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


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


Combined thrust of 4400g.

Combined mass of 424g.


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


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."



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 




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  • @james, when you rebuild, you should think of using 4 of these LOL


    Xtreme EDF

    only 30 pounds of thrust :)

    Xtreme Power Systems
  • found a link:




    sorry they are german, but I think you see from the pictures what's going on

  • True, but I was actually thinking more along the lines of going from flying like a quad, pulling 20+Amps from the batteries per fan, versus rolling on the ground similar to some of the neat spherical robots.   The difference being that the rotational torque on flat level ground could come from miniscule, well-timed usage of the fans at very low current draws.

    That, in fact, will be my next project if the tri-rotor I'm working on this weekend doesn't work out as hoped.

  • if you fly close to the graound ( like pretty dam close) you can take advantage of ground effect i guess.


    ie you can hover for less thrust when close to the ground, without risking anybody's ankles because it's all enclosed

  • something of a safety cage if you know what i mean...
  • weight of the sphere would need to be taken into account yes, but can you imagine the sphere lighted with led's at night? :) that would be so sweet. but like I started with... no issues of getting fingers or pets in the props
  • PS- The hoberman sphere is interesting.....OK...so it's heavier.

    But if the layout of the quad was right, you'd have a vehicle that could save energy by rolling itself on the ground until it got to an aerial waypoint or obstacle; then orient and liftoff as necessary.....I wonder what kind of range extension that would give?


  • Unfortunately, I didn't get to do any testing beyond a "Give them all 0-50% thrust while hand-holding to verify it can lift it's own weight (it could easily), and check for stability (almost none).

    Based on a few ideas I had while putting it together, suggestions I read from the group, and just a little bit of spite, the beginnings of the next design are together.

    Pictures tomorrow or Saturday.


  • I had one of those :)

    Like with the decision to use ducted fans, spending a lot of weight on a sphere would be a bit of an endurance problem, to say nothing of the durability of the foam.

  • My concern is that ducted fans aren't efficient.  Have you tried figuring out what your maximum endurance is (at hand-hover level) with various sizes of battery payload?

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