This is the engine that was converted from an old special tilt piston air compressor. This is the exact same principal from a certain type of "Air Hogs" plane engine. In the opener the engine was running at 35-50 psi and the second start was around 75-80 psi. Top RPMS so far is 1700 at 110 PSI. The timing still needs some work. Solenoid Valves with a Reed Switch and a Magnet are great ways of testing air/steam engines to perfect the timing. A slide valve will eventually be needed as the solenoid valve is rated at 100,000 - 1,000,000 cycles. This engine would wear it out in a day.