More About the Stirling Steele:
    In the Stirling-Steele engine, four gamma type Stirlings are daisy chained together. This is done by driving the displacers via linear drive rods which are attached to the top of power pistons. The rods pass thru a sealed bulkhead and the displacer cylinders are ported to power piston cylinders that are phased behind them 90 degrees. This allows an engine that only requires one crank throw per piston where other types  of Stirlings require two. Fewer crankcase penetrations along with a simpler crank permit for a more cost effective engine to manufacture.

     Building four cylinder engines instead of single cylinder units has several strong advantages such as easy starting, good balance, smooth running even at very low speeds, increased heater and cooler surface area and good low end torque. 
    As an external combustion engine, the Stirling-Steele engine can easily meet the EPA standards for carbon monoxide and hydrocarbon emissions. Since it is a closed cycle device, it runs very quietly without the need of a muffler. 
Volume = 2.25 cu-in rpm=1000
Pressure = 40 psi Helium or 20 psi air T hot=~600 degrees C, Tcold=70 degrees C
Hot heat exchanger = unfinned shell Cold heat exchgr = 24 channels 0.0625 x 0.0625 x 0.625 in.
Regenerator = stainless steel cloth 0.625 x 8.75 in., 60 mesh Drive = Sinusoidal beveled gears
Power output = 40 Watts max (Helium) stirling steele website