Look at that Jet: It's Got Winglets

From now on, more than 90 percent of all new Boeing 737s will have winglets fitted during manufacture. Among them will be 10 737-700s that Dutch airline KLM has ordered. Credit: Boeing Photo

Boeing 737s aren't the only airliners with winglets and Aviation Partners isn't the only company that makes winglets. Bombardier has been putting winglets on its hot-selling line of CRJ regional jets for many years--including the new CRJ900, shown here--and from the outset rival Embraer designed its new family of E-Jet large regional jets to have winglets. Meanwhile, Airbus designed smaller \"wing fences\" for some of its airliners, such as the A300, A310 and A320 families, as well as the A380; but its A330 and A340 models feature tilted winglets. Credit: Bombardier Aerospace

You've probably already noticed that commercial jetliners are getting a new look these days. It's those little upturned pieces at the tips of the wings, often sporting the airline's logo.

They're called winglets (cute, eh?) and Delta is the latest airline to install them on its jets. But why? Are they just for decoration? Hardly. They boost the aircraft's efficiency by improving its aerodynamics.

These near-vertical, fin-like extensions are small, compared to the size of the wing and the rest of the plane, although on a Boeing 747-400 they're nearly six feet tall. But they pack a powerful punch.

So how do they work?

The way a wing works is that when the plane goes fast enough, the air pressure above the wing becomes less than the pressure below the wing, which lifts the plane. Because of the nature of aerodynamics, the air pressure near the body of the plane is different than at the very tip of the wing.

Winglets compensate for this pressure difference, which in turn reduces the air vortex that a plane makes when it flies. The reduced vortex, in turn, makes the plane fly with less "wobble" (or "induced drag," in aviation parlance) and that makes it fly more efficiently.

By installing winglets, airlines will enjoy significant fuel savings, reduced engine maintenance costs and increased carrying capacity on each aircraft. And this helps keep fares low.

Why haven't winglets caught on earlier and why don't all airlines install them if they're so great? The winglet concept is at least 100 years old, according to Craig McCallum, director of sales and marketing for Aviation Partners, the sole airliner winglet manufacturer in the United States. But it didn't become commercially viable until a Boeing employee, after retirement, started fiddling around with the concept.

New materials (winglets are mostly made of graphite) and software came together to make winglets a reality. But they're not right for every airline or type of aircraft, which is why they're not industry-wide and fleet-wide.

The longer the plane flies in a given year, and the longer the route it typically flies, the greater the payback for installing winglets. So they don't make sense for every airline or type of aircraft, especially those used mostly on shorter hops. But they're catching on. Over 90 percent of future Boeing 737s (the 600, 700, 800, and 900 versions) will have winglets pre-installed at the factory.

On Aviation Partners' website (www.aviationpartners.com) the company claims that its innovation is saving fuel at the rate of almost 5 gallons per second. Also, on the front page it has a real-time tracker of the gallons of fuel winglets are saving—their contribution to a greener Earth.

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