Barrel engine with opposed pistons with the inclined sliding point in the center, as seen with the components in the hands of its designer Alvin R. Earnshaw of California.

“Barrel engine system"

-The engine has 8 cylinders with double pistons, and rigid connecting rods. It works with the two-stroke cycle, and supercharging with compressed air under each piston.

-It gave 90 HP at 3,000 rpm. weighing only 78 pounds without the propeller, support nor tank.

“Complete Stimson engine"