This is a reasonably accurate model of the Saturn I-B rocket used to launch low-earth-orbit Apollo missions (Apollo 5 (LM test), Apollo 7, Skylab 2,3, and 4, and ASTP).
Some liberties were taken in various places to allow for spiral printing (apart from the base).
The photos show three printed models done during scad development sitting next to a commercial injection-molded saturn 1b rocket model for comparison (which I started assembly on when I was about 12 years old...).
To spiral print this chose a location to split the model and print both halves. The example in the photos was split just above the S-1B stage. The S-IVB and apollo section was printed right-side-up. The S-1B was printed upside-down. Sadly Cura will not close the top of a spiral print, so the engines won't print using this approach. You'll have to print them separately if you want them.