How do you measure the force of a Stirling engine?

[ageattack]

I was wondering how the force of a Stirling engine was measured? I mean, for every degree Celsius that the temperatures differ. how much more force (or horse power) is the engine generating? Are there any other variables to this? What I'm getting is can Stirling engines power cars if enough heat is given? I've seen NASA's Mod II, but there isn't a whole lot of information.

 

[Simon Bridge]

Welcome to PF;
You would not normally measure the force since that will vary with time and depend on how the engine is driving the load.
You could measure the torque, or the energy, (and the efficiency) - you do this by getting it to move a load around.