Saw this on frother's thought I'd share:
From Khurashan:
I've got a VTOL gunship with anti-grav drive coming out soon in 15mm, and it will be made eventually in 28mm too. After some feedback on the anti-grav drives I've decided to have an option to retrofit more conventional ducted fan rotor drives to it as well.
Check out this size -- too small? Just the right size? Consider the amount of table space the model will take up, and the stability of the model as well if mounted on a flying base. These rings are just placeholders of course showing the circumference of the drives -- they'll be thicker top to bottom I reckon, and will be filled in with rotors of course!