Then from some ancient modelling stories I'd heard, it seemed the idea is to have large fan area (like your jetliners), but because there is so much blade drag, the air coming out the back has a lot of 'swirl', so you then need to have stator blades behind to 'unswirl' the air and redirect it rearwards for more thrust?
So that is Airbus E-fan 2.0, which is all-electric.Ducted fan produce 30% more static trust than free prop(same diameter) with same HP engine and have better efficiency, but only to flying speed up to 100mph. If you need fly fester with ducted fan - you need to use more powerful engine to compensate for less efficiency.
But it's all compromise as we often do in aviation!
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Even if exhaust velocity is less, can we not compensate with bigger ducted fans?Thrust vectoring with ducted fan can be done, but it wouldn't be much efficient as with turbojet engine - because much less exhaust air velocity of ducted fan system, than with turbojet.
I thought that as long as fan is producing enough thrust, then afterburner flame will not reach it.For same reason afterburner can't be used on ducted fan propulsion system - the fan would simply borned up!
Another idea that is frequently mentioned but which is impractical is use of hydrogen as a fuel for aviation internal combustion engines. Check out the problems/weight of storing it, the practical implications of making it, and the challenges of moving it. Hydrocarbon fuel can be "greener" and much more practical.Can't hydrogen be the future instead? That's zero-emission, and it's lightweight.
The quietest powered aircraft ever made use propellers.But can ducted fans reduce noise compared to a jet, or even a prop? Sometimes efficiency is not the only thing to be concerned about.
Actually ducted fan is not very noisy and not more then open propeller. Ducted fan itself sound more like "vacuum cleaner", but more unpleasant noise come from hi rpm small motorcycle engine without muffler!The noise would be a big concern. From the videos, very loud with an unpleasant note.
1000cc BMW engine.
Is a motor cycle engine (they don't say which) driving an internal fan to give the appearance of a jet aeroplane. Other videos used to exist -may still but...
Personally I'd be looking at using a large vehicle cooling fan driven at high speed. Injection moulded ready made fans ready balanced and with some future stock availability seem like a good plan rather than any attempt to fabricate something
Yup. But the guys that want a "jet" without the million-dollar price tag are determined that they will do it. Of course, they might be happy with it, but I bet that the novelty will soon wear off for most as their airplane will just be another relatively slow homebuilt that needs an 8000-foot runway.The quietest powered aircraft ever made use propellers.
If you want a quiet, practical powered airplane, use a propeller and turn it at a relatively slow tip speed. You'll get good efficiency, good power to weight, and maybe good performance per dollar spent.