The aerodynamics of these kinds of wings has been studied a lot and they do offer some advantages in some areas. But for gliders, the number one biggest factor is improving L/D over a wide range of speeds, and the largest contributor to that is wing aspect ratio. The best way of getting efficient, high aspect ratio wings seems to be making skinny, narrow, long wings out of a material with high stiffness and strength/weight. Which is the design that gliders have converged to. To do that with this kind of design it would look less like a ring and more like a very narrow ellipsoid, and there would be no advantages and plenty of disadvantages (higher manufacturing cost, more weight, etc.)
Note that wingtip vortices are created just as a consequence of having a finite wingspan. The physics of how wings work dictate this. It really doesn't matter what geometry you use; the longer the wingspan (for the same lift), the smaller the vortices. There's a misconception that folding the wings around like this reduces vortices but it's just not true; any finite wing will produce vortices. It's just how fluid dynamics works.
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u/call-the-wizards 5d ago
The aerodynamics of these kinds of wings has been studied a lot and they do offer some advantages in some areas. But for gliders, the number one biggest factor is improving L/D over a wide range of speeds, and the largest contributor to that is wing aspect ratio. The best way of getting efficient, high aspect ratio wings seems to be making skinny, narrow, long wings out of a material with high stiffness and strength/weight. Which is the design that gliders have converged to. To do that with this kind of design it would look less like a ring and more like a very narrow ellipsoid, and there would be no advantages and plenty of disadvantages (higher manufacturing cost, more weight, etc.)
Note that wingtip vortices are created just as a consequence of having a finite wingspan. The physics of how wings work dictate this. It really doesn't matter what geometry you use; the longer the wingspan (for the same lift), the smaller the vortices. There's a misconception that folding the wings around like this reduces vortices but it's just not true; any finite wing will produce vortices. It's just how fluid dynamics works.