How Does the Dihedral Effect Work in Aircraft?

#dihedral #aviation #physics
In aviation, dihedral wings increase aircraft stability on the roll axis. In this video I wanted to explain the physics and engineering behind this phenomenon. There are a lot of misconceptions and false physics surrounding many aerodynamics topics, and I specifically wanted to address dihedral wings since they're very common in RC and full scale aviation.

[@Doctoberfest-ch2ml]

I’m taking an aerodynamics course right now and this is quite honestly the best explanation and visualization of it I’ve seen. Thanks!

[@Benjijart]

That is literally the best compliment!

[@WinginWolf]

This is beautiful. I can only ever accept it in textual terms but never could perfectly visualize it.

[@blink882]

Been flying for ten years, best explanation of side slip and dihedreal I've seen!

[@bobbytaylor2349]

Shut it bucko

[@finleyjohnson192]

Cheese 🦦

[@eternalray8194]

Thanks so much your explanation was the best one because it cleared out a lot of my confusions. Easily beats out those 12minute explanation on this effect lol

[@terracoon9882]

Thanks, there are a lot of confusing (wrong) videos about this effect, you explained it well.

[@billglass9371]

You really popped off with this one king keep up the good work

[@devrajyaguru2271]

Literally best explanation in shortest time

[@victoryavar]

thanks a lot! Wasnt easy to understand this concept only by reading, but your animations and explanation made it really easy!

[@peternelson7545]

Great explanation. I teach CPL ground at a 141 school and this is simple and easily understandable - I'll be adding this to the videos I show in class!

[@katlynsmith662]

Oh this makes lots of sense this was very interesting. Also great animation! :3

[@hansookim1843]

Really nice explanation among dihedral vids. Couldn’t understand well with texts but this imagine and simple animations let me understand easily. Thx!

[@Benjijart]

Happy i could help! I'm often the same way!

[@blakecuthbertson4141]

Awesome explanation! 👏🏼

[@pumpkinspice6118]

Really good explanation with animations, thanks!

[@felipereyes1440]

Very interesting effect, great explanaition!.

[@Kb-yb7ot]

the best explanation so far

[@vojtechslavik8262]

awesome explanation. Thank you.

[@sigistrele5835]

Thank you. That's the best explanation for the dihedral. Many greetings from Austria🙌🙌🙌🙌👍👍👍👍👌👌👌👌

[@isagumus1]

Beautiful explanation! Thank you

[@prathibhaperera7406]

Only explanation that was clear and simply explained the theory. Everyone else is talking about AOAand I can’t visualize it no matter how much I think about it. But torque due to side slip is the best way to understand this phenomena.

[@danieldekel8268]

Exellent explanation

[@Eli-we1rs]

Bro....amazing video thank you so much.

[@theastuteangler]

Excellent video, thank you

[@monish6394]

awesome video

[@blackvideohd2075]

Very useful video

[@strato6049]

Well explained

[@SL8408]

Dude AWESOME VIDEO.

[@FullOilBarrel]

the demonstration of slip in video form made me understand it better

[@keithdmello]

Well explained!

[@fartge]

well done!

[@federicotribbia3099]

nice exp

[@blackbirdpie217]

You're one of the few who explains dihedral stability correctly. This works for low wing designs. However because of the side slip dynamic, a heavy HIGH WING aircraft is more stable with anhedral. This is because of the massive fuselage that adds to the equation. Side slipping with that big panel at the wing root will actually generate a huge high pressure against it which adds to the roll. In this case anhedral helps to blank out the fuselage from side air pressure, reducing the plane's tendency to continue the roll. So anhedral in a high wing design will add stability.

[@Benjijart]

you are correct that the pressure exerted over the fuselage during slip will induce a moment and in a high-wing where the center of gravity is above the center of pressure this will contribute more to the bank but anhedral is not used as a countermeasure against this. In the case you're describing anhedral would actually present the same amount if not more area to the oncoming slip wind that is below the center of gravity therefore contributing even more to the roll and, in fact, making the aircraft more unstable in the spiral mode. The wing does blank out the fuselage from the slip wind... but that wind which hits the wing still exerts a moment on the aircraft.

[@blackbirdpie217]

@@Benjijart The inside wing, in a slip, with a high wing design will accumulate high air pressure in the crux of the wing root and fuselage. This pressure is enough to lift the wing restoring the roll to level. The anhedral wing tip of the outside wing is low, but because of the high wing configuration, is blanked out by the fuselage and receives no slip air, no extra air pressure or lift. the anhedral is also not extreme enough to present the inside wing tip (i.e. left wing in a left roll) a negative angle of attack to the relative wind, but close to or at neutral in the worst case. I've heard it explained a little more elegantly than this but here's a video doing a pretty good job of explaining the concept. kzbin.info/www/bejne/f2nMfYVorbeBgbs

[@Benjijart]

@@blackbirdpie217 the video does not corroborate your explanation. the narrator says anhedral is used to offset the inherent stability of high wings. the pressure built in the "crux" is a feature of all high wings that can lead to an undesirably high amount of stability so anhedral is implemented to make the aircraft maneuverable in the roll axis to the degree that is targeted by the the designers.

[@alone_sh4t]

Thanx much :)

[@MrPilotStunts]

I have a question! Since the lower part of the wing here 1:14 has a higher vertical component of the lift, wouldn't it stabilize the aircraft even without any sideways moving air mass? Or is that a fallacy, since both sides of the wing still apply the same amount of torque to the center of mass?

[@Benjijart]

Actually the reason it has a higher vertical component is because of the side slip. The dihedral angle makes it so one wing has a higher angle of attack than the other when the aircraft is side-slipping.

[@MrPilotStunts]

@@Benjijart okay, i visualized it and now i seem to get this. Thank you for clarifying. I also wanted to ask, if the center of mass of the aircraft is in front of the wing, the dihedral must also act as a vertical stabilizer? Though it wouldn't provide a lot of stability.

[@Benjijart]

@@MrPilotStunts yeah that’s true

[@MrPilotStunts]

@@Benjijart thank you a lot!

[@jaycal1920]

You also need to remember that the C.O.G isn't something that only effects the horizontal plane.

[@JustTayo]

Thanks

[@bulamoves2987]

Well explained however, I wouldnt necessarily call it more "angle of attack" on the lower wing as AOA is in relation to the chordline of the airfoil and relative wind. Maybe more surface area for the wind to make contact? Idk what to call it

[@Benjijart]

The lowered wing actually does have a greater aoa relative to the raised one even by your definition. Your explanation about surface area is kind of another way to look at it although the raised wing has a similar amount of exposed surface area the relative wind strikes it on the top surface of the wing instead of the bottom. It's all quite hard to visualize which is why I made the video.

[@bulamoves2987]

@@Benjijart the chord line of both wings are at the same angle to the relative wind. The AOA will never be different on any wing unless aircraft manufacturers come out with wings that would somehow twist inversely from each other

[@Benjijart]

​@@bulamoves2987 The wings do not need to physically be at different angles of incidence to have different angles of attack. They are experiencing a different angle of attack because of the slip condition and the dihedral angle of the wings. During the slip, a component of the relative wind pushes on the bottom surface of the lowered wing while pushing on the top surface of the raised wing. You can see this at 1:10. Of course most of the relative wind, is coming head-on hence the drawing at 1:16. Without a different AOA there would be no difference in lift between the wings and therefore no net torque on the aircraft around its roll axis.

[@bulamoves2987]

@@Benjijart i completely understand what you are saying. Just referring to the definition of relative wind does not equate to your examples. You are absolutely right on the concept but the terms you are describing on relative wind i believe is not correct. If i am wrong, PLEASE refer me to a certified book

[@Benjijart]

​@@bulamoves2987 Relative wind is just the oncoming flow of air. The slip adds a sideward component to the relative wind. If the wings have a dihedral, the relative wind will hit each wing with a different angle causing a different angle of attack and thus a different lift. Here's a NASA paper, refer to page #134 practicalaero.com/wp-content/uploads/2010/04/NASA-SP-367.pdf

[@user-sc7cj5yu1s]

I still don't understand the side view you showed in the video. No matter how much you roll or bank. the side view of angle of attack should be same

[@Benjijart]

Not with side slip

[@daviddavids2884]

this video should should have begun with a discussion of pendulum effect. which is another principle that is Not well-understood, by most people/explainers. d googletranslate

[@FlyNAA]

@@daviddavids2884 there is no pendulum effect, although it is sometimes falsely used as an explanation for lateral stability.

[@FlyNAA]

Here's an easy way to visualize this. Make a basic paper airplane. (Extremely basic, it doesn't even have to be able to fly. The simpler, the better. Just fold a piece of paper once). Give it a ridiculous amount of dihedral, like 45 degrees up. Now, look at it from the front. What your eyes see, is what the air flow sees. Hold it at a positive AOA so you see some of the bottom of the wings. Equally, since you're looking at exactly from the front. Now, turn it sideways a little. You'll see a lot more of the bottom of the nearer wing, than you will the farther. This is the higher AOA of the nearer wing because of dihedral.

[@daviddavids2884]

information. bla-bla-bla you SHOULD BE talking about stabilization from pendulum effect. it is the same thing that causes a high-wing airframe to be inherently more stable that a low-winger; when flying right-side-up. googletranslate

[@Benjijart]

Lmao