Friday morning, and with it the weekly column "A Taste of Physics" — issue #48.
This week: a very unusual aircraft, and its connection to flocks of birds and smoke rings.
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As strange as it may sound, the aircraft in the video might just be the future of aviation.
It showcases a concept design by Lockheed, and although technical limitations still make actual production challenging, the physical principles behind its structure promise exceptional efficiency.
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Next time you board a flight, take a look at the wingtips of the aircraft.
You'll notice that at the end of each wing there's a small vertical fin — and it's there for a good reason.
As the aircraft accelerates down the runway, the air pressure beneath the wings is higher than above them, which generates lift.
But that pressure difference also produces a less welcome effect — wingtip vortices.
Air flows toward the wingtip in an attempt to rush upward into the lower-pressure region, creating a vortex at the tip.
Wingtip vortices significantly increase the drag acting on the aircraft, causing energy losses of up to 40%.
The small fins at the wingtips — known as winglets — are designed to reduce these vortices, and their equivalent can also be found in the feathers at the wingtips of certain birds.
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Another problem with conventional aircraft is the distribution of weight and structural loads.
The wing root must simultaneously bear the weight of the aircraft and support the wings extending outward to either side.
This heavy loading demands a massive, heavy wing root, which in turn increases the aircraft's overall weight and fuel consumption.
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The idea of wings without tips is an old one, and can be found in a variety of configurations — squares, ellipses, and Lockheed's ring-wing design among them.
The ring shape eliminates wingtip vortices, distributes lift more evenly, and also enables smart weight distribution through the rear support fin.
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The reason smoke rings linger in the air longer than ordinary puffs of smoke is that the ring structure is inherently more stable — precisely because it has no edges, much like the ring wing.
Bird flocks sometimes make clever use of wingtip vortices.
They fly in a V-formation, with the energy shed from each bird's wingtip serving the bird behind it as an additional source of lift.
The dream of a commercial closed-wing aircraft has not been abandoned, and realizing it could give rise to a new generation of aircraft that are efficient, lightweight, highly energy-economical, and subject to low wear.
Shabbat Shalom 😊
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