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Hello all, I am posting this here, because I have noticed some odd behaviour in conjunction with engines using liquid hydrogen (LH2), such as from the Cryo Engines pack by @Nertea or from BDB by @CobaltWolf. I am not posting the relevant threads, as I believe this is not a bug of these specific mods but rather something underlying, which makes these engines work. The issue is that with any LH2 engine, that I have used so far, the dV calculation within the game seems incorrect. This becomes apparent, when using a mod such as MechJeb and/or KER, which calculate the dV per stage and for the whole ship. Following please find some screenshots to illustrate what I am referring to: In the first screenshot, I am at the beginning of executing a manouver node of ~350m/s, I have 3,770m/s left in my rocket. You would expect that after the burn, you'd be left with ~3,418m/s. Instead, you end up with roughly twice the dV expended, with only 3,114m/s left in your rocket. FWIW, I installed KER as well, to see if the error can be traced back to some error with MechJeb, but this does not seem to be the case, as the remaining dV is calculated almost to the same value (#floatingpointerror) in both mods. Now, I do believe there is only one way to calculate the dV of a rocket, hence the error must be somewhere else?! I heard that others, @RocketPCGaming specifically, wondered about this inconsistency as well. As I have currently no idea, what might be causing this, I would like to stick some heads together to try and find the cause for this. As a start I would like to ask others, whether or not they have seen the same kind of behaviour and if so, was/is it similar to what I have seen (roughly twice the dV expended than anticipated) or was it a different kind of inconsistency? Your feedback will be very welcome!