747-8 gets tunnel wind over its wings

 - November 16, 2006, 8:59 AM

Boeing is using Qinetiq’s low-speed wind tunnel for continuing evaluation of the 747-8, the latest iteration of the world’s first twin-deck widebody jetliner now midway through its fourth decade. The facility is located here at Farnborough, on the north side of the airfield.

The five-meter (16.4 feet) Qinetiq pressurized low-speed wind tunnel is a high Reynolds number facility for the investigation of flow physics and the prediction of full-scale performance. Its simulation capability, said to be unique in the UK, provides high-quality data. It has a speed and pressure range up to a maximum of Mach 0.34 and three atmospheres respectively.

Boeing’s latest top-of-the-line offering incorporates recent technology developments to provide higher lift capacity and range through a stretched airframe, improved wing aerodynamics, and increased commonality with the established 777 and planned 787 twin-aisle twinjets.

The degree of novelty in the 747-8 wing is apparently a matter of opinion, according to program product development chief engineer Roy Eggink. “If you look at the structural [load] paths, it is a derivative but we tell the customers it’s a new wing,” he told Aviation International News.

Certainly the wing does benefit from numerous enhancements, not least an “advanced technology” aerofoil section, as well as new double-slotted inboard and single-slotted outboard trailing-edge flaps. Boeing also has redesigned the flap tracks carrying those panels and has developed the “canoe” fairings around them to reduce aerodynamic drag.

As Boeing continued its wind-tunnel testing here, Eggink reported “excellent progress” toward meeting all 747-8 performance targets. The company conducted at least two sets of high-speed tests in the Boeing transonic wind tunnel last year, with a further four exercises there slated for this year along with a session in the facility at NASA Ames.

Also on this year’s program are three periods of low-speed work here in Qinetiq’s low-speed tunnel, as well as other research in various low-speed acoustics and noise-test facilities.

Earlier in 2006 Boeing completed high-and low-speed aerodynamic lines development and began work on design-load development.

Boeing has completed more than 3,000 hours of wind-tunnel time on two 747-8 models: a 3-percent unit for high-speed work and a larger 5-percent example for the low-speed exercise.