or multi-plane:
For those who may not know, multi-wing air planes or multi-planes are aircraft that exceed the three sets of wings.
The idea is while increasing the number of wings,...
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Rate and radius of turn formula
From this question and answer here there is a formula for both rate of turn and radius of turn. The formulas input are knots and degrees.
I have no doubt the constants in the formula (11.26 and 1,091)...
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Helicopter total power required: zero wind speed while climbing --vs-- down wind speed while hovering
I've been stumped on this for a while. Let's say you have a helicopter in climb mode (i.e., 100 ft/min) with zero wind speed present. Would the total power requirement be the same as if the helicopter ...
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The F104 tail pipe is not parallel to the runaway when the aircraft taxi.What is the reason?
The tail section is upward for clearance or to vector up the engine exhaust that will help to rise the nose when the aircraft take-off?
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Streamwise Pressure Gradient on Curved Walls
Could someone help me to understand how can a wall generate differents streamwise pressure gradients just by its curvature? I can understand how it works in cross-flow (perpendicular to the streamline)...
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Other than looking cool, what is the reason behind the TSR-2's anhedral wingtips?
Pretty much what the title says. What is the purpose of the TSR-2's anhedral wingtips? I've heard someone say that they use it to counter yawing I think but is this the true reason or is it something ...
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Can an aircraft use ram air to generate power while flying?
I am a student carrying out a project focused on efficiency on aircraft. I have arrived at an idea I believe to be feasible. I am looking for suggestions, specification of what I would need, and any ...
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Lift direction at non-zero angle of attack for a swept wing, or for a straight wing in sideslip
When the direction of forces is popularly explained, they say "the lifting force is directed perpendicularly, and the drag force is parallel to the oncoming flow".
But what if it's a swept ...
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Why are the trailing edges of wings not always made as 'sharp' as possible?
I noticed that wing trailing edges of new airliners like A220 (CSeries) are not completely sharp. Instead, they are blunt. I always thought that the sharper the better in subsonic flow. What is the ...
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Thrust = Drag. What about Power?
Understanding all this has been a work in progress, but now from start to finish we have:
Fuel/second ---> shaft Horsepower---> RPM ---> Thrust ---> Drag
Drag Force = $\rho$ × Area × ...
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Subsonic Bump Inlet?
Contemporary high-performance supersonic aircraft such as the F-35 use bump inlet (alternatively known as DSI). These have a sophisticated 3-D bump that causes a 3-D weak shockwave in supersonic ...
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Why use indicated airspeed instead of dynamic pressure [closed]
It uses the difference between total pressure and static pressure, provided by the system, to either mechanically or electronically measure dynamic pressure. The dynamic pressure includes terms for ...
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Making sailplane go faster
Sailplanes have much higher L/D than jetliners. But they are three times slower.
Is it practical to make a vanilla sailplane glide at 600mph by lifting it to a ridiculous altitude? If so, what would ...
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A Confusion about Digital DATCOM Calculations of a Tail Pitching Moment Coefficient
I'm using D DATCOM to estimate cm-alpha curve for a small tail planform with NACA-0012 airfoil using the namelist ($HTPLNF).
When taking the Tail planform aerodynamic center, ac (about 25% of MAC), as ...
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Why do the wings in these pictures go from swept back to parallel with the airflow? [duplicate]
To better understand my question, look at this A320 below
As you can see, the wing becomes parallel with the airflow at the wing root. Same thing on this 737
But this is not found on bigger planes ...
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Will two counter rotating vortices cancel each other?
Suppose that an aircraft flies with its wing through a tip vortex of another aircraft which flew in the opposite direction. Suppose that the shed wing tip vortex of both aircraft are exactly the same ...
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Lifting-Line Theory - Numerical solution for a wing with dihedral angle
I'm trying to calculate lift for a wing with a dihedral angle using the Lifting-Line Theory. While using the thesis "Non-Planar Lifting-Line Theory for Fixed and Deformable Geometries" as a ...
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What happens to aerofoil downwash with Flaps extended vs retracted and how does it affect the Tail down force?
In my logic: Flaps extended will cause a greater Angle of Attack, to maintain Straight and Level Flight, AoA will be reduced, due to the increased "Surface", this allows to fly at lower ...
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Why does an aircraft fly a looping when pulling the stick?
let's assume an aircraft flies in straight level flight in the direction of an x-axis with an angle of attack of 3°. When the pilot pulls the flight stick, an additional lift is produced which acts ...
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aerodynamic forces on an engine cowling
In Mendenhall's book about the Gee Bee racers, he describes that on the Models Z, R-1, and R-2, there was a strong tendency for the engine cowl to get pulled forward and into the prop during races, ...
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Why cut off the tips of a delta wing to form a cropped delta?
According to wikipedia, the reason to cut off the tips of a standard delta wing is
maintain lift outboard and reduce wingtip flow separation (stalling)
at high angles of attack
This type of delta ...
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What are some advantages of the ogee-delta wing compared to standard delta? [duplicate]
A delta wing is designed for both subsonic and supersonic flight. This wing planform ensures sufficient lift in all conditions (vortex lift and supersonic lift).
A ogee-delta wing is a modified ...
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P Factor vs Spiral Slipstream
Does anyone know of any real aeroplane or wind-tunnel tests that quantifies the effects of asymmetric propeller blade loading (P factor) versus the Spiralling Slipstream effect in creating yaw.
Which ...
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What are the aerodynamic characteristics of the flying saucer?
It seems that Canadian VZ-9 Avrocar was aerodynamically unstable. Particularly at high altitudes, and so the project was cancelled. IIRC there was considerable interest in flying saucers in the 1950s ...
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