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5 votes

Why is it inefficient to expel high speed gas?

seems to me like attempting to "capture" the expelled air is akin to putting an air-powered generator behind a turboprop propeller to turn another propeller You're close, but why not put ...
Robert DiGiovanni's user avatar
23 votes

Why is it inefficient to expel high speed gas?

It depends on what you call efficient. In principle, the force imparted on the airplane is equal to the momentum expelled backwards: $$F=\frac{\Delta m}{\Delta t} \cdot v$$ The power requirement to ...
Sanchises's user avatar
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3 votes

Most Efficient Commercial Aircraft Design?

The most efficient designs, based on lift, drag and fuel consumption, for heavier than air craft, were the ones that could fly slowly enough and still have sufficient Reynolds numbers to generate lift ...
Robert DiGiovanni's user avatar

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