Great Stirling Engine Video

There's some interesting videos there & some good engineering.

yes the workman ship is beutifull. its a shame about the relativley poor power output.

im no expert on any type of engine, but i think the general rule on stirlin engines is the less 'dead' air the greater the efficiancy, where this desighn seems to have a large crank-case with lots Dead air.

would i be wrong in sayin he could up the efficiancy by filling as much of this as posiable, ie running a slim crankcase, with full circle cranks (ballanced on the outside) ?

thanks in advance

Mike R