# Questions tagged [wing]

For questions on an airplane's main wing

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### Is Centre of Gravity located behind or in front of Aerodynamic Centre? [duplicate]

I was reading CAE Oxford POF book 2014 edition found online, and in lesson (10-Stability and control), page239, it stated that CG must be BEHIND AC in order to maintain aircraft's stability, but I ...
311 views

### What's the optimal taper ratio for a commerical short/medium haul aircraft?

I'm designing an R/C plane with interchangeable winglets and I've so far calculated the taper ratio to be .246 (aspect ratio 9.5 if that helps). I'm taking some design/geometry cues from the A320. How ...
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### Why will a positive stagger increase biplane efficiency, while a negative stagger will decrease efficiency?

On a biplane, why will a positive stagger (top wing more forward relative to the bottom one) be more efficient than a negative stagger? In both cases the wing’s pressure fields are more separate, so ...
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### Split Flaps and lift?

Do split flaps produce lift? I don't see how, because there is no change in camber. It seems like an upside down speed break, producing only drag
127 views

### How does the air molecules provide wing lift force when only wing is moving or when only the air is moving?

We use to calculate lift force of a wing as function of air speed squared. We can imagine 2 different situations: 1 - the wind has speed thus kinetic energy and momentum while the wing is stationary 2-...
1 vote
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### Why don’t closed wings eliminate tip vortices?

It’s clear that tip vortices never really can be prevented, but why doesn’t a closed wing do that? There is no ‘tip’ on a closed wing so where does the air go to make a vortex? On a normal plane the ...
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### Is it possible to tell what aircraft this is?

On a flight a few years ago, I got this picture. Is it possible to tell the aircraft by just this image? I’ve found a few similar but they are a bit different than this one. Someone I was with said ...
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### wave drag: Lift coefficient in Korn's Equation

I have been using the Korn equation: $$M_c = \frac{0.95}{cos(\lambda)}-\frac{t/c}{cos(\lambda)^2}-\frac{C_L}{10cos(\lambda)^3}-\sqrt[3]{\frac{0.1}{80}}$$ to estimate the critical mach number of a ...
1k views

### How can the wing generate more lift than the thrust? [duplicate]

I recently checked about the max takeoff weight of an A380 and the thrust it can provide at TO/GA power and I was quite shocked by the results. The total thrust by the engines was only about 127000 ...
861 views

### Why Cessna 152 has different airfoils at the root versus at the tip of the wing?

I recently read that C152 have two different airfoils on its wing. NACA 2412 at the wing root and NACA 0012 the wingtip. Why? And why are those particular airfoils (with their inherent aerodynamic ...
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1 vote
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### Lift Coefficient question

I am making a RC Airplane, it has a wing profile as shown above. What might be the approx. lift coefficient of this? The wingspan is 80cm, what will the lift provided be by this wing at 65kmph ?
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### NASA's and Boeing truss-braced wing fuel savings breakdown

According to its Administrator Bill Nelson, NASA is working on a project with Boeing that will reduce single-isle aircraft fuel consumption by 30%. He described it as a higher and thinner wing and ...
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### How does the lift-to-drag ratio depend on absolute sizes?

A dependency is provided here $$(L/D)_{\max} = \frac{1}{2} \sqrt{\frac{\pi \varepsilon ~ \mathrm{AR}}{C_{D,0}}}$$ AR significantly affects the outcome in this dependency. AR varies significantly among ...
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### How do I choose Cl during cruise flight with a given MTOM and variable S?

Currently I'm challenging myself to build an airplane from scratch. I have a background in aeronautical engineering but I have no experience in actually designing an aircraft from the ground up. (FYI: ...
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### Lift distribution of a swept wing with twist, dihedral, taper

I am trying to get the lift distribution of a swept wing with taper (in chord and thickness along the span), twist, and dihedral. I know that Kuchemann Index method is used for swept wings but I am ...
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### What is Effective Wingspan?

what is Effective wingspan and why it is said ground effect increase "effective wingspan" of an aircraft? Why would vortex affected by surface result in an increase of "effective ...
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### Airliner sharp wing tip vs elleptical [duplicate]

Now that most airliner manufacturers are using composite materials for wings, making compound curves is much easier to produce, why aren't we seeing elliptical wings, outer panels or wing tips? ...
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### Has a supersonic airplane with a truss-braced wing been studied/developed?

The X-66 truss braced jet is to be transonic. But have any published studies or development programs been done for a supersonic equivalent? Seems like someone considered it, given that it allows ...
1 vote
106 views

### Drag breakdown of a typical civil airplane wing

How much of the drag produced by a typical GA/airliner/cargo plane's wing at cruise is induced, frictional, and pressure drag?
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### Is the clamshell on the AN-72 what causes the Coanda effect?

The AN-72 uses the Coandă effect to improve lift and give it better STOL features. In this image of an AN-72 (presumably on a takeoff roll) one can see a clam-shell bucket open at the top of the ...
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1 vote
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### Spanwise lift distribution units

I was recently reading NASA/Boeing’s report on the Transonic Truss Braced Wing (the SUGAR IV final report), and noticed that when they graph the spanload for the design they graph lift coefficient ...
123 views

### what are the compression forces in a strut if the strut is fixed

i am trying to match an experiment i have done and i dont know how to compute the force in the strut in terms of F given these boundary conditions. i have attempted to use fixed end moment equations ...
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### Swept outer section of the wing on turboprops

It's quite common to see turboprops having a wing with the outer part of the wing with a small sweep (around 3 deg at 1/4 of the chord). What's the reason? It's usually stated that wing taper is used ...
438 views

### What is the mathematical relationship between mass and speed for constant thrust in level fight?

Imagine that we have a wing with constant thrust in level flight. Then imagine that we add mass to that wing. In order to maintain level flight, I would expect that the angle of attack would need to ...
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1 vote
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### How do I get rid of this chord line along the x-axis when importing an airfoil into XFLR5?

Whenever I try to import an airfoil into XFLR5, I always notice the chord centerline along the x-axis as you can see in the picture. Is there a way to somehow get rid of this line? I'd be thankful for ...
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### Are there any sources that contain information on the airfoils of the Boeing 737-500 and 737NG Aircraft?

I have found some information about this on airfoiltools.com (http://airfoiltools.com/airfoil/details?airfoil=b737a-il) but it doesn't specify the exact version of the aircraft, as the generations ...
174 views

### Why does the F/A-18 use external aileron and flap hinges?

As seen in the picture, the legacy Hornet uses ailerons and flaps with external hinges, and I was wondering what were the advantages of external hinges compared to flush hinges in the land-based ...
490 views

### Different Engine/Prop Sizes on Same Wing/Single Craft?

On a four propeller/engine wing, I’m wondering if theoretically at least, you could have a larger engine near the root of the wing with smaller engine(s) further out on the span..?.. If you could have ...
114 views

### Incidence angle in Sailplane

I am determining the shape of the fuselage of a sailplane and I found something that gives me a little conflict, and that is that in most sailplanes it has an inclined tip, I read that this helps ...
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### Moving from 2D wing to 3D wing design

In terms of the design perspective of an Aircraft, once we decide on the airfoil that would be used for the wing, how would an Aerodynamics Engineer (or you) proceed to construct the wing? The ...
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### Is there an equation to solve for bank angle using load factor and wing loading as variables? If so, what is it?

The problem is that I'm looking for both wing loading and load factor as variables to solve for bank angle and cannot find any equation that represents this. After searching various websites and not ...
171 views

### Effect of wing flexible in stall

How true is it that the deflection (due to large aspect ratio, flexible wing ) of a wing has a certain effect on the stall characteristics? I read about this in the case of large wingspan gliders. ...
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### Pitching moment due to control surface deflection

How can you predict the change in lift and pitching moment produced by control surface at a certain deflection angle? I am aware that the effectiveness of the control surface is affected by ...
550 views

### How is the wing area of an airplane determined?

Picture source is from here. Here are wing areas of several airplanes. As we can see the Spitfire, B747-400, and Mirage 2000, their wing area are not rectangular. The line drawn from left side to the ...
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### How is a turboprop engine mounted to the wing?

For a given turboprop plane such as the ATR-72, there doesn't seem to be a pylon as on turbofan driven planes. This question: How are engines mounted onto wings? has answers that detail how a pylon is ...
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1 vote
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### What are some of the advantages of inverse-tapered wings?

Inverse tapered wings are rarely used in aviation. The only legitimate plane I know about with inverse-tapered wings is the XF-91 Thunderceptor. So why aren't they used. What are the disadvantages of ...
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### Any instances of circular wings in full scale gliders/airplanes?

As a kid building from The Great International Paper Airplane Book I was intrigued by the very unconventional plane seen near the bottom of this page with the two circular wings connected by a rigid ...
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### What is the material of the wing spar on the Mitsubishi MU-2?

I read that the spar on Twin Commanders are made of steel. Is this also the case for the MU-2?
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### Is an airfoil's critical angle of attack measured using "geometric angle of attack" or "effective angle of attack?"

One of the first things we learn about stalls is that they occur when a wing exceeds a certain critical angle of attack, which depends on the specific design of the wing. But if a given wing has a ...
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### What is a wing theory?

I have an assignment to summarize the topic "wing theory", with the preferred reference used is the book Fundamentals of Aerodynamics by John D. Anderson. But there's no dedicated chapter ...
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### Why does the trailing edge have a more pronounced taper than the leading edge on the Cessna 172?

Why does the Cessna 172 have a more pronounced taper on the trailing edge as opposed to the leading edge?
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### Why is this screw on the wing of DASH-8 Q400 sticking out, is it safe?

Was flying with the Dash-8 Q400 and saw the screw sticking out? It's on the wing near the wheel compartment as shown in the picture. Even if safe, it doesn't look pleasant to the passenger. Are loose ...
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### What control inputs to make if a wing falls off?

If a wing is severed due to structural damage or from a mid-air collision, what is the best control input to make? I would think opposite aileron and rudder, i.e. if right wing falls off, input full ...
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### How to calculate boundary layer thickness?

So I have a flat plate with a surface of 7sqm and an aspect ratio of 12 with air blowing straight at it (like a wing) at a speed of 50km/h. I would like to manually calculate the thickness of the ...
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### What are these pipelines for between the folding wing mechanism of F4 Phantom II FGR2 and Buccaneer?

The top picture is from Buccaneer and rest are from F4 FGR2. There's not any sealing mechanism between the joints, so these can’t be fuel or hydraulic related. They might have something to do with the ...
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### Determining optimum area of parafoil, and then drag

I am designing a parafoil recovery system for a small payload of 300x100x500mm (2.4kg). I have chosen an Aspect Ratio of 3, and from a NASA wind tunnel test report, the coefficient of lift and drag is ...
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### Are there any known aircraft (experimental, otherwise) with non-fixed vertical/horizontal stabilizers?

Imagining contortions of the vertical/horizontal stabilizers and possible use cases for dodging or acrobatics, I was wondering if there were any known aircraft with such a design.
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### Why doesn’t lightning punch a hole in the fuselage?

Electric arcing creates a huge temperature in the air around it. When lightning strikes planes, why doesn’t this high temperature air melt/deform the aircraft skin? Also can these high temperatures ...
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