PrintJet - the 3D printable pulsejet engine

thingiverse

These pieces would be printed and assembled using M3 screws, reducing the size to match five pounds of thrust. The parts would be oriented as shown in the disassembled snapshot, with no supports required. Two tailpipe pieces would attach securely to the combustion chamber via glue. Petal valves would bolt into place through the valve plate and into the intake cone using M3 screws self-tapped into holes. These components would then attach to the combustion chamber using M3 screws and a short rubber hose for clamping a small carburetor, such as one from a moped or other small engine, in place. It is recommended to print petal valves from semi-flexible materials like TPU or Ninjatek Cheetah or Armadillo filament due to their flexibility. To start the engine, with the carburetor ready for fuel flow, apply a vacuum cleaner to the tailpipe to draw air/fuel through. For ignition, use heated sewing pins pushed into the combustion chamber until they nearly touch and then connect wires from those to an electric grill ignition button. Note that there's a chance your vacuum cleaner may explode if it draws too much air/fuel mix in and any of it sees a spark from the vacuum motor. Always follow safety rules when playing with fire, keep an extinguisher ready, and most importantly, film whatever you do! This engine is expected to run for just a few seconds before melting apart at the tailpipe but if it can sustain its pulse jet combustion cycle for even a moment that would be considered successful. If printed using sparse fill from water-tight filament, it might be possible to increase engine life by pouring water in and letting it freeze so that it has an ice jacket inside of the printed engine parts.