I've never seen an 8' floppy drive.
8" is the largest FLOPPY that I'm familiar with.
In HARD drives, I have a damaged 2' diameter platter,
that I have been told came from a 1620 (but I have also been told
that there weren't no sech animal, and that it must have come from
a 1401)
I find it amusing that when I show the 2' platter to my students,
then put it away, then ask about it, they tend to estimate its
size as 3 to 4 feet!