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Comment by upofadown | Hacker News Reader

Not sure I understand the images. The cables seem to be connected to the end of the wing units. A wing can't normally generate force longitudinally. So how is the wing generating cable tension?

Added: OK, it is all generated by the centripetal force caused by the mass of the wing units. So fast spinning and lots of cable/parasitic drag to get the wings reasonably level. Seems like a lot of wing area for a small payload. How is this better than just a wing large enough to support the payload with cables to distribute the load across the wing length?

Added2: This scheme still has the problem that the downwash from each wing will affect the other wings, just like in the helicopter case.

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The wing generates lift, the engines on the edge of the wing generate thrust. That thrust is at a tangent to the circle the wings travel. Essentially the wings are pushed forward but cabled at the side.

Seems that the four wings rotate around the central unit creating centrifugal force that will keep the cables tight.

Wouldnt a single wing being buffetted by a downdraft or sudden turbulence cause catastrophic loss of tension between all wing tethers and the whole thing collapse?

What if instead of teathers, you just had two large circles of composit, as a hub and a rim, that were stiff enough to keep all wing positions but stiffer than a flimsy string - and thus keeping formation?

I didn't watch the video (or read most of the page!) so it's possible I'm missing something, but the images show the wings having a propeller at each end, so I don't think a loss of cable tension would be catastrophic (at least not in the same way it would be if there was only one propeller per wing). The wing would presumably keep flying straight until the cable was tense again and it all started rotating again. Seems fairly self-correcting, with the second propeller.

I'm a paraglider pilot, not an aerospace engineer, so take this with a lot of salt... but:

Paragliders can have asymmetric collapses of the airfoil due to turbulence, but usually it's no big deal (other than being a little scary). Catastrophic loss of tension is avoided because there's still airflow over the rest of the glider, which remains pressurized. All the pilot needs to do is maintain safe directional control until the full wing re-pressurizes. You feel a sudden loss of pressure and then an abrupt surge of pressure, then things normalize.

My guess is that something if similar happens here, it'll happen asymmetrically, and the props might keep airflow over the other 3 wings, which are still flying. They maintain stability while the wing that went floppy drops, regains its tension, and then resumes normal flight.

Last: I'd wager that they plan on deploying these in stable air, at very high altitude.

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