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Nitrous Liquid Pressure Fed Engine Control Script

​This is a script for controlling the engine pipes of a Liquid Pressure Fed rocket engine that uses Liquid Nitrous and Liquid Volatiles as fuel. The script attempt to keep the fuel ratio in the pipe at the right molar ratio so that optimal thrust is achieved. This is a separate script from the liquid oxygen version and will not work with that.

Pin Setups:
d0 - Pressure Fed Liquid Engine
d1 - Pipe Analyzer
d2 - Volatiles Volume Pump
d3 - Nitrous Volume Pump
d4 - Purge Valve

Rocket Setup:
Build the rest of the rocket as you'd like. Ideally load this program onto a chip and put in a rocket IC housing with the above pins. The purge valve is not optional for this type of fuel for the rocket. Liquid Volatiles is too cold and will freeze Nitrous Oxide if it is not heated up. The script will use the engine's heat exchange port to keep the fuel pipe at approximately 0 Celcius so that the liquid nitrous will not freeze. This in turn will cause any liquid volatiles that get pumped into the pipe to immediately evaporate. The purge valve is there to catch these volatiles so that they can be vented out of the rocket in a gas pipe network with a broken pipe, stored to be offloaded when docked, or pushed into your liquid volatile fuel tank.

How this script works is that it will inject a small amount of fuel into the pipe to begin prefiring the engine. The engine has to ramp up to speed and will read the rocket's PassedMoles parameter to ramp up how much liquid nitrous and liquid volatiles it will pump into the engine pipe. It has been tuned to make sure not a lot of liquids stay pooled in the engine pipe, but it can be adjusted if necessary. After about a minute, the engine will stabilize at approximately 5.9MPA (with the purge valve) and get over 50kN of thrust and more once the fuel ratio of N2O and Volatiles equalizes.