There is a walking beam Stirling engine kit available on ebay to build a similar engine, have a look here
Step 1: Cut Out and Assemble the Cardboard Base and Bricks.
I hot melt glued all of the cardboard parts. It should be easy to figure out where the parts go because they are all matching. Stone for the base, bricks for the tower.
Step 2: Glue the Beam Together
Step 3: The Displacer Cylinder
Epoxy the bottle lid to the can so that the two holes line up. The epoxy will want to run all over the can so keep rotating it in all directions until it sets up. When its dry, you can remove the other coke can, it will be used later.
Step 4: Displacer
You'll need a hook to so that you have something to tie the fishing line onto. I used a bit of copper wire, but a paper clip will be fine. The exact shape is not too important so long as it grips the wire wool. This hook is threaded through the centre of the displacer.
Step 5: The Diaphragm
Cut the neck off the balloon so that you can push the M4 bolt through. Fit an M4 penny washer to the bolt. I stretch the balloon tight over the bolt and poke it with a knife, this is usually enough to puncture the balloon. Stretch the balloon taught over the penny washer and add the another washer and an M4 nut. Tighten it up!
The balloon is pulled loosely over the bottle cap. Secure it with an elastic band. You can screw the bottle back into the bottle cap now. Hold the bottle cap not the can when you do this. Make sure it's tight because you don't want any air leaks here.
Step 6: Cranks and Bearings.
The cranks are very simple a single arm bent out about 6mm and about 30mm long. Make the cranks long enough to span the distance between the cardboard brick sections plus about an inch either side.
I tried this engine without steel bearings and it worked absolutely fine without them. I didn't think that it will last very long with cardboard bearings though, so I made some simple metal ones out of the scraps from the cans. They are about 40mm square pieces of the cans. I pierced a hole in them with a pin and then widened it using the 1.6mm wire.
I made large holes at the bearing markings using a ball point pen and glued the bearing plates to the brickwork
Step 7: Fit the Beam
The displacer connecting rod rests on one of the40mm pieces of wire you cut earlier with a straw spacer. Thread this through the bearing hole farthest from the centre of the beam.
The beam is off centre. It has a straw spacer either side. The space at the back is approximately 35mm and the one at the front about 20mm. The 100mm piece of wire supports the beam, it should be loose and move freely.
Step 8: Balancing
Untie the displacer when it's balanced.
Step 9: The Cap for the Displacer Cylinder.
With the displacer wire hole O.K, cut the can down to about 30mm tall from the base. I epoxied a bottle cap in the centre of the can, the cap has an 6mm hole drilled in it to allow the fishing line to pass through. This allow you to put cold water in the top of the engine, without it getting into the displacer cylinder through the displacer wire hole.
Step 10: The Fire Tin
Push the top part of the can into the fire tin. This creates a flat surface for the candle to sit on. The fire tin is just pushed onto the base of the displacer cylinder. I taped around the fire tin and around the top of the displacer cylinder just to be sure that there were no air leaks.
You can epoxy the displacer cylinder in place onto the cardboard base. The diaphragm should point towards the crankshaft.
Step 11: Connecting Rods and Spacers
But before you can connect it to the cranks you must make the diaphragm connecting rod. The diaphragm connector is made in the same way as the displacer connector, a zig zag with a hook at one end for the M4 bolt and hoop at the other end to connect it to the long rod that connects the beam to the cranks.
I made small stops out of a straw to prevent the diaphragm connecting rod from sliding down the beam connecting rod.
Thread the cranks into the bearing holes.
With the diaphragm connecting rod attached to the beam connecting rod, you can form the other hoop to connect the beam rod to the cranks.
It should be finished now!