This Otto-Langen atmospheric engine was built by Ramon Hoagland, of Colorado, circa 2000. The engine was built at 1/7 scale and measures about 11” in diameter by 24”-high. It is a model of the world’s first production combustion engine. The piston starts at the bottom of the cylinder. Rather than compressing the fuel/air mixture the Otto engine simply raises the piston slightly to draw in the fuel air mixture. Then a slide-valve closes off the intake port and ignites the flammable mixture forcing the piston to the top of the cylinder. The piston, which is connected to a one-way clutch and rack gear, is pulled down by gravity causing the flywheel and pulley to rotate.