42

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 outside the 80 m "box". A longer wingspan, which the An-225 has (10% over the limit), is better at producing lift. The An-225 is a special purpose cargo ...


33

I've talked to a couple of aerodynamicists, and for small aircraft when you run the numbers the improvement offered by winglets is often less than the drag penalty caused by their weight (which also reduces allowable payload). For larger aircraft that fly long distances, the proportion of the aircraft's weight that is due to the winglets is much smaller than ...


31

they reduce the wingtip vortex and the associated drag by deflecting the air that wants to escape over the tip back down (source: wikipedia)


31

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 and came into service in early 2014. They are available as a retrofit to existing winglet aircraft. A set of SSWs weigh 133kg (294Lb) per aircraft but give fuel ...


28

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 other pursuits). Not so long ago, I had to write a similar report: lacking the resources and knowledge of the aerospace giants, I, too, wondered why I could ...


27

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 software but do in Boeing's (or not even in there but do in a windtunnel). Second is that I only saw one flight configuration being tested. Airplanes do more than ...


25

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 moment is limited, winglets bring a small improvement in efficiency at high lift coefficients. On propellers, however, the winglets would run through air which ...


25

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 further out. Source: zenithair.com There are a few reasons for having this wingtip device: The drooped wingtips act in a manner similar to the winglets and ...


24

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 continue to be made in the study of aerodynamics, with modern computing power and methods allowing much better modeling of flow patterns to evaluate designs, and ...


23

As others have pointed out winglets don't make much aerodynamic sense for small aircraft. The point of a winglet is basically to deflect the wingtip vortex away from the lift-producing part of the wing, granting an increase in effective wing span without the added form drag of actually making the wing longer. The winglet itself creates some form drag ...


19

Wing generates lift by creating area of higher pressure below and area of lower pressure above. At the wing tip, some air flows around the tip, reducing the pressure differential and thus the efficiency of the wing. This is called transverse flow. The wing tip reduces this flow, thus improving the efficiency. The effect of wing tip is actually similar to ...


17

Horizontal stabilizers don't generate as much pressure difference as the wings. Generally the stab deflections are very small in flight, and there's so much other drag during landing -- when the stab gets the most use -- that wing vortices from the tail are probably the least of your problems. Stabilizer winglets on their own, when there's no pressure ...


17

First, winglets look fancy but will not help that much in drag reduction. They were pushed less by engineers than by marketing, Boeing's in particular. They help a litte in ideal conditions, but in sideslip or at high speed they can quickly increase drag. Then, most small aircraft are designs from a pre-winglet era. Adding them means to invalidate the type ...


15

Many small aircraft designs are rather old and winglets were not common on airliners either when they were certified. For airliners that fly 8 or more hours a day saving a few percent on fuel quickly pays off the additional development and certification, so winglets were adopted quickly there. But typical general aviation aircraft does not fly anywhere close ...


14

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 moment, or for size limitations Putting them on the tail surface would not help to limit the wingspan: The horizontal tail can easily grow and still be much smaller ...


12

Winglets, raked wingtips, fences, sharklets all do the same thing; reduce drag. When the wing is working hard (high AoA), it will produce a lot of this kind of drag since vortices of all kinds will be stronger. Winglets makes the passage of air from the bottom of the wing to the lower pressure top of the wing more difficult, thus reducing induced drag. The ...


12

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 usually sell advertising elsewhere on their livery for much the same reason (though they do occasionally dedicate a livery to advertising some charity or some ...


12

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. At low lift coefficients (think cruise), when the induced drag is low, they add more friction drag and reduce the L/D overall. There are three aspects to ...


12

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 precious space on aircraft carriers, it had no use when flying. There have been some incidents where wings have either started to fold during flight or where the pilot ...


12

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 by GE in 2010 and following maintenance and interior modification in Xiamen, China, by Taikoo Aircraft Engineering, was delivered to Evergreen Aviation ...


11

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 more lift than other variants. Source There are more aircraft that employ this type of wingtip device: Source Source


11

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 aircraft also known as Kuchemann Carrots Vortex generators and relievers - used to enhance aircraft aerodynamics and modify fuel consumption Mass balance - in ...


10

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 aerodynamic force and the arm. image: NASA The aerodynamic force is the the side force on the rudder, the arm is the distance between the rudder and the centre of ...


10

The tiny mass of air that this device can affect will in no way have the claimed effect on induced drag. This wingtip vortex pseudoscience is just bullshit. What can be observed as a vortex behind the wing is actually the consequence of the vortex sheet rolling up due to downwash behind a lift-generating wing. But air flowing around the tip has almost ...


10

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, it's not as good. If I add an autopilot, like Ardupilot, the raised wingtips will make harder for the autopilot to instantly correct the leveling when passing ...


10

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 pressure drag. Unfortunately, the Internet is full of memes which attribute induced drag to those wingtip vortices, but some swirling air behind a wing can ...


9

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 profile.


9

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, don't cost too much and are strong (and compliant to the regulations). Last but not the least, you have to test the drag over multiple phases of the flight and in ...


8

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 maneuvering is added: Now the downward-pointing winglet is superior especially if it carries a rudder. When roll is commanded by deflecting the ailerons, the lift ...


8

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 USAF versions of the Phantom, on the other hand, had this hydraulic capability removed, and there was a pin in the top of the wing, (if I recall), just inboard of ...


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