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 ...
  • 17.8k
31 votes
Accepted

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 ...
  • 47.5k
28 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 ...
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 ...
25 votes

Is this a wing-tip device on the A-10 "Warthog"?

The wingtip devices used in A-10 Warthogs are called drooped wingtips (also called Hoerner wingtips in some cases), which essentially increase the aspect ratio of the wing by forcing the vortices ...
  • 98.8k
25 votes
Accepted

Why do propeller blades not have winglets?

Winglets on wings help because they increase the volume of air on which the wing can act. Extending the wing span would be much more efficient, but when span is restricted or the maximum wing bending ...
24 votes
Accepted

Is wingtip design mature?

The wingtips are a unique part of the aircraft in that they really have one job; minimize drag. Their design is easy to see, and they are a fairly recent addition to transport aircraft. Developments ...
  • 69.9k
14 votes

Why don't horizontal stabilizers have winglets?

Short answer: In all cases these are not winglets, but fins. Winglets are worse than an equal span extension and are only used if span should not increase: for limiting the wing's root bending ...
13 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 ...
  • 3,613
12 votes
Accepted

Why don't airliner winglets have consumer advertising on them?

Why airlines don't put third-party ads on winglets I would assume that a significant part of the answer is that it would look and feel cheap (i.e. not good for the airline's brand image.) They don't ...
  • 19.1k
12 votes
Accepted

Why do winglets reduce maneuverability (of fighter jets)?

Your observation about roll inertia is correct: Winglets add proportionally more roll inertia for their small increase in L/D, and this increase exists only for the higher range of lift coefficients. ...
12 votes
Accepted

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 ...
  • 346
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 ...
  • 98.8k
11 votes

Is this a wing-tip device on the A-10 "Warthog"?

It's called a drooped wingtip. The general idea is to move the vortex away from the wing, reducing it's influence. As with all the winglet variants, opinions vary about whether or not it generates ...
  • 6,193
11 votes
Accepted

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 ...
10 votes
Accepted

Why don't airliners have rudders on the winglets?

The purpose of the rudder is to control the heading of the aircraft. It turns the aircraft by creating an aerodynamic moment about the vertical axis of the aircraft. The moment is product of the ...
  • 75.4k
10 votes

Is this a wing-tip device on the A-10 "Warthog"?

If I add raised wingtips to one of my RC planes they significantly decrease the aileron authority, meanwhile improving the dihedral effect and the self-stabilizing tendency. But for maneuverability, ...
  • 101
10 votes
Accepted

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 ...
  • 1,726
10 votes
Accepted

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 ...
  • 110k
9 votes
Accepted

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 ...
9 votes
Accepted

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 ...
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, ...
  • 1,461
8 votes

Why don't airliners have rudders on the winglets?

Short answer: Vertical tails create more yawing moment per unit of drag. Vertical tails create less adverse rolling moment for a given yawing moment. The rudder works by creating a side force, just ...
8 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 ...
8 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 ...
  • 110k
7 votes

Why don't airliner winglets have consumer advertising on them?

I doubt the space is worth very much. The interior side of the winglet is really only visible to people on the plane and even most people on the plane can't see it well. You're only advertising to ...
7 votes

Why are there different types of winglets?

Winglet design is driven more by marketing than by engineering, so every aircraft brand tries to cultivate their own, supposedly better, shape. A study by Nita and Scholz (PDF!), Chapter 6 gives a ...
7 votes

Why don't airliners have rudders on the winglets?

It is possible, but just not that useful. Controllability In order to maximize the moment incuded by the rudder (or keep the rudder as small as possible to provide this moment), you want to place ...
  • 6,193
7 votes

Why do propeller blades not have winglets?

Hartzell make propellers that appear to have winglets (tips bent aft) called Q-tips. The name seems to refer to them being quieter. I have read that they do the same job as a slightly larger diameter ...
7 votes
Accepted

How can I get started on a winglet design for a small remote controlled aircraft?

For best results, put good flaps on the wing and forget using a winglet. If you insist on bending the wing up at its end, just continue with the tip airfoil and select the incidence such that your ...

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