Although it was hardly noticed against the background of the usual landslide of orders, new product launches and first flight news at Paris, Boeing’s 747-8 program gained five more valuable orders for the passenger model from Korean Airlines. The order, when confirmed, raises the overall backlog to 60 which, for the first time in the program’s eight year history, is balanced evenly between the passenger and freight models.
The Korean deal, which included six 777-300ERs, raises the airlines’ 747-8 commitment to 17, seven of which are freighters. (Boeing)
The Korean win is a boost for the program which has been focused on continuous improvements since 2011 when the -8F entered service and “was not quite the aircraft we’d promised originally,” says 747-8 Vice President and General Manager Eric Lindblad. Upgrades have included re-rigging of the ailerons and rudder for more efficient cruise, an increase in payload of 12,000 lb. following analysis of the flight loads survey, and improvements to the display system and flight management computer to boost precision navigation and efficient climb. The company is also in the midst of flight tests to re-activate the tail fuel tank which was closed out in the original aircraft following the discovery of potential situation for vibrations and flutter under particular conditions.
Tail fuel flight tests are underway using an aircraft originally destined for 747-8I launch customer Lufthansa (Joe Walker)
The additional tail fuel, plus a performance improvement package for the GEnx-2B engines worth around 1.8% in lower fuel burn, is expected to restore the aircraft’s range capability to the 8,000 naut miles originally specified by the program. Together with structural weight savings that have reduced operating empty weight by 7,200 lb, the anticipated cumulative benefit is a 3.5% efficiency improvement over the 2011-standard aircraft.
But there is more to come as Boeing knows it needs to bolster sales of the passenger model as part of efforts to sustain the line long enough for the freighter market to pick up again. “We have series of weight reductions to come, so we’re not done,” says Lindblad. “We have a few hundred pounds left and we believe there’s more. We have identified a series of additional weight reductions and, as we get to 2015 and 2016, we’d like to have in excess of 8,200 naut miles out of this aircraft from a passenger version perspective.”
Lower drag side-of-body fairings in place of the current design (circled in red) are being studied as part of Project Ozark (Guy Norris)
In the tradition of previous Boeing code names based on U.S. National Parks like Glacier (Sonic Cruiser), and Yellowstone (from which emerged the 787), the study is believed to be called Project Ozark. Although virtually nothing detailed is known about Ozark, it is thought to include further weight reductions as well as aerodynamic tweaks, including potentially a lower-drag side-of-body fairing. “We have not made decision on that yet,” he adds. Weight reduction target is 10,000 lb lower OEW by 2016, of which 7,200 lb is already “fully committed” to production.
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