Model Aircraft Styled Air Engine, Experimental

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The first model aircraft compressed air powered engine design in my series, "Model Aircraft Styled Air Engine, Experimental," was a direct result of taking on the challenge to build a single cylinder compressed air engine using the fewest number of parts possible. The catch: all 100% 3D printed. This tiny engine tips the scales at just .8 ounces (25 grams) and requires only 8 carefully crafted 3D printed parts, one more than my "3D Printed 'Wobbler' Style Air Engine" design. No purchased parts were needed for this build, which also incorporates a rotary valve that's similar to what I used in my previous "Four Cylinder Air Engine, Experimental" design. The innovative aspect of this rotary valve lies in its design, inspired by Joseph S. Ott's work from 1933, where the propeller axle serves as both an axle and a valve. The valve timing is cleverly determined by the angular offset between the flat surfaces on the axle and the pin on the journal. An added bonus: this design provides a fairly decent exhaust system. Through the design process of this engine, I gained valuable knowledge that later influenced my subsequent model aircraft engine designs. Although this early version may not propel an aircraft, it's sure to spark interesting conversations around my workshop. Be prepared to put your 3D printer through its paces! To bring this engine to life, you'll need a 1/4" threaded compressor adapter and a reliable compressor. If you're not up for printing the propeller yourself, a 6 by 5.5 E propeller with a 6.2mm center hole will work just fine. As always, I'm human and prone to mistakes, so don't hesitate to reach out if you have any questions or need clarification on anything. After all, I probably forgot something along the way! This design was carefully crafted using Autodesk Fusion 360, sliced with Cura 3.0.4, and printed in PLA and PVA on both an Ultimaker 2+ Extended and an Ultimaker 3 Extended.