B9 HX was king of megaship parts packs back in its day but times have changed. There are so many fancy fuels to mess with now, HX is out of style and no longer "stockalike" at all, and the kerbal universe has grown far, far wider than Eeloo's orbit. The performance ratings of its one mighty engine mean nothing to today's megaship junkies. B9 Aerospace (HX and the plane parts), alongside OPT Spaceplane, were the first two part mods I met and quickly grew to adore. Eventually, in essence, this nee