Unwanted Spinning

[davidpsummers]

I've gotten new tech and I'm building my new heavy lift booster. I'm having problems with unwanted roll (rotation or spinning about the vertical axis). I fixed the problem where it would just spin uncontrollably from the the start by finding some parts that were clipping.

But when I do my gravity turn, I still start to spin. Any help? It doesn't do it in the first 10,000 m of ascent, and I think I have found all the clipping parts ,so I think it must be something else?

Edited July 13, 2014 by davidpsummers

[Pecan]

Necrobones does some nice tutorials.

[NecroBones]

Necrobones does some nice tutorials.

Beat me to it. Thanks!

[Kerba Fett]

Very nice video. Short, to the point, explained the problem and showed the solution. I wish more people did videos like that.

Not sure I agree that you can't completly get rid of the rotation. I would think RCS could eliminate the last of it, but you probably meant just by stiffening the structure.

I've been playing KSP for quite a while and I had no idea that fuel lines would act as struts.

[davidpsummers]

Thanks, the video was helpful. (Even if it did tell me that the struts, which I find a pain to deal with, have to be more carefully placed...)

[SRV Ron]

Strut placement is most critical for control on large designs. But, it can be tricky to see if they all placed properly.

It can make the difference between this in this asparagus hybrid design;

and this;

It was a failed strut, not seen in the upper picture, that caused this rocket to swap ends.

[AgesGeneral]

I've been dabbling with KSP for months, and list pushed on through with spinning craft. As I've been perma-low-end career I've never had to face up to actually having to solve the problem. After watching the video, all seems so obvious!

[NecroBones]

Not sure I agree that you can't completly get rid of the rotation. I would think RCS could eliminate the last of it, but you probably meant just by stiffening the structure.

Yes, that is what I meant. With enough SAS/RCS, it should be possible to completely stabilize it. But the strut placement will never be perfect, since there's no snap on the second end. But even so, as shown, the twist can be almost negligible with careful strutting.

[Vigelius]

But the strut placement will never be perfect, since there's no snap on the second end.

Try putting something (anything, lights work well) as a guide where you want the second end to go. Snapping will apply to the guide object, you can place your strut and then remove the guide. Saves all that faffing about trying to eyeball where the strut should end.

[NecroBones]

Try putting something (anything, lights work well) as a guide where you want the second end to go. Snapping will apply to the guide object, you can place your strut and then remove the guide. Saves all that faffing about trying to eyeball where the strut should end.

Good tip!

[Red Iron Crown]

You can actually put the snap target on the opposite side of the tank and pull the strut "through" to it, makes it a bit easier to line up. I use linear RCS ports, the exhaust port is a very small target allowing good precision.