I'll definitely take a look at that, thanks for the link! My end goal is to write a kos script to launch my vehicles into whatever orbit I want. I'm using MATLAB to solve the differential equations for the gravity turn. I pretty much have it figured out except drag, KSP seems to be all over the place. I have one very simple rocket for which drag force remains almost constant up to about Mach 0.2, spikes to a maximum value around Mach 1, then drops to an almost constant value for all faster speeds. A second, more complex rocket has a drag force that follows a more exponential model, so I'm a little lost haha.