Are Skinny Aircraft Wings Better? 

I once wrote an aspect ratio design analysis program for RC sailplanes The program was based on Martin Simmons book on model aircraft aerodynamics and ran in basic 7 on a commodore 128D, gives you an idea of the vintage. What I found was that for a 100 inch span and fairly light wing loadings achievable in a balsa & spruce construction, sink rate was generally minimised at an aspect ratio between 10 - 13. Just prior to that, this had in practice work out pretty well for a slow high lift floater flying calm & relatively inactive conditions. The model was a stretched and tapered wing version of a Soar Birdy 86" span with which I got 2nd place in my LSF national soaring comp Jerilderie Australia with just such a model. However, higher aspect ratios resulted in increasingly higher wing loadings and air speeds on an increasingly flatter glide slope. The improved glide slope did not out weight the adverse effect on sink rate due to higher airspeed. However, it did improve the models range and therefore ability to search for lift over a larger area & especially it's ability to do so in stronger wind conditions. So basically, it became a gambling game. I have put quite a lot of effort into optimising height from a bungee launch. I could pretty much get more launch height than than anyone else Because of the high camber wing & more rearward tow hook position, I had to hold a little down trim at the start of the tow to prevent the model doing a premature auto release while climbing vertically. It was astounding how much more height I was getting & there was winging to the committee, but everything was comp compliant. The only difference was that I had put the time and effort into trimming & preparing the equipment to get then best performance out of it that I could. Anyway, I had 2 models at the time. 100" span using a scaled down Bird Of Time wing section. This is a much less cambered and thinner higher aspect ratio wing than the other model. Bothe models had similar wing loadings but this higher aspect ratio model was notably much faster had had a much flatter glide. It could cover a lot more ground searching for lift. However, that particular competition had cool weather and calm conditions & the floated won out over it by quite a lot. My opinion though remains that it would have gone the other way if conditions had been windier with more active lift. For these 2 modes, it would normally be the case that the broader wing should have the less cambered section and the higher aspect wing should be the more cambered section, but this was early days for me, before I read Martins book. It's just that having studied the aerodynamics and then written the program removed the mystery & with it the interest, so I didn't continue to pursue sailplane design. I had also designed a few models with too short a moment arm which unfortunately led to overloaded (stalled) tailplane during F3B speed runs & diving into the deck. Normally the moment arm would be between AC wing and AC tailplane would be 4 times the mean wing chord for most model sail planes. In order to achieve balance with less nose weight, I went for 3 chords, which was fine for normal soaring flight, not fine at speed though. I think the 3.5 chords might have been adequate though. As it was, I would start a ballast loaded speed run and at some point the nose would continue to drop despite up elevator control. After that I bought a Sirus (2Ch) that someone else built, it clapped it's wings slope soaring over sand dunes. Repaired it, strengthened the wings with a new I beam main spar, redesigned the tips & rebuilt the rudder & tailplane with a geodetic structure. Installed a completely hidden in a closed loop rudder hidden cable system as the fin is suitable thick. The model died one day when another pilot switched on their TX on an adjacent channel. I had had many thermal flights well over an hour with that model, only landing to rest my neck. That model had a fairly high aspect ratio high camber wing. It could cover a lot of ground sniffing out lift, reasonably good upwind speed, not exceptional. It could would loose out against a floater if no lift was found, but most time I'd find lift. It had no provision for ballast though. I had it disappearing into clout a few times. The fully flying tailplane had differential control throw. I could half loop over to inverted to drop out of the cloud base lift & bring it back home. Rudder roll it to upright flight again for landing. All in all it was a rather nice model to fly. see below. Soar Birdy Var 86 inch Span about 78 drive.google.com/file/d/1UM-ZV-CWWSXPEDwUoD5rfBmplhYUEEB8/view?usp=share_link Bird Of Time Section 100 in Span about 79 drive.google.com/file/d/1iqbyN6a5l76PElb6qGHS8oobFz6cb9hM/view?usp=share_link An RC flying wing glider I designed about 77: drive.google.com/file/d/1s-Z7ob6zHEiKgaB_0w8HHgwYFyc8hrrZ/view?usp=share_link A Sirus I had in the 80s Many thermal flights well over an hour. drive.google.com/file/d/1cDgETfMoPqNyu_TfJcuCd4v6dA-A6w60/view?usp=share_link

Love these technical shorts. I'd love to see some content on how to pick an aerofoil based on the type of model you're building.

Great breakdown, I think its worth mentioning that swept wings, and the delta wing of your foam model, are generally designed with trans and super sonic effects in mind. Swept wings can lower the effective mach number and delay the formation of transsonic effects. Delta wings keep the wings out of the shock formed by the nose at supersonic speeds and generate lift differently at lower speeds, hence the larger angle of attack

I just finished my Aerodynamics class. It seems like at low speeds M

Almost seamless these adlibs (focus on almost) brilliant chaps I am always in awe of your work.

Great edit! Good times!

At the speeds reachable by our RC airplanes where compressability effects are not a concern a high aspect ratio wing of the same wing area will consistently outperform a low aspect ratio wing even at high speed. The low aspect ratio wing will not have a smaller forward profile area because the thickness of the wing is proportional to the chord length. There's a reason the speed records for RC planes are held by high aspect ratio sailplanes dynamic soaring. When a lower aspect ratio wing makes sense it's because of structural limits, span limits, stall characteristics, and manufacturability, not because you want to fly faster.

Amazing video as always, also loved the YF-23 at the beginning. Just a correction on a tecnical note: multiple time you said that high AR (aspect ratio) is for grater efficiency at lower speed. This is not entirely correct, in fact the AR determines mainly the max aerodynamic efficiency (lift to drag ratio), while the speed where the peak efficiency is achieved is determined by the wing loading (aircraft weight over wing aera). Also sometimes is better to think about not the speed of max efficiency, but rather the dynamic pressure of max efficiency (q = 1/2* TAS^2 *rho); in this way you take out of the equation flight altitude (the higher you fly the lower the air density so the speed of max eff. increases). In my opinion the best way to undesteand intuitively those concept is by "playing" with the equation; I use Desmos for plotting the graps (you can set up sliders to visualize what happens when you change various parameter); than Matlab for more complex optimization.

You can see the same effect in birds: the long slender wings of an albatross, vs the wings of a peregrine falcon. Another important part of the equation is maneuverability. Multiple factors are at play, but one important aspect is the spatial relation between the center of mass and the center of the lift.

Long skinny wings (high aspect ratio) have lower drag than fat wings (low aspect ratio) also at low aspect wings have greater resistance to stalling, the high aspect can stall unexpectedly. See gliders and jet fighters.

I smiled through the whole episode all while learning more about aerodynamics! And I did enjoy the montage, keep it coming Think Flight!

Its interesting how this can change based on scale...from my understanding, once you start getting small enough, leading edge drag starts to become higher than skin drag, so shorter wings start to become more efficient again. ...at least, thats what I remember...yeah dont quote me on that lol

For your cool flying wing: How much maH does the 2s lipo you are using have? Also what motor are you using?

if the wing area is kept contant, there is a point after which an even higher ar will decrease performance due to the decrease in re number, meaning the airfoils stop working properly so the saying "higher ar is always better" is technically not correct i once did a number of simulations testing this, on a rectangular planform wing with a wing area of 0.1m² (10cm chord at 1m span) i varied the ar and aoa and compared performance with L/D can't remember the airfoil rn up until an Ar of 25.6 (span 1.6m, chord 6.25cm) L/D kept increasing to a maximum value of 18.5 at higher Ar's L/D dropped again

its amazing to see ppl creating such creative designs...

Now I wanna make the ~lowest~ aspect ratio wing

It would be cool if you could design retractable wings that change the frontal area and aspect ratio of your plane as you change speed

The flying wing looks truly awesome.

You two guys are the coolest bros out there in this aeronerdy youtube world. I wish Samm was still around and that Peter Sripol lived closer to the West Coast. Did you catch any ridge lift off of that bluff my dude? the efficiency was probably most epic if you did!

Please share the design for 3d printing or make a build video. Does it really fly for 3 hours with 2s battery? please elaborate it

guys, nice video, but maybe keep the very obviously fake acting down. we like you guys as you are, technical, nerdy, and detailed. not like a reality show. My two cents anyways

Very interesting and fun show!!! Your shop is the cat’s meow! I appreciate you explanation of wing design and will implement it on our next balsa glider build! We are having mathematics, art/ design, fabricate school over the summer. Thanks a ton!!!

You sir have a amazing skill set. I really enjoy your content. Thanks...

I'm loving the content man! Neat to have the performance of both type of wings demonstrated. Can't wait to see more. Keep the great videos coming!

the wing is beautiful , so elegant !

You knwo something about to teach you more than primary school when it start with "This video is brought to you by Squarspace"

The mountain in the beginning is in my back yard...too bad I missed seeing the SR cleaning up all that litter!

I keep coming back to this video because of the cool music when you are flying at the beach.

Long skinny wings are definitely good for efficiency, but I've noticed issues with very light planes. When the wing span is large in relation to the airplane weight, the reynolds number is fairly low. Below about 50,000 most airfoil designs have lots of issues, so the L/D is very low. In this case having the airplane fly faster at a lower AoA is better due to the increased reynolds number and therefore increased L/D.

Great video, footage and explanation Building skills 100 👍 Acting skills 0 🤣

I'd love to see a build video on the skinny wing! Particulary on the profile(s) used.

Great Collab video, well done fellas!

The proper term from "skinny" wings is "high aspect ratio" which is the span squared divided by the wing area

I'd love to see your process for designing when using a computer

You just described the most commonly described differences between low and high aspect ratio wings. But, you should also note the reasons why some people have suggested replacing the stubby wings of the F-16 with a delta wing, and why relatively high aspect swept wings might be preferred in some cases vs a delta wing that "fills in" all that space behind the leading edge of the narrow wing. In other words, there's a lot more to the wing form than just whether the wing is high or low aspect ratio.

Wing shape and size comes down to what kind of performance the plane is being designed for, a lot of factors are considered when designing a wing

I love that wing. Efficiency is beautiful

Here's a question: At what *actual* velocities does the crossover happen between induced and parasitic drag? Is this different for our small RC aircraft? How does airfoil shape (or other important factors) effect this? What other important factors contribute? Obviously, there are (I'm sure) decades of math to figure this out based on as many variables as there are stars in the milky way galaxy. I would *LOVE* if you could do an in-depth analysis of choosing a specific aspect ratio and/or airfoil shape. How did you choose the specific wing profile for your high efficiency wing in this video?

I like this partnership

I know skinny wings are more efficient, but what about solar powered aircraft? The problem is I'm not a mathematician or an airplane designer so I don't know how to figure this out. I have identified a few issues. 1.Skinny wings are more efficient, but broader wings, for the same length, are stronger and larger so can attach more solar panels but are heavier... I'm getting rocket equation vibes. 2. Do we even want to put solar panels across the entire exposed surface of the wing? 3. Solar panels have essentially fixed weight per unit area, wings do not, or don't have too. 4. Solar panels are also really heavy compared to normal wing structure materials. I think the takeaway is that solar aircraft have very different design requirements and shouldn't be just 'regular' wings modified for having solar panels.

Low and slow. Beautiful 😊

Nice seeing the Queen Mary some 15 miles to the north, in Log Beach!

Anybody else jealous of what looks like an amazing dynamic soaring spot? If you have not DSd up there yet I will be very Angry! 😁

omg yes. ever since this was shown in the shop tour I've wanted to hear more

All I can think about in this video is getting a few more nano goblins and taping them together.

Generally, a high-aspect wing-one that has a thinner foil-is more aerodynamically efficient.

Does anyone have the plans for the flying wing or another similar wing please?

You guys make a great team. Coupla dorks partying with planes. Entertaining.

i much prefer the thin airfoils, this looks much more elegant in flight

I really hope a Strix version of this airplane lands in store soon

Slope soaring is just the best of flying. Seeking air flows surfing with them I cannot stop doing it (well until my eyes tell me stop with tears)

Awesome video man

It's all about flight envelope. Skinny wings have no air brakes, so they go fast on little power but fall out of the sky at low speed. Wider, thicker airfoils have a wider flight envelope, sacrificing a little top speed but needing more power. Thick and wide airfoils are much more fun to fly.

How much does the ballast cost? ''EXACTLY 25 cents''

@thinkflight What is the music artist & title at the end of the video? Also, I do really like the color scheme on the slender flying wing.

It's almost scary the timing of these educational videos you have been making. Started coming out right as I started asking these exact questions

Man i wanna make that wing so bad

The downside of long skinny wings is that they stall easier.

02:21 ...and the Piaggio avanti is loud a fudge

That plane with the skinny wing would make a good FPV cruiser glider if fitted with a bigger battery and long range antennas, also if fitting with a 360 degree gimbal for FPV camera with head track on the nose would basically give you the best flight experience but due to FAA regulation would make such flight impossible without the flight clearance waiver. Still would make a good slope or flat land e-glider, now would be nice if plans are available to build one.

An old question: does sweeping back (keeping its transectional profile) increase the wing area without changing its aspect ratio?

Doubt you will see this but I was wondering why you designed the low speed aircraft with swept wings. I did an extremely minimal amount of research and found that swept wing designs specifically deal with wave drag from transonic and supersonic flight. In the case of an electric drone, those speeds are not possible.

Would you consider using this platform to test using mid wing mounted motors to counter act the mid wing vortex you noticed in your wing tip mounted motor? I've always wondered if that's the key to efficiency in flying wings. It looks like you either had the same or a similar idea with the vertical stabilizer placement. Just a thought, I'd be very interested in the result. Love your videos! Keep it up!!

High aspect ratio more efficient. Minimum of 4” chord.

Looks like you had fun!

What is the wing thichness?

Insults vegans in the first minuet. Subscribed

Great in-flight footage!

Love comparison videos while teaching aero concept; more please. Also great aerial chase video on the montage. Was that from a quad?

Summary: at higher speeds, you don't need a lot of wing to produce lift. It creates unnecessary drag. But honestly, i expected you to talk about skinny wings vs wide wings, while the length is the same.

That was my 1st thought as well 'how are you going to land that thing', I mean, those rocks are rather unforgiving.

I would immediately say yes without seeing the video yet and just pointing to world record in paper planes.

Great Video. Need a build video on that one! Wouldn't extending the front end out another inch moving everything slightly more forward create a more balanced load so you don't have to add quarters or will that create more drag causing making it less efficient ???

Where was this shot?

They are; just from a purely aesthetic perspective, IMHO. 🙏

1:29 i thought my headphones were giving up here

"Just catch it" he's sokka

So.. this couldnt be done in Canada legally, as in flying on a beach I think. Is this allowed in US?

have published the flying wing plans?

In Germany gliders have been built by student clubs, akaflieg, with telescoping wings and one with variable chord length. And there's of course the f14.

bell shaped or elipse shaped lift distribution?

Hello I love that skinny flying wings and I built same type today please I will want to know more and how you found the CG . Am you biggest fan

Would love a video on pusher vs tractor configuration.

I am loving this series

I'm a low aspect ratio kind of person lol

High Aspect Ratio = skinny I love reading all the comments , seeing everyone accomplishments. lol

You forgot your surfboards...

At what velocity does low aspect ratio start to perform poorly

Hello, please one question.. How many degrees have the swept wing? And what wingspan have the wing?thanks

My favorite low wind slope soarer is a Zupair Z1. It has a similar silhouette to your powered "skinny" wing.

Thats beautiful

Was that SLO?

Yap i saw that wing on your wall and it looks cool af

Better at what ? flying fast, flying slow, flying high, flying low, lifting heavy objects, going long distances, or short... there are as many different types of wings and airfoils as there different types of aircraft ....but in a glider .... for sure...skinny wings are better...

If you look online, you can find the charts for weight speed vs wing loading and aspect ratio.

would it be feasible to make an rc plane with dynamic wings, or would the extra weight negate any benefits?

is that grey skinny plane 3d printed? if yes how can we gey the stl files

How does the slender wing thermal? I have always wanted to try that with this type of wing.

I’m loving this wing … what … where can I get one it would be perfect for my area SilverWood Lake

Slower flight intrigues me.