u/Tiny-Desk_Engineer

The engine itself can fit in just a space of 9x3 and height of 4 blocks only. (if you don't count the trapdoors that surround the water source because they are only for demonstration, a wall will do the same). also the lava tank is also excluded.

I mainly designed this for use as a reciprocating steam engine for an ocean liner i'm working on

Schematic: https://createmod.com/schematics/steam-powered-airliner-survival-friendly-has-interior

I initially used 3 steam engines but it made the plane very underpowered, so now there's 4. The plane can be refueled from top trapdoors that are right above the lava tanks. each "jet engine" produces about 30KpN of thrust, yes i know the engines are wooden lol. The plane has interior, though i didn't consider a lavatory so far.

SKIP TO 2:13 FOR FLIGHT.
Will likely publish the schematic someday

EDIT: forgot to show the water pump part of the plane but its behind the engine boiler in a very tight space between the elevators:

Image showing the pump unit: www.photopea.com/g/kzEumub6

yes ik the takeoff was very cursed but it made me realize that this thing can takeoff vertically lool.