3D Air Engine with Rotating Valve

     This is a piston air engine with only 3 moving parts that I designed after several iterations. The engine uses a rotating valve that is actually part of the crankshaft, which simplifies the design significantly.

When printing this engine, there are several important specifications to follow. The two flywheels should be printed at 35% infill so they will weigh just under 1 ounce. These flywheels also serve to hold the crankshaft in the proper position. You may need glue to secure one of the flywheels and to secure the piston rod and its retainer. The crankshaft should be printed with supports, and you may need to sand down any raised bumps where the supports were attached after removing them. The block and crank case are also printed with supports, so it is important to ensure all supports are completely removed from the air channels. These components can be printed at 10% infill so that they use very little filament. PLA is fine for printing this air engine.

     The technical specifications are as follows: the crankshaft radius is 10 mm, which determines how far the piston travels up and down, and the piston is 18 mm in diameter. After assembly, be sure the engine spins freely—it should spin a few complete turns when you spin it with your fingers.

To see it working, you may watch:

https://youtube.com/shorts/zDQa5AioSVg