How to make a real homemade minijet engine. Part 2 (diffuser and combustion chamber)

Final assembly

We are continuing with the Maggie Muggs™ project, our homemade stratoreactor. This time we will explain how to build the diffuser of the mini jet, once we have the support to support the jet engine and then we will continue with the start up.

Diffuser and combustion chamber materials

Materials for the minijet

  • Strong metal glue (Nural type). Make sure the glue can withstand high temperatures.
  • Two aluminium jugs or shakers of the required shape (see picture).
  • Aluminium metal grating (as used in sinks and other drains).

Note: All measurements are detailed in the following image.

Click on the image to see it in detail

Procedure for constructing the diffuser and the combustion chamber

Now it's time to create the diffuser and combustion chamber of the minijetThe most important parts of the reactor. Of the two aluminium jars or shakers, we will first start working on the one on the left of the photo (the one with the more pronounced narrowing at the bottom).

  • We take the aluminium jug and proceed to cut it with a hacksaw. The cut must be precise, so we can leave the saw fixed, using a jack to help us to cut it. anchor it to our desk. The cutting blade must be at the right height, for this we can use tables to regulate the height of the jug. Once we are sure, we proceed to cut. You can also use an electric saw with a metal cutting blade to save effort.

Cutting the minijet

  • Now we will cut the lid of the butt of the jug to leave it open at both ends. The cutting procedure is the same as the previous one, only this time we can fix the metal jug instead of the saw. After freeing the desired part, we have to sand the edges of the cut to remove the burrs. To do this, we can use a metal file.


  • Now we move on to creating some details of the combustion chamber. To do this, the first thing to do is to remove all elements (if any) contained in the drain grate. Then with sandpaper we will roughen the outer edges of the drain grate and the inner edges of the jug that we have cut, it is only necessary at the end that has the larger diameter hole. Again we will make use of the Nural glueWe spread it around the edges of the grid and the jar we are going to glue. First smear it all over the top edge of the grid and mount the cut jug on top of it to glue it. Make sure that the pieces do not move during the drying period.

Diff_gluing_crop1 (Copy)

  • It is important that let's fill the gap between the narrower rim of the grid and the wider rim which is the one we have glued to the jug. To do this we can use a plastic mould or the other shaker to create a glue rim.


  • Now we move on to work on the other metal jug, getting rid of the plastic attachments and the top and bottom lids to leave it with two openings. If the bottom of the jug is metal, we will proceed to cut it to open an outlet. Once ready, we sand the edges as we did previously with the other part.

Shell_roughing_crop1 (Copy)

  • After all this work, we glue the jars together to form the body of the reactor. Just smear the edges with glue and glue the parts together. You can wipe off any excess glue with a napkin. Of course, before handling them, you should let them dry. After hardening, you can sand the joint to smooth out any imperfections.

Engine_gluing_crop1 (Copy)

  • Now it's time for the final assembly, where we will attach the reactor to the support we have created in the first part of the article. To do this we will use the same glue as before and mount the engine in its place, by securing it in position with a cable or clip until it is dry. Screwing the stand to a stable table or bench will facilitate further work and set-up.

Engine_to_mounts_crop1 (Copy)

  • We can secure all joints by giving them a glue coating. This will make the joints more attractive and strengthen them.

Engine_fillet_crop1 (Copy)

Now we have the most important part, the final result should look like the following image. In the next part we will explain how the most important parts are integrated, because without them, the engine would not work, we are talking about the valves through which the air and fuel are injected.

Final assembly

More information - How to make an authentic homemade minijet engine. Part 1 (support), How to make an authentic homemade minijet engine. Part 3 (completion and commissioning)

Source - Cottrill Cyclodyne

2 thoughts on “Cómo fabricar un auténtico motor minijet casero. Parte 2 (difusor y cámara de combustión)”

  1. Good afternoon, I ask you, what is the function of the metal grate in the combustion chamber?

    1. Hello,
      This is what they call the "flame holder" in the combustion chamber of stratoreactors. It is necessary for jet engines, and its function is basically to keep the flame inside the combustion chamber by generating air vortices at low velocity.

      Best regards and thanks for following us.

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