Yet another question about drag - wings

[Jestersage]

So upon finding I have issues with my SSTO, I decide to traceback my step, and recall on one of the operation, I have rotated slightly along the horizontal plane for looks -- ie not pitching or rolling, which will definitely change the lift, but instead sweeping forward or back like F-14

Does that affect drag? My understanding is that KSP simplified atmospheric phsyics do not change lift based on the angle horizontal plane's angle (eg if you sweep a wing a bit more), and thus drag is not affected.

EDIT: Okay, now I realized if I change it to "sweep" (instead of rotated), I actually asked this question before:

https://forum.kerbalspaceprogram.com/index.php?/topic/184891-breaking-ground-request-drag-effects-on-collapsable-wings/

So which one is correct??

Edited November 23, 2019 by Jestersage

[Starhawk]

13 minutes ago, Jestersage said:

Does that affect drag?

Yes.  The orientation of the part relative to the atmosphere determines the drag being produced.  Rotating the part on any axis is very likely to change the drag.

16 minutes ago, Jestersage said:

My understanding is that KSP simplified atmospheric phsyics do not change lift based on the angle, and thus drag is not affected.

I'm not sure whether the lift provided by a wing changes when rotating it around a vertical axis, but I'm sure the drag changes.  Probably significantly.

Happy landings!

[Jestersage]

7 minutes ago, Starhawk said:

Yes.  The orientation of the part relative to the atmosphere determines the drag being produced.  Rotating the part on any axis is very likely to change the drag.

I'm not sure whether the lift provided by a wing changes when rotating it around a vertical axis, but I'm sure the drag changes.  Probably significantly.

Happy landings!

Hi Starhawk, Just want to make sure that when we are talking about "rotating around a vertical axis", we are talking about the VAB operation similar to typical sweep wing of the F-14

[Starhawk]

24 minutes ago, Jestersage said:

"rotating around a vertical axis", we are talking about the VAB operation similar to typical sweep wing of the F-14

Yes.  Exactly.

Now, I don't know how different the forward and side drag profiles of a wing part are (I expect it varies quite a bit from part to part), but I expect the drag cubes to represent different values for these except in the case of the simplest shapes.

Happy landings!

[CBase]

Wing drag and lift directional components are only based on the cosinus between wing's lift normal and surface speed. So as long as you are not changing the lift direction like sweeping neither the lift nor drag changes.

As a side note: Drag cubes are normally not used for wings, you will find dragModelType = none in all stock wing parts. So sides are only visual.

f_drag = -v_surface/v_surface * A_wing * f_drag(abs(cos(angle))) * f_mach( mach ) * rho * v_surface² *global_constants

Note: Bold are vectors, all other scalar. angle = angle between v_surface and wing lift normal. f_drag and f_mach are quadratic bezier curves, one to model angle dependency and the other mach related non linear effects. rho is the local air density.

 

 

[Starhawk]

Well, there you go.

Drag for wings is a special case.

I was completely wrong.

Happy landings!