Not satisfied with the specs of off-the-shelf brushless DC motors? Looking to up the difficulty level on your next quadcopter build? Or perhaps you just define “DIY” as rigorously as possible? If any of those are true, you might want to check out this hand-wound, 3D-printed brushless DC motor.

There might be another reason behind [Christoph Laimer]’s build — moar power! The BLDC he created looks more like a ceiling fan motor than something you’d see on a quad, and clocks in at a respectable 600 watts and 80% efficiency. The motor uses 3D-printed parts for the rotor, stator, and stator mount. The rotor is printed from PETG, while the stator uses magnetic PLA to increase the flux and handle the heat better. Neodymium magnets are slipped into slots in the rotor in a Halbach arrangement to increase the magnetic field inside the rotor. Balancing the weights and strengths of the magnets and winding the stator seem like tedious jobs, but [Cristoph] provides detailed instructions that should see you through these processes. The videos below shows an impressive test of the motor. Even limited to 8,000 rpm from its theoretical 15k max, it’s a bit scary.

(Dan Maloney -


But, How it works? 

This is the Halbach array setup. Every 5 magnets the pattern repeats. for more information.

Here is the explanation / assembly video

Alexandre Mainardi

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  • Developer

    Yeah, I was thinking the same. Integrating parts of the motor into the gimbal structure would be interesting.

  • Takes a fair bit to crack the 90% efficiency mark for a BLDC motor.  Most are peaking shy of 85% and some a long way.

    Impressive job though.  I suspect that 3D printed halbach array motors might have more use in gimbals - potentially as sector motors or as torque motors.

  • This is amazing! It shows how far 3D printing and home electronics parts building has come.

  • Hi Rob,

    What props / diameter / RPM / thrust are 75% efficient?

    At any single speed, that is extremely high efficiency for a prop - in hover?

    I am not doubting you, just want to know.



  • You are right, I meant that the motor itself can be 90%+ efficient when the prop generates a torque and speed in the most efficient torque-speed region of an efficient motor.

  • Prop efficiency should not be included in the motor efficiency figures.  Also, it would be nearly impossible to see prop efficiencies near 90%. Highest I've seen is 75%.

  • Motor vendors are often optimistic ;) But you can get over 90% mechanical efficiency with the right motor prop combination.

  • MR60

    Impressive work!

    What's the motor weight and how does it compare to standard BLDC motors of same wattage ?

  • Yes, incredible work.  And I love to see real practical applications of high-performance 3D Printing.

    But I'm curious about the efficiency numbers. 80% seems to be pretty low compared to typically claimed BLDC efficiency of 92%.  Is this less efficient because it's made of plastic?  Or are the motor vendors optimistic?

  • If this heats up much I suspect there will be issues.
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