Winglet Design - CFD Study and Aerodynamics

[@tomricotta5984]

You have done a fabulous job. In the 80's I worked for Aerodyne Engineering. I was just a fiberglass laminator building experimental winglets for private planes. Our winglets were approx. 20" hi. setback from the leading edge, and sloped radically. They had a semi symmetrical airfoil They sloped out at the end of the trailing edge of the wing but the tip extended passed the the wing. They reduced drag and increased lift.

[@WynnofThule]

5:14 Perhaps as the outboard air travels up the winglet, it's inward curving profile itself also generates a little bit of lift.

[@williamfraser]

Nicely presented video. It is generally better to model the control volume (i.e. your wind tunnel) as a large cube. Or half-cube if you are using symmetry on the centerline boundary. Make it a large as you can in each direction. You can keep the outer mesh very course to keep the overall mesh size moderate and sim run-times reasonable. If you see a big difference in results between your current size tunnel and a much larger volume then you can safely assume that your current results are not that accurate. Conceptually, a winglet should extract energy from the tip vortex. It is essentially a mini vertical wing that experiences a strong "side-draught" of air. The result is a lift component pointing inboard. In order for this lift component to be of any help you need to give the winglet a slight toe-out at its root with increasing twist towards the very tip (washout). When viewed from the front you should be looking at the low pressure surface of the winglet. That way the winglet's lift component actually points slightly forward, basically generating a bit of thrust.

[@sadraorangi3958]

My man is underrated Appreciate your work G

[@brucetenhave6952]

Very interesting! I will be looking forward to you further test and vids.

[@ColtonCampbell]

Thank you! I'm looking forward to diving deeper into the subject

[@RegisMichelLeclerc]

Interesting, but in the end, it raises more questions than it provides answers. For instance, does it make a difference if your main wing is straight, backswept, back-delta or forward swept? Does the angle and the curvature of the winglet to the main wing make a difference, especially for the curved one? I'm pretty sure the winglets I saw on the Boeing and Airbus have a curve leading to the winglet and that the winglet is not 90degrees. When you have a winglet above and below, have you tried changing the angle? I'm sure I've seen winglets top and bottom curved in such a way they have a right angle between them. ...And, of course, there's the ground effect, especially for the under-winglet. Thank you for the wind tunnel trick, I'll try that soon.

[@hu5116]

Great video! Pondering the differences in your results, I think your bottom winglette was notably shorter than the upper. Recent theory on these finds them to be generally ewuivelent to increasing your wing span by height of the winglette. If the bottom one is shorter it’s going to have less lift, but likely similar drag since most of the drag is interference drag at the fillet, which would be about same as other winglette. I’ll be if you made the lower winglette the same as upper they would be similar. The one surprise is the curved, but still maybe not. If we use the same analogy of winglette height equaling wing span addition, then the circled winglette will have about pi/2 longer length ie about 1.5. You showed 16/12 = 4/3 = 1.333. Your winglette had a taper in it so that will reduce the 1.5 IAW geometry. I’ll bet it’s right about 1.333 ;-)

[@MegaDada1995]

A finer mesh (specifically, adding some boundary layers) would have probably made the top&bottom wing fence perform even a bit worse still, due to the interference drag. However, this goes for all winglets. Having a blended transition from wing to winglet should reduce interference drag and increase performance.

[@zultandimitry572]

Is there a way to make autodesk flow design work this days ?

[@justgriff1295]

Did it calculate induced drag or just pressure and viscous? I’m trying to do the same essentially in Simscale.

[@moren0d1]

Great video! Im doing research on winglet design for FPVWRA spec race wings. Current spec race wings achieve speeds of 80mph. I think little thought has been given to the current designs. A reduction in induced drag is more important. Any suggestions?

[@ColtonCampbell]

Hmm that sounds like a great follow up study... Let me think about it more when I get some time! Until then, try this curved design in the video

[@AGGELIAFOROS]

Nice. It would be interesting to see in the same simulation what is the comparative effect on efficiency of an increased aspect ratio of about the same area, to get some perspective on what the true advantage of winglets is. Using a symmetric aerofoil for the wing extension to achieve the aspect ratio increase, would produce no lift in cruise

[@niconicgamer]

Hey Colton, Great work on winglets. Got me an insight about my project on morphing winglets. Can you suggest me how to make a geometry of morphing winglet?

[@alexdharmdas7546]

can u please tell me the name of the software ???

[@cidharshit90]

Hi sir can I know the dimensions of the curved winglet of your design , it will be helpful for my thesis

[@Intelligent_Bot]

Did you have the same portion of the wing taken into account in every single study? Maybe you should do these studys again with a bigger area around the wingtip taken into account.

[@Michael-yn7iu]

Taking a page from your curved design, I wonder what the difference would be if the tip below the airfoil was curved like your new tip curved inwardly verses outwardly.

[@ColtonCampbell]

Good idea, i'll have to look into this in the future

[@nismax0822]

@@ColtonCampbell have you come up with anything on this question? I'm curious to know if it's possible to curl the wingtip vortices in the opposite direction, and what effect it would have on your lift/drag ratio?

[@bruce.lambert]

Many thanks, great info! What air speed is needed before the winglet shows any effect?

[@ashtonhartley2662]

Can you try it with the curve going outward?

[@jamesomega]

Great comparison! Did you get a chance to fly these at all? FF efficiency aside, a winglet's main job on an rc flying wing is for low airspeed handling and consistent stall characteristics. I don't know if you've moved on from this topic at all but it would be very interesting to see how these winglets would react in a high bank fall, like the apex of a hammer head. Keep up the great work!

[@ColtonCampbell]

Thanks for the info! I haven't had a chance to dig into this more but someday hope to and will keep that in mind, I appreciate it 🙃

[@5ty717]

If performance is L/D for a given wing across the airspeed range then conbobulating drag reduction with performance is problematic. Moreover, describing downwash or tip vortices as performance degrades without accounting for lift variation and parasitic drag replacing induced lift drag is also problematic. If you review your language perhaps improve your aim and gains.

[@xristosconsta]

Thanks for sharing! How would your results compare to a twisted wing with bell shaped lift distribution?

[@gwenellaabutal7793]

What is a winglets?

[@scottyh72]

Can you increase the speed and run the test again? 20mph is pretty slow. My wings are usually flying at 80mph or so.

[@ColtonCampbell]

Sure I can do some high speed stufies in the future. This was a test for the typical cruise conditions of simple foam board wings. Also these were done at 5deg AoA which simulates a decent pull out at 20mph Tip design is Reynolds number dependent so changed with speed; I can do an overview of wingtip design when I make my pylon racer

[@scottyh72]

@@ColtonCampbell Thank you!

[@johnroyal4913]

I have made a small balsa glider with there wingless. I had the idea a while ago but never tried it. I came across this while researching more about it. I have fusion but not the CFD program. Ill see if I can model it up in cad and get you a file if you want to try it out. I have more ideas as well.

[@alisioardiona727]

Very interesting video. I shall do some winglets for my RC planes as well now.

[@vamoa3448]

Very interesting indeed. You said you wanted questions you can answer in you video so here’s one: Can I attach a multicopter propeller to a plane? I have a catalina on which I made one engine turning right and now I’m looking for a pair of propellers. In most online shops you find left and right turning propellers only for multicopters so I wonder, why not? What’s the difference? Thank you for your answers.

[@learningtocrash4030]

I've used smaller quad props and motors with great results, from 3 to 6 inch ones, because they're cheap and I crash often. There's no real reason that I know of for why plane props turn CW (from the pilots perspective). Maybe in the RC world it's because of the way nitro engines are designed to rotate. You can get pusher props for planes, they turn the opposite way. My main concern is that the prop nut tightens rather than loosens when power is applied. If you have a twin motor plane than thrust angle isn't an issue; but if you put a CCW prop on a single motor tractor plane you have to give it left thrust rather than the normal right.

[@ColtonCampbell]

The main difference in "multicopter" props vs plane props are the way they are designed; most multirotor props are design for high static thrust conditions, i.e. creating alot of power without alot of oncoming airflow. Most plane props are optimized for a good amount of incoming airflow as the plane moves through the air. In practice, you won't notice much difference for small models unless you are looking for a high speed fixed wing plane.

[@learningtocrash4030]

@@ColtonCampbell Most of my flying is slow and close so quad props are great on my micros. They give them lots of pull. Great video BTW. I look forward to more.

[@ColtonCampbell]

Thanks for the compliment! New video will be out this Thursday!

[@learningtocrash4030]

Great I look forward to it. Your presentation was very good. I couldn't be on that side of the camera, lol. Fluid dynamics is fascinating and the animation was very interesting, I slowed it down to see the flow better. I use Inventor at work and it's fun to put different parts in the FEA to see what happens...I wish we had CFD. Check out my first wing kzbin.info/www/bejne/eZnHgGWAmr6UebM

[@plewisto]

Very interesting conclusions.👍👍

[@1freedlander]

Very interesting experimenting. You may want to further refine your study by having the winglet more gently curve from the horizontal to the vertical (as do the winglets on full size craft). According to some, the blended winglet has less interference drag than the 90 degree angle of the basic type winglet (about 10% less drag). You are doing really good work, thanks Rudolph

[@garthlee8166]

many thanks for sharing and an inquiring mind :)

[@ColtonCampbell]

Glad you enjoyed it! Someday I'll get around to making more 👍

[@nikleiser5888]

Winglets are way more efficient if you add a sawtooth design on all edges with different heights like a Sounddiffusor. reverb.com/item/11532350-3-black-and-red-acoustics-panel-wooden-sound-diffuser A guy on KZbin tried this technic for a different purpose with outstanding results. And one more tip: put the winglets further to the tail.

[@ColtonCampbell]

Interesting note on the sawtooth design. I might have to look into that, thanks for the comment!

[@nikleiser5888]

@@ColtonCampbell Hey Colton, I finally found the videohttps: //kzbin.info/www/bejne/nJCWamiCZdaUha8 .

[@ColtonCampbell]

Thanks Nik, I will check them out

[@hanoverview]

you dont need winglets on a wing . !

[@ColtonCampbell]

Depending on the design, lift distribution, and operation envelope they may or may not be beneficial... 99% of the time for older designs or simple RC models they are beneficial because of non-optimized wing load distribution and tip design

[@hanoverview]

i get that :) but you dont NEED them :) flying wings fly perfectly without winglets . but that brings me to another question .. how important is it to have a smoothe wing . i am thinking about covering my EPP wing in covering film

[@ColtonCampbell]

Haha well... That depends on what you consider essential for your flying 😁 on 99% of designs if you don't want Dutch roll you need vertical stabilizers on your flying wing (tailless aircraft) and those are typically found in the form of wing fences or "winglets"