pedter

I've had a look through the three old threads; there are lots of multi-stage submissions in the 26-28% range but the only SSTO submission that made the leaderboards is your own 21.19% D2/D1B SSTO from 1.2.2. The 2% up from 19.15% can very likely be wrestled back out of the vessel but I don't foresee any way for >25% SSTO.

Long time lurker, first time poster here with a Purist SSTO (rocket); to no one's surprising it is Mammoth-powered. Initial mass of 319,105kg and payload mass of 61,105kg for a payload fraction of 19.1489%. I suspect someone could improve aerodynamics and/or flight profile to improve the payload mass slightly but short of switching to a plane there's not much more that stock rocket motors can do. Mechjeb couldn't figure out the dv for a whole two staging events (and shows initial mass as including the two 100kg hold-downs) but KER gets the liftoff mass and dv correct. The 258t left behind is nothing but the Mammoth and three S3-14400 tanks (15t+81t+81t+81t); simple is good! Barely limped to 72x77km orbit so additional payload will be tight.