The Spinner

The "Spinner" was, and is, a project to make a 3D printable and iterable version of a toy I had when I was a kid. This was a all plastic propeller toy, with a set of big blades above a small plastic shaft one would spin between their hands. I got started on it as a short and easy way to make a toy for my cousins Christmas, but proceeded to make a more than twenty iterations of the object over an entire semester. It was an awesome introduction to 3D printing and 3D printing design and got me started in the Forge Maker space.

Version 1 - The Pathfinder

The Overview

While no V0 CAD or even images exist anymore, I do have things for the V1 spinner. This was a seven part assembly, comprising three blades, three components to lock those blades together, and a single long shaft for spinning the part up. This was all 3D printed out of PLA and all the work was done in Siemens NX. It was my first experience with 3D printing or any real design and... it really shows.

What Worked?

The largest thing that worked about V1 is the very basics of the design. This comprised a lower section that interfaced with the bottom of the blade, a upper section that held the top of the blades, and a clip that held all both of these clips together. This clip was then held by the center shaft to keep everything nice and stable.This general design was retained for the rest of the program, albeit in different forms.

What Didn't Work?

The largest issue with this spinner is that it was extremely heavy for what it was, and extremely difficult to assemble. The assembly difficulty came in some... questionable clearances and the design of the slots for the clips. Without ends on these slots blades would slide around and jiggle free. The clearances were also far from perfect, mainly due to my underestimation of just how good additive manufacturing is, it's great!

Version 2 - Trying to Get Operational

The Overview

The V2 Spinner was a monumental improvement in the overall design. From a CAD perspective, I started working assemblies correctly and some very very basic parameters. This was also was the first version with significant revisions within the version, these were known as "Blocks," of which five or so were produced in iterating through the version. I was still sticking to some basic design, but I produced a large volume of these V2 spinners giving me valuable insight into the manufacturing stage of engineering.

What Worked?

The design of the clip mechanism stayed as a highlight of the design, and I was really successful in reducing the mass of the prototype. Here the clips between the blades and the top segment, as well as the clip holding the entire propeller together. The linkage mechanisms were strengthened significantly over V0 and the wing itself also got stronger over this revision. I also experimented for the first time with changing up the printing parameters for the spinner, strategical shedding and adding weight to the part as I went.

What Didn't Work

The largest issue with this prototype is that the wings kept stalling. This was due to a frankly insane angle of attack the blades had with the airflow (15 degrees is nuts). Late in the V2 process I spoke some other students who took a look at my CAD and politely suggested I look at my airfoils in XFoil. These wings are super stalled, but I was able to optimize and find some better regions for these wings. Within the V2 CAD I was unable to make enough changes to the wing profile to really remedy this, so onto V3 it was

Version 3 - Getting Better at CAD

V3 was a CAD only revision of the spinner, and represented a titanic leap forward in my CAD skills. The largest thing was parameterize of the entire model, giving me the flexibility to really mess around with wing profiles and geometries interacting with both the airflow and the rest of the body. This prototype never reached production as it was very rapidly succeeded by the V4, but it served as an awesome experience into how CAD and especially parametric design works. This was also the first version done in Autodesk Fusion 360 as a way to expand my CAD program profile.

Version 4 - The Final Design

The Final Iteration

The final V.4.7 spinner ended the design linage. It massively improved the clips and wing assemblies and in working with an actual aerodynamics professor, the blades started getting really refined. The clearances were dialed in to work perfectly on the printers I had access too, and the CAD has been thoroughly set up to allow a single parameter to control these clearances. Bonus points for this being the lightest version of the design while still having substantially more lift than the next best spinner.

Massively Parametric

The V.4 CAD allows the spinner to be fully parametric. Each wing has 4 segments where the airfoil can be modified, along with the chord, thickness, and rake. The number of wings is also parametric, so I was able to test designs with as few as two and as many as five blades. I was able to give testing to a huge number of configurations in order to find the final design that is a good compromise of lift, strength, and stability.

Material Agnostic

Another feature of the V.4 was a testing campaign on the different ways to print the wing and hub structure in order to find the best settings and compromises for any given material. The true final product uses PETG printed in different infill levels for all the shaft and hub components, then TPU 60D for the blades in order to make the entire toy both easier to use and more able to withstand the loading of high velocity impact.

CAD files for these will be made available upon request

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