American Airlines 767-300ER fitted with API winglets (photo: API)
Fri 27 Jan 2012 – Seattle-based Aviation Partners Inc (API) estimates its blended winglets have saved customers worldwide an estimated 3 billion gallons of jet fuel, based on typical utilisation, since they were first installed on a Gulfstream II aircraft in 1993, representing a reduction of over 32.2 million tons of CO2 emissions. By adding effective wingspan, the winglets reduce by around 6 to 7 per cent the drag caused by wingtip vortices and result in increased fuel efficiency and boost range. The company’s winglets are now flying on more than 5,000 individual airplanes comprising more than 20 airplane types, mostly business jets but also commercial Boeing aircraft.
API expects the amount of fuel saved through its winglets to grow exponentially to more than 7 billion gallons in the next four to five years.
The blended wingtips can be installed during production or retrofitted to existing aircraft, and are certified on a range of Gulfstream, Hawker and Falcon aircraft types. Through its joint venture with Boeing, they can also be retrofitted to 737-300 to -900, 757-200 and -300, and 767-300ER/F series aircraft.
Back in 2009, American Airlines started to equip its 767-300ER fleet with API winglets and estimated the initiative would save it around 29 million gallons of fuel each year. Southwest Airlines is another that fits its aircraft with the winglets.
Winglets reduce wingtip vortices, the twin tornados formed by the difference between the pressure on the upper surface of an airplane’s wing and that on the lower surface. High pressure on the lower surface creates a natural airflow that makes its way to the wingtip and curls around it.
At last October’s NBAA convention, the company unveiled new winglet designs – the Scimitar Blended Winglet, Spiroid Winglet and Blended Split-Tip Scimitar Winglet – which promise a 10% improvement in the benefit provided by the existing technology.
API began discussions with Airbus in 2006 regarding the use of its blended winglets on Airbus A320 series aircraft, resulting in a memorandum of understanding in July 2011 with the intent, claims API, of forming a joint venture. API says that without notifying the US company, Airbus has filed a patent in Europe for its own Sharklet wingtip and has now also brought a lawsuit seeking to invalidate API’s own patent.
“API’s engineers analysed the Airbus materials and noticed the striking similarity between API’s Blended Winglet and the Airbus Sharklet design,” responded API founder and CEO, Joe Clark.
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