how to find general efficiency?

[fullofhotair]

Is there a simple formula to get a general idea of how efficient a little tin can stirling is? Amount of alcohol burned and how much work down or something. What do you have to know and what do you need to record? Would winding a long string with a set weight work?

[Ian S C]

More or less you want to measure the torque which is what the weight on a string idea is, and you then need the revs its working at, that gives the power out put, in watts or horse power, depending on the units of measurement. I'm not too sure how one finds the in put energy, but even a candle is in hundreds of watts.
Ian S C