Printing a model jet engine is quite an accomplishment. But it wasn’t enough for [linus3d]. He wanted to redesign it to have a turbojet, an afterburner, and a variable exhaust nozzle. You can see how it all goes together in the video below.

This took months of work and it shows. This probably won’t make a good rainy-day weekend project. You do need a few ball bearings and some M2 hardware, but it is mostly 3D printed.

True turbojets are most often found on military planes. They are loud, don’t perform well at low speeds, and are generally not very efficient. A variation, the turbofan, is what you usually find on passenger jets. They are quieter and work better at low speeds, but have more parts and, thus, more maintenance.

Unlike a true turbojet, turbofan engines have a cold section and a hot section. The bypass ratio refers to how much air flows through the cold path relative to the amount flowing through the hot path. This cold air provides additional thrust, making the turbofan engine more efficient, especially at lower speeds. The reduced demand on the hot air thrust also reduces the amount of noise.

Plastic isn’t going to cut it for a real jet engine, although you can 3D print some parts of one. Bonus hacker cred if you build your jet engine by hand.

An EDF (electric duct fan) is a motor that basically functions as a jet engine for RC aircraft. They’re built for speed, but to improve maneuverability (and because it’s super cool) [johnbecker31] designed a 3D-printable method of adjusting the EDF’s thrust on demand.

The folks at Flite Test released a video in which they built [john]’s design into a squat tester jet that adjusts thrust in sync with the aircraft’s control surfaces, as you can see in the header image above. Speaking of control surfaces, you may notice that test aircraft lacks a rudder. That function is taken over by changing the EDF’s thrust, although it still has ailerons that move in sync with the thrust system.

EDF-powered aircraft weren’t really feasible in the RC scene until modern brushless electric motors combined with the power density of lithium-ion cells changed all that. And with electronics driving so much, and technology like 3D printers making one-off hardware accessible to all, the RC scene continues to be fertile ground for all sorts of fascinating experimentation. Whether it’s slapping an afterburner on an EDF or putting an actual micro jet engine on an RC car.