Linked Questions

-1
votes
1answer
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 ...
14
votes
5answers
21k 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?
37
votes
3answers
9k 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 ...
24
votes
4answers
13k 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?
19
votes
6answers
14k views

Do box-wings suffer from induced drag the same way as normal wings?

Most wings suffer from induced drag due to a pressure difference above and below the wing causing air to sneak around the tip, forming a vortex. There are various methods to minimize these effects, ...
21
votes
3answers
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?
18
votes
2answers
18k views

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 ...
8
votes
5answers
16k 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 ...
5
votes
4answers
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 ...
8
votes
3answers
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 ...
8
votes
4answers
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 ...
4
votes
3answers
2k 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.
7
votes
3answers
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. ...
7
votes
1answer
3k 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.
8
votes
1answer
860 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 ...

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