I like these steam engines. I like the Stirling ones even better though they are trickier. You don't need water in the Stirling engines. It is a closed loop. The are called external combustion engines and I have seen them powered by parabolic mirrors! There are 1000's of these on YouTube.
sign1Depends on the design. They do not scale up, which means every design is different, but I have seen some Stirling engines that really crank pot power, comparable to steam engines of the same class. The link below shows one of the finest machine jobs I have seen. The ration is reduced four times to slow the vehicle down. This is a very clean and precision machined example of a Stirling engine driving a car. There was a time in the U.S. before electricity when most homes had Stirling engine powered fans to cool the house down. It i s amazing that 10's of 1000's of these were made and they are now almost impossible to find! The fan shown nelow is a floor model circa 1910! It is beautiful, must be worth a fortune.