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1500 questions
35
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14 answers
Why don't small planes use turbine (turboprop) engines?
Turboprop engines are more fuel efficient1, lighter for the same power, mechanically simpler and consequently more reliable. They are also slightly easier to operate (no need to fiddle with mixture) and burn cheaper fuel. As a result they replaced…
Jan Hudec
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35
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6 answers
On which point(s) in a jet engine does the reaction force act?
Turbojet and turbofan engines are part of a family of engines referred to as reaction engines to emphasize the fact the aircraft is pushed forward mostly by Newton's 3rd law of motion when gases are accelerated.
Diagram of a turbofan jet engine,…
mins
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35
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5 answers
Is it illegal for Joe Public to listen to ATC in the UK?
I recall that in the UK (unlike in the rest of the world) we have a law forbidding the listening to of air traffic control, dating back a century, to the days of paranoia over spies!
What is this law, exactly? Is it illegal for a member of the…
Danny Beckett
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35
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7 answers
Why do airplanes use AC electric power?
Primary electric power on larger airplanes is provided as AC. What aspects of aircraft make AC a better choice than DC?
fooot
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35
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8 answers
How does stall depend on angle of attack but not speed?
Everyone says that the angle of attack is what determines a stall, not the speed. I understand the theory and understand that it is separation of the airflow that matters for stalling.
However, I don’t understand in a practical sense. Let’s say…
Peter
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35
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8 answers
What happens if you exceed the maximum speed on a C172?
The airspeed indicator has a red marking that means: "never exceed this speed" ($V_{NE}$, around 160 KIAS). Why can't you exceed that speed?
user13197
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4 answers
Have jet engines ever "Sheared" off?
I have read that jet engines, at least the under-wing ones, are attached to the airplane by shear nuts and bolts so that in case of unstable forces in or on the engine, the engine would fall off to prevent further damage to the airframe. Have there…
SMS von der Tann
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4 answers
What is the meaning of the crosshatch marking on altimeters?
What does the crosshatched area on an altimeter tell you? It's only visible when below 10,000 ft indicated altitude. Can't be terrain awareness, a lot of terrain around here is over 10,000 feet.
This sample altimeter display from the FAA manual on…
Barrie Strachan
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3 answers
How do airlines pay for their planes?
Taking easyJet as an example, they have a fleet of over 200 A319's and A320's. At a price tag of around \$90m per plane, that equates to about \$18bn.
Given that their turnover for 2012/13 was around \$7bn, and their net profit was only \$660m, how…
Danny Beckett
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35
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4 answers
Why is the rear seat ejected before the front one?
On aircraft with 2 crew placed one in front of each other (tandem) equipped with ejection seats, the rear seat is ejected before the front one (described here for the F-14).
Why is the rear seat ejected before the front one?
Is an aircraft without…
Manu H
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35
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4 answers
What do winglets do to increase aircraft performance?
It seems like a lot of the newer airliners have winglets or wing fences. How do they improve aircraft performance?
flyingfisch
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35
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2 answers
What is the purpose of the "Mirror-Thing" over the Mig-29 Cockpit?
I noticed that some Mig-29 Fighter Jets have a little mirror-like-thing over the cockpit. I can't imagine a possible usage from it (If it's really a mirror).
Here's a picture from Wikipedia:
As you can see on the following picture, not every…
jklingler
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35
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2 answers
Which engine is more efficient between turboprop vs jet?
Are turboprops really more efficient than jets?
If yes, does that mean that airlines who use jets sacrifice fuel for faster flights?
Taher Elhouderi
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35
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9 answers
Why don't combat aircraft have rear-facing weapons?
This excellent question addresses the role of dogfighting in modern aerial warfare. However it seems that most ACM concentrate on maneuvering into shooting position. Why don't combat aircraft have rear-facing weaponry?
Even WW-II bombers had rear-,…
dotancohen
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35
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2 answers
Why are listed times of useful consciousness so low?
I've been reading about Time of Useful Consciousness (TUC), and it says that at FL 180, the time of useful consciousness is 20 to 30 minutes at rest.
But I've been to a trip to Tibet, and we went on a bus trip around the places, and at one point the…
ithisa
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