The "Spirolize" feature in CURA, sometimes called 'vase' printing, is especially useful for printing an EDF duct.
As it prints continuously the result is remarkably strong and relatively quick as there is no 'travel' time.
A single wall duct for a 50 mm EDF Folland Gnat.
View attachment 171091
Printer bed limitations means it is built up from 4 pieces that exactly fit together allowing small but strong glue joints.
Unusually the EDF is right at the back but it does mean the entire inlet is 1.2 times the FSA. The duct is also smooth and the bends have a gentle radius.
In fact the duct is so rigid it was used as a 'spine' and the all Depron fuselage simply built around it.