N474WN heads on out at Atlanta Hartsfield-Jackson. Note the blended winglet and how it “seems” just a bit off-angle in relationship to the lower wing surface. Part of this is due to the supercritical airfoil section of the 737NG’s wing, but the winglets on the 737NGs are also toed out. Winglets have two primary angles- the obvious one is the cant angle- how far off vertical is the winglet canted. The less obvious one is the toe angle- how far off the direction of travel is winglet angled. On the 737NG, the winglet is toed out 2 degrees. The primary reason is to reduce wing bending- keep in mind a winglet acts like a wingspan extension. With the winglet at zero degrees toe angle, the 737NG’s wing would need more structural reinforcement as the winglet would be exerting an upward force (lift) that wants to bend the wings further. By toeing the winglet out 2 degrees, a slight downforce is created which reduces wing bending, making extensive structural reinforcement of the outer wings unnecessary without sacrificing the attenuation of the drag-inducing wingtip vortex. During the development of the blended winglet, it was found that the 2 degree toe out also helped reduce other forms of drag but it did result in an increase in induced drag- that’s the form of drag that results from the wing changing the direction of airflow as it hits it. Obviously a zero degree toe angle had the least amount of induced drag. However, the tradeoff was deemed acceptable given the decrease in wing bending as well as the decrease in other forms of drag like trim drag (the drag from keeping the aircraft trimmed in level flight) and wave drag (the drag from transonic shock waves). #avgeek #aviation #aircraft #planeporn #KATL #ATL #Atlanta #Hartsfield #HartsfieldJackson #Georgia #airport #planespotting #instaplane #Boeing #737 #Southwest #SWApic #N474WN #instagramaviation #splendid_transport #instaaviation #aviationlovers #aviationphotography #flight #AvGeeksAero #AvgeekSchoolofKnowledge #AvGeekNation (at Hartsfield-Jackson Atlanta International Airport) https://www.instagram.com/p/CXv_UMsLbev/?utm_medium=tumblr
