Test · 2023-07-15
Self-starting and restart behavior
The question
Will the engine start on its own when heated, and restart after cooling?
The answer
Yes with a lighter magnet. A 25 × 5 mm magnet was too heavy to self-start; a 20 × 2 mm magnet started unaided and restarted faster after cooling.
- Kind
- Test
- Status
- Built
- Date
- 2023-07-15
- Heavy magnet
- 25 × 5 mm (no self-start)
- Light magnet
- 20 × 2 mm (self-starts)
Video
What it is
Viewer question: does it start by itself? Tested by swapping magnet size and cycling heat.
Results
- →Larger magnet means more output but blocks self-start.
- →Restarts are quicker because the excess air already left through the one-way valve on the first run.
- →On cool-down the internal vacuum pulls the diaphragm visibly inward.
Lab notes
Implication
With the air charge already set, the engine could run unattended under a solar Fresnel lens, starting when the sun heats it and stopping when it doesn't.
Notes transcribed from the build video.
Related
Does the design still work scaled to 3 feet?Yes. It runs at 3 ft, and it's the channel's most-watched build.See more →Does less air make the engine run faster?Yes. Venting the excess lets the small air volume oscillate faster.See more →Can the clamp itself be the heat sink?In simulation, yes. About 2× the heat rejection in still air. Not yet built.See more →
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