People only see all jets as just jets. But away from that, there are many types of jet engines. This is based on how they work. You often hear about, turbojets, ramjets, and scramjets. Another type that is not known a lot is the pulsejet.

These types of jets are not the best when it comes to performance. However, they are straightforward to make. Another kind of pulsejet was inadvertently discovered by a juvenile Swiss boy having fun with alcohol. This was in the early 1900s. This is due to their simplicity, they have been built by various individuals. This comprises rocket engineer Robert Goddard, who fixed one to a bike.
Tesla, the inventor not the vehicle, discovered many things. Some of the things include a one-way valve design without moving pieces. Pulsejet expels exhaust and takes in air through the same opening. Therefore the best ones utilize a one-way pipe.
Tesla’s is unusual since it’s nothing more than a molded channel. It has a low impedance to move in a single direction and great resistance in the other way. The method is in a teardrop form that is light on the channel side and thick on the exit part. It is not excellent, but it does offer a basic and automatically good single way performance.
The biggest issue with a 3D printed engine is that the motor becomes hot and plastics usually melt. But if you get one that uses PVA casting with plaster it works well. While the PETg or nylon worked well, there are other good options for heat resistance.
For Goddard, it took him several iterations, but he eventually got some pretty impressive outcomes. While it is not clear if you would want to utilize a 3D printed pulsejet in a real task, but checking out a model like this helps to know the guidelines.