Four Cylinder Air Engine, Experimental

A few months ago (February, 2017) I posted a normal and slow motion video of a four cylinder air engine on my YouTube channel (https://www.youtube.com/user/popzct0214/videos). After experimenting with the design, given its weight and air flow requirements, I put in on the shelf and decided not to publish it. Since then, I've had a number of requests for the STL files, so here they are. Remember, this engine is experimental. so be prepared for precision filing and fine adjustments if you decide