[whiskypeters]

Initially I thought the "hole" was meant to be enclosed within the airframe, but it is there. See Fig 2 - Fig 8 in the patent application. They have even diagrammed a method for boarding passengers using retractable escalators from parallel hatches located on the forward and aft planes of the inner-torus, as well as using an elevator to board passengers from within the hole! Fig 9 - Fig 16 diagram the invention applied to a more conventional airframe (without the hole).

The patent title is "aircraft including a passenger cabin extending around a space defined outside the cabin and inside the aircraft." My understanding is that the patent covers the torus-shaped passenger cabin within any larger aerodynamic envelope as a method of reducing constraints related to cabin pressurization (the "hole" is incidental). Very interesting stuff. I'm not an aeronautical engineer or patent attorney.

[dalke]

Paragraph 0030 says that figure 2 is without the aerodynamic envelope. The aerodynamic envelope is labeled 22, and visible in figure 7. Other parts of the description mention how the hole can be filled with cargo or other items, and that a non-pressure skin can be used as a cover.