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This graph is different from those I have done in the past. It differs in that all types of engines are presented here (previously I left the SRBs out of the load tests since their propellant mass was limited when compared with a liquid propellant engine). Also previously, all engine load tests relied on an arbitrary 50/50 ratio of propellant mass to payload. This time I capped the liquid fueled engine propellant mass ratio to that of the SRBs; all engines having a starting TWR of about 1.2. However, to complicate things, the game does not impart the same propellant mass ratio to SRBs when launching with a TWR of 1.2. As you will see in the chart's 4th column, there is a range of propellant mass ratios, and some of these were derived. The Kickback and Thumper propellant mass ratios are about 39% of the total ship launch mass when the TWR is 1.2, however all the other SRBs have lower ratios when launched with the same TWR. My percentage for radial SRBs (Sepratron) is based on the use of 3 radials when testing these engines. You will also notice that I equated various size/ diameter liquid propellant engines with various size/ length SRBs. This is how I determined which propellant mass ratio to be alotted to each liquid propellant engine. I feel that this is justified, since in real life larger rocket engines are allotted more propellant than smaller ones. Also, since some "engines" are actually multiples of smaller engines, I equated the Twin Boar to two "small" engines (in terms of perceived diameter and bell nozzle size), the Mammoth as four small engines and the use of 3 radial Thuds as 3 small engines. Accordingly I adjusted the propellant mass ratio for these engines. Another change is how the air breathing mode engines were tested. This too is arbitrary, in that their launch mass and altitude allow them to achieve flame out, which is a measure of their operative range. The Juno and Wheezley altitudes are at their maximum loads but while the "flameout" sound effect did not play, the fact that these engines did not use all the jet fuel means that they became sufficiently oxygen starved. Unused fuel became part of the payload. For engines not exceeding an altitude of 150 meters (launch altitude in this case), the total mass is the approximate minimum mass of parts and propellant required for a particular engine to operate in space. You will notice that some engines are listed more than once, tested in various ways or modes. I hope to use this methodology when testing the stock engines in KSP version 1.1. Please comment suggestions or concerns or questions below. This is a work in progress and the intent of the graph was to compare the diverse set of KSP stock engines for practical applications, on a single graph. Below is the same graph without the Mammoth engine results, which gives us a somewhat zoomed in view. The averages for all are retained.