137 views

How to distinguish the induced drag of a lift-producing wing from its pressure drag?

Quote John Anderson Fundamentals of Aerodynamics: "The three-dimensional ﬂow simply alters the pressure distribution on the ﬁnite wingin such a fashion that a net pressure imbalance exists in the ...
156 views

Why do most authors use wingtips vortices as reason for 3D flow around wing?

Quote John Anderson Fundamentals of Aerodynamics: The three-dimensional ﬂow induced by the wing-tip vortices shown in Figures 5.4 and 5.5 simply alters the pressure distribution on the ﬁnite wingin ...
166 views

How pressure fields change around wing?

In the 3D case,downward turning is immediately above and below the wing is stronger than in 2D case,for the same lift.This is because more rapid dying off the pressure above and below the airfoil ...
197 views

How can the 777X's longer wing reduce vortices? [duplicate]

I saw the following on this web page: The purpose of the longer wing is to reduce drag caused by vortices, or wake turbulence, that form at an aircraft's wing tips. The less drag, the greater the ...
1k views

Why do wall-to-wall airfoils in wind tunnels produce no (or infinitesimal) downwash?

There are several induced drag explanations out there saying that tip/wake vortices “come from” downwash and downwash “comes from” lift. I’m using quotes because the concept is that there are no cause ...
352 views

What can a new student pilot do on their own to prepare for class and instruction?

What is the best way to start for beginners learning to fly? I have a class set up and a instructor but not for another week or two. I just want to know if there is anything extra that I can start now,...
3k views

How is drag created from wingtip vortices?

What is the reason for the drag due to wingtip vortices? This question is about (general) performance, but doesn't answer the drag aspect.
234 views

How does the extension of inboard flaps raise the effective critical angle of attack of the outer wing?

I raised a question about this on this post in the comment section and was suggested by Peter Kämpf to create a new question. So here it goes: How does the extension of inboard flaps raise the ...
2k views

Can this design provide more lift force than thrust from engine?

The problem is depicted in the picture: Generally, why we don't use engine blow wings to fly? Can we use wind-tunnel-like wing to generate lift force? Can it generate more lift than thrust? If it ...
2k views

Is induced drag caused because of the tilt of the wing backwards?

In this question: Why is induced drag less on a high span wing? In the answer it was stated that wing tip vortices do not cause induced drag. If this is the case then what causes the induced drag. ...
3k views

When leaving ground effect, why is there a nose-up change in moment?

The Airplane Flight Handbook states: The aircraft leaving ground effect will Require an increase in AOA to maintain the same CL Experience an increase in induced drag and thrust required ...
1k views

Is induced drag not caused by tip vortices?

According to most online resources, including NASA, induced drag is caused by wingtip vortices which induce downwash. However, in StackExchange I have found a few answers (Peter's and Jan's) that ...
4k views

Why does the elliptical wing have the lowest drag?

I read that the elliptical wing has the lowest induced drag. Why is that so? I welcome a mathematical and intuitive explanation.
1k views

What is downwash on a wing and how does it form? [duplicate]

This is a subject I have been very confused with lately about thrust coming from downwash on a propeller and helicopter, but to understand how the downwash increases thrust is to know how it forms and ...
19k views

Why does condensation form on the wing especially during take-off and landing?

To start off, yes this question was asked before, yet I don't find the answers satisfying and here is why: It appears to me that this phenomenon only appears during the approach phase of a flight and ...
22k views

Why do airplanes have to retract landing gear?

Why do all the airplanes have to retract their landing gear, once they reach some specific height? Why can't they simply leave their landing gear deployed all through the flight?
15k views

How do paper airplanes create lift if their wings are flat?

Paper airplanes' wings are completely flat, unlike the droplet shaped curvature of a full sized wing. How does a flat wing generate any lift if both sides have the same air pressure?
701 views

Do ducted fans eliminate induced drag?

It has often been said on this site that induced drag on wings is the inevitable result of producing lift over a finite length. Converting this to the realm of propulsion, I assume that propellers ...
10k views

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 ...
5k views

Why is the use of tail-down force so common?

Why is the use of tail-down force so prevalent in aircraft design? Why not use canards to avoid induced drag?