restarting my falcon 9 project

i've decided rather than giving up on it i would reboot it, it was not as good as i thought and i couldn't fix it how i wanted to -so i'm starting from scratch, my main PC is still broken but this one will have to do, i'm also busy with school a lot so updates will be few and far between, i also have a question, when you edit the size of tanks 1 unit in the in game editor is equivalent to what irl? thank you!