I have a pretty broad question. I, with several others, am working on some stirling engines for a science fair of sorts. I have done enough research to understand the concept of how they work. I also understand that there are several different types; single cylinder, double cylinder etc. What I am wondering is if anyone knows some general equations. For instance, if I have a copper tube of a certain diameter being heated by a flame of a given heat, How tall should my cylinder be? I have not been able to find any types of equations involving the stirling engine. Any help would be appreciated.