Copying Nature - Feathers On a Glider Wing to Reduce Drag and Soften Stall

| IMPORTANT. This will be my last weekly video for a while. I have a lot to take care of academically and can no longer produce weekly videos. I may, however, post occasionally.
As for today’s topic; feathers! Birds use what are called ‘covert‘ feathers to reattach separated airflow during what would have been a wing stall. This stabilizes the wing even in the most turbulent of airflow, and allows continued lift production well into the stall angle range for most man-made aircraft. I was inspired to look into this idea by this video from Felix Schaller, linked here: • Dynamic morphing Airfo...
I experimented with the covert feathers in much the same way Schaller did; by making fake feathers from a thin, bendy material, and affixing them to the wing‘s upper surface. I used only one row of smaller feathers, but was still able to notice improvement in glide ratio and stall recovery. I have no doubt that, had I put more time into the fabrication of the feathers, and arranged more bird-like feather rows, the improvement would have been more drastic.
If you enjoyed the video, your like and subscription are highly appreciated! As I will be away from this channel for a while, I do entreat you to share my videos with friends, and to help me maintain viewership during my absence. I have hundreds of other videos, so there always something new to watch! That said, thanks for watching!
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[@boomfiziks]

Very interesting. I teach an Aeronautics STEAM class and this video is going into “must show my students “ list of videos. Keep up the great work!

[@AeroCraftAviation]

That's so cool! Makes my day to hear that this video will be used in an educational context! :) Thank you so much!

[@yassermasood3423]

I am genuinely impressed young man. At your age you are extremely knowledgeable and at the same time explain it. Your parents must be very proud of you. Keep going, best of luck. Stay blessed.

[@AeroCraftAviation]

Thank you, truly, for such kind words my friend. I am really devoted to aerospace and so I enjoy the learning and especially the explaining. Putting these videos together was such a lot of fun. I really must get back to it. Thank you so much for your support. :)

[@wunkus]

I'm a licensed Aircraft Mechanic and can say that you have a very good understanding of aerodynamic properties as they relate to an airfoil.

[@AeroCraftAviation]

Thank you so much! That means a lot. :)

[@goldenfish77]

At 6:46 is my favourite part. Very nice break and flying movements.

[@AeroCraftAviation]

@@goldenfish77 Thank you!

[@BikingVikingHH]

I’m a licensed automotive mechanic and unlicensed remote control aircraft mechanic and I can tell you have a very good understanding of his good understanding of aerodynamic properties as they relate to an airfoil.

[@wunkus]

@@BikingVikingHH I didn't realize anyone needs a license to do maintenance on a car.

[@BikingVikingHH]

You’re a really smart kid. I hope college is serving you well. You’re innovative and industrious, one of the few individuals that will actually benefit from a college experience. I’m curious to know what you are studying if you ever see this message.

[@AeroCraftAviation]

Thank you for your kind words! I'm at RPI now majoring in Aeronautical Engineering and minoring in Chinese Language. Currently I'm living in Tianjin interning at a small startup doing speciality UAVs. When I get back to the States I'll start my junior year. Upon graduation I plan to return to China to do my master's at Beijing University of Aeronautics.

[@paulpaulsen7309]

... the phenomenon existed "in the past", when people went from rough paper covering to smooth foils, a very narrow (approx. 1mm) wide strip of adhesive tape on the top, approx. 1 - 2cm behind the leading edge, helped ... ... just my two cent ... ... by the way, ... good vid ...

[@wingnutzster]

You can’t go wrong in aeronautics if avian is your starting point this is easily my favourite video of the month.

[@AeroCraftAviation]

I agree totally. Thank you! Glad you enjoyed.:)

[@joshuawfinn]

Very cool stuff. That's one beautiful airplane too.

[@AeroCraftAviation]

Thank you!

[@ethanhermsey]

Wow! I did not expect such a drastic improvement! Noticeably a bit more drag but that plane is virtually unstallable. They're like active vortex generators. They only pop up ( on their own ) when they are needed. I can't find anything about covert feathers on plane wings. You might be the first to document on that. I like the animations, nice job on the video edit :)

[@AeroCraftAviation]

Yeah the improvement is really significant. In theory,. the drag should actually be considerably less. There is a paper I found that described wind tunnel tests of similar surface-mounted elements, showing up to 15% drag decrease. It may just be that the feathers in this case catch passing air currents and cut down on the aircraft's momentum thereby. As for functioning like vortex generators, in certain cases they do, but there's also a way to think about it where they don't necessarily. Notice that, when the feathers raise, they are effectively lowering the downward deflection of the upper wing surface, relative to the freestream. If we assume the freestream is laminar, then this means that the feathers allow the high-energy boundary layer to remain laminar for longer as it can easily flow around the shallower curvature of the feathers. By the time the airflow is leaving the back edge of the feather, it is right above the adverse pressure gradient, and the stagnant area. Thus, it can separate from the feather in a low-energy region, where it does not turbulate so drastically. It then rejoins the freestream and flows away. I would presume this is where the theoretical decrease in drag comes from. Well, whatever the case, I am definitely not the first to have employed this idea. Felix Schlaller has done the same thing here: kzbin.info/www/bejne/jHnHqJ2nfaaYo7s. Glad you liked the video. Thanks! :)

[@loganreuter6072]

Wow! I did not expect them to improve the performance of the aircraft that well, especially during a stall. Very nice work!

[@AeroCraftAviation]

Yeah it's really quite surprising. Thank you!

[@CallSign_CoinSniffer]

I can see how the feathers can "augment the airfoil." From the footage that I saw of how the feathers move about, I can only theorise that the feathers create a more gradual path for the air to follow, thus reducing the stall characteristics to a mere gentle fall, combined with the already good tendencies of the stock sail plane. I'd love to see how you can optimise the feathers' shape to achieve better performance. Amazing work

[@AeroCraftAviation]

Right that's what i think, too. Essentially they flatten the curvature so that the oncoming air doesn't have to angularly accelerate as much. Thanks for your comment.

[@AdamCourville]

The performance was more than I expected! Awesome experiment and great video about it too!

[@AeroCraftAviation]

Yeah it worked really well! Thanks!

[@fredtedstedman]

great to see the aerodynamics of the Red Kite , they have been reintroduced to a lot of Wales in the last 30 years . love 'em ! this glider is wonderful .

[@AeroCraftAviation]

They really are amazing birds. I've never spotted one myself but someday hope to be in a place where I can.

[@fredtedstedman]

@@AeroCraftAviation Now living in England and Scotland , re introduction and protection , from only 40 breeding pairs . we can now watch them over our house , VERY aerobatic for a bird with 48" wingspan , hope you see one >

[@ricomon64]

VERY interesting! I thought the stalls were fine with the unfeathered wing, but WOW, what a difference the feathers make. I wish you all the best in your academic en endeavors.

[@AeroCraftAviation]

Yeah well, it is rather lightweight (just over 80 grams), so the stall was bound to be pretty gentle to begin with. But for sure the feathers do help a great deal. Thank you! :)

[@56Seeker]

Very nicely done.

[@dickiebrewer1232]

Glad I found your channel. Pretty cool.

[@quentincalabrese3300]

Once again, very interesting. Thanks for sharing.

[@AeroCraftAviation]

Thanks! Glad you found it interesting. :)

[@georgehiotis]

I see this dude as an engineering PHD graduate soon. Excellent vid.

[@Y13A]

Very cool, did not know about these covert feathers before watching. The alula, another type of feather on birds, serves as natural “leading edge flaps” for birds, but this is something entirely different. Very cool experiment!

[@AeroCraftAviation]

Yeah the alulas are like the steering feathers. They are used at low speeds for high maneuverability by altering the lift and drag and boundary layer stability right at the leading edge.You can really see the alulas in action when watching birds like eagles that need to maintain high lift production and have extreme maneuverability at low speeds. Similarly, poultry like chickens and pheasants have some cool alula deflection at high angles of attack. I think the coverts are in a way passive extensions of the alula function. I mean they help maintain lift at low speeds and prevent wing stall. The whole function of these feathers is really quite nuanced and I think oughta be looked into more. It's all such cool stuff.

[@keithhudspith5245]

I'll be adding this theory to my small foam planes, thanks for figuring this out!

[@AeroCraftAviation]

Good to hear! I am interested to hear whether it makes a noticeable change for your aircraft. Let's hope science works! haha

[@Flyzguy]

I love the energy and curiosity! The kids are all right! One question: why do you consider ground-based wind speed in your assessment of air-relative aircraft motion?

[@gogotrololo]

Damn thats cool!

[@lucywucyyy]

thats really cool

[@1967250s]

Great experiment. A couple notes: DLGs use a fairly well designed airfoil working at fairly low Reynolds numbers( look that up ). As such, it works in an area of fairly easy stall, along with the tapered wing design. Thicker airfoils on larger aircraft would react differently, also along with a wider chord more prone to stalling, heavier weight loading, etc. Much to be learned. Best wishes on your schooling!

[@AeroCraftAviation]

Thanks. Yeah for sure, stall occurs very easily at low RE. That's mainly because the boundary layer is quite laminar, and so flow contact is tenuous and subject to small surface aberrations or changes to free-stream velocity and turbulence. This poses a difficult challenge for designers of modern drones and MPASs and MAVs and such, as the best L/D efficiency for small UAVs tends to lie in the 0-75,000 RE regime. ( And in fact DLGs are sometimes below 40,000) BUT if you can control that boundary layer (which even the best AG airfoils aren't too great at) you can get this 'natural separation', where flow turbulates right before the secondary stagnation point and separates aft of the adverse pressure gradient, which can be super efficient. So you want to be able to cure that instability and get consistent natural separation. That was the prime goal of this experiment; to see if this was a viable solution or partial solution to that boundary layer instability. Such a mechanism would not be very applicable on a thicker wing with higher wing loading, because such a wing would operate at higher RE and would have more stable boundary layer contact. And a wider chord will actually increase RE even more (because of chord/Kviscosity) so then there's even less use for these feathers. All you really need for such a wing are good vortex generators, like we see on A319s.

[@luke_atthat]

Wow! You are the best! So cool demonstration. I learned a lot here. You are choosing the good field of study, aerodynamics! Thank you so much for your video. Good success in your academics and you do good to take great care of it! God bless you, au plaisir de visionner votre prochaine vidéo!

[@AeroCraftAviation]

Thank you so much! I'm glad you found it interesting. An exciting field of study for sure, aerodynamics.

[@toolbaggers]

you should look into how NASA's F16XL used microscopic holes in the wing and negative pressure to keep laminar flow. I know it was for supersonic laminar flow but the concept of "sucking" at the stagnation points is interesting. you would obviously have to use a much larger plane to offset the weight and size penalties of a "vacuum" wing.

[@toolbaggers]

Congratulations! You discovered vortex generators.

[@AeroCraftAviation]

Not quite, although you are partially correct and they certainly do look similar. Naturally they cause some turbulation of flow in cruising low-incidence flight as a by-product. But their function is to bend upward when high angle of incidence causes extreme liow pressure near the top side of the leading edge. They thereby allow airflow to stay attached to the wing "surface" throughout what otherwise, with a complete separation bubble extending back from the leading edge, would be a violent stall. Theoretically, with very precisely shaped "feathers", one could achieve this function with absolutely no vortex gerenation whatsoever. Birds, especially very aerodynamic ones like albatrosses, show this function very well. (Note that they also have extremely small, rougher feathers along the very leading edge of the inboard section of their wings which do generate vortices but are not actually large enough to alter the apparent incidence of the top side of the wing and to thereby reduce flow separation).

[@shobhitprakash]

I do know aerodynamics well enough but hey .. your experiment is an eye opener to me too..... a must watch video to understand and explain stall and stall prevention (adverse effects of stall kn aircraft). Good work...

[@AeroCraftAviation]

Thank you! I am glad that you appreciate my work. Cheers and happy flying. :)

[@paulbizard3493]

Very interesting. As said below you are quite fluent with aerodynamics. This experiment reminds me of the Me 109 leading edge slats.

[@AeroCraftAviation]

Glad you found it interesting. The function is not quite the same, but perhaps in effect the two are similar, yes.

[@AerialWaviator]

Great experiment and demonstration. Since the time of this recording, there are now micro camera's (

[@allenmoore9848]

Very enjoyable to watch, love your work. Now my question is: Why are no aircraft full size or models that take advantage of the phenomenon and add those feathers? It would be revolutionary to to see Cessna turn into a super STOL because of it. There must be some disadvantages! Tons of material for investigation.

[@wunkus]

I believe the answer to your question would be: unlike a bird's wing, machines such as aircraft can take advantage of mechanical alterations that would be impossible to recreate in Nature, such as Fowler Flaps. Many aircraft are equipped with this type of flap that, when deployed, allows the airflow to pass through the airfoil; thus allowing a vast increase in camber and angle of attack without delaminating airflow from the top of the wing.

[@allenmoore9848]

@@wunkus yes, quite true.

[@GrandadsOtherChannel]

Interesting stuff 🤔👍

[@AeroCraftAviation]

Thanks!

[@marinpopski867]

i enjoyed this video ATLEAST AS MUCH i enjoing lets say Flite Test videos, think about ways to support your channel, keep up working,building and having fun !!!! We want more

[@AeroCraftAviation]

That is really nice to hear. Thank you so much! If you want to support me on Patreon, you can here. www.patreon.com/aerocraft?fan_landing=true I haven't posted much there yet, but I will start posting more if I get more patrons. Thanks for watching and thanks for your kind words! :)

[@martinhobby5739]

Omg, the solution of masive stalling????? Very god video, and felicitations for the 1,30k

[@AeroCraftAviation]

Thank you!

[@somethingelse2740]

Glad to see you finally got around to a feather experiment like we talked about. Seems it actually had some good results. Well done! I'd think that actual bird feathers would give more lift during stall event due to actual feathers having the means to actually lift using the quill as a mini flexible beam in the feather to transfer that feather flex back to the wing. When separation occurs, the tip will flex away from the wing and this can also physically pull the wing upward gently. Unlike paper which just separates and flaps. I would have thought paper would be more of an indicator of separation, but as your test shows, it does actually have a good effect on separation. I'd like to see you use real feathers and see how much difference it makes over paper. You could just tape some feathers in place in the same orientation as the paper, and see what happens. Make sure you use the same size/length feathers as the paper pieces to keep the comparison equal-ish. You really got my hopes up at the beginning of the video when you said feathers.

[@AeroCraftAviation]

Yeah the improvement was quite noticeable. Certainly promising results. That's a cool idea, about the lift force of bending feathers. However, I'm not certain that it would work out that way, mechanically. If a feather is capable of providing mechanical lift, then it must have some resistance to bending. If it has resistance to bending, then it will only bend upward until its resistance matches the air's upward pull. So the two will reach an equilibrium where neither force overcomes the other. If the forces are at equilibrium then there can be no inherent mechanical lift. The only way to possibly get mechanical lift that way would be to have a sudden burst of low pressure which pulls the feathers up, and then a sudden normal pressure which allows them to spring back all the way. Now keep in mind, the 'springiness' of the feather is not an inherently upward force. It is simply a tendency for the feather to close the distance between itself and the wing. Since the wing weighs a whole lot more than the single feather, its tendency for inertial rest would be much greater. Thus, if there is a tension force between the bent feather and the wing, the feather is the one pushing itself down onto the wing, and the wing isn't really getting pulled up towards the feather. So I guess theoretically if the wing weighed as much as the feather, and the feather as much as the wing, then the wing would tend to accelerate upward towards the feather, instead of the feather accelerating downward towards the wing. But in that case the pressure gradient required to lift the heavy feather would be absurdly high. It does seem intriguing though. I can't quite work out in my head for sure if there would be mechanical lift. I might try representing it mathematically to try making sense of it. It's kind of an interesting physics problem.

[@somethingelse2740]

I understand what you are saying, but just to be clear, The feather being used does not necessarily have to be a large one with a 4-5 mm strong shaft which probably would not work well on a wing, but a smaller one with say a 2-3 mm" quill at base would flex quite easily towards the tip of the feather and still do what i said, transferring "a bit" of lift through that quill at stall better than flappy paper strips. And I may be totally wrong. Modelling it might not work properly either, as a single feather is a very complex machine, very hard to model properly. How would you measure the flexibility and all the other forces involved? I'd say best and quickest to just try the experiment, what can it hurt? Of course having all those feathers taped to the top of your wing would make for some relatively dirty airflow compared to the regular smooth surface. Always a price to pay. But hey, feather work well on birds at your glider's type of speed envelope, so why not try?

[@AeroCraftAviation]

@@somethingelse2740 Hmm yeah I see that. I'm still not sure about it. It's one of these things that I just can't figure in my head. It reminds me of that pendulum fallacy, where people falsely think that a helicopter has inherent stability by acting like a pendulum underneath its rotor disk, whereas in reality it doesn't. Same thing here. I feel like there's some logical fallacy here regarding how the forces should interact. I guess if I have time I could have a go at building it. I would definitely need to have some means of measuring the force produced. If there were any extra lift force, I doubt it would be much more than a few tenths of a gram. Perhaps a homemade wind tunnel and some way to mount the wing onto my gram scale. As for dirtying the airflow, yes it does, but surprisingly, the turbulence ends up in the proper place, right before the adverse pressure gradient, such that drag is lowered quite significantly. Felix Schaller has some tests of this showing upwards of 20% drag decrease.

[@somethingelse2740]

I think we are having a communications breakdown here. I am not making claims of adding feathers giving you extra lift during normal flight. Your video was all about giving your low speed glider better stall recovery. Not giving it extra lift. The feathers would be taped down flush with the wing. When the stall happens what were the paper slips effectively doing? I am merely thinking the feathers might work better than paper slips. No helicopter pendulum fallacies here sir. :-) I have no belief that feathers will add extra lift in normal flight, only when the turbulence of the stall happens, the lifting of the feathers by such stall turbulence might give momentary lift helping the wing come out of stall faster than paper slips simply flapping about. Don't overthink it. :-) And I agree with you, I'm not "sure" about it either. But I do believe it would work better than paper slips. To keep the experiment equal, the feathers would have to be equal to the paper slips in size and amount already installed on your wing. no wind tunnels needed, just try it like your paper test and see how the stalls feel.

[@tappan48]

I know its off subject but perhaps this idea I have regarding drones, a sticking point with drones is the noise made by the propellers. My thought is to experiment with the leading edge of the propellers to mimic owl wings. Putting a serrated leading edge on the propellers might have the same effect as the Owl's leading edges making them quiet and perhaps more efficient as they would act as vortex generators. Thoughts?

[@johndagg1081]

I hope you are going into aerospace engineering! Always great work.

[@AeroCraftAviation]

You bet I am. :) Hoping for either MIT or Stanford. Thank you!

[@altbob]

Hey, great video! I can't believe I'm just seeing it now, but things have been crazy busy on my end too. Best of luck with the SAT's and other stuff you are dealing with at the moment!

[@AeroCraftAviation]

Thanks! Just got my scores back. 1540, so I'm pretty satisfied. I might retake it and shoot for 10 or 20 points higher. Applying early action to MIT and Caltech in a couple days. Everything's lookin good. Stressful, but promising.

[@altbob]

@@AeroCraftAviation That's fantastic! Congratulations!

[@romannovikov4374]

Замечательно. Ещё бы сделать видосик с борта, посмотреть как ведут себя "пёрышки" на крыле в полёте на высоте.

[@AeroCraftAviation]

Это было бы интересное видео. Сейчас я изучаю космонавтику в университете, так что, вероятно, скоро буду изучать что-то подобное.

[@NickChitty]

Brilliant work did the cg not change by adding the weight

[@AeroCraftAviation]

Thanks! No, not much. The feathers weighed 1.99 grams all together. Being only an inch or so in front of the CG, they only moved the CG, at most, a small fraction of a millimeter.

[@crankhandle]

It's interesting that evolution chose feathers over something like a bats wing. this characteristic probably explains partly why. Also feathers provide better damage resistance than a skin membrane and were even used as primitive armor by the Chinese!

[@AeroCraftAviation]

The interesting thing is that bats have a great deal more precise control over their wing shape. While a bird just controls the arm joints and the tilt of the various feather groups, a bat can articulate the membrane with its arm joints, wrist joint, and all its finger joints. It can also effect the incidence of the inboard portion of the wing with its legs, which is very advantageous for short takeoffs and landings. I suppose all of the enhancements to aerodynamic control still don't outweigh the dangerous fragility of skin-and-bone wings, especially since without feathers the bat doesn't really have any appreciable airfoil shape, and thus is not terribly efficient in terms of lift-to-drag. That puts quite a weight limit on the creature. Also with the intricate wing control comes the extra weight of the muscles that operate those joints, all of which are within the wing, increasing its rotational inertia about the shoulder and setting a hard limit on flap rate. An interesting consequence is that by positioning their relatively heavier wings in relation to their body, the bat has a great deal of control over its trajectory and attitude regardless of aerodynamics. I think the fact that feathers' stall-softening characteristic is effective at larger sizes, such as for my glider, for seagulls, and for all large birds, explains why bats are so smashingly successful at small sizes but only barely viable at larger sizes. The inertial control afforded by their heavy wings probably becomes more a hindrance than a help for the larger bats, while the rigidity of the keratin in feather shafts probably limits deflection of feathers in small birds where aerodynamic forces are exponentially lesser.

[@georgechristoforou991]

I saw once, a multiple winged plane with many wings staggered above each other that prevented stall and allowed the plane to fly at very high angles of attack without stalling..

[@afilos]

Super interesting, how did you even come up with this idea?

[@AeroCraftAviation]

Well I'm currently working on a big morphing-wing project. It involves a lot of strange and interesting aerodynamics. So, as an exercise in controlling wing airflow, I decided to mess around with different kinds of flaps on the wing to see the effects. I then found the videos by Felix Schaller, which show good results from the feather-type flaps. So I decided to do the experiment.

[@alfredlebeau1553]

Nice expleinign aerodinamic 👍🏻👍🏻👍🏻👍🏻👋🏻🇵🇦

[@AeroCraftAviation]

Thanks you!

[@KipH57]

Where have you been? Hope all is well. Love your planes, experiments and vids.

[@AeroCraftAviation]

I have been applying to colleges, doing a Senior Research project on morphing wing aerodynamics, taking AP classes, learning Japanese and writing poetry. No time for videos. I have really been trying to sneak in the occasional hour of time in the workshop in recent days, but I just can't gather enough hours to do any projects worth documenting.

[@jagadishkandivalasa1720]

Great video. I got something to do in my project with this video. But I was said to show this effect on a simulation software ☹️

[@AeroCraftAviation]

Hmm. It is difficult to simulate flexible materials AND turbulent flow in a single simulation. Maybe you can use a Fusion 360 simulation to find the necessary load for bending the feathers at θ degrees deflection. Then, use a CFD program to find the pressure load on the feathers at θ degrees deflection. See if it is enough load to make them bend.

[@timothystone4998]

Very astute of you excellent work. I'll work on some development off of Your feather Data . It's almost like self articulating vertex generators God's awesome

[@AeroCraftAviation]

Right. It is like an automatically articulating portion of wing surface that moves wherever it needs to be in order to grab ahold of that separating boundary layer. Brilliance of nature.

[@plreeve]

Would this have any benefit on a 12" catapult launch free flight glider on flight times and performance please?

[@AeroCraftAviation]

Sorry for late reply. Yes, it may have some small benefit. That size has very dominant skin drag, so surface aberrations will induce greater relative drag. You will have to be careful with how many fathers you add. You will have to play around with it. But I could see some hypothetical small advantages coming during transition from launch to cruise.

[@remaijonatan3040]

It’s a very nice job, but I could still suggest trying to put a turbo thread on the wing for 6% and it would fly much nicer and further.

[@AeroCraftAviation]

Yeah thread at the airfoil high point for turbulation works well. But I have done that before. This was a test of something new. I wanted to see if it would work.

[@demarzel6193]

The leading edge flap has the same effect. The Japanese bullet train uses the structure of the owl's feathers to mute sound. Birds are often ahead of humans. the way of this video is smarter than the bf-109's automatic leading edge flap.

[@AeroCraftAviation]

Yep, those shinkansen trains are really advanced aerodynamically. It's always fruitful to take a look at what nature has discovered and try to emulate. Always more to be learned.

[@d4ro]

nice observation of this detail of bird flight ! implementation and demonstration are super good. if you want to exercise on tip stall what about trying a more swept forward wing?

[@AeroCraftAviation]

Thank you! That's good to hear. Oh yeah, forward swept wing is a good idea for tip stall testing,. Maybe it would not hold up to throwing, though. The force would act unevenly on the wing. Good idea though. I hadn't thought of that.

[@Flyzguy]

Forward swept wings, without wash-in are quite tip stall resistant. Aft sweep would induce tip stall. Doing some lift distribution studies in something like open VSP or AVL will show this well.

[@d4ro]

@@Flyzguy tip stall quicker in FWS than the rest of the wing, which works as a stall recovery, and adds overall stall resistance because the stream of flow that generates lift on the wing is not affected by it just diminished, i mean your „feathers“ on the inner wing would benefit from added stall resistance of forward weep wings

[@skatetoexplorevideos2477]

i wonder what would happen if you use actual feathers of a bird or synthetic ones?

[@AeroCraftAviation]

The difference would probably not be noticeable. Much of the reason why birds' feathers work the way they do is not because of their unique structure, but more because of how they are affixed to the wing. The elasticity of the bird's skin, as well as the articulation of each scapus effects how the airflow can move the feather. Also, some feathers or more generally some pterylae can be articulated on command by the bird's muscles meaning the bird can change the way their feathers respond to airflow. In terms of mechanical properties, bird feathers really aren't all that special. Really the challenge is getting the feather to attach and to MOVE like a bird's feather. We could get into hinges and mechanisms, and compliant leading edge materials and all sorts of challenges to that end.

[@skatetoexplorevideos2477]

@@AeroCraftAviation oh wow, i never knew about this stuff. interesting. thanks for taking the time to respond so delicately

[@kenkingsflyingmachines2382]

I guess I know what I will be doing this winter: making feathered wings.

[@AeroCraftAviation]

Haha yeah you should give it a go! I'd be curious to see if it also shows noticeable benefits on your aircraft.

[@yassermasood3423]

I have an 8 year old son who is just started to get in to the planes. Can you please make a tutorial for a good catapult launch balsa glider. Thank you.

[@AeroCraftAviation]

I am very busy starting at university now. I will try to make the video. I probably won't be able to.

Good morning, I wisk you a great weekend... Thank you so much for sharing your video with us!!! Let's go forward together... best regards! What's new on our channel? I started a new series of videos abou "How to land an RC Plane?"... I would like to have your suggestions and tips to improve... be welcome...

[@Flyingwigs]

maybe use lightweight covering film but only attach the front portion of the feathers to the wing surface. you could even overlap a second row of feathers like a bird and see what the difference makes.

[@AeroCraftAviation]

Yeah, good idea. I had been thinking of something similar. Will revisit this project sometime and implement better methods.,

[@keithhudspith5245]

@@AeroCraftAviation I'm planning on making a STOL high wing, I'll be adding two rows of "feathers" I'll update you as I go!

[@RiXFortuna]

Glue true feathers, with the correct sizes in a birdlike pattern and test it please

[@AeroCraftAviation]

I have considered doing that. I doubt that true feathers would make much difference. If the theory about the feathers' function is correct, then true feathers would only improve efficacy slightly and would not change any of the fundamental effects. Still, it could be tried just to see the increase in efficiency (would probably be a very small increase, maybe even unnoticeable).

[@daviddavids2884]

1:30, ummm, wrong yes, the coverts are passively LIFTED by turbulence/reduced pressure.! consequently, in this context, coverts don't do anything.

[@AeroCraftAviation]

Yes, that's correct. Covert are lifted into the lower pressure zone, where the airflow attaches to the surface of the feathers. That's what happens here. The low pressure pulls the covert up; at a certain point, the airflow can "coanda effect" back onto the feather surface. Then the pressure below the feather will be lower and the feather will droop back down a bit. There will come an equilibrium where the feather is pulled up just slightly, to meet the boundary layer where it can attach. This is precisely the situation in which coverts do their job best and most clearly to see.

[@abdullahgoraya1383]

What is your country name

[@AeroCraftAviation]

Haha, are my vowels not American enough? Just kidding around. I'm from the United States. :)

[@rvllctt871]

Not all aircraft stall.

[@AeroCraftAviation]

All flying surfaces are capable of stall, and even though a well-designed canard may stall very softly or even imperceptibly, or a helicopter may have an aerodynamic threshold speed much higher than it ever needs to fly, yes truly all aircraft are capable of stall.

[@gardentools2553]

Elon Musk baited

[@AeroCraftAviation]

Ah yes he really is the epitome of world-improvement. I am devoted to developing my skills and intellect and perhaps someday I will be able to help the world like he is doing.