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42 votes

Why does the Antonov AN-225 not have any winglets?

Winglets are less effective at producing added lift than an equal-length wingspan extension. They are used on airliners when simply enlarging the wing would put the plane into a larger size class, or ...
Therac's user avatar
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31 votes
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How did this flydubai 737NG get Max winglets?

These are called Split Scimitar Winglets and they are offered as an upgrade for some existing Boeing 737 NG series aircraft: Split Scimitar Winglets are offered by APB for the 737-800 and 737-900ER ...
Bianfable's user avatar
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27 votes

Would an 8% reduction in drag outweigh the weight addition from this custom CFD-tested winglet?

The first possibility is that that the CFD in your cad isn't as sophisticated as the software used by boeing's engineers. Which means that your design may have flaws that don't show up in your ...
ratchet freak's user avatar
27 votes

Would an 8% reduction in drag outweigh the weight addition from this custom CFD-tested winglet?

First off, awesome question and great investigation! This kind of let's-see-what-happens inquiry will take you far should you decide to pursue aerodynamics at an advanced level (and, of course, in ...
Peter Schilling's user avatar
25 votes
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Why are almost all winglets turned upwards?

Up winglets are less likely to hit the ground. The clearance from the wingtip to the ground in a worst case situation is important. Sometimes there is a requirement on the wingtip clearance when one ...
Rob McDonald's user avatar
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18 votes

Why are almost all winglets turned upwards?

Just to complement the other answers a bit. I was looking around and I found that the A-10 has downturned winglets Those wingtip devices on the A-10 are not really winglets but much simpler "...
sophit's user avatar
  • 13.5k
14 votes

Do F-4 Phantom II pilots actually fold the wings?

As several of the comments have mentioned, the F-4 have the option of folding the outermost section of their wings, as shown in the picture below. The main purpose of this was simply to save ...
bjelleklang's user avatar
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12 votes
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Why do some aircraft have pods on their wing tips?

Wingtip pods or winglets differ in installation reason from aircraft to aircraft. Here is a non exhaustive list of possible reasons: Fuel tanks Whitcomb bodies to enhance the area rule of the ...
Talonhawk's user avatar
  • 346
12 votes
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How is drag created from wingtip vortices?

Wingtip vortices don't create drag, just as wet streets don't cause rain. Lift creation and viscosity create drag. Drag is composed of pressure drag and viscous drag, and induced drag is one part of ...
Peter Kämpf's user avatar
12 votes

Why doesn't the 747 that is testing the GE9X have winglets?

That's because its been removed for testing. The aircraft used in for flight testing the GE-9X belongs to GE and is a modified JAL 747-400. The aircraft, a former Japan Airlines -400, was acquired ...
aeroalias's user avatar
  • 100k
10 votes
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Do F-4 Phantom II pilots actually fold the wings?

In U.S. Navy and Marine Corps F-4 Phantoms, the wing fold mechanism was controlled and powered by hydraulics, since the pilot had to fold the wings after landing for taxiing around on the deck. The ...
Charles Bretana's user avatar
10 votes
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What is the purpose of the winglets on the Socata TB-31 Omega vertical stabilizer?

What you observe here are VHF nav antennas for a VOR receiver. This antenna design is lower drag than wire whip antennas. The antenna serves no aerodynamic purpose except to minimize its own drag ...
STWilson's user avatar
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10 votes
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Are the aerodynamic benefits of winglets similar for both powered airplanes and gliders?

Technically yes, but you have to consider that the benefits are weighted toward higher AOAs and lower indicated airspeeds, where the vortice flow is strong enough for the energy extraction benefit to ...
John K's user avatar
  • 132k
9 votes
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Why are downward pointing winglets more efficient?

For efficiency the orientation of winglets is not important. Best would be to stretch them out horizontally, but on a canard they do double duty as vertical tails. Things look different when ...
Peter Kämpf's user avatar
9 votes

How is drag created from wingtip vortices?

The short answer is this: Drag is not "created from" from wingtip vortices. Says McLean, The trailing vortex sheet and the rolled-up vortex cores are often seen as the direct cause of the ...
Peter Schilling's user avatar
9 votes

Why do newer 737s use two different styles of split winglets?

Since a winglet is basically a sail generating thrust (lift with a modest forward-tilted vector) from the circulating flow around the tip, extracting beneficial energy from the circulation (the thrust ...
John K's user avatar
  • 132k
9 votes

Would an 8% reduction in drag outweigh the weight addition from this custom CFD-tested winglet?

First of all great analysis! I am not expert in aerodynamics but from the little I know, aircraft are a compromise. When you design a plane you have to make shapes that are possible to manufacture, ...
Afe's user avatar
  • 1,501
8 votes
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What is the purpose of these winglets on the Chinese version of the An-2?

As you said, the Y-5 and Y-5B are Chinese variants of the Antonov AN-2. The Wikipedia page gives this info on the Y-5B: Shijiazhuang Y-5B-100 – Y-5B aircraft fitted with triple tipsails on the ...
Ron Beyer's user avatar
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8 votes
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Why do newer 737s use two different styles of split winglets?

The 737NG was originally introduced with with no winglets. A company called Aviation Partners worked with Boeing to develop the "blended" winglet, originally for the NG-based BBJ (Boeing Business Jet)....
fooot's user avatar
  • 73.4k
7 votes

Why do some aircraft have pods on their wing tips?

Many aircraft have had fuel tanks mounted on the wing tips. These were sometimes main tanks, but often were auxiliary tanks, or even "Drop Tanks" which could be jettisoned for combat. The tip tanks ...
Mike Sowsun's user avatar
  • 37.8k
7 votes
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If a winglet disconnected from an airplane mid-flight, what would be the consequences?

this actually happened to the Rutan around-the-world flight, where one winglet was shaved off against the runway pavement during the takeoff roll. the pilot then stabbed the controls to overstress the ...
niels nielsen's user avatar
7 votes

Why doesn't the 747 that is testing the GE9X have winglets?

To quote from this article in Popular Mechanics, In preparation for the flight, GE removed six-foot wing extensions from the 747 to reduce the wingspan to just over 195 feet, stiffening the wing ...
Daniel K's user avatar
  • 5,518
7 votes

Why can’t more older 737s be retrofitted with more newer winglets?

Winglets change the spanwise loading on the wing. By increasing the effective span of the wing, lift is increased towards the tips of the wing. With more lift there, you get an increased bending ...
user71659's user avatar
  • 6,636
6 votes
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Why has Boeing used mini winglets on the 737-200?

When originally Richard Whitcomb of NASA developed the winglets, he developed the split winglets with one above and one below as shows in image below: The one above starts at 0.4x chord from the ...
jayS's user avatar
  • 918
6 votes
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Why do some airplanes have their winglets at different angles?

Winglets are symmetric, meaning they are the same shape, size and angle on both sides of the airplane. Different shapes and/or angles would mean the wings would have different aerodynamic properties, ...
GdD's user avatar
  • 54k
6 votes
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How do endplates reduce induced drag?

The vortex itself isn't the issue, it's the "leakage" that is resulting in the vortex. The leakage is from the air near the tip being free to flow around it and results in wasted energy. The wing ...
John K's user avatar
  • 132k
6 votes

Are the aerodynamic benefits of winglets similar for both powered airplanes and gliders?

Perhaps a better question might be swept wings vs straight wings. Gliders gain efficiency through straight high Aspect Ratio wings that have relatively weak wingtip vortices, especially near the best ...
Robert DiGiovanni's user avatar
6 votes

Why did Pipistrel design the Sinus with core wing sections just at 40' instead of well under?

Per the Pipistrel USA Sinus FLEX web site, the wingspan without tips is 39’11” to fit in standard 40’ US hangars. After pulling it out of the hangar, you would likely attach the long tips, which aren’...
StephenS's user avatar
  • 27.7k
6 votes

What are the techniques that delay the formation of shock wave over wing?

Winglets are not used to delay shocks. They help to squeeze a bit more lift from a wing and reduce induced drag for a wing of given span. Winglets help to increase the pressure difference between the ...
Peter Kämpf's user avatar
5 votes

Why does the Grumman Bat feature inverted winglets?

Without knowing what was going on in the minds of the designers it's difficult to tell exactly, however there are a few reasons as to why the vertical stabilizers are featured both above and below the ...
andy-m's user avatar
  • 549

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