Yaatri

But how, and why? Efrem's post provides the real answer.

Using winglets increases lift and therefor shortens the take off distance. It also shortens the distance between two successive aircraft. I don't think the highlighted part of your claim is correct. I can't think of any reason why it would increase fuel consumption during take off and climb.

Efrem

I think it's the name of a word game, with point values after each letter.

Yaatri

Boeing 777 will have wingtip devices.

Cholula

Since OMNI is, generally, a forum for everything other than miles, points and travel topics, we're going to switch this over to TravelBuzz!

But we'll leave a re-direct here in OMNI too so it'll reach eyeballs in both forums.

Please follow at its new home.

Thanks.

_______________

Cholula
OMNI Co-Moderator

peteftlaud

exactamundo. It spells scrabble for 14points ,unless it 's on a double or triple space.

slawecki

it is my understanding that if the wing is "perfectly" designed, winglets are not necessary. the winglets correct errors after the "perfectly" designed wing is found to need a bit of assistance.

s1c3r1a1b3b3l1e1

S1C3R1A1B3B3L1E1 is plenty fun by itself, but drunken S1C3R1A1B3B3L1E1 with Mojitos is even more fun!

Thank you for the information on the wing tips. I was curious about the 777. Plus, weren't the wingtips on the 747 added in the 1990s and 2000s? Why did it take the engineers so long to discover this and correct this? As I recall, wingtips were on the A300 and A320 for quite some time before being added to the 747.

Does anyone know the difference in design between the 777 wing and all the others that the engineers originally thought that it did not need a wingtip? I have also noticed that the 777 wing appears much stiffer than the A330 wing, in that it does not sag at the ends. Does this give it any advantages/disadvantages or is it just a difference in design?

Finally, thanks for moving this thread. I did not know where to start it.

Flaflyer

Despite it's simple looks, a winglet is not just a piece of Home Depot 3/4 inch plywood bolted to the end of the wing. Winglets can cost hundreds of thousands of $ to retrofit.

Even if the advantages were known when the 747 was designed, it was designed in the 1960s when kerosene was 25 cents/gallon. Not cost effective to install.

Fast forward to 1990 or so, when the the next generation planes are being built, offering better fuel economy on two big engines than a 1969 design with 4 engines. Oh, and kerosene is now $2 a gallon. New generation were designed from the start with every fuel saving device known like winglets as standard equipment Adding winglets on later model 747-400s to cut fuel flow made economic sense and keeps the plane in the market so we can enjoy Upstairs.

The Lev

The 747-300 first flew in 1982 and apart from the extended upper deck didn't get much of a redesign at that time, so it's wing design dates back to the 1960's. The A-320 was a completely new design that first flew in 1987, so was able to incorporate more modern design. the A-300 had very small winglets.

sbm12

Not all of them. The newer models (773, 77L) have a raked wing design that provides similar benefit. The 77A and 772ER (the earlier 777 models) do not have the raked wingtips and can potentially benefit from winglets.

As for why they are less efficient at climb-out/landing it is an aerodynamics and speed thing. At the slower speeds the vortexes aren't as big a deal. At higher speed they are and that is why the winglets help at cruise. At least that is my understanding of it.

pinniped

That's my understanding too: at low speeds, the winglet does not add anything (or much). And since it has a nontrivial weight to it, the take-out / climb-out requires more fuel consumption.

I've noticed that WN uses a mix of wingletted and nonwingletted 737's. I've wondered if they purposely assign the wingletted planes to their longer routes. Knowing that there always seems to be logic and purpose behind everything that WN does, it would not surprise me at all.

hwmorth

Actually there is a benefit at takeoff/landing as reduced vortexes allow for closer spacing and therefore higher capacity of the runway.

flyingfkb

Yes technically these are winglets, too. Still the A380 has a wing geometry which doesn't make it necessary to put very large winglets on the ends. If you take a look at the the A380 wing it is bended already. So you only need this little tips at the end unlike the large ones you see on the 737-800 or the retrofitted 767.

DeafFlyer

The 747-400 passenger version has had winglets right from the beginning (1988, i believe). The 100, 200, and 300 series did not have them. I forget when the 320 had it's first flight, but it was clsoe to the same time the 747-400 came out. The A300 has had them for a long time.

s1c3r1a1b3b3l1e1

Judging from the pictures I have seen, the 787 wing looks very different than the other wings with the tips more steeply raked. (I hope that is the correct terminology.) I guess that extra bit of raking at the end does the same thing as winglets. But, it is interesting to see the evolution of the shape of the wing over time.

I still remember watching the slats on the 727 fold forward from underneath the wing. I think the early generations of the 747 did the same thing, but I don't remember. They look so much more aerodynamic now with the slats sliding forward from their location. I always find it interesting as the slats and flaps are deploying and redeploying that the plane doesn't violently pitch up and down as the amount of lift changes dramatically.