Experimental Ducted Fan Aircraft Designs

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BJC

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Blackhawk

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YH,

You don't get more HP, that never changes; what you get is:

Eliminates the torque effect, (plane pulling in the direction of the propeller rotation)
Creates much less noise (low frequency noise),
Improves the power (the thrust; - which could be up to 20% more),
May improve fuel consumption (slightly ?),

You should be able to make a spinner to suit the Coax-P,
Also you can shorten the longer shaft to give you closer distance between the two propellers to suit yourself.
 

henryk

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crusty old aviator

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Another limitation of ducts is they create a LOT of drag at higher (>130 mph) speeds. That's why I laughed at Moller’s hype that he was conning investors with.
 
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-iff duct inlets are RADIAL,drag is not increased,
in contrary=thanks sucked via fuselage air we got longer laminae flow...
I really do like this design and I think it gets around some issues with ducted fans. I would be interested to see how a scale model performs. I think you may need to include some kind of tail for stability though.
 

Hephaestus

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Wouldn't a planetary gear system work better?

I read an article a while back about efficiency of a lower RPM off the rear fan. Think it was an old NASA paper.

Run the rear off the sun gear carrier, front off the ring gear. Get some gear reduction and reverse rotation on the rear. But the TV issues are way over my wrenchbending brain
 

Hephaestus

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=planetary gear is compact,big numbers of gear,
but inner/auter (R1/-R2) cant be optimal=greater loses...

=I cant see CR propeller gear in planetary device.
Pretty sure a significant number of the Russian, English and US counter rotating prop systems used one - they call it a coaxial gearbox...

I don't have the engineering skills to put numbers to it but knowing the industrial side - most aren't huge. They're usually chosen due to the compact size.
 

Blackhawk

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OK, Lets get back to the Ducted Fans.

This is a concept drawing of the Ducted Fan Jet I will be building to use the 420mm 12 blade ducted fan I have designed

At the moment this will be the only information I will be posting until I have built and tested the ducted fan unit.

Cheers,

Hope everyone is doing the right thing; looking after themselves and their families.

DF-420 Ducted fan jet.jpg
 

henryk

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the 420mm 12 blade ducted fan
-for 2-place (DF 420) ?

=Power/ RPM=?

BTW=Schuebeler=


"
“We can give people a much higher efficiency,” Schübeler said.

Even the smallest error in an aerodynamic system can cause a loss of 30% to 40% efficiency. By designing EDFs that optimize energy use, Schübeler said his company is accelerating green aviation. His goal is to make battery electric flying platforms good enough to fulfill serious enterprise missions.

"
 
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