Why does a 737 have those huge winglets?

Question

I realize they are there to reduce vortex drag, but if 8 foot winglets are a good thing for a 737 why don't other similar planes have them?

Answer 1

Many other planes do have them.
Many airlines are in the process or retrofitting their un-wingleted 757s with much the same type winglets, designed by APB, a Boeing subsidy specifically focused on winglets. American Airlines is the first customer to announce that it will also put the APB winglets on its 767-300 fleet.
As for Airbus aircraft, the A300, A310, A320, and A380 series all are designed with Wingtip fences. These do the same basic job as the larger Boeing winglets, but they work better on a slightly differently designed wing. Recently JetBlue did have an A320 delivered with the larger Boeing style winglets, but they found that the added weight negated any added aerodynamic gain, and had them removed for the conventional wingtip fences.
As for non Airbus or Boeing aircraft, they simply have not been designed with winglets in mind. Embraer sells a version of its ERJ-145 with winglets to add to range and fuel efficiency, but the cost of the winglets has kept many airlines from buying the option on all of their jets.

Answer 2

At the wing tips, air with higher pressure from under the wing "spills over" the wing tips into the air with lower pressure above the wing. This turbulence at the wing tips causes the streamlines to form wing tip vortexes. The streamlines below the wing bend towards the wing tips and the streamlines above the wing bend towards the center of the wing. This turbulence absorbs energy and increases the drag. This kind of drag is called induced drag. Induced drag can be said is created by lift.

Induced drag is affected by airspeed, the wing aspect ratio and wing tip design. The B737 has a relatively low wing aspect ratio. The induce drag created by the it's wing is quite high compared to other aircraft. Obviously the can't put a bigger wing on the B737, so they put bigger winglets. The winglets reduce the energy of the wing tip vortexes reducing it's induce drag.

The earlier versions of the B737 (200,300,400,500) had no winglets. Its only the new generation of B737 (700,800) that incorporate winglets. And yes, the are huge. Cheers!

Answer 3

Why?

It's much more than reduced drag. Blended winglets also:

-Reduce Engine Maintenance Costs
-Lower Block Fuel
-Higher Initial & Optimal Cruise Altitudes
-Permanent Fuel Price hedge
-Increased Payload / Range Capacity
-Environmentally Friendly
-Improved Takeoff Performance
-Improved Operational Flexibility
-Dramatically Different Appearance
-Higher Aircraft Residual Value

With increasing fuel costs, you will see more and more aircraft with them. Many fleets are being retrofitted. As of mid-October 2006, Aviation Partners Boeing have equipped over 1,400 aircraft with their Blended Winglets. They conservatively estimate that these aircraft are saving:

146,550,000 gallons per year
401,507 gallons per day
16,729 gallons per hour
279 gallons per minute
4.6 gallons per second

WOW!

See a video of how they do this here-
http://www.aviationpartnersboeing.com/winglets/features/reducedmaintenancecost.html#

Answer 4

Not all aircraft designs produce large vortices, so they don't all need the winglets. Also, the full benefits of winglets were only learned recently, and it costs quite a bit to retrofit a large fleet with these.

Answer 5

they reduce drag by not producing a wing vortex. its not only the 737 that has them. 747-400's and a lot of embraers and candair CRJ's. they are optional but increse fuel efficency alot. i dont know why they are so big. mabey its a look thing or they help even more by being bigger.

Answer 6

They look cooler, not all 737s have them either though, -900 -800 series have them , there is another series with them too. A lot of corporate jets have them too

Answer 7

They help decrease fuel consumption.
Other planes are slowly being retrofitted with them. It takes a long time to get them approved for installation on each different model plane.

Answer 8

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Answer 9

To save fuel

Answer 10

winglets are better for dipping in hot sauce.