The Winglet Option

You may have noticed that an increasing number of commercial and private jets are adding winglets as a standard feature. Winglets are nothing new -- the first winglets appeared on the Learjet 28 in 1977 -- but they have only become ubiquitous on jets in the past few years. Many private jets on the market today offer the option of adding winglets at the time of building, or later as a retrofit option. Adding winglets can be fairly costly: retrofitting a Hawker 400XP takes three weeks and costs $438,000.

So, what do winglets really do? And are they worth it?

Winglets are designed to decrease the wingtip vortices that develop at the tip of a wing. These vortices develop as the high pressure air from beneath the wing meets the lower pressure air from above the wing. To get a better idea of what the interaction ofthe high- and low-pressure air looks like, take a look at the picture below, taken from a NASA study on wingtip vortices:

Winglets serve to reduce the severity of the induced drag created by these vortices, which has a myriad of side benefits. Reduced drag translates into faster cruise speeds, a lower fuel burn, and an increased range. The winglets also add stability in flight, which is particularly noticeable in small aircraft susceptible to turbulence.

The payoff for adding winglets to a jet is subtle, but an increasing number of private jet owners agree that the cost is more than justified by the benefits.

for more information on winglets and a detailed cost-benefit analysis of the retrofit, visit this site: http://www.jetadvisors.com/articles/2007-1-winglets.htm

for more information on the NASA research on winglets, visit this site: http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-15-DFRC.html