United Airlines is testing the latest innovation in airplane design that may prompt passengers to do a double take. Called a split scimitar, it's reminiscent of a medieval sword and is a variation on those doodads, known as winglets, that extend up from the tips of wings.
United is trying it out not to win any design awards but to make the plane slice through the air more efficiently and, ultimately, reduce fuel consumption.
The airline estimates that, if all goes well, the new design will help save $200 million a year once installed on its newest Boeing 737-800 and 737-900 models.
It will be introduced by the beginning of next year. United said it could improve a plane's performance by an extra 2 percent compared with the current winglet design it uses on much of its fleet.
Since the dawn of the jet age more than 60 years ago, the basic design of an airplane has changed little. But new materials, better computing power and more refined mathematical models have allowed aerospace engineers to improve the basic features of large passenger jets, including the performance of their wings.
Winglets reduce drag at the tip of an airplane's wings and can improve fuel performance by as much as 5 percent a flight. Multiplied over thousands of flights, the savings can exceed $1 million a year for just one plane.
“They smoothen the airflow over the wings and help improve lift,” said Capt. Joel Booth, United's managing director of operations planning and fuel efficiency. “It's an efficiency device.”
The search for improvement in a plane's efficiency, no matter how small, comes after a surge in the price of fuel, which now accounts for roughly a third of an airline's costs. Jet fuel is now well above $3 a gallon, up from 85 cents a gallon in 2000.
To offset this increase, airlines have pursued a variety of fuel-saving strategies, like taxiing with just one of two engines running, shutting off the plane's auxiliary power when parked at the gate or using more direct flight paths for landing. But the big difference to the economics of flying will come from more fuel-efficient engines and planes.
New jet engines are being developed, but airlines also want to improve the efficiency of their existing planes. That's where the winglets come in, since they can be bolted onto existing models.
Using estimates from the maker of the new scimitar design, a joint venture between Boeing and a Seattle-based company called Aviation Partners, the winglets would save United 45,000 gallons of jet fuel per plane every year and cut carbon emissions by 476 tons a year.
Winglets cost anywhere from $500,000 to more than $2 million, depending on the plane's size. But the payoff can be rapid. Southwest Airlines estimates that it saves 54 million gallons of fuel every year thanks to equipping 93 percent of its fleet of 737s with winglets.
“In an environment where the price of fuel is high, you can pay off a set of winglets in under two years,” Booth said.