747-8 test flights uncover minor problem
An aerodynamic design problem with Boeing's new 747-8 jumbo jet is causing shaking when the wing flaps are fully extended and the main landing gear doors are down, but the company says it's easily resolved.
Seattle Times aerospace reporter
An aerodynamic design problem with Boeing's new 747-8 jumbo jet is causing shaking when the wing flaps are fully extended and the main landing gear doors are down.
Boeing said it is addressing the problem and it will not affect the program schedule.
"This is the nature of testing," said 747-8 spokesman Tim Bader "We find issues, make the necessary adjustments and resolve them."
Buffeting, as the problem is called, occurs due to a disruption of the air flow around the airplane's surfaces.
Wings flaps are movable control surfaces on the trailing edge of the wing that are deployed on take-off and landing to increase the wing's lift at slower speeds. The 747-8 flaps are completely redesigned from those of the previous 747-400 model.
If the flaps are fully extended when the wheels are raised or lowered — so that the landing gear doors swing open, then fold back up — turbulent air flow between the flaps and the doors causes the buffeting.
The problem was noticed on the new jet's first flight in February and was reported online Wednesday by Flightblogger.
Buffeting is not uncommon early in flight tests. When a similar problem arose with the nose landing gear doors of the 777 during flight tests in 1994, it was solved by inserting metal plates into the nose wheel well that redirected the air flow.
Dominic Gates: 206-464-2963 or firstname.lastname@example.org