Study for blended design revealed on eve of launch for similar product for 767-300ER

Aviation Partners Boeing is studying a blended winglet design for the 777-200ER variant as it approaches the launch of a similar effort for the 767-300ER.

"We are working on a winglet shape for the 777, and particularly the most popular version, the -200ER," says Aviation Partners Boeing chief executive Mike Marino.

"We are investing a few dollars and Boeing is supporting us and looking at the possibility of providing it as an option for the -200ER." Marino says the study, which was quietly kicked off in the first quarter of 2004, is expected to conclude by the end of the year.

Unlike the later model -300ER and -200LR versions, which are designed as standard with a variant of the raked tip originally created for the 767-400ER, the earlier 777 versions have a semi-raked tip.

Boeing has "encouraged us to see if we can make it better and you may see new 777s coming off the assembly line with winglets, but it will be a few years down the road if it happens", adds Marino.

The outline design calls for winglets 3.95m (13ft) -tall that are expected to increase overall span to just over 64m. Details of the 777 study emerge as the company nears the possible launch of a winglet programme for the 767-300ER.

"We're looking for launch partners and a customer to share an aircraft with for flight tests and certification," says Marino, who concedes the "chicken and egg" situation "adds a little complexity".

Firm proposals have been made to four 767 operators, including a cargo airline, with a target entry-into-service date of around 12 months after formal launch.

The 767 winglet design is 3.35m tall compared with 2.44m on the 737, and together with added root area increases overall span from 47.6m to almost 51m.

Weighing around 910kg (2,000lb), the modification is expected to generate drag reductions of 5-6%, says Marino. "The business case changes all the time with the rising fuel price, but with the longer average sector length of the 767, we're showing some significant value with this winglet," he says. The installation weight includes the winglet itself as well as structural strengthening of the outboard wing, which is required to handle the additional lift.

The strengthening includes reinforcing four stringers on the lower surface, one on the upper side and strengthening of outboard wing skin panels. Conversion down time is expected to be "about 10 days" says Marino.

A lead contender for launch is expected to be Continental Airlines, which recently completed its first 737-800 winglet conversion and which is launch customer for the 757-200 winglet programme with 11 orders and 30 options.



Source: Flight International