Another attempt at it, keep trying to lower drag and mass while keeping the current engine lay-out. Resulted in an 1800.4 m/s flight with an stock unmodded craft. 3 Turbojets and altough take off is rather difficult, once it reaches hight it is a rather nice plane to fly really. Rocket versions is even faster I think, but burns fuel very fast... So I'll need a carrier for that plane, let's build that now then