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I can't help it...It's an illness I tell you...

Posted by James Cann on January 13, 2011 at 5:30pm
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I have clinical multi-projectitis.

It's incurable.

After seeing the GRASP lab video sof quads literally jumping through hoops, I HAD to make one of my own.

The beginnings: 

Although everyone else seems to be going open-rotor, I want zero collateral damage to people, pets, and the living 

room walls, so I decided on a ducted-fan design.

4 EDF combos from Hobby King

https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=11166

Combined thrust of 4400g.

Combined mass of 424g.

 

The 5Ah 4S 40C LiPo from my currently grounded Swift Heli:

https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10307

Mass: 578g.

 

For testing, the initial fuselage is a chunk of extruded poly insulation.

5 Deans connectors and a new soldering iron later (the old 30Watt one couldn't make a decent joint for the wiring harness), this is the result:

I christen her "The Ugly Pink Quad."


3689385013?profile=original

 

At present, she's brainless.   I just did a test with a little solderless breadboard sending the throttle signal to all EDFs simultaneously and, not surprisingly, things were learned:

 

1) With 4400grams of max thrust pushing 1220grams of pinkness, it only took about 1/3rd throttle position to hand-hover.

2) It wants to rotate.

 

Next issues: Basic landing gear (The motors are outrunners), basic brains, and an IMU 

 

 

 

Tags: pink, quad, ugly
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Comments

  • hamish January 14, 2011 at 5:13pm

    You'd be better off with bigger, slower props . .. . plus you'd be able to pick up some counter rotating ones

     

     

  • Hopper January 14, 2011 at 3:18pm

    I had a similar thought a couple years ago. Used foam poster board for the airframe. Initially tried two fans on paddles and quickly discovered the need for two more.

     

    3692152224?profile=original

     

    Added two more fans but they were only supported by whimpy axels and quickly broke off on power up.

     

    3692152241?profile=original

     

    Came up with a better design that supported the fans on both sides

     

    3692151800?profile=original

    Unfortunately, I used whimpy ducted fans. It couldn't even support its own weight using an external power supply! Didn't have the cash for brushless, so the whole project went on the shelf. I never even got far enough to discover the counter-rotating issue. But I still learned a lot.

     

    Keep plowing forward, James. Who knows what you might discover.

     

    Worst case, it's good free entertainment for the rest of us!  ;)

  • Matthew Dugal January 14, 2011 at 12:32pm
    Obviously, I did not think that through.
  • Moderator
    Sgt Ric January 14, 2011 at 12:10pm

    "think about it: make the motor spin backward and then turn it around -> spins in the same direction as before ;-"

     

    ..and since it spins in the same direction, isn't the moment of torque the same as before?

    Have we gained anything?

     

  • Sebastian Gralla January 14, 2011 at 11:58am

    "Maybe you could just reverse two wires from the speed controller to make them spin backwards. Then just point two of them down and two pointing up."

    think about it: make the motor spin backward and then turn it around -> spins in the same direction as before ;-)

  • Danny Lombard January 14, 2011 at 10:58am
    You carry the saying less is more.
  • James Cann January 14, 2011 at 10:13am

    Yes, they are brushless (3 phase synchronous motors), so reversing any two lines will reverse direction.

    However, ducted fan blades are curved for aerodynamic efficency, and the stator blades would then be the wrong way as well.

     

  • Matthew Dugal January 14, 2011 at 10:07am
    Aren't they just normal brushless motors? Maybe you could just reverse two wires from the speed controller to make them spin backwards. Then just point two of them down and two pointing up.
  • Ryan Fraser January 14, 2011 at 8:53am

    I think it's cool...

    Also gave me an idea to build a "Safety Body" for my Arducopter.

    I've been racking my brain to come up with some kind of bumpers to protect my props and frame.

    Right now I just have fiberglass rods attached to the frame protruding past the prop diameter with foam on the ends.

    I'm thinking I could just carve a nice "AR Drone" type body to fit.

    All the points made seem quite valid, but the beauty of this hobby (sickness) is the ability to fly what shouldn't and experiment.

     

    Cheers and thanks for posting... This is what DIY is all about!

     

  • Ron Holley January 14, 2011 at 8:38am

    seems to be 2 counter rotating fans on this device

    http://www.martinjetpack.com/video-gallery.aspx

This reply was deleted.