I'm just starting out and so completed the Basic Construction and Basic Flight Training. I thought though before going on I'd replicate the rocket in Sandbox mode and try to vary some parameters and get a feel for the differences they make. But when I replicated the rocket (using the MK1 Command Module, MK16 Parachute and RT-5 Flea engine, checking that all the parameters were the same as in the Basic Flight Training) I found the rocket I built with the sandbox climbed to an altitude of 22,850 meters whereas the one in the Basic Flight Training only climbed to 14,226 metres!! Interestingly the thrust and duration of the engine were identical between the two so I have no idea why one would go higher than the other. I'm now struggling to continue without understanding what's going on here!
Can anyone give me any pointers?