In 1999, Aviation Partners Boeing (APB) was formed, a partnership with Seattle-based Aviation Partners Inc. and The Boeing Company. The companies created APB initially to equip Boeing Business Jets, a 737 derivative, with Aviation Partners’ unique take on the NASA-proven winglet technology: Blended Winglets.
Like other winglet designs, APB’s Blended Winglet reduces drag and takes advantage of the energy from wingtip vortices, actually generating additional forward thrust like a sailboat tacking upwind. Unlike other winglets that are shaped like a fold, this design merges with the wing in a smooth, upturned curve. This blended transition solves a key problem with more angular winglet designs, says Mike Stowell, APB’s executive vice president and chief technical officer.
“There is an aerodynamic phenomena called interference drag that occurs when two lifting surfaces intersect. It creates separation of the airflow, and this gradual blend is one way to take care of that problem,” he says.
APB’s Blended Winglets are now featured on thousands of Boeing aircraft in service for numerous American and international airlines. Major discount carriers like Southwest Airlines and Europe’s Ryanair take advantage of the fuel economy winglets afford. Employing APB’s Blended Winglets, a typical Southwest Boeing 737-700 airplane saves about 100,000 gallons of fuel each year. The technology in general offers between 4- and 6-percent fuel savings, says Stowell.
“Fuel is a huge direct operating cost for airlines,” he explains. “Environmental factors are also becoming significant. If you burn less fuel, your emissions will go down as well.” APB winglets provide up to a 6-percent reduction in carbon dioxide emissions and an 8-percent reduction in nitrogen oxide, an atmospheric pollutant. The benefits of winglets do not stop there, Stowell explains. Reduced drag means aircraft can operate over a greater range and carry more payload. Winglet-equipped airplanes are able to climb with less drag at takeoff, a key improvement for flights leaving from high-altitude, high-temperature airports like Denver or Mexico City. Winglets also help planes operate more quietly, reducing the noise footprint by 6.5 percent.
If all the single-digit percentages of savings seem insignificant on their own, they add up. In 2010, APB announced its Blended Winglet technology has saved 2 billion gallons of jet fuel worldwide. This represents a monetary savings of $4 billion and an equivalent reduction of almost 21.5 million tons in carbon dioxide emissions. APB predicts total fuel savings greater than 5 billion gallons by 2014.
APB, the only company to currently both manufacture and retrofit winglets for commercial airliners, is currently equipping Boeing vehicles at the rate of over 400 aircraft per year. It is also continually examining ways to advance winglet technology, including spiroid winglets, a looped winglet design Aviation Partners first developed and successfully tested in the 1990s. That design reduced fuel consumption more than 10 percent.
While winglets require careful customization for each type of plane, they provide effective benefits for any make and model of aircraft—even unmanned aerial vehicles. Consider other winglet designs on commercial carriers, as well as blended and other winglets on smaller jets and general aviation aircraft, and the impact of the original NASA research takes on even greater significance.
“Those flight tests put winglets on the map,” says Stowell.
Blended Winglets™ is a trademark of Aviation Partners Inc.