air-butane "rocket engine"

[shadow seal]

Printed outer shell and manifold, refractory mortar inner liner and injector plate, designed with NX and RPA.

[mild dawn]

That's friggin cool as hell

[marble plume]

Yeah I’m going to need way more info on this! What’s it printed in?

[shadow seal]

yeah so its printed in petg mostly! the outer shell you can see in the video has a refractory liner cast into it with an inner mould out of tpu.

[shadow seal]

I had to calculate the butane's mass flowrate with a little jig I made with a 1l bottle of water that empties through a small hole because of the pressure from the butane, then measuring the time it takes and the average pressure during that time.
By plugging the pressure and ambient temperature into the ideal gas law i can find it's density, using how long it takes to fill 1l with a certain density of gas i can get the exact mass-flowrate for my butane bottle.

this is the inside of the combustion chamber

this is the setup for making the moulded part

but yeah it was loads of fun!

[lucid brook]

damn nice

How thick is the liner?

Figured it out by looking at the picture

[shadow seal]

this is it running with a way smaller compressor at home, unfortunately I had to go to my grandma's to use a proper compressor and test with the full flow, and even then I .could only do one small run (the video i posted at the top of the thread)

[plush cairn]

What pressures do you get?