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  #1  
Old 12-03-2005, 04:51 AM
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Default Ducted fan is the future

I always told you...
Ducted fan is the future:

http://www.aurora.aero/TacticalSystems/GoldenEye80.aspx

Our next type of VTOL recreational vehicle.

Last edited by PTKay; 03-15-2010 at 03:27 AM.
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  #2  
Old 12-03-2005, 10:25 AM
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Quote:
Originally Posted by PTKay
I always told you...
Ducted fan is the future:

http://www.aurora.aero/tactical/GoldenEye-100.html

Our next type of VTOL recreational vehicle.
It looks like a giant cup.
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Old 12-25-2005, 09:03 AM
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converging and prior to this design are the offerings of
Alexander Lippisch (Me 163 and GEV fame) the Aerodyne concept
and the Hiller VZ1 flying platform

but being that this particular form is a 'tail sitter' the risks are broadly well known, as the transition from vertical flight to horizontal flight is easily percieved, it is less so when landing. But ok for a UAV i guess.
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Old 12-25-2005, 02:29 PM
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speaking of ducted fans....does anybody remember the movie "Slipstream" it had Mark Hamill (Luke Skywalker) in it from Star Wars. Anyway he flew a pusher powered aircraft with some sort of ducted fan I would like to know what aircraft that was and get some info on the ducted set-up they were using. This was not some Hollywood make believe craft as my Dad seen one years ago at Oskosh.

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Old 12-25-2005, 02:53 PM
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Ok, a little research and I found it...a bit to much HP though.

http://www.utility-aircraft.com/catalog/forsaleoa7.htm
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Old 01-25-2006, 10:29 AM
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Default Pegasus Mk III Gyroplane

http://www.pegasusrotorcraft.com/peg...esentation.pdf
This is a three seat gyro with jump-takeoff capability.
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Old 01-25-2006, 10:45 AM
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Heather - as far as I know, the Pegasus was never manufactured and the company bankrupt many years ago.

Too bad though... Nice gyro.

Udi
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Old 01-25-2006, 10:56 AM
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there are indeed some useful advantages with ducted fans
and they are appropriate to gyros because

* they exhibit better static thrust for the same power

* diameters are usually given to engine rpm and are therefore somewhat narrower, the thrust stream has a wider footprint than a prop therefore a comparable footprint means a smaller ductfan.

* in fact, you can dispence with the redrive, and run the fan at engine rpm
this saves the weight, maintenance and expense of the redrive, also a lot of other engines become more viable.

* performance usually exceeds that of a free prop untill around 100mph, where the drag of the duct begins to impact on performance. The speed regime matches the gyro quite well.

* noise is abated, and the sounds are stronger at vectors about 45 degrees out

* safety in ground handling, the path of the fan being protected by the shroud and being more obvious to see and avoid while on the apron.

the downsides are considerable too:

* they are more complex to engineer, and its not like you can go out and choose one off the rack.

* tollerances like tip to shroud clearances need to be quite tight, by thou

* mounting the duct and fan in some sort of stable union can be difficult too
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Old 01-25-2006, 11:14 AM
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If ducted fans were truly effective, radio control pilots wouldn't be shelling out $1500 for a true turbine.
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Old 01-25-2006, 11:24 AM
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i dont know much about model radio guys doc but the physics of the technology is irrefutable, its just more difficult than bolting on a prop to execute

ducted applications are common where diameters are restrained, high performance and ground safety is required, take a look at many of the UAVs that have limited airspeeds, or torpedo technology some day
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Old 01-25-2006, 11:56 AM
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This is a design by Piasecki, I believe.

Here's a Long-EZ with ducted fan
www.ductedfan.com
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Old 01-25-2006, 12:20 PM
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Hi,
Nice plane. Saw one down at Sun N Fun years ago. Sounds just like in the movie. More of a woosh when overhead. Not in production.
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Old 01-25-2006, 02:14 PM
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Let's try this a different way.
Based on resounding success of Moeller Skycar...uh...
The unusual 700 mph "Flying Saucer" with it's twin turbine engines being tested by the US Air Force...never mind, that one became the basis for every hovercraft in the world.
Bell's development of the X-22... forget that one, it couldn't lift enough fuel to clear the airport.
Other than the Optica, I can't think of a single manned ducted or ringed fan that was successful. The Optica flys well enough, but based on production numbers, you can't really call it "successful". Even the "Flying Jeep" was abandoned.
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Old 01-25-2006, 03:50 PM
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Even the guy who put the ducted fan on his long EZ eventually took it off because it didn't perform well. If ducted fans were so good they would be everywhere. They have many drawbacks. I think by far the biggest reasons it's on that uav are for noise reduction and to reduce radar signature.
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Old 01-25-2006, 07:08 PM
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Cobra Doc said
"I can't think of a single manned ducted or ringed fan that was successful."

Doc manufacturers always prefer to be able to take components 'off the rack', and their pre-requisite is build economy, not complication, and small manufacturers are even less likely to pursue it. Axial fans, although efficient when correctly done, have a narrow f'up margin, and that would add significantly to development costs if they tried to do it inhouse. Add to that, the market for sub 100mph aircraft is what exactly? Its not hard to figure out why duct fan applications havnt worked out. I could fill the page with aircraft the usaf hasnt been able to make meet the specification, but that would be dumber than a broken bell. Based on that ideology one would quit every method of propulsion known to man.

jazzenjohn said
"Even the guy who put the ducted fan on his long EZ eventually took it off because it didn't perform well"

They are really only ever going to be any benefit to sub 100mph aircraft
the long eze was never going to be a good choice, even on paper he may as well have never started the modifications, hell if he couldnt figure that out, what hope would he have with the rest. I believe he had 3 attempts before he cancelled the cheque which supports my previous fudge/difficulty factor.

I believe this is the long eze mentioned
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Last edited by Ga6riel; 01-25-2006 at 07:19 PM.
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