Stirling History

Robert Stirling was not the first to attempt an air engine, but he was the first to create a viable commercial product, and his engine design was put into use in 1818 to power a water pump at a quarry.

Supplies for Building a Coke Can Stirling Engine

Take away Stirling's regenerator and you have a hot air engine. How a hot air engine works is simple. Air becomes what is termed the "working fluid." A heat source, in the case of most soda can Stirling engines, this is a tea light candle, heats the air causing it to expand. The air is then cooled, causing it to contract. The expansion and contraction of the air, or working fluid, is a thermodynamic cycle. Now, use this thermodynamic cycle to move a piston and you have effectively allowed the thermodynamic cycle to produce useful mechanical work. When you attach a crankshaft to the piston, and add on a flywheel, you have the basics of an engine.

Get through building one Stirling engine and you'll learn more than a few lessons on home-brew engineering. Most of all, building one is a lot of fun, and gives you a chance to get creative with what most people consider junk. And seeing it work takes it to a whole new level.

Sound simple? It is, but there is still a while to go before the engine is built. You'll need more components, a few materials and an understanding of how they all fit together before your engine is chuffing away.

Here's what you'll need:

  • Three (3) soda cans
  • One (1) balloon
  • Two (2) spoke nipples
  • Four (4) 5A electrical terminal blocks
  • Steel wire wool
  • A bottle cap from a plastic bottle
  • Steel wire
  • Copper wire
  • Dowel rod
  • Electrical wire
  • Fishing wire
  • Three (3) compact discs
  • Can opener
  • Utility knife
  • Super glue [source: ScrapToPower.com]

Let's take a tour of the components you'll be constructing, see how they work, what they do, and how it all fits together.