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Nano Tornado drone swaps props for ducted fans — Parallax Forums

Nano Tornado drone swaps props for ducted fans

Ron CzapalaRon Czapala Posts: 2,418
edited 2015-05-27 16:17 in Robotics
http://www.gizmag.com/nano-tornado-ducted-fan-drone/37683/

Although personal drones are becoming increasingly popular, a lot of people are still understandably intimidated by their exposed propellers. Not only can those whirling blades hurt people, but they also regularly get damaged in crashes. That's why Pasadena, California-based Polyhelo created the Nano Tornado. It's a quadcopter, but instead of open props it utilizes four ducted fans.

Comments

  • W9GFOW9GFO Posts: 4,010
    edited 2015-05-26 10:44
    No mention of flight time that I could see, most likely because it is quite low. Ducted fans are inefficient, especially at zero velocity (hovering).
  • JonnyMacJonnyMac Posts: 9,181
    edited 2015-05-26 11:08
    Fifth paragraph:

    Flight time is only about five minutes, although the battery can be swapped with a fully-charged extra on the spot.

    That's fine for indoor fun, but for outdoor flying and photography, it's pretty useless.
  • davejamesdavejames Posts: 4,047
    edited 2015-05-26 11:23
    W9GFO wrote: »
    Ducted fans are inefficient...

    Why so? Too much air restriction?
  • W9GFOW9GFO Posts: 4,010
    edited 2015-05-26 12:27
    davejames wrote: »
    Why so? Too much air restriction?
    The rule for efficiency is to move a lot a little bit. That's why sailplanes have such long wings, same for wind turbines, human powered aircraft, helicopters, ship propellers etc...

    The slower you can move the airfoil the better. A ducted fan has a very small 'bite' on the air so has to accelerate that little bit much faster to generate the same thrust. So all the aerodynamic losses increase plus skin friction is increase due to the ducting. Ducted fans are also used to accelerate the air faster than a propeller could by way of restricting the exhaust duct. This can work well in high speed model jets - jet boats too. But they will always use more energy than an equivalent open prop.

    Even transport aircraft have switched to large turbofans (instead of turbojets) over the last few decades. For best efficiency you want to use the largest diameter propeller that you can. If that is not enough thrust then you add more blades.
  • davejamesdavejames Posts: 4,047
    edited 2015-05-26 14:42
    ...well, I've read more today on the subject of open fan and ducted fan than the previous 63 years of my life.

    Seems they both have their pros & cons:

    http://en.wikipedia.org/wiki/Ducted_fan
    http://www.esotec.org/hbird/HTML/DuctMyths_F.html
  • xanaduxanadu Posts: 3,347
    edited 2015-05-26 18:40
    Whats wrong with prop guards? Oh right, they've already been sold. People will buy it because it looks cool and sounds different. Lipo packs are cheap and sub 5 minute flight times are common on small multirotor from lots of other mfg.

    It would suck if you were flying it and a leaf got sucked against an intake and you crashed.
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2015-05-27 15:24
    How much air spoiling do prop guards cause? The area to protect is actually fairly narrow. Surely there must be some sweet spot between efficiency and effective blade guarding.
  • W9GFOW9GFO Posts: 4,010
    edited 2015-05-27 16:15
    Prop guards are sensible and they shouldn't impact efficiency in a meaningful way.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2015-05-27 16:17
    I wonder if it's even a real product yet. Closeups in the video revealed 3D-printer layers. (And what a pompous twit they picked for a narrator!)

    -Phil
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