The spreadsheet is acting up on me, it's giving the "#name" for the flight characteristics, gearbox cost, powerplant cost, and engine cost, I've filled in all categories and have values for static thrust, required power, and all propeller derivatives. Am I missing something?
Edit, never mind user error I guess, downloaded on my phone and it's working fine.
Another edit. Question, So would it be reasonable to say that powerplant cost should fall between 10-20% of the stated airframe cost?