Just a few thoughts:
I am guessing that a new anti-grav propulsion system would not be constrained by aerodynamics. Hence, using an aircraft structure would be unneeded
and (I think) complicate the design tremendously.
On the other hand, if I am bass-ackwards and aerodynamics still apply while in an atmosphere - why use a helicopter body? If the propulsion system
were anti-grav, I would guess it would be capable of almost any manover while "flying". Wouldn't a sphere, or "ball" be a better choice?
Further, until you proved the system somewhat reliable, would the 'body' that it's contained in matter at all? Meaning, wouldn't it be more likely
the new propulsion system would look like "machinery" on - say - a large pallet for proof of concept tests?
Honestly, I have no idea. Interesting pictures and fun to talk about.

