These are called “winglets” or “sharklets”, depending on the manufacturer, and whilst they may look cool, they are definitely not there for looks alone.
While winglets could cost $1 million or more per aircraft to install and add several hundred pounds to an aircraft, they pay for themselves in a few years through fuel savings.
A new type of winglet, called a “scimitar”, because it does look similar to the Prince of Persia’s sword, is capable of saving an extra two percent of fuel costs. The American airline United is fitting these to its fleet.
The way that they work is that winglets reduce drag and increase lift at the end of the wings, where the physics of flight create small tornadoes. Winglets essentially reduce the size of those whirling air masses and improve the plane’s “gas mileage” by helping jets more efficiently slice through the sky.
Savings of 4 percent and an extra 2 percent might not sound like much, but the actual reduction in costs are enormous. For instance, consider that United uses 4 billion gallons of fuel in a year. Unbelievably, this represents 1 percent of the world’s annual oil supply. At today’s prices jet fuel costs around $3 per gallon.
A single set of scimitar winglets on one plane at United saves about 45,000 gallons of jet fuel in a year. That’s a cost saving of $1,350,000 per plane per year. For perspective, that saving is as much fuel as an average car would use in 72 years. Given that most people don’t actually drive for 72 years’ that’s more than an average person would use in a lifetime of regular fill-ups.
United expects the new and older wingtip designs on its 737, 757 and 767 fleets to annually save it 65 million gallons of fuel, $200 million worth, and the equivalent of 645,000 metric tons of carbon dioxide emissions.
So as well as cost savings, the winglets are much better for the environment too.
Adding winglets is not a cheap exercise either, as each one costs about $1 million to install. The engineering, too, is more complex than simply about bolting on the extensions. The aircraft’s wing must be reinforced to handle the additional weight. And a blended winglet requires substantial strengthening before converting it to a split scimitar.
But the significant upgrade is worth it because the business case for winglets is so strong, with payback in about two and a half years.