Seattle's Aviation Partners is Flight Testing Winglets for Classic 747s

Aviation Partners of Seattle has begun flight-testing a winglet retrofit for "classic" 747-200 and -300 transports. A prototype set, extending 14 feet over the planar part of the wing, has accumulated four hours of flight time and "cleared all flutter issues," according to Aviation Partners CEO Joe Clark. Initial indications show a 6%-7% reduction in drag, he said. Flight tests to fine-tune performance will start in about 30 days. A go-ahead determination on the retrofit then will be made based on winglet cost and the additional wing structure needed. Production versions are envisioned to weigh about 1,500 pounds per set. The testing is being performed on a leased 747-200F operating out of the former George AFB, near Los Angeles.