Jager798

Thanks guys for the help. Seems like it was the CoT that was slightly lower than the CoM as you suggested. I have adjusted the engine layout so the CoT is now inline with the CoM and will see if it works later when I have time. Thanks for your help as I am kinda new to SSTOs.

I created an SSTO which works fine in Kerbin atmosphere, has plenty of fuel to get into orbit, however, when trying to circularise the orbit and using the nuclear engines in orbit, the SSTO keeps on pitching up, even when all control surfaces are turned off. Any help please? The SSTO has a mass of 56.3k kg, 4900 units of liquid fuel and 880 units of oxidiser, with 4 rapier engines and 2 nuclear.