Aviation Partners targets later summer for second-generation spiroid winglets
By John Croft
Aviation Partners plans to fly its second-generation spiroid winglets on a company Dassault Falcon 50 in the third quarter. The flight is part of the $2 million earmark the company received last year to further investigate the novel devices, in part to analyse the potential for reducing aircraft separation distances.
API founder and president Joe Clark says the new spiroids, now in design, are likely to eliminate wingtip vortices in the near field region, although the effects in the far-field, roughly 4.6-5.6km (2.5-3nm) behind the aircraft, will have to be determined by test. API plans to equip its Dassault Falcon 50 with the devices as part of the research programme, which is being managed by the US Department of Transportation's Research and Innovative Technology Administration (Rita).
Rita will make progressive payments to API based on milestones, the first of which is a report on the company's early 1990s' flight tests of first-generation spiriods in a Gulfstream GII. Results from those tests reportedly showed a 6-10% drag reduction in cruise flight with the devices, although API is not providing quantitative numbers. Rita plans to publish the milestones for the spiroid test programme on 14 June.
Hank Thompson, API vice-president of operations, says the new aerodynamic configuration for the winglets will take advantage of "all that we've learned over the past couple of decades". He says the analytical results are "very promising", but he'd be "reluctant to put performance numbers on it".
Aside from aerodynamic performance, Thompson says there remain "significant" manufacturing challenges in building a structure that will be stiff enough to be aerodynamically correct through all flight regimes, but also economical to manufacture.
Engineers are investigating a variety of materials, from composites to metal, from which the looping wingtips might be constructed. A vendor has not yet been selected to build the devices for flight tests that are expected to begin in the summer or early autumn, says Thompson.
