Important note: It has been found that aluminium drinks cans need additional cooling around the top because the aluminium is so thermally conductive. Use steel cans if you can, such as Pepsi, Tango etc. Scraptopower has many other plans for simple Stirling engines, have a look here.
Thanks to David Williamson for the diaphragm design/ construction method. Check out his website here!
Materials1 Coke can
- Steel wire wool
- 1.6mm steel wire
- Spring paper clip
- Normal paper clip
- 0.4-0.6mm fishing line
- Super glue
- Thin cardboard from a cereal box
- A balloon
- 6.35mm electrical connector/spade connectors .
Step 2: Bend a paper clip
Step 3: The displacer
Step 4: The diaphragm
Step 5: Fit the diaphragm
Step 6: Cut the main bits of wire
Bend the wire around the top of the can and twist it to secure it.
Do the same on the other side.
Step 7: Make the base
Step 8: Cut the bearing supports to size.
Step 9: The cranks
About 5mm along from this, and rotated around by 90 degrees, start forming the two crank arms for the diaphragm.
The diaphragm cranks arms should be a short a stroke as possible, 2 - 4mm is good.
You should have about 80cm worth of wire left to form the flywheel. About 30mm from the diaphragm crank arm bend the wire in the opposite direction to the displacer crank arm. This is so you can counter balance the displacer it later on. Then about 12 cm along, start forming the circle for the flywheel.
Step 10: The displacer connecting rod
Step 11: Diaphragm connecting rods
Step 12: Assembly
Glue the ends of the diaphragm connecting rods to the cardboard discs using super glue. Keep an eye on the fishing line so it doesn't get glued down too!
Step 13: Tie on the displacer
Step 14: Secure the flywheel
It's finished now! All you have to do is light a candle under the coke can and let it heat up. Once it's hot, turn the flywheel to start the engine.