Summary

Straight forward problem. I bought 6 Dr Mad Thrust 50mm 5 blades for a project. Then worked out I really needed 3xCW and 3x CCW and you cannot spare blades in any event.

So, borrowed code from

Linear or parabolic: https://www.thingiverse.com/thing:689564
Aerofoil: https://www.thingiverse.com/thing:2790219/comments

I did have to hack at the code to get designs that fitted snugly and dropped a couple of features in the hub. I also had to add a disc to the hub.

I note that the aerofoil version of the original crazily opted for razor sharp trailing edges and so failures on edges either during printing, removing from bed or in operation. So, I opted to clip the trailing edge with a disc, since the blade is at an angle in any event.

To produce CW versions I just reverse in my Flashfinder software. Noting the metal hubs are not designed for the reverse operation (threads the wrong way) but the fit is deliberately tight and a dab of epoxy is always a solution.

I also went for a pusher and a puller version of the NACA blades, the linear blades themselves low efficiency by bi-directional.

So, yes. The author of the blades is worried that I might be expecting too much of them if they were being used as a drone set of blades. In fact, I have this kooky idea of filling a pool toy (Nemo of course) to turn it into a blimp that floats around the pool area. So, the performance requirements are less, though I guess we'll see.

The blimp "design" will be based upon the impeller setup on the Saab Double Eagle.

I will build a frame of 10mm OD carbon fibre tube. So, see the rear motor brackets attached. What did you say? Will it float with all that weight? Who knows mwahahahahaha! We'll find out I guess. In the meantime I am going to play with the ROS UUV simulator to see about a HIL, since a blimp is a UUV in the air - if you get my drift.