We wonder if mechanics are as annoyed when we say “engine” as we get when someone talks about a “computer” or a “radio.” Sure, you know what all three of those words mean, but there are many different kinds of radios, computers, and engines. In [3DprintedLife’s] case, he made a compressed air engine of the Wankel style.
The Wankel — a rotary engine — is most famous for its use in some Mazda cars. If you’ve done a lot of 3D printing, you know that creating an air-tight piston on a 3D printer is no mean feat. Of course, he didn’t do it right off the bat. It took what looks like a number of iterations to get it going, and he shares some of what he learned doing this project.
The engine isn’t particularly efficient and you can see it spins for a while and stops, but it is a great demo, especially when he replaces the 3D printed cover with a clear plastic one. Getting the tight tolerances you need can be a real challenge. One thing that helped was printing on a raft so that the bottom of the parts were flat instead of matching the slight tilts in the printing bed.
We were impressed with the two-part design and the 3D printed springs and valves. Even if you don’t want to build a Wankel, you can pick up some tips on creating mechanical parts with filament 3D printers.