I made this really cheap smoke machine for creating a smoke trail behind my radio controlled electric plane. It is a simple design using things that I already had lying around my shop. The "smoke" is created by releasing talculm powder from a small container attached under the wing of my rc plane. To control the release rate of the powder & to prevent clogging, I added a wind-driven auger that keeps the outlet clog-free.
This is the first prototype and it has some limitations: 1. the container (a McCormicks spice container that held 0.7g of Ground Tyme) is very small so the smoke trail doesn't last very long before the container is emptied 2. I lose about 30% of the powder on take-off so I need to add a servo to keep the outlet closed until I get airborne