N8526W, one of Southwest’s Boeing 737-800s, starts its takeoff roll at Phoenix Sky Harbor.
Note the split scimitar winglets. Back in the early 1990s when Aviation Partners (developer of the blended winglet) was looking at pushing winglet technology, the most dramatic improvements came with the unique spiroid winglet which was a closed loop shape- imagine a blended winglet that curves back on itself. Flight testing on a Gulfstream GIII showed an impressive 11% drag reduction. The spiroid winglet was flight tested again on a Dassault Falcon 50 in 2010 and validated the earlier tests.
However, even with modern manufacturing materials, a spiroid winglet would have been a challenge to fabricate and would have required more structural strengthening of the outer wing of any candidate aircraft than what would have been economically feasible.
The split scimitar emerged from the 2010 flight tests as a compromise between the existing blended winglet and the aerodynamically ideal spiroid winglet. The split scimitar offered performance gains over the standard blended winglet without the weight penalty and bending moment of the spiroid winglet. Even more attractive, the split scimitar was a refit to the standard blended winglet with a new “streamwise spike” on the tip cap of the blended winglet and the addition of a downward canted winglet- computational fluid dynamics showed that the downward element further attenuated the drag-inducing wingtip vortices.
The streamwise spikes on both the upper blended winglet and downward canted element also further attenuated the vortices- just the upper streamwise spike alone offered a 0.5% performance gain over a standard blended winglet- with a large fleet with high utilization, even a 0.5% gain adds up over time.
#avgeek #aviation #aircraft #planeporn #KPHX #PHX #Phoenix #SkyHarbor #Arizona #airport #planespotting #instaplane #Boeing #737 #Southwest #N8526W #SWApic #instagramaviation #splendid _transport #instaaviation #aviationlovers #aviationphotography #flight #AvGeeksAero #AvgeekSchoolofKnowledge #AvGeekNation #TeamAvGeek