Here’s how you can build a can stirling engine out of materials you can find in your home.
#1 – Prepare the materials
To build the most simple Can Stirling Engine you need:
- 10mm-thick wood board
- 10mm-thick balsa wood
- 1.5mm diameter wire
- a fishing thread
- balloon (very important)
- square lumber (5mm)
- two thumbtacks
- wood screws
- rubber bands
You’ll also need some tools to get this done:
- cutting pliers
- wood glue
- super glue
- (a drop of) machine oil
The Can Stirling Engine uses a wood frame, its crankshaft is made out of a wire, the cylinder from a can, and the diaphragm is that important rubber balloon. You’ll be using the fishing thread to connect the wood piston to the crankshaft.
Basic view of the Can Stirling Engine
#2 – Cutting the wood board appropriately
You have to make two side boards, two boards to fix the can, and a bottom one. All of them will be 10mm in thickness. The crank’s holes have to be a bit bigger to reduce friction with the wood.
#3 – Manufacturing the Can Stirling engine’s wood piston
After you fit the cut balsa pieces with glue, you can glue the fishing line to the center of the piston with SuperGlue. You have to take into account that the diameter of the can has to be matched with the one of the piston, so they fit into each other. You also have to provide a clearance of 2 or 3 mm.
#4 – Cutting the diaphragm
You’ll have to cut the (very important) balloon in two (just like in the figure) and reinforce it by sticking the cardboards to it. Then make a small hole in the middle of the cut piece and get the fishing thread through it. Warning, the hole has to fit the thread, not too big.
The Stirling Engine Diaphgram
#5 – Building the Crankshaft and connecting rods
Using the 5 mm square lumber, make the holes in the crankshaft a bit bigger (for less friction), put on the connecting rods and then bend the 1.5mm wire.
#6 – Fitting together the Crank mechanism and Diaphragm
Using two thumbtacks, attach the connecting rods and the diaphragm, just like in the picture below:
#7 – Building the frame
The crankshaft has to rotate inside the wooden frame with minimal friction, so please be aware of that when assembling them.
#8 – Construct a Wood Piston and Crank Mechanism
Remember that fishing thread you passed through the hole in the diaphragm? Now you have to link it to the crankshaft so it moves the piston along with it.
#9 – Setting up the can
The can is the actual cylinder of the can stirling engine, so cut off the top side of a can and fix the can to the wooden frame as well as you can. Then, put the diaphragm over it with some rubber bands. The length of the fishing thread has to be adjusted so that the piston doesn’t touch the can when moving. Put a drop of machine oil in the hole of the diaphragm.
And that’s it!
#10 – Operating the Can Stirling Engine
Like any Stirling engine, this one works with heat. Put a candle below the can and, when you consider it’s heated properly, rotate the crankshaft by hand.
Again, just like any other heat engine, the air has to be perfectly sealed inside and the parts have to move as freely as possible (with as little friction as possible). Otherwise, the engine won’t move, because its very fragile constitution and power source are only fit for experimentation (unlike a car that eats up more gasoline than normal when the bearings are used).
Note: the pictures above and the whole idea are not mine, I have to credit this site for them.