Designation	Sirius
Bore	1 inch
Stroke	1 inch
Configuration	Vertical twin cylinder, single acting
Height	6 inches
Length	5 inches
Extra equipment	Drain cocks Displacement lubricator
Notes	Designed in the 1930s for generating and pumping. The engine has a fully-enclosed cast-iron crankcase containing a steel 180 degree throw crankshaft. Light cast iron pistons with stainless steel piston valve. Stuart claimed 0.4 bhp at 2800 rpm on 80 psi superheated steam. This engine was used during the war in the Alco Firefly generating set where it was run at 30 psi for radio battery charging duties. After the war it enjoyed much success in flash steam hydroplane racing.