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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Are there polar plots and airfoil data points available for the RAF4?

Are there polar plots and airfoil data points available for the RAF4? I understand this is the airfoil used for the horizontal stabilizer of the Zenith 701, which should be similar to a NACA4412 ...
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What exactly happens when power is reduced in trimmed, straight and level flight?

I understand that trimming an aircraft at a particular airspeed e.g. 100kts will keep the aircraft flying at that airspeed (100kts) even if you were to e.g. Lower power. This is apparently ...
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Dynamic modes at supersonic speed

Our teacher gave us an assignment where we have to study the longitudinal stability of an X-15. I have to study it at 353.9 m/s which is Mach 1.2. Another group has to study it at 235.9 m/s so Mach 0....
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What is the amount of lift produced by friction?

As Mr. John D. Anderson states, the aerodynamic forces on a body are due to only two sources: pressure distribution over the body and shear stress distribution. Shear stress is acting tangential to ...
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60 views

Tailplane/Equilibrium conditions [duplicate]

In regards to achieving equilibrium conditions, what is the relation between airspeed and the tailplane?
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Do pilots ever intentionally land a monowheel glider on the main wheel and a wingtip wheel in crosswind conditions?

Do pilots ever intentionally strike a wingtip when landing a mono wheel glider in gusty crosswind conditions? I understand the Lazair changed from a mono wheel to a standard tail dragger layout for ...
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294 views

Why did some Spitfire variants have their wings clipped?

Some Spitfire variants have clipped wingtips instead of the round, elliptical wingtip. The reason for this is to increase the roll rate and low-altitude performance. My question is: How would clipping ...
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Can i use diverter less intake in design based on MiG-29?

Which type of boundary layer diverter has been used in MiG-29? Also, can I use diverterless inlet in my design that is based on the reference aircraft MiG-29?
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1answer
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Considering a piston engined aircraft, what resistance pressure would be generated within its engine bay against its cooling intake?

Consider a piston engine with all its coolers and components within an aircraft engine bay. To cool this engine, cooling intakes are positioned facing the direction of flight. Now, the condition at ...
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1answer
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Why is the nosewheel of the MiG-29 placed in front of the engine intakes?

Why do MiG-29 have a front-wheel of landing gear placed in front of an intake? would not it throw water or stones into the intake as mentioned in Raymer? I am designing an aircraft based on the ...
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What are the pros and cons of wingtip tanks?

I am looking into the aerodynamic pros and cons of wingtip tanks. Let's assume they're perfectly streamlined, optimally placed and sized for a given airframe. I am aware of the purpose of fuel ...
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AltFlap switch in F16 jet fighter at various stages in flight

If you apply ALT Flap in F16 the flight quality is somehow similar to the CATlll or TO/Landing gain (lower max AOA available - only 18 degrees - , roll rates halved) because this is emergency mode. ...
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how does the rudder work? [closed]

What do you know about yaw control and more precisely about the result caused by the rudder (R on picture)? Below the right pedal of the airplane has been depressed, and the rudder creates a rotation ...
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Tapered Wing Providing low Coefficient of Lift

Hi I am currently analyzing different wing designs using ANSYS Fluent. One of my designs has a straight leading edge but a swept trailing edge thus it is tapered with wing root chord at 50mm and wing ...
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How does an aircraft maintain an orientation that was actually caused by a external disturbance?

What is the difference between centre of pressure, aerodynamic centre and neutral point? At this link, there is an image used to explain the answer, but not much has been spoken about it. I ...
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what is the différence between sharklet and winglet? [duplicate]

I see that airbus mostly have sharklet,contrary to boeing which have winglet. What is the difference apparent?what is the aerodynamic differences?which is better? Edit:question duplicate ,sorry i ...
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When do the lift and drag vectors contribute a force component along a glider's path of travel as seen from the ground?

It is often said that the lift vector helps to propel a glider forwards. The lift vector has no component acting parallel to the glider's trajectory through the airmass, but in many cases the lift ...
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Why do swept wings decrease the drag increase that occurs in transonic flows?

Swept wings are used in aircraft that fly in the transonic regime because they 1) delay the critical Mach number 2) reduce the drag increase that occurs (smaller drag divergence). I am trying to ...
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Does this web page really correctly depict the angle that is called “incidence” in the French language in the aviation context?

Does this web page really correctly depict the most common usage of the term "incidence" in the French language in the aviation context, in the context of speaking of an entire aircraft and not just ...
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122 views

A question about the exact meaning of one British usage of the term “Angle of Incidence”

This answer to a related question stated: Most anything can have an angle of attack. If you must be specific, you mention 'angle of attack of ...' ... When we talk about airplane as a whole, ...
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259 views

How to reduce the noise of the supersonic passage(bang)?

as you know the transonic phase is often associate with the bang. The principal cons of the transonic phase is the noise,it's why there is not supersonic passenger aircraft( cause the end of the ...
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197 views

Could a triplane fly using a dihedral wing in the middle?

I wonder if a triplane glider whose front view is shown in the figure can be built and flown successfully. As you can see, the middle wing has a dihedral angle, but the top and bottom wings do not. ...
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1answer
137 views

What is the total EXTRA lift produced using an 80 deg flap and distributed propulsion?

What is the total EXTRA lift produced using an 80 deg flap? ( 50 deg flap at 30 deg AOA ) and distributed propulsion. Specs: Ultralight, stall speed 20mph, ROW of 12 x 15" props along entire wing ...
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What are the disadvantages of a tailless ultralight design?

What are the disadvantages of a tailless ultralight design with say 20 deg swept back wings with wing tip rudders, 20-60mph, max 25 hp? I'm not an aerospace engineer, so I stand to be corrected: The ...
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Is the lift vector reversed during inverted flight?

Heard a physics professor say that when an aircraft flies inverted, the wing assumes a significant angle of attack (by pushing the stick forward) to continue to generate the necessary "upward" lift ...
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1answer
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Why is the pitching moment of this symmetric aerofoil non-zero?

As I understand it, the pitching moment coefficient of a symmetric aerofoil should be zero, under potential flow assumptions. Obviously, approaching stall and post-stall, these assumptions are invalid ...
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Rotor Tip Speed vs Forward Airspeed - IAS or TAS?

I created this graph to illustrate how the tip speed of the advancing and retreating blades vary with forward airspeed but am confused as to what would be the most correct way to label the x-axis: ...
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4answers
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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 is the maximum height for deploying a parachute? [closed]

i see a detachable plane cabin project .When an airplane crashes, the human toll is generally heavy. Based on this observation, Vladimir Tatarenko, a Ukrainian engineer who worked in particular for ...
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How to calculate the mass moment of inertia of a symmetric wing like NACA-0012?

I am working on the pitching mechanism of a NACA-0012 wing. I have the mass and found out the centre of mass of the wing but the software (OpenFOAM) needs more parameters such as the mass moment of ...
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Why are highly cambered airfoils rarely used in propellers or wings?

Highly cambered airfoils like the Seligs and Epplers are hardly ever used in propeller or wing sections. Why? Does their performance reduce at high Re? Are they only adequate at low Mach, low Re? ...
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Is there a standard word or phrase in the English-speaking world to describe the angle between the fuselage and the flight path / relative wind?

Is there a standard word or phrase, or several alternative commonly-used words or phrases, in the English-speaking aviation world to describe the angle between the longitudinal axis of the fuselage, ...
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How common is it in current British usage for the angle between the chord line of a wing and the flight path to be called the “angle of incidence”?

In American usage, the angle between the chord line of a wing and the flight path is called the "angle of attack". The angle of attack is also represented by the greek letter "alpha". However, some ...
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Why are there two red lines on the G-meter in the MiG-29?

Why are there two red lines on the G-meter on the MiG-29 aircraft? One at 7.5G, another one is at 9G. Also on the AOA scale the red line is at only 15 degrees. That is max AOA. It looks very low to me....
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Why weren’t large, high-power radial engines built to take advantage of the Meredith effect?

Most aircraft piston engines fall into two general categories:1 Radial engines (radials for short2) have their cylinders radiate out from the crankshaft in a star pattern; they tend to have a blunt, ...
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171 views

why some airplanes have their exhaust gases vectored above the wing?

I was looking at images of the SkyCourier shown below and i have noticed the asymmetrical exhaust pipes in both engines (one pointing up and one is straight), doing my research on the internet, i ...
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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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Do horizontal stabilizers on airliners have varying angle of incidence in the span-wise direction (washout or negative twist)?

Reading this question and answers, I was wondering if modern airliners with cruciform tail have some noticalbe washout or negative twist along the horizontal stabilizer's span. During cruise, if wing'...
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Would it be beneficial to limit AOA in fly by wire type a/c like F16 jet in dogfights? [closed]

Would limiting the angle of attack to a maximum of 13 degrees by the fly by wire system help pilot gain advantage over his/her enemy during aerial one to one combat? Using such limits would reduce the ...
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Why does camouflage make some planes fly slower?

Why does camouflage decrease some airplanes' speed? I have noticed that some planes fly slower with camouflage than without it. For example, when the RAF applied camo on the P-51 Mustang, they noticed ...
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198 views

What is the role of a bound vortex?

From what I know the term bound vortex comes from potential flow theory and is a part of circulation around a wing. Does it mean the same as circulation or lift? Is it a cause of generating lift over ...
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An airplane has an engine that pushes its flight. What force pushes a glider to fly? [duplicate]

An airplane has an engine that pushes its flight. What force pushes a glider to fly? Is it gravity? I think the flight of a glider is driven by gravity, but some people disagree with me. They say ...
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What exactly is a “coordinated” turn?

I am wondering what turn coordination really means and what makes a turn uncoordinated? I know that when the turn is coordinated, there is no slip and skid, an aircraft is flying a perfect circle ...
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What factors/equation(s) are used to relate aircraft weights and cruise speeds?

With the recent coronavirus issues, there have been lots of empty seats flying around, especially on long haul flights. I checked the seat map for a recent SFO-SYD flight (777-300) and there were 224 ...
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Why is a rectangular wing planform less efficient than others?

I read somewhere that a rectangular wing is inefficient compared to other wing planforms. Can someone clarify why this kind of wing planform is inefficient compared to other planforms and what causes ...
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Is airflow deflected inwards or outwards by wing sweep?

We are often told that wing sweep causes the airflow to be deflected outwards. I can understand this for the underside, but for the upper surface it seems inconsistent with other effects. For example ...
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Does the Prandtl flying wing have a lower maximum speed than other designs?

Does the design of the wing with its "twist" near the wingtips necessarily limit the maximum speed of an aircraft utilising that technology? Also, with the leading edge profile/attack angle varying ...
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1answer
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Procedure for simulating nonlinear flight dynamics

I am trying to simulate F/A-18 Hornet on Simulink. So, here is how I have made the model: Firstly, the initial flight parameters(Alpha, beta, V(magnitude), rho) are being calculated based on the ...
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Why does Google's Wing drone have dimples?

The question What operational aspects of Alphabet's Wing drone delivery service will be the same as that of an airline? includes a cropped photo of a google drone from FAA Certifies Google's Wing ...
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What frame of reference should I use for my Simulink simulation of the F/A-18 Hornet?

I want to simulate the Equations of Motions for F/A-18 Hornet (12 states & 6 DOF) on MATLAB using Simulink. I have the Aerodynamic model, from which I will get CL, CD, CY, Cl, Cn, Cm that are ...

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