Hi everyone, I've just embarked on trying to figure out some of the math behind launching rockets. Forgive me if this is a novice question, but for some reason I've been staring at this for the last hour and am unable to see what is probably obvious: I'm trying to calculate specific impulse. In its simplest form, specific impulse is just Isp = thrust in newtons / fuel consumption in kg/s, from Kerbal's wiki on the matter. Yet I can't seem to get that to work using the info on the parts wiki. For example, the max thrust of the Thumper is 275 kN and the consumption at 1 atm is 22.63 kg/s...yet 275/22.63 is 12.15, or an Isp in seconds of 12.15 x 9.80 = 119.09s. The wiki says the Thumper has a 165s Isp at 1 atm. What am I missing here? Am I not suppose to use Max Thrust for FT? Is there some conversion I was suppose to make? Hmmmm... Thanks,
