Center of Lift is always off-center (to the left)

[Dethyr]

I have been building spaceplanes for the past few days and I noticed a problem that exists in every space plane I make and I can't seem to fix it:

The center of lift on my spaceplaces is always angled very slightly to the left when using symmetry placement.

Here are some screenshots of a space plane with only 5 parts as a simple example.

Here you can see the left side perfectly aligned behind center mass, as I wanted it to be.

Here is the right side, where the center of lift is slightly in front of of the center of mass instead of be

View from the back where you can see the angle is clearly off.

Overall view just for reference.

Please help, I can't figure this out and it's driving me insane!

[HoY]

I honestly can't see the problem your talking about.

Another problem tho is having theCoL and CoM that close will be extremely unstable.

As your fuel burns your CoM will shift causing even more stability problems.

[Scorpi15]

Maybe your camera isn't centered on the back, it could be off by a bit and make the CoL indicator look off-center. And I think you want the CoL in front of the CoM, but I'm not sure.

[HoY]

You want lift behind mass

An aircraft with a center of mass in front of its center of lift flys poorly

An aircraft with a center of mass behind its center of lift flys once.

[Dethyr]

I honestly can't see the problem your talking about.

Another problem tho is having theCoL and CoM that close will be extremely unstable.

As your fuel burns your CoM will shift causing even more stability problems.

I understand this plane is not ideal by any means, it is simply being used to illustrate my point: The CoL appears to be angled slightly to the left and I can't figure out why. Every combination of cockpits and parts is the same.

Maybe your camera isn't centered on the back, it could be off by a bit and make the CoL indicator look off-center. And I think you want the CoL in front of the CoM, but I'm not sure.

Even if the camera in the back is skewed so that it doesn't correctly show the CoL, you can see on the side views that it is off. The left wing has it's CoL sitting flush against the back of the CoM. The right wing has it's CoL overlapping so that it is almost centered on the CoM.

Basically, from what I can see in the VaB, is that the left side has its CoL further to the rear than the right side CoL.

[Roytronix]

Firstly, to avoid confusion, I believe Dethyr means that the CoL is rotated (i.e. along the yaw axis) slightly to the left, or port. If you look closely at the third screenshot, you can see the rear arm of the CoL is just to the right of the + formed by the CoM marker:

Secondly...what in the name of Jebediah. I see no reason for that to happen, unless you're not using symmetry (which I assume you are). Does this affect how your planes fly? Any of them skew off?

Thirdly, It really shouldn't make any difference. If the CoT on a vertical rocket is slightly rotated the same way, it still goes through the CoM. Ergo, it flies straight. Likewise, the CoL just needs to go through* the CoM, regardless of rotation on the yaw axis (note that the yaw axis here would be the roll axis in the vertical example I gave).

*I'm aware that the CoL shouldn't go through the CoM at first; it should be slightly behind. I said "through the CoM" to make my point.

Edited July 21, 2013 by Roytronix

[Coneshot]

I get this sometimes when I attach a wing and have it in single symmetry then switch to double.. usually if I remove the wing and pull a fresh one from the parts menu before reattaching it fixes it. I have a theory that it somehow puts 2 wings in the exact same spot on one side resulting in the difference.. just a theory though.

[Dethyr]

Firstly, to avoid confusion, I believe Dethyr means that the CoL is rotated (i.e. along the yaw axis) slightly to the left, or port. If you look closely at the third screenshot, you can see the rear arm of the CoL is just to the right of the + formed by the CoM marker:

Secondly...what in the name of Jebediah. I see no reason for that to happen, unless you're not using symmetry (which I assume you are). Does this affect how your planes fly? Any of them skew off?

Thirdly, It really shouldn't make any difference. If the CoT on a vertical rocket is slightly rotated the same way, it still goes through the CoM. Ergo, it flies straight. Likewise, the CoL just needs to go through* the CoM, regardless of rotation on the yaw axis (note that the yaw axis here would be the roll axis in the vertical example I gave).

*I'm aware that the CoL shouldn't go through the CoM at first; it should be slightly behind. I said "through the CoM" to make my point.

Thanks for clearing up what I was trying to say, as I am not very familiar with the jargon and terminology of KSP yet. Honestly I don't know if it affects my flights. I think it does because my plane will often pull one direction, but there could be a multitude of reasons why most likely including operator error. It's hard to say if it actually affects my flights as I don't have anything to compare it to; All my space-planes are like this.

I get this sometimes when I attach a wing and have it in single symmetry then switch to double.. usually if I remove the wing and pull a fresh one from the parts menu before reattaching it fixes it. I have a theory that it somehow puts 2 wings in the exact same spot on one side resulting in the difference.. just a theory though.

Thanks for the tip, but it didn't work. I tried applying symmetry before and after placing the wings, and also placing a new wing from the menu several times with no luck.

I have a few mods installed: Kerbal Alarm Clock, the UDKLD station parts, Docking Cam, Protractor, MechJeb, Kethane, Procedural Fairings, HOME 3M, Flight Engineer, CleverWalrus' version of CleverBobCat.dll and two carts, and Quantum Struts.

I am going to try removing mods to see if anything changes.

[Coneshot]

Weird, I made the same plane using the same parts and mine is a bit off to the left too.. must be a glitch:

Edited July 22, 2013 by Coneshot

[Dethyr]

Weird, I made the same plane using the same parts and mine is a bit off to the left too.. must be a glitch:

Thanks for posting those pics, it's good to know I'm not the only one with this issue. I have tried removing all mods, but it did not change anything.

Is anyone else having this issue? If so please post pics & info.

[orangexception]

I had a similar problem today when I started playing with planes. Although, I wouldn't use the word slight.

[orangexception]

My guess is that there's some left/right calculation and it's using the vertical area of the tips of your wings. The tail fins in my picture seem to suggest that possibility.

[Frederf]

Maybe the node art is in error. Is the vector line angled too?