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1500 questions
25
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2 answers
How do insects decrease aircraft performance?
Is it true that insects hitting the fuselage could decrease aircraft performance and increase fuel consumption? Insects are small in mass. I think even a large amount of them accumulate on the aircraft's outer skin, it wouldn't be significantly…
TBBT
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25
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Why are turbofan inlets leaned/angled forward?
(Image Source: Wikipedia)
Seeing that everything is radially symmetric (apart from the nacelle mount, naturally), I wonder why the inlet (the front part of the nacelle) is usually skewed?
Pavel
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5 answers
How do modern helicopters tackle Vortex Ring State?
According to the wikipedia page :
Air vortices can form around the main rotor of a helicopter, causing a dangerous condition known as vortex ring state (VRS) or "settling with power". In this condition, air that moves down through the rotor turns…
Victor Juliet
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25
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1 answer
Why open up the window shades before takeoff and landing?
On commercial airlines, I've noticed that the flight attendants always ask everyone to open up their window shades before landing or takeoff.
I've always wondered why this is. Is it something to do with the mechanics of the plane? Is it some kind of…
jlouzado
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25
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4 answers
Does temperature affect takeoff performance?
A few days ago, a Copa flight from Porto Alegre to Panama was delayed from noon until 12:30 AM. The company explained that the high temperature (about 40 degrees Celsius) would require a longer runway for takeoff since the air was thinner, and that…
woliveirajr
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25
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6 answers
Which airplane designs have the greatest longevity?
What airplane designs have been around the longest, from first flight through last retirement from active commercial or military service?
My guess is that the DC-3 will win, since it has been around since before WW II and is still in service,…
Ralph J
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25
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8 answers
What is the purpose of having contra-rotating props on an aircraft?
Why do planes, like the famous XF-11 and the Tu-95, have contra-rotating props? What is their purpose?
Image credit: Mike Freer / Touchdown-Aviation / Wikimedia
Madhav Sudarshan
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25
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7 answers
Given the same engine, why install a gearbox on a turboprop but not on a turbofan?
I am reading the book Mechanics and Thermodynamics of Propulsion, by Hill and Peterson. I found out this image while reading the chapter 5, "Thermodynamics of Aircraft Engines":
Why would there be a gearbox in the turboprop but not on the turbofan?…
Jose Lopez Garcia
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5 answers
Is there a maximum lift to drag ratio?
If I recall correctly, the best competition gliders have a L/D ratio as high as 60:1. What imposes this limit? Is there a maximum theoretical L/D ratio, or could sufficiently advanced materials allow a glider with a L/D ratio of, say, 200:1?
raptortech97
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25
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9 answers
Why does manifold pressure increase with power?
Whilst writing an answer to this question, I remembered something I don't really understand.
The partial vacuum in the inlet manifold is caused by the piston descending with the inlet valve open during the "suck" phase of the Otto cycle. It is this…
Simon
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25
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5 answers
May an emergency aircraft land on a closed runway?
Let's say that you're on approach to a remote airport to refuel (for arguments sake, Funafuti International Airport, Tuvalu), with 1-2 hours of fuel remaining in your aircraft. Contacting ATC to request permission to land, they tell you that the…
Danny Beckett
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25
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6 answers
Can a passenger request to visit the cockpit during a flight?
As a kid, I remember going to the cockpit of a plane with my mom (I believe the airline was AOM French Airlines).
Is this still possible now?
I understand the answer might differ with different airlines/countries, I'm mostly interested in European…
Antzi
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25
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3 answers
Why does "no aircraft cross directly over the pole"?
This is from the last paragraph here:
... no aircraft crosses directly over the pole – the closest route is
60 nautical miles (nm) away.
User Michael Shen of York University asked this originally under the article.
user128
25
votes
2 answers
How do birds coordinate their turns?
I am building a plane that looks like an Eagle, so I was watching YouTube videos so I can see how to realistically fly it.
One thing I don't understand is how do birds like this coordinate their turns? The bird's tail is flat and flexes a…
fool4jesus
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What exactly is a 'hard landing'?
In my shareholder agreement, there is a very reasonable line that states:
Any hard landings to be reported immediately to [head instructor] or [club name]
The thing is, I'm not exactly sure where the line is, i.e. when does a non-great landing…
Cloud
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