Building a stirling engine

https://www.youtube.com/watch?v=2JWbnpCKH1M

Here is a step by step instructional showing how i built a stirling engine. before starting let me emphasize the whole system must be as airtight as possible or it may not function.

Here are most of the main materials i used.:

• The displacer piston is Styrofoam cut out to just fit inside the cylinder which is a tuna can
• the power piston and cylinder are test tubes. One must fit perfectly in the other to function. as a substitute a semi loose balloon on a bottle cap would also work
• The metal rod that comes out of the displacer piston must fit perfectly inside of the part it will slide through. i used whatever i could find however brass tube from your local hobby shop tends to work well. The seal must be airtight

I now attached the piston rod to the displacer piston. The displacer piston itself should be a little more then half the length of its cylinder

I now attach the power piston's cylinder to the displacer cylinder with a brass tube

• I put the displacer piston inside the cylinder. 
• the can going over it has a hole where the connecting rod will stick out.
•  I also have a metal piece that has an airtight fit with the rod so no air will escape.
• After this all that's left is building the crankshaft with a clothes hanger.

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To finish off the top can is glued to the bottom one . Next the crankshaft and all the connecting pieces are built and attached . A counterweight is added to counter balance the weight of the pistons. a crank shaft is also added in the end