Hexacopter

[vimeo=http://vimeo.com/6194911]
Quad copters have been pretty popular for the last few years, but this one is new to us. Take the same basic layout, but bump it to 6 rotors. Then you’ll have the hexacopter (google translated). With 6 rotors, built in GPS and stabilization and a camera mounted on the bottom, this thing is pretty well equipped. You can see how agile and stable it is in the video above. We know it isn’t necessarily new, but it is new to us. Of course, you don’t have to stop at 6 rotors. You could always just continue on to 8.

70 thoughts on “Hexacopter

  1. @jimmys

    shouldn’t there be close to an ideal point for the number of blades? Having more will lower the amount of RPMs needed, but the additional motors will increase the weight, I would think, considerably more.

  2. You know I had one simple request, and that was to have hexacopters with frickin’ laser beams attached to them! I don’t recall anybody informing me that it couldn’t be done!
    Where are the frickin’ laser beams? Can you remind me of what I pay you people for? Honestly, throw me a bone here,.. I thought I said I wanted frickin’ laser beams mounted on that thing!

  3. @taylor

    The design decision to choose four MOSFETs ist because of efficiency.
    If you use a half-bridge with one MOSFET and one (schottky) diode, you roughly have the forward voltage drop of the diode times the motor current times one minus the duty cycle as a loss.
    Typical MOSFETs have even lower conducting losses as schottky diodes at typical motor currents nowadays.

    And by using a full bridge (four transistors), you further get regenerative braking and better control characteristics.

  4. Sorry, correction: two transistors are enough for regenerative braking, if you have a DC motor. I mixed that up with another circuit. An H-bridge is needed for a single phase AC motor to invert the polarity.

    In this case you have a three-phase motor and you even need six MOSFETs.

  5. Sikorsky experimented with up to 8 blades for a heavy lift helicopter, and indeed that’s about as far as it goes, it’s basically the same thing as having bi-plane or tri-plane on a standard aeroplane. You gain more by rotating the planes faster than by adding more. On heavy lift helicopters though it was found that having more blades, or planes, is more efficient, up to that 8 blade maximum.

    And for those interested in bigger applications of this particular demonstration, I’m afraid this vehicle won’t scale up well, even using cowling on the rotors, but in a small UAV this kind of approach might be very interesting.

    Aerodynamics doesn’t scale well, you can easily make a model plane fly, but the huge version of it won’t fly. That’s why you’ve never seen a 100 meter long airplane folded out of meter thick paper.

  6. @autogiro: Not sure your comment about the paper airplanes really works as a good argument about aerodynamics (though I don’t disagree about the difficulty of scaling)

    A paper airplane is generally a glider that is initially launched with a lot of force. If you were to launch a 100meter long, meter thick paper airplane with the scaled-up force of a human throwing a small paper plane, it would probably glide a bit, but you never see it because it’s pointless and would be quite expensive and difficult to set up.

    That being said, I’d like to see it anyway.

  7. @ERIC: Military have “recoiless rifles” which could be mounted on a larger version. They come in various calibers. Were used on Aircraft during Vietnam-“Puff, the Magic Dragon” check it out on Google or…
    Could easily design a 9MM one that would be great for covert night operations. Noise could be reduced.

  8. Integrate this with people that are publishing their GPS location (ie Iphone GPS or Google Buzz) and if the Hexacopter was within a certain range it could “BUZZ” them, every time they “Tweeted”.

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