Southwest Airlines Boeing 737 with winglets designed by Aviation Partners Boeing. Winglets on the 737 will save up to 100,000 gallons (45,360 kg) of fuel annually.
W
hile boarding a Southwest if it forced to travel further than save? In a typical year, a 737
flight recently I overheard air flowing under the wing. This with winglets will save upwards of
a woman saying the air- creates lift, but it also creates 100,000 gallons (45,360 kg) of fuel;
plane looked “old.” Her husband induced drag, which comes off the a 757 will save up to 500,000 gal-
responded with a confident, “No, wingtip in the form of vortices or lons (226,800 kg), and a 767 will
it has those ‘wing-things’ on it, so “wake turbulence.” save up to 600,000 gallons (272,150
it must be new…” A quick glance By effectively increasing the air- kg). Aviation Partners estimates
at the analog flight deck told me craft’s wingspan, winglets increase that there are about 3,000 aircraft
the “Mrs.” was on the mark. the lift generated at the wingtip flying with their winglets and cal-
Nevertheless, those “wing-things,” while reducing lift-induced drag culates that, as of early September,
or winglets, do knock years off the caused by the wingtip vortices. they have helped save their airline
perceived age of an airplane (they The vortices from below the wing customers close to 1.735 billion
just look so, well, 21st century), but strike the winglet surface, generat- gallons (687 million kg) of Jet A.
most of all, they provide a host of ing a force that angles inward and While adding winglets to small-
real money-saving benefits to the forward. By converting some of the er, business jets will save fuel, too,
aircraft’s operator. otherwise wasted energy found in their biggest benefit to owner/
“You get two primary benefits the wingtip vortices to thrust and operators is increased range,
from winglets,” explains Hank improving the wing’s lift-to-drag which translates into saving time
Thompson, vice president-opera- ratio, winglets can deliver all their and increasing flexibility.
tions, Aviation Partners Inc. (API), added benefits: increased range “On one popular aircraft model,
Seattle, Wash. “You can fly longer/ and speed, while decreasing fuel operators were saying that their
further or faster for the same [fuel burn and engine maintenance. ability to achieve the OEM’s long-
used] – you get to pick which one How much fuel can winglets range published mission without
you want.”
“They make the aircraft more
efficient both from a flight charac-
teristics, as well as a fuel efficien-
cy, perspective,” he adds. “There
are very few, if any products that I
know of that can make that state-
ment. It’s a very ‘green’ product. It
just doesn’t have a downside…”
What They Do
The benefits of winglets can be
learned in aerodynamics 101: air
flowing over the upper curved sur-
face of a wing accelerates because
Aviation Maintenance |
avmain-mag.com | Oct/Nov 2009 19
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