I plan to replace this design in time, it has a flaw in that the CoM is behind the overall centre of the airframe. While stable at lower airspeeds and altitudes, it has a tendency to flip during manoeuvres at higher altitudes and velocities.

Tinkering with the design is insufficient to fix the problem without a complete redesign, and frankly I like the aesthetic of this airframe too much to make any drastic adjustments. Reducing fuel capacity would make it stable in early stages of flight, but as the fuel level drops the issue would return.

Nevertheless it fulfilled my desire to create a high-altitude supersonic circumnavigation craft, and can get to anywhere on Kerbin for high-altitude mission contract requirements, and it looks rather nice while doing it.

Air-frame number decals are from the 'ID Flags and Decals' mod by TerraVexillar. https://www.curseforge.com/kerbal/ksp-mods/id-flags-and-decals/