Introduction: Air Powered Spinning Top

About: I like to improve myself and things I find :) Learning new things every day is next to impossible but I still try - only a working brain can work. I have no special sector to cover, electronics, electrical stu…

I am currently reading a lot about the work of Victor Schauberger and needed a way to test different turbine designs.
As a result I came up with the idea to "mis-use" them as a toy.
The Air Powered Spinning Top was born.

Ever wanted a toy that is just totally different?
How about a spinning top that you can power and speed up by blowing on it?
Make a contest and see who gets the longest spinning times from a single blow.
Find out how to change the direction of travel by blowing the top at different angles.

Here is a short video of the thing in action:

Tools and things you will need:
1. Access to a 3D printer or printing service.
2. Depending on which model you choose some ABS juice to glue the parts together, if using PLA or other materials please use suitable glue.
3. Depending on the print quality some fine sandpaper to clean the printed model.

Here are the STL files for printing:

Download from FilefactoryDownload from Filefactory - added copy

As printing with support usually results in bad surfaces I made the toy in two halfs that can be printed indepently.
Simply glue them together when done.
Or better said, the top and the little cone it spins on.
You will need to print with a quite fine nozzle, like 0.4 or 0.3mm as I think bigger nozzles will have problems with the impeller.
The entire model can be printed without support and I suggest to print the cone at the same time to have more time for it to cool.
Recommended print settings:
0.3mm nozzle
0.1mm layer height
3 perimeters (outer shells)
4 bottom and 5 top shells/layers
15% honeycomb infill to keep the weight down.
I would not recommend printing without infill as the bridging can cause some sagging that resticts the airflow, less weight is better so if you want to try and trust your printers bridging skills...

To get it going simply isert a drinking straw loosely into the top and start blowing, you might need a few attempts to get to good speeds.
If you want to get even faster speeds use a needle as the tip for the toy.
Before assembing the two parts, heat a long needle with a lighter - be careful not to burn yourself!!
Push the hot needle through the cone from the inside, the cone shape will act as a little guide to make hitting the center easier.
It is not easy to get it perfectly centered though and I had no problems with the printed tip in terms of speed as you can see in the video.
If you do you use a needle please do not use the spinning top on any soft or expensive surface as the needle will scratch them!!
For more or less unrelated background info check the next steps, otherwise just ignore and enjoy your new toy!

Step 1: What's the Trick?

Well, there is none to be honest.
The main part is a hyperbolic, four sided, impeller.
This impeller diverts all air comin in from the top onto the output spirals.
These spirals compress the air and force them through a quite small gap at the end.
As a result the airstream coming out is quite fast and due to the coanda effect it creates a space of fast flowing air around the outer circumfence of the toy.
In return this "air cushion" helps to stabilise the spin.
If you use a pump or compressor (low pressure please!) you can get quite extreme speeds out of it.

Step 2: Why Did I Design It This Way?

I designed it this way so I have a base for my bigger project, a model of a Repulsine.
So I first needed a suitable impeller design to divert the incoming air from straigth down into a spiral motion with a lot of spin.
As a matter of fact the toy works quite well just with the impeller in the center but does not have the UFO look to it.

Step 3: Things to (hopefully) Expect in the Future

Designing these shapes is quite hard on an old computer especially when want to consider air flow, vortex creations and pressure differentials.
The basic impeller design with a suitable air inlet can be used as an extrem high speed turbine or like the Harman Impeller to move the water in big water tanks.
Also in the opposite direction the impeller can be placed into the centre of a water vortex to be used as a generator.
All that's needed for it to work is a funnel shaped basin with the water outlet in the centre (bottom) and the inlet on the rim.
But my next design if I find a cheap waterproof motor for it will be a "Tornado lamp" with the impeller creating a huge vortex in a acrylic tube or oversized water bottle.