Fuel Priority for Engines

[Corona688]

My suggestion:  Give engines a configurable, minimum fuel priority.  When available tanks above that priority run out, an engine will stop drawing fuel.  You could call fuel priority "Pressure" , with the intuitive principle that a high-pressure tank is needed to drive a high-pressure engine.

This is simple to understand, backwards-compatible, and fixes everything.  Ugly fuel pipe hacks will no longer be useful for anything but piping fuel.  Engines can be told exactly what tanks to use by priority and and crossfeed alone.

An example rocket where this feature would be helpful, my twisted-candle heavy lifter:

Fuel crossfeed is enabled in all decouplers, and all engines fire simultaneously, burning the bottom tanks first.  Stages are discarded from the bottom up in order until orbit is reached.  Tank levels must be watched, because stages won't expire once they run dry.  Yes, I could fix that with an ugly fuel pipe hack, but that would be an ugly fuel pipe hack.

 

Edited May 2, 2018 by Corona688

[qzgy]

Didn't quite get what you meant at first, but I like this!

Yeah it does make sense and could be very useful