I noticed all the wings you use have what I would call dihedral tips. Is that for lateral stability? {IIRC a lot of Free Flight model airplane designs have that feature.}
It seems to me that the latest scientific understanding is that it is the downwash of air (via the camber of the airfoil or the angle of attack or both) that creates the majority of the lift, not the low/high pressure distribution. Hence there are no aiplanes that have airfoils with no camber and with zero angle of attack. Or are there?
The redirection of the airflow happens because of the variations in pressure. The analysis of the Navier-Stokes equations, especially the conservation of linear momentum, establishes that the term involving the pressure forces acting on the fluid are just as relevant as the biggest other cause for change in momentum. This is because pressure (specifically pressure differences) cause movement. Source: I'm an aerospace engineering student and I've just started my profile aerodynamics subject
@@Ohmyus111 - Thank you for your answer. So..., both are imporant. Would it be fair to say that pressure changes become more dominant at higher air speeds? As in: A commercial jet can level out a lot more at higher speeds because it isn't so much the angle of attack that creates the needed lift but rather the shape of the wing?
@@my_dear_friend_ The lift equation already takes into account that at higher speeds more air will be redirected, since Cl in the most approximations depends only on AoA. L= 0.5*rho*V^2*S*Cl ; so as airspeed increases without changing AoA, lift increses. As for the pressure term becoming more relevant at higher speeds, I think I'm missing some context to your comment, since you seem to be comparing flight at different speeds but only mention commercial jets. Still, it's not that the pressure term (*) becomes more relevant as speed increases, or at least not directly. This is the way I like to think about it: as airspeed increases, the convective term of the equation increases (this is the redirection of the airflow) while the viscous terms, although relevant, become less and less so, to the point where under certain other conditions it's possible to use simpler equations that do not take viscosity into account. As for the pressure term, it's as we discussed before, it will adapt to be as relevant as the convective term, which is the most relevant at higher speeds. Basically I'm saying that pressure differences will be those the fluid needs to help adapt to the speed gradients, so both will remain equally as relevant and increase in magnitude at the same rate. Finally, excuse me for overlooking in my original comment your question on camber. The aerodynamics involving camber and the change of lift produced by different profiles with different camber is mostly experimental right now, or maybe I've not gotten far enough along my course, so I don't have much in the way of justification except refering you to Magnus' theorem about circulation around profiles and the vortices involved. Experiments show that wing profiles with high camber, about 12-18% of the chord length, provide the best lift to drag ratio at low speeds. So in that way, cambered profiles are more efficient. As you probably can tell, the conditions in which flight will happen are very important, as well as the desired handling of the aircraft. For instance, almost all aerobatic planes have symmetric profiles (that is zero camber) to allow for inverted flight without needing an exaggerate angle of attack. Commercial wing profiles are designed with camber to delay transonic effects and to accommodate lift-increasing devices such as flaps. I hope that answers all your questions (*) These are the terms of the conservation of momentum Navier-Stokes equation
@@Ohmyus111 so basically, pressure vs downwash is a bit of a tomato tomato, wave-particle situation where both are simultaneously correct and it's just a matter of what's more convenient for the math at the moment?
I'm sorry buddy but your mistake. If what you were saying was correct an airplane with a flat bottom of lawyer would not have Lyft in level flight and it most certainly does have left. Airfoils generate lift because of the relationship between the vacuum above the wing and the static pressure below the wing
Can you be more specific about what I said that you suspect is incorrect? I'm not following what it was I said that implied an airfoil with a flat bottom would not produce lift.
@@DesignYourOwnAirplanes-xd6lz I actually don't recall the video that well and exactly what it was you said. However it did become clear to me that you don't have a full grasp on why it is that an airfoil produces lift. I referenced the flat bottom airfoil because it produces the maximum amount of lift in level flight. It's not a redirection of the airflow across the top that causes an airplane to fly. It is the relationship between the atmospheric pressure below the wing and the negative pressure that is created as it moves through the air. That's why a flat bottom airfoil will produce lift in level flight
@@engineered700 But there's more to that. What you said here is true but it's not complete story. You can always go into more detail. That being said this channel goes into what you need to know to build your own - home made - airplane. Now, with that being said there's 80% chance you're bot and you're not attuned to context of this channel.
This series is awesome, I hope you keep making content once its done! keep up the good work
You are so right... thanks for this video about how it really works.
I noticed all the wings you use have what I would call dihedral tips. Is that for lateral stability?
{IIRC a lot of Free Flight model airplane designs have that feature.}
How nice :)
You’re amazing
It seems to me that the latest scientific understanding is that it is the downwash of air (via the camber of the airfoil or the angle of attack or both) that creates the majority of the lift, not the low/high pressure distribution. Hence there are no aiplanes that have airfoils with no camber and with zero angle of attack. Or are there?
The redirection of the airflow happens because of the variations in pressure.
The analysis of the Navier-Stokes equations, especially the conservation of linear momentum, establishes that the term involving the pressure forces acting on the fluid are just as relevant as the biggest other cause for change in momentum. This is because pressure (specifically pressure differences) cause movement.
Source: I'm an aerospace engineering student and I've just started my profile aerodynamics subject
@@Ohmyus111 - Thank you for your answer. So..., both are imporant. Would it be fair to say that pressure changes become more dominant at higher air speeds? As in: A commercial jet can level out a lot more at higher speeds because it isn't so much the angle of attack that creates the needed lift but rather the shape of the wing?
@@my_dear_friend_ The lift equation already takes into account that at higher speeds more air will be redirected, since Cl in the most approximations depends only on AoA.
L= 0.5*rho*V^2*S*Cl ; so as airspeed increases without changing AoA, lift increses.
As for the pressure term becoming more relevant at higher speeds, I think I'm missing some context to your comment, since you seem to be comparing flight at different speeds but only mention commercial jets. Still, it's not that the pressure term (*) becomes more relevant as speed increases, or at least not directly. This is the way I like to think about it: as airspeed increases, the convective term of the equation increases (this is the redirection of the airflow) while the viscous terms, although relevant, become less and less so, to the point where under certain other conditions it's possible to use simpler equations that do not take viscosity into account. As for the pressure term, it's as we discussed before, it will adapt to be as relevant as the convective term, which is the most relevant at higher speeds.
Basically I'm saying that pressure differences will be those the fluid needs to help adapt to the speed gradients, so both will remain equally as relevant and increase in magnitude at the same rate.
Finally, excuse me for overlooking in my original comment your question on camber. The aerodynamics involving camber and the change of lift produced by different profiles with different camber is mostly experimental right now, or maybe I've not gotten far enough along my course, so I don't have much in the way of justification except refering you to Magnus' theorem about circulation around profiles and the vortices involved. Experiments show that wing profiles with high camber, about 12-18% of the chord length, provide the best lift to drag ratio at low speeds. So in that way, cambered profiles are more efficient.
As you probably can tell, the conditions in which flight will happen are very important, as well as the desired handling of the aircraft. For instance, almost all aerobatic planes have symmetric profiles (that is zero camber) to allow for inverted flight without needing an exaggerate angle of attack.
Commercial wing profiles are designed with camber to delay transonic effects and to accommodate lift-increasing devices such as flaps.
I hope that answers all your questions
(*) These are the terms of the conservation of momentum Navier-Stokes equation
@@Ohmyus111 - I had to get this translated but I think I understand this somewhat better now. Thanks!
@@Ohmyus111 so basically, pressure vs downwash is a bit of a tomato tomato, wave-particle situation where both are simultaneously correct and it's just a matter of what's more convenient for the math at the moment?
3:46 you could have explained induced drag by putting the lift arrow to correct direction but you failed to do it.
great video, but tbh; (feet per second) sounds extremely ridiculous
bot
I'm sorry buddy but your mistake. If what you were saying was correct an airplane with a flat bottom of lawyer would not have Lyft in level flight and it most certainly does have left. Airfoils generate lift because of the relationship between the vacuum above the wing and the static pressure below the wing
Can you be more specific about what I said that you suspect is incorrect? I'm not following what it was I said that implied an airfoil with a flat bottom would not produce lift.
That's bot
EDIT: Lesser bot - not worth your time
@@DesignYourOwnAirplanes-xd6lz I actually don't recall the video that well and exactly what it was you said. However it did become clear to me that you don't have a full grasp on why it is that an airfoil produces lift. I referenced the flat bottom airfoil because it produces the maximum amount of lift in level flight.
It's not a redirection of the airflow across the top that causes an airplane to fly. It is the relationship between the atmospheric pressure below the wing and the negative pressure that is created as it moves through the air. That's why a flat bottom airfoil will produce lift in level flight
This argument never gets old! Wings divert air, if they didn't they wouldn't fly.
@@engineered700 But there's more to that. What you said here is true but it's not complete story. You can always go into more detail. That being said this channel goes into what you need to know to build your own - home made - airplane.
Now, with that being said there's 80% chance you're bot and you're not attuned to context of this channel.