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Yet another thing you will notice is the placement of the igniter hole. It was quite difficult (if not impossible) to fit O-rings and screws along the faceplate surface to prevent leakage from the igniter exhaust and nitrous. It was discovered that a better way to do this was to extend the faceplate and oxidizer annulus upwards and have the O-rings be radial seals and bolts be radial bolts.
That's pretty much the design – there are many seals because it's important that fuel, oxidizer, and igniter exhaust do NOT mix prior to combustion. There are also O-rings on the bottom of the face plate that prevent combustion gases from leaking through the mating surface between the phenolic and injector; by the way, the outer sides of the injector sit on top of the combustion chamber, but the injector is secured to the chamber by radial bolts (shown in cross section 2 (ADD THIS)). Lastly, the injector face was filleted to prevent stress concentrations.
We created a Jupyter Notebook to calculate parameters for the injector.
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