An aircraft's fuselage in fact it is a collection of truncated cones. 

As long as they are symmetrical it's a rather simple mathematical computation, but once the cone gets a bit inclined you're in trouble. Based on the idea that a bunch of very small chords approximates a circle I 'handed over' the far right picture  to my good-old friend QB64 . . . 

The programme has been zipped and enclosed in a thread on PaperModelers.