In my younger days, I spent a lot of time on airplanes — a lot of different kinds, military and civilian, and lots of time on commercial airliners. All that travel tapered off in the early 80s. It occurred to me that when I flew most of the airplanes didn’t have those fin-like airfoils protruding from the tip of the wing. These things are called winglets, at least mostly they’re called winglets — apparently Airbus calls them sharklets. They use that name as opposed to winglets to get around a patent on the winglet technology held by Boeing.
Anyhow, Chris is an aeronautical engineer, so I asked him about them a few years ago. His explanation was fairly technical… something about equalizing the pressure on the upper surface and the lower surface of the wings and reducing the vortex formed because of the difference in pressure. I think he told me the bottom line was that they basically reduce drag and allow throttling back the engines to increase fuel savings. During my extensive research on the subject I discovered that NASA became aware of winglets aerodynamic benefits in the 1970s. Use of the devices typically yield a 1-2% increase in fuel efficiency — that amount of fuel savings is very significant to airlines.
Vertical wingtips certainly aren’t anything new — airplane designers have long known that modifying wingtip flow is important. Soaring birds, such as eagles, have strong feathers that flip up at the wingtips to reduce drag and give the birds more lift. So as smart as we think we are coming up with these innovations, nature and the birds beat us to it.
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