Ailerons not deflecting properly when rolling?

[drtricky]

When I try to do aileron rolls with this plane, the inner set of ailerons deflect slightly in the opposite direction of the roll, even if roll is set to off. The even stranger thing is that setting both pitch AND roll to off for the ailerons is required to get them to stop moving.

Spoiler

(It's not very visible, but the inner set of ailerons are deflecting in the opposite direction of the roll)

Does anyone know why they're deflecting that way?

Edited June 14, 2017 by drtricky

[DrLicor]

It has probably something to do with either:

1. Your center of lift compared to ailerons.

2. Your root part.

To fix it you can move your wings further to the back, make the most frontal part your root part en by right-clicking on the aileron, you can set the value to negative instead of the positive 20.

The last opion is for when both first option don't work.

[drtricky]

38 minutes ago, DrLicor said:

It has probably something to do with either:

1. Your center of lift compared to ailerons.

2. Your root part.

To fix it you can move your wings further to the back, make the most frontal part your root part en by right-clicking on the aileron, you can set the value to negative instead of the positive 20.

The last opion is for when both first option don't work.

How is the CoL supposed to be relative to the ailerons?

Changing the root part to the nose cone didn't work, and setting the authority to negative values didn't change the rolling deflection problem. Changing authority only changed what direction it deflects when changing pitch. has the side effect of changing it's behavior when it changes pitch. It also doesn't solve the problem of the ailerons deflecting very little when rolling.

Edited June 14, 2017 by drtricky

[bewing]

Actually, it's probably the CoM instead of the CoL. Parts that are ahead of the CoM deflect in the opposite direction to parts behind the CoM. And sometimes it has a hard time figuring out where your CoM is. So -- those ailerons -- what part are they attached to?

 

[DrLicor]

Your CoL has to be slightly behind your Com for maneuverability, further behind for more stable.

Also when you have swepts wings, ksp has the weird habit to get the bug to do things incorrect, moving the wings further behind the CoL can solve this problem most of the time.

[drtricky]

7 minutes ago, bewing said:

Actually, it's probably the CoM instead of the CoL. Parts that are ahead of the CoM deflect in the opposite direction to parts behind the CoM. And sometimes it has a hard time figuring out where your CoM is. So -- those ailerons -- what part are they attached to?

They're attached to the rearmost wing piece, which is located behind the CoM.

Spoiler

 

[Foxster]

Coupla thoughts...

There is some weird stuff around swept wings. I now just avoid them. The usual issue is having ailerons attached to the rear of them work inverted. 

The symmetry method (radial v mirror) they were placed with can make ailerons act odd. Try detaching a whole wing with all the parts and re-applying it.

[DrLicor]

Yep symmetry mode can also make things a but rusty.

When I make planes, I first make the wings, and after they are finished, I never put them back om again, not with elevons. I always put my elevons on the ship as the last step. 

Putting wings with elevons together in one step to symmetry mode can give issues, however. Looking at your plane, the inner elevons don't need to rol do they? The outer will give enough rol control.