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### Why am I seeing extremely high L/D ratio of (e.g. L/D = 90) in my 2D airfoil analysis?

Can anyone explain/justify why, using the 'Theory of Wing Sections' by ABBOTT the lift/drag ratios seem so high. For example, I'm doing an analysis of the NACA0012 airfoil and using their experimental ...
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### How does downwash affect angle of attack?

Many aerodynamics textbooks, as well as many answers on here and similar websites claim that the downwash downstream of a wing induces a net angle of attack that is lower than just looking at flow ...
1k views

### How to recognize the horizontal winglet in the Horten design, or the experimental glider in this video?

Comments below the NASA Armstrong Flight Research Center video Proving Prandtl- With A Twist! incclude: This video is entirely a hidden jewel in youtube, it deserves much more attention than what it ...
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1 vote
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### Could reduced-lift wingtips allow an airplane to generate less wake turbulence?

Would it be possible to weaken the wake vortices generated by a large aircraft (which can be dangerous to smaller aircraft behind the large aircraft, and are the limiting factor determining how ...
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### What creates most drag during flight: fuselage or wings?

From pic 1, I know the drag line is below the thrust line, but I am puzzled about where the drag line is in pic 2? Secondly, what creates most of the drag in flight, is it the fuselage or the wings?
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### What is the relation between drag and weight?

Given an aircraft type and fixing its wing configuration (flaps, slats) and fixing its speed and altitude and assuming it flies horizontally, what is the relationship between the aerodynamic drag and ...
4k views

### How to calculate the drag on an airfoil from momentum equation (Fundamental of Aerodynamics 5th edition, J.D.Anderson)?

If you got the book, please read 2.6 section (page 135). Here is my sumary of this section: An airfoil in a wind tunnel (wingtips were butted against both sidewalls of wind tunnel). The control ...
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### Why is induced drag less on a high span wing?

I have a basic question and sorry if it is a well known fact. I understand that the induced drag is due to the tip vortices changing the effective angle of attack (downwash). I searched some ...
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### How is the induced drag calculated for a wing with elliptical planform?

How is the induced drag calculated for a wing with elliptical planform ? Is this wing shape the most efficient ?
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### Where does upward momentum come from in leading edge vortex?

I believe I am beginning to understand how a leading edge vortex creates lift. Faster air creates a lower pressure above the wing making lift. But I am hoping to get another view of this in terms of ...
• 143
49k views

### How do wings generate lift?

Just the basic question that every aviation enthusiast must be curious about: exactly how does a wing generate lift?
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### What is the method to calculate a finite wing's lift from its sectional airfoil shape?

I am struggling to get my head around a concept that I believe should be fairly simple to understand. Lift versus drag and AoA data of many airfoils are freely available, for instance the NACA 4-...
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### How does an aircraft form wake turbulence?

This question discusses how wake turbulence can affect planes flying in formation. It got me wondering, how do aircraft (the wings in particular) form wake turbulence to begin with? It can't be as ...
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### How does chord length affect wing design?

In comments on the answer to a question about transonic speeds and control surfaces I came across this comment and I'm having a hard time understanding it. If you increase the chord, lift goes up ...
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