Ducted Fan propulsion

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by yankeeclipper, Jun 3, 2009.

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  1. Dec 29, 2011 #21

    delta

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    I'm convinced it's possible to have a constant angle of attack fan that will rival the props efficiency and cost. I'm not holding my breath, but I'd really like something like that for my design and have a few more experiments to run before I'm done with it one way or another.

    Rick
     
  2. Nov 22, 2013 #22

    hover

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    Hi there

    I'm currently thinking of building an electric ground effect vehicle using 2 x 25" ducts for lift and 4 x scorpion HK-7050-340KV electric motors. I'm currently in communication with trek aero: Trek_Aerospace_Home to arrange for them to build the props and have sourced the 25" ducts.

    The ducts i have selected have been tested with hirth f33 26hp gas engines and are only 41% efficient using there setup which i need to get to 80% with the help of trekaero, who will be making the props.

    The operator of the craft could control lift, thrust and direction by altering the degree of rotation of the gimbal fan When a gimbal fan directs its stream of air straight downward, it provides pure lift. When the Fan is tilted at varying degrees, it provides some lift and also some thrust in a particular direction. Two Fans combined give the pilot of the vehicle precise control, the ability to go against the wind, sideways and diagonal motion, reverse motion and quick stopping.

    Four 20 HP motors will give me 80 peak HP to play with, but since I can only run them at 60% continuously, I will only get about 48 HP continuous, I have seen that 50 hp should give me 150 kg thrust. 48 HP is probably enough to hover with though.

    In theory I can increase the horsepower rating simply by increasing its voltage and rpm until I reach the mechanical limits of the design.

    Any thoughts, comments, criticisms, ideas or suggestions are more than welcome.
     
  3. Nov 23, 2013 #23

    henryk

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  4. Nov 28, 2013 #24
  5. Jan 18, 2014 #25

    henryk

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    Trek_Aerospace_Strategic_Alliances

    =Trek Aero seems to be very sukcesfull...

    igor113 -

    =detailed FANTREINER pics.
     
  6. Jan 19, 2014 #26

    Aircar

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    I think igor is a spy:gig:.. didn't miss much on the Fantrainer . (not hard to see why it was heavy and draggy either)

    Compare the long coming Trek 'backpak' VTOL with the recent NZ Martin JetPack -totally different shroud geometry etc but similar mission --they are both ridiculously inefficient to keep the ducts at 90 degrees to the direction of flight and no wings to offload in cruise. I only hope they have good ballistic chutes .
     
  7. Jan 19, 2014 #27

    rotax618

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    G'day, If you want to fly a FA18 lookalike,(not ducted fan but interesting). How about this one.
     

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  8. Jan 20, 2014 #28

    Aircar

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    Where is the propulsion? (not visible ) -- no doubt there are many such lookalike or 'decoy' F 18s being kept ready for use if the big one ever breaks out .... The glider factory I worked for in Germany built 'dummy' F 86s just after the war to lure Warsaw fighters into wasting ammunition on them in the event of attack (they were to be 'carelessly' left out unprotected ...) The allies built blow up rubber tanks and Spifires etc to deceive attacking aircraft with too little time to double check . I only hope he doesn't stray into NATO airspace ......
     
  9. Jan 20, 2014 #29

    henryk

    henryk

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    =pusher,unducted propeller...
     
  10. Jan 20, 2014 #30

    Xanadrone

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    Unless you're going to use some complicated and possibly unreliable reduction drive (but I guess not), a 340 kV HK (helicopter-use) electric motor would be out of question (rotating at approx. 17,000 rpm with a 50V/14s input for the max. 10 kW power at 200 A absorbed.) Then the prop-tips, even if it's only 25" in diameter, would work way over Mach-1.

    Anyway, I still wonder if the low efficiency of the ducted fans (the big ones commercially available for RC-use included) could really be improved in such a radical manner, even by specialized companies.

    ...And a last tidbit of advice from an old RC-modeller: Scorpion E-motors are good indeed (magnets, bearings) but the very big ones used to have some problems in the long run - although rarely.
    That's why I'd go for those of max. 150 kV produced by Plettenberg and delivering up to 15 kW (or at least Hacker - a tad less "pro", but also less expensive).
     
    Last edited: Jan 20, 2014
  11. Jan 20, 2014 #31

    rotax618

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    G'day, The little fighter look alike is an Archeon, it is an all metal pusher, could be converted to ducted fan, uses a Rotax 503. Go to the website there are more photos and videos.
     
  12. Jan 20, 2014 #32

    Xanadrone

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    P.S. Some more details and maybe drawings of your ground-effect project (?) would be welcome for further opinions and/or estimations.

    Anyway, this type of vehicles need generally less power than a comparable size aircraft.
    Why then the need for over 150 kgf vertical thrust?!

    This kind of thrust suggests a JetPack-alike VTOL (v. gimbals etc.) or at least a STOL small homebuilt, not too easy doable considering the considerable weight of the battery-packs - even those of newer generation (LiPo's used mainly for some extremely efficient E-gliders.).
     
  13. Jan 21, 2014 #33

    henryk

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    http://www.luftbau.tu-berlin.de/typo3temp/pics/4/4b3c35465e.jpg

    =seriouse project...with Ejector system!

    Das Rumpfheck umfasst neben dem Antrieb auch die strukturelle Voraussetzung zur Aufnahme eines Ejektors. Zudem ist das die Kabine abschließende Druckschott Bestandteil der Heckkonstruktion (Abbildung 37).

    =? ubersetzung?
     
  14. Jan 29, 2014 #34

    Aircar

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    Henryk -- are you asking for a translation of your link ? (ubersetzung?) -- the idea of a flow mixing ejector is used on several VTOLS to increase exhaust momentum and lift in a somewhat similar fashion , maybe this is related to that . The idea of an internal ducted fan is interesting in the context of replica jet fighter/trainers -- and even maybe for some roadable designs so this thread ought to be followed up when your friends get their Russian fighter style ducted fan aircraft flying --and any technical links to the design would be appreciated I am sure.
     
  15. Jan 29, 2014 #35

    Aircar

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    Henryk (again) - I just revisited "Igor's" Fantrainer picture album -- you might be interested in my ravings on the "Me 262" thread about doing a 'pseudo jet trainer 'fighter' replica using an internal ducted fan like this but with an external 'cylindrical' normal rear fuselage just like a normal jet eg Sabre F 86/Mig 15 etc --the hollow tailcone carries the tail loads rather than the cross shaped open arrangement of the Fantrainer ( actually I was competing against Hanno Fischer and the Fantrainer in 1979 for the RAAF basic trainer design contest (with my "sapphire" version of the Opal --itself somewhat like Hanno's own earlier Fischer Multoplane RW3 . The possibility to do such a thing for a Folland Gnat or Alphajet 'look alike' and fly fast but not so fast as the real thing but at 1% of the cost... is the concept and parallels your guys Su27/F 18/Mig 31 style twin 'jet' replica --pretty soon we could have enough scaled down fighters for our own "Civil (air) war" -- a non- military airforce .:gig:
     
  16. Jan 29, 2014 #36

    John.Roo

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    Matt G. and rv6ejguy like this.
  17. Jan 29, 2014 #37

    Aircar

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    Fantastico!--good to see someone is working along these lines -see the "me 262 replica" thread for an unaffordable full size and fire breathing copy that no one can fly (due to the economics and regulations at this size and powering)

    more later when I can read the link, Good work!
     
  18. Jan 29, 2014 #38

    henryk

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    Robert Theiner | Ultralehký letoun s ventilátorovým pohonem 1 - SlidesLive

    =presentation...\1900 N thrust from 150 HP\.
     
  19. Jan 30, 2014 #39

    Aircar

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    Henryk and John- I just looked through all the links, I found three words I could read ! "jet feel" "ultralight" and "problem" --of course these are 'international' words but I got a very good impression from the videos --the L39 is an ideal design for this purpose (straight wing helps a bit in handling and build ) and the standard of construction looks very, very good . This is exactly the sort of 'hybrid' powering that I was speculating about on the other threads ("Me 262" mainly) and will do the job at a lot less cost than jet engines . I will keep track of your progress (which I hope will be reported here from time to time.

    The very best of luck with the project, Ross.
     
  20. Jan 30, 2014 #40

    henryk

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    -compare with FLARIS LAR1...
     

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