Kevin Kohler “The Backyard Scientist” demonstrates how to build a simple DIY multicolor fire tornado with no moving parts. The design uses split glass tubes that create convection currents around the fire and various fuel sources that burn with different colored flames.
The best way to make a fire tornado (in my opinion!) All you need are 2 glass half-cylinders. No moving parts, no fans, no squeaky bearings, just fire and forget!