A hand-built jet engine—can you believe it? Holy cow, the results are insane! Let’s get started. The materials are simple: recycled soda cans costing just a few cents each (you can even use your own), and the tools are all common household items. First, mark a guideline two to three centimeters from the bottom of the can to facilitate cutting later. Cut open the top as well, measure the inner diameter with a caliper, then use a basic school compass to lay out the blades and begin cutting. Remember, blade cutting must be precise with standard tolerances to ensure efficient air compression. Make a few extra blades as spares. Next, salvage some scrap aluminum plate to fabricate the bearing bracket, ensuring coaxial alignment with the blades. Fabricate the other components one by one and set them aside for later use. Use a compass to draw two circles on the aluminum plate, sketch a few straight lines to cut out four corners, mark the points, and drill holes. Find an aluminum tube, press the circular disk into it using a vise, align the holes properly, install the propeller, and tighten the screws as much as possible. Once assembled, the cylinder fits perfectly over it; mark and drill the holes, then secure with bolts. At this point, the main body of the engine is complete. Take four copper tubes. Trim plastic tubing neatly with pliers, insert wires, and connect to the homemade ignition device. Three, two, one—ignite for testing. It’s a huge success! Now proceed with installation: place the propeller, tighten the screws, insert it into the engine housing, give it a few spins—not bad, quite smooth. Install the remaining propellers; due to limited resources, secure them temporarily with glue. To approach sonic speeds as closely as possible, add a conical fairing. Cut slots in the soda can, place the engine inside—it’s a perfect fit. Connect the fuel supply and prepare for startup. Not bad at all—the advantage is mine. Building a larger version should definitely work.