This is not finnished because it won't work. You could make it work though according to rajat1sharma by making a bigger multistage compressor, or mabey with a big centrifugal compressor. Sorry to anyone who started building this, you will have to do your own problem solving if you want it to run.
The concept of a jet engine is basically a rocket that uses air as the oxidizer instead of something that's already stored on board. There are many types of jet engines, but I will focus on turbojets. The purpose of a turbojet is to push a lot of air out the back of itself at high speed to provide forward thrust. It does this by combining the air with a fuel like propane or kerosene in a combustion chamber and igniting it to cause it to expand and rush out the rear of the engine. The heated, high pressure gasses flowing out spin a turbine at the back of the engine which provides the power for the compressor. The compressor is a fan at the front of the engine that forces air into the combustion chamber to be mixed with fuel.
This instructable will show you how to build a small turbojet from scratch. This design could be scaled up to be used on anything once you have practiced with a small one.
Step 1: Gather Materials
-Stainless steel water bottle, the mouth should be narrower than the main part.
-Steel tube that fits snugly in mouth of water bottle (1 3/4" diameter on mine). Make sure it has no weld line or a flat weld line on the inside.
- ~ 1/32" thick stainless steel pan or tray.
-1/2" diameter steel rod.
-1/16" steel wire and 1/32" steel wire.
-Bearings that fit over the rod and can handle high RPMs and heat.
-1/2" diameter bolt (x 3) with fitting nut (x 3).
-Spark plug with short threads ( x 3) with fitting nut (x 3) and washers (x 3). 9/16" with 18 threads per inch works for the nut.
-Propane cylinder and valve.
-Small diameter copper or steel tube for fuel line.
-Electric motor for starter (optional).
-Battery and switch for the motor.
-Note: If possible, use stainless steel in place of regular carbon steel on every steel part. I used mild steel on some parts because it is easier to get and cheaper. Do not use any aluminum, plastic, or glue, only use steel.
-Angle grinder or other metal cutting saw.
-Grinding wheel (or a hand file).
-Lathe, helpful but not absolutely necessary.
-Dremmel tool or other small cutter/grinder. Optional but very helpful.