Ducted fan designs, an early project sneak peek

3d printed ducted rotor aircraft engine

This post is an early sneak peek at a project I have been working on in my spare time.  I showed a friend who stopped by and he told someone else an I was pestered to share pics and a video.  I have been experimenting with ducted fan thrust generation with a planned application.  As for what  that application is…  Well it is not ready for the world yet and I will let you use your imagination.

thrust generating ducted rotor     3d printed ducted fan thrust generator

Mostly eye candy at this stage of the game, I have tested 3 different rotor designs without getting into complex blade geometries to date. I have primarily been focused on printing rotors that have little wall clearance and hand finishing them to minimize the gap between the duct and rotor blade.  Research papers I have read shows that this area is critical to ducted fan efficiency and design.

ducted fan design 3d printed-9400

I am currently using a set up with a friction fit on a taper to lock the two halves together so I can get at the motor.  This little bad boy screams when she spools up.  In the shop it sounds like a mini jet engine starting up.   I am working on test platform speed a controller for it using an Arduino nano and components..

rotor design for ducted fan

You can see that this needs lots of cleaning and smoothing before final thrust measurements.  I plan to put it through an acetone bath treatment and then do a bit of hand finishing to smooth out the inner walls to reduce any drag from the 3d printed irregularities.  Eventually I’ll make a rotor balancing jig to fine tune the balance on the rotor.  Future iterations will likely have continually reduced rotor mass to decrease inertia.  I am testing behind a 1/4″ polycarbonate shield in case of catastrophic failure.

ducted fan design 3d printed-9401Here’s one with my hand to provide you with a sense of scale.  I will try to get a video of it spinning at moderate speed.  Without a speed controller I’m reluctant to limit test the high speed operation at this stage of development.  I will put a video up here later this weekend if I can find time. 

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