15ccm Compressed Air Engine

thingiverse

UPDATE: I added a new version of the tappet, V2, which sits tighter into the cylinder and causes less blowby, making it more efficient even at lower air pressure. This engine is inspired by Tom Stanton's Compressed Air Engine, but with some key changes. Tom's engine has about 2.7ccm capacity, while mine has about 15mm. It produces way more torque at higher pressures, and I've tested it up to 16 bar (232psi). However, it's less efficient at lower pressures, around 0.2 bar or 3 psi. I didn't like Tom's solution of gluing the cylinder head to the crankcase, so in my version they're screwed together with 4 M3x10 screws, just like the cylinder head itself. It needs a heavy flywheel to run smoothly; I use a 160mm rotor from a bicycle. You can make your own or take a look at the photos for dimensions. BUILD The building procedure is similar to Tom's engine; check out his video below. For the valve, I don't use a rubber seal and BB pellet like Tom does. Instead, I found a 6mm rubber ball that works just as well (link below). Make sure the bearing is tight inside the crankcase by tapping it gently with a small hammer. I also changed the pressfit air connector to a simpler design using an AV valve from a bicycle tube. You can get one for free at your local bike shop. The head gasket is made from a bicycle tube as well. All parts are printed with a 0.6mm nozzle. You'll need: * Bearing dimensions: 16x31x10mm * 8 M3x10 allen screws for cylinder and cylinder head * 2 M3x15 piston and connecting rod * 2 M3x20 for flywheel and tappet; sand down the head of the tappet-screw (picture) * Rubber ball 6mm diameter, available at most bike shops Links: * Tom's Video: https://www.youtube.com/watch?v=YLPY8CY5Fm4&t=730s * Rubber ball: https://bicycles.de/p/sks-ventilset-fuer-vx-kompressor/8146706/?gclid=CjwKCAiAo7HwBRBKEiwAvC_Q8RU4yS8geeQgu-MLbJCzaCxkI-chVI87wnEUfQEUJ0OsL8bXnklP8hoCiMkQAvD_BwE EDIT Sorry for the mess with the pictures when you downloaded them. I don't know what's going on with Thingiverse... You can download them here: https://www.dropbox.com/sh/l131ctee5q5t9vj/AABXvaJrRZYtSF09hHnYk1DGa?dl=0 Last but not least, if you'd like to support me, check out my YouTube channel. It's not related to DIY stuff; I post cool mountain bike videos instead! https://www.youtube.com/channel/UCpvRg6Igsevopo50N8gS-Fw