Adding these devices to aircraft wings can make the planes look sleeker, but they bring with them some serious savings in fuel and emissions as well: between 3% and 6% off a single aircraft’s CO2 emissions per year.
Aviation Partners Boeing has made its “Blended Winglets” available for several models of commercial jet. A typical winglet-equipped 737 in airline service saves 380,000-570,000 litres of fuel per year compared to a 737 without the devices. Savings climb to 1.9 million litres per year on the 767ER. Aside from fuel and CO2 savings, co-benefits include a reduction in aircraft noise and as much as 8% reduction in NOx emissions. A new model launched in 2014, “Split Scimitars”, brings down emissions a further 2% compared to the Blended Winglets.
Taking this technology another step, Boeing will offer its “Advanced Technology” winglet on the new 737 MAX. Aerodynamicists used advanced computational fluid dynamics to combine rake tip technology with a dual feather winglet concept to improve efficiency by up to 5.8% relative to a wing without a winglet, and by more than 1.5%, depending on range, over current designs.
Airbus has also developed the “Sharklet” product for its own A320 aircraft family. These deliver more than 4% fuel saving on longer sectors and are available on new A319, A320 and A321 aircraft, or for retrofit. In fact, an A320 equipped with Sharklets can cut between 500 and 1,000 tonnes of CO2 per year in typical operations, depending on the average flight length. Around 90% of new A320s being delivered today are equipped with the devices.
Other aircraft, such as the Bombardier commercial and business jet lines, Embraer and some existing Airbus and Boeing aircraft also have wingtip devices in-built, including some that may not appear to be as obvious – like the Boeing 777’s “raked wingtip”.