This my interpretation of the Helmet worn by the Black Knight in the film Monty Python and the Holy Grail.
The helmet has been designed as a Halloween costume for myself. The dimensions of this model are:
Inside Helmet Diameter : ~22cm
Inside Hemet Height : ~ 32cm
MidPoint of Eye Slot: ~ 22 cm
It should be entirely possible to scale this helmet for your dimensions.
I have included several models.
Set 1 (2 Parts): Hemet_Top.stl and Helmet_Main.stl, should you feel brave and want to print this in its entirety or scale and section manually.
Set 2 (Sectioned): Which is the model set that I printed and consists of seven parts (top to bottom order).
The helmet was printed in PLA on a Lulzbot Taz 5. I used a Brim for all the parts, as for supports this is only required for the Helmet_Main_Middle.stl to support the grill. For assembly, I glued the helmet parts using Unibond Power Epoxy.
Enjoy and feel free to send me a pic if you print one!