usmc helo
You're right! I went through every V-22 post that Nick and others wrote and could not find that specific post. Until/if Nick responds to this I can only apologize for leading you on a wild goose chase.
Please check this reference out as it does touch upon this a little:
http://www.pprune.org/rotorheads/116124-vortex-ring-settling-power-merged.html