Custom airframe for solar blimp

I’m trying to create a custom airframe for an autonomous solar blimp as part of a research project. Any suggestions on how I can do so?

Have you looked at the documentation page https://dev.px4.io/en/airframes/adding_a_new_frame.html

I am curious to know your progress for custom airframe. FYI this man is working on same project but guess using different auto pilot hardware than px4 : http://scottlobdell.me/2017/03/successful-rc-blimp-autopilot-flight-test/