Liquid rocket engine

Liquid rocket engine:

Under Construction

Fuel: gasoline

Oxidizer: gaseous oxygen @ ??? psi

Injectors: dirt bike jet for gasoline, four 1/8" convergent injectors for oxygen, intended to make a gasoline-oxygen mist

Nozzle: mild steel (maybe liquid cooled?)

Chamber: approx 3.5" diameter

Thrust: not yet tested

Injectors: The gasoline and oxygen come into contact about 1/4" from the gasoline jet. The oxygen injectors are drilled at a 45 degree angle, facing towards the center of the plate.

This is a picture of drilling one of the oxygen injectors. When you try to drill at a 45 degree angle, the bit just bends, so I had to make a small piece which holds the bit 45 degrees in respect to the plate.

Construction of the nozzle:

Marking where to cut

A plasma cutter is used to cut along the lines.

This is what it looks like after it has been cut, but before it has been bent.

This is what it looks like after it has been bent

This is after it has been welded together

The "flange" at the top was made in an unconventional manner. Blocks with holes drilled in them were individually welded to the chamber. It is very difficult to align them properly, so they deviate by about 1/20". Two of them deviated by 1/20" adds up to 1/10", so the top only aligns one way (this is very irritating). The gaps were welded in, and the weld beads were ground off. A gasket will be used to seal the chamber to the top plate (which houses the injectors).

This is the engine with the fuel tank (black tank), and the oxygen hoses connected. The fuel tank is positioned vertically, and the fuel is pressurized by some sort of gas (I have used the fuel tank for other purposes, and compressed air works just fine). A ball valve is used just below the fuel tank to shut off the flow of fuel. A spring loaded check valve is used so nothing can get back into the fuel tank. A 1/2" female connector is welded to the top of the injector plate for the fuel to flow. Four 1/4" male connectors are welded to the top of the injector plate for the oxygen injectors. I have not yet decided how to open the valves. Also, I have not decided what pressure to run the oxygen/fuel lines at. I may have to replace the oxygen hoses with ones rated at a higher pressure to give the proper oxygen/fuel mixture.