Thanks @Dark_Ansem! I don't remember getting inspiration from anything specific for this ship. That's not how the design process works for me. Instead, you usually start out with a brief that clarifies the topological relations of individual parts.
From this, I start to block it out with rough, simple forms. It's mostly about proportion and flow and gesture at this point. Also overlap to a degree. Once this is set, it just increases in complexity: forms and shapes are added, refined and made more expressive, elements are repeated, flow is supported and emphasized, but also deliberately broken.
Anyway, here's an update: The Armstrong got some teeth now: