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Ducted fan project

  1. Aug 27, 2009 #1
    I am working on a project that requires 4 ducted fans, each producing approximately 40 N of thrust for approximately 10 minutes using battery power.

    Is this feasible? Any suggestions about which fan and battery I should use if it is feasible?

    Thanks
     
  2. jcsd
  3. Aug 27, 2009 #2
    That's very do-able. As for finding a ducted fan, you're on your own on that one. I don't recall offhand any RC ducts. The propeller is probably going to be around 8-10". You're also looking at, I want to say, 4-6cell LiPo batteries. This isn't going to be cheap.....probably around 1k for everything.
     
  4. Aug 27, 2009 #3

    minger

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    What other requirements do you have?
     
  5. Aug 27, 2009 #4
    The fans are going to be used for a hover craft. So the 4 fans producing 40N of thrust each should balance out the weight of the vehicle. Additional thrust will be needed for movement. I pretty new to this sort of thing so I am not sure how to determine what fan, motor and batterie I will need.
     
  6. Aug 27, 2009 #5

    Danger

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    While it's not a really effective means of propulsion, remember that if your lift fan is more powerful than is needed for levitation, you can simply vent excess air from the rear of the skirt for thrust. That can save you a few bucks, but you won't have great performance.
     
  7. Aug 28, 2009 #6
    If you are building a hovercraft that weighs 9 pounds, you do not need 9 pounds of thrust for it to work. If you are talking about using thrust to weight ratios equal to or greater than one you are looking at making a vertical take off aircraft.

    In order to make a hovercraft you simply need a fan that will create a pressure difference equal or greater to the pressure in the skirt with enough flow rate to keep up with air leaks. Think of a hovercraft as sort of a hydraulic jack. The fan doesn't need to be able to lift the aircraft, it only needs to create enough pressure inside of the skirt that the craft can be lifted. Understand?

    The project is certainly doable. What's your budget?
     
  8. Aug 29, 2009 #7
    Sorry, hover craft was a poor choice of words. What I am making is more of a VTOL aircraft.
     
  9. Aug 29, 2009 #8

    Danger

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    Whoa! Whole different story. Gotta think on it for a bit.
     
  10. Aug 29, 2009 #9
    i think there is no need for the 4 fans ducting in the craft.
    it required tube and air compressor to lift your vehicle
    a fan for changing the direction's
     
  11. Aug 29, 2009 #10
    If you're looking to make a VTOL, then ducted fans are not a good choice. In the case of a VTOL, efficiency is proportional to fan/rotor diameter. Because of this, you will want to use large rotors instead of ducted fans. This is why helicopters have large rotors instead of small ones. If you decide to go with ducted fans for what ever reason then be prepared to spend some serious cash on motors, fans, and batteries.
     
  12. Aug 29, 2009 #11
    I will most likely be using ducted fans, they are an important part of the project I am working on. What would be the best way to go about determining the proper equipment I need. Fan, motor, battery, speed control.

    Does anyone have experience in this sort of thing, I unfortunately dont have much.
     
  13. Aug 29, 2009 #12

    FredGarvin

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    Electric RC airplanes have this stuff in everything now. The technology is really pretty impressive. RC helicopters have 3 axis gyros as well. A little time at a hobby shop and some RC magazines and you'll get all the beginning info you'll need. The sizing and what to get will fall out in your design.
     
  14. Aug 30, 2009 #13
    Most RC helis only have only single axis gyros. The helis that have 3 axis gyros are flybarless where the flybar is removed from the head in order to increase efficiency, but this gets very expensive. It would be easier just to pick up a generic INU and program in this case since most RC heli INUs have built in mixing for controlling the cyclic.

    You will probably have to build your own ducted fan units. I have never seen an RC plane ducted fan unit with more than 5 lbf of thrust. Does the total 160 N of thrust include the thrust required for maneuvering or is that just to lift the weight of the craft?
     
  15. Aug 30, 2009 #14

    FredGarvin

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    Last edited by a moderator: Apr 24, 2017
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