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Tethered Flight

Discussion in 'General Discussion' started by UNMND, Feb 1, 2016.

  1. UNMND

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    Hi all,

    I'd love to share with you all a project we've been working on, it's a low cost tethered power system that can replace the battery on any small size quad or hex. We've been testing it on a DJI F450 and the F550 flamewheels so far and it should work on the Phantom 1 or 2 (not yet the 3, as they encrypt the battery signals but we're working on it). Basically we wanted to be able to do long time-lapse videos and just get a fixed bird's eye view on things without having to swap batteries every 20 mins.

    [​IMG]

    The system is in 3 parts that all pack into a small briefcase:

    1. The power box on the ground, which takes any of the usual power options; mains supply, car battery (deep cycle) or generator etc... and turns it into a high voltage output.

    2. The high voltage cable, in order to keep it's weight to a minimum.

    3. Finally the transformer system in the air which takes the high voltage and drops it down into the 15V for the motors. This is approximately the size of a 5000mah battery pack.

    [​IMG]

    So far we've tested it to 50m with a gopro onboard, but it used much less power than we thought it might so it should be able to reach 100m. Slight delay now as we're just sourcing a more suitable cable as this one tangles really easily.

    Anyway I'd love to know your thoughts, I know a tethered system isn't for every application, it's horses for courses. But if you're in the UK and want to have a play with it, do let me know. We're wondering about putting it on kickstarter... not sure, all comments welcome.

    We've got some more photos etc... on our instagram page. @unmnd • Instagram photos and videos

    Thanks
    Ed
     
    LosDosMonitos and SilverStone641 like this.
  2. Digger7719

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    Sounds pretty neat


    Sent from my iPhone using PhantomPilots mobile app
     
  3. brianrmartin

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    Could be a great solution for a stable airborne radio repeater solution.
     
    Brink likes this.
  4. TheRealNick

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    Sounds cool. Perhaps you could try helium balloons to help with cable weight...if it starts to be a problem....just thinking out loud
     
  5. Imabiggles

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    balloons would be a sail. I wonder when you start pushing the distance if DC to AC, AC up the wire, and AC to DC on the bird would improve line loss and allow you to shrink power line size. You would need efficient and light converters, but they exist (if a bit pricey).
     
  6. Helijoc

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    It is going to be tough as you go higher and the weight of the tether increases. I would suspect you will be looking at aluminum wire. Search Rutger university and drone. They are developing a drone that transitions to under water. They currently have it on a tether.
     
  7. Wolfiesden

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    For medium lengths I am sure a simple buck converter on the bird could take care of things. But for longer lengths, I would think medium voltage AC feeding up the wire should be way more efficient by reducing the crossectional core needed to supply the power as you could send more power up a lighter conductor.

    The other issue you need to pay attention to is static buildup and differential charges. These build up over time and can eventually reach very high static voltages that could damage equipment or nail people touching unshielded conductive materials.
     
  8. Fat City

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  9. Helijoc

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    Tesla coil?
     
  10. UNMND

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    Interesting discussion, we've gone for a DC solution here. Makes the transformation in the air into something we can use more straightforward. I've seen systems that use AC and even 3 Phase so I suspect there's many ways to skin a cat, so to speak.
     
  11. josh333

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    This is fantastic. I'd love to know more about this. How did you go with the phantom 3 battery? What voltage are you sending up the cable and what step down are you using on board the flame wheel?
     
  12. AndreyG

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    Interesting, I am doing similar development. With some success. Yesterday I got my Phantom 3 flying tethered for 2 hrs 15 min. Had to land because iPhone I use for controller display got discharged.
     
  13. Richard R

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    Check out the FAA webpage for waivers approved. Some of those guys are flying multiple sUAS's and on tethers. they might be potential customers.