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1500 questions
31
votes
6 answers
Why the ground effect has such a different outcome for wings and cars?
I have some confusion concerning the ground effect.
If we take two applications: Aircraft and Cars, they seem to have completely opposite effects.
Aircraft
From Ground effect (aerodynamics), we can read:
During normal flight, the upper wing surface…
ROIMaison
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31
votes
4 answers
Why is the fuselage on an airliner circular-shaped?
Consider the fuselage of an A300. I have noticed this not only with airliners, but also for private jets and turboprops: why is the fuselage circular-shaped? Why don't aircraft have square-shaped fuselage? Does it have to do with too much drag?
Ethan
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31
votes
2 answers
What is vortex lift?
In a recent question I asked, I was given an answer by Peter Kämpf and he described something about lift being created by a vortex used on delta wings and the Bird of Prey wing.
How exactly does vortex lift form to generate lift and on what other…
Ethan
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31
votes
2 answers
What is the difference between centre of pressure, aerodynamic centre and neutral point?
I have just started learning some aerospace concepts, and I am not able to understand the difference between the three terms centre of pressure, aerodynamic centre and neutral point. What are their functional differences?
What would be an example…
Tarun Mohandas
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31
votes
1 answer
What is this pattern on the windshield of aircraft?
The image is extracted from this Airbus A350 video (at 3m40s, when taking off)
I circled in purple the strange pattern formed by few black straight lines. I'm quite puzzled as I have no idea of what it is or what purpose it can serve.
EDIT: I would…
Manu H
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31
votes
6 answers
What is the difference between a POH and an AFM?
Some aircraft come with a Pilot Operating Handbook and some come with an Aircraft Flight Manual. Why the different name, and is there a difference between them?
Lnafziger
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31
votes
3 answers
Why does the speed tape on the Lockheed U-2 go the opposite way?
I found this clip online that shows the speed tape on the Lockheed U-2 going what I perceive is the opposite direction to the 'normal' convention. On most aircraft, the higher values are above and so the tape scrolls downwards, but in this case it…
Thunderstrike
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31
votes
5 answers
Can large aircraft go VFR?
Is it legal for large, multi-crew, aircraft (such as the A380 or B747) to go VFR? I would guess it's legal just as any other aircraft. Is this ever done, like during training or test-flights? If it isn't legal, what's the limiting factor?
I'm…
falstro
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31
votes
1 answer
Why is cabin pressure increased above ambient pressure on the ground?
As far as I know at least some (e.g. some Bombardier Dash-8 series) airplanes during takeoff may increase cabin pressure above air pressure on the ground, before starting to decrease it. In one case pressure was increased to around 760 mm Hg (1013…
DavisNT
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31
votes
1 answer
How does a commercial airliner measure its weight/mass?
Other questions currently being answered cover situations regarding planes near, at or even above their MTOW. It raises a more basic question: how is the exact "ramp weight" of an airliner measured or estimated?
On most airlines, luggage is weighed…
KeithS
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31
votes
3 answers
"What's our vector, Victor?": What does this mean?
In Airplane there is a famous sequence:
Roger Murdock: Flight 2-0-9'er, you are cleared for take-off.
Captain Oveur: Roger!
Roger Murdock: Huh?
Tower voice: L.A. departure frequency, 123 point 9'er.
Captain Oveur: Roger!
Roger Murdock: Huh?
Victor…
Jason
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31
votes
3 answers
In what circumstances could a 787 stay powered on continuously for 248 days?
The FAA has issued an airworthiness directive for the 787:
SUMMARY: We are adopting a new airworthiness directive (AD) for all
The Boeing Company Model 787 airplanes. This AD requires a repetitive
maintenance task for electrical power…
John Wiseman
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31
votes
5 answers
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?
Ewen W.
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31
votes
6 answers
What is propeller / engine sync and how does it work?
In some models of multi-engine airplanes there is a switch labelled something similar to "prop sync" or "engine sync".
My questions are:
What is engine synchronization?
How is it achieved?
Why is it important to use?
What happens if you don't use…
CGCampbell
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31
votes
4 answers
How do conventional and T-tails differ?
What design considerations go into the decision between conventional tails and T-tails? Functionally the horizontal stabilizer/stabilator are the same in both cases, providing negative lift, the elevator control and a method for pitch trim. What…
casey
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