Rockomax Quadcoupler Engines Causing Spin?

[CoriW]

Well, ever since 0.21 came out I've started using a 2.5 meter Quadcoupler with four LV-T45's on it instead of the Skipper for my lifters, since it gives a higher ISP and a bit more thrust than the Skipper (800KN thrust instead of 650KN, and ISP of 320/370 instead of 300/350), and I've always thought cluster engines look cooler than a single, larger one.

But I've run into a problem with this design, it seems to induce roll. Now the SAS does hold the heading for the most part, but it always seems to be slightly off (It will hold a position maybe 2 degrees pitch/yaw and 5 degrees roll off from the heading I told it to hold.), so all in all this is something that is really annoying and I can't figure out how to fix it because the SAS just doesn't want to hold exactly where I tell it to during initial liftoff.

Is anybody else having this issue at all? And does anybody know if there's a good way to correct or fix it?

[Jarnis]

Wild guess; The quadcoupler model has a tiny imperfection so it isn't properly balanced.

I've done tons of "manual" quading-up using strut plates and they never cause uncontrolled rolls when installed precisely.

[CoriW]

Actually, I just discovered the problem.

So usually with the Quadcoupler I'll turn the engines by 45 degrees (Pressing Shift-Q 9 times) so that the engines all have their nozzles facing directly outwards from each other, however because the engines are angled diagonally it seems that the gimbals mess up and begin to induce roll... In other words the solution is to simply not angle the engines by 45 degrees, which I only did for aesthetic purposes anyways.

[Shuttle]

CoriW , wow, I never thought about it! I build rolling rockets since KSP0.11 or so, I'll follow your advice. Thank you!

[littlebattler]

Same type of problem happens if you place canards backwards (rotated 180 degrees) on planes. Controls get reversed.

[KerbMav]

Sooo ... when I rotate the nuclear engines so they dont damage each other when their protective covers are jettisoned (in a single2triple2single arrangement) they will make my rocket spin too?

[Kerbonautical]

I have this same problem but I haven't been putting my rockets on at an angle as far as I know, just using the standard placement that symmetry chooses for me and it cause a ridiculous amount of spin.

It's a bit annoying since all my new designs have resulted in less efficiency due to the spin and I've had to return to my 6-way asparagus Rockomax setup for the billionth time. I'm not sure if it's my lack of skill that's at the heart of the issue but I always end up with the same boring rocket design every single time and just change the payload. It's not that I don't try new designs, just none of them ever seem to be able to outperform the asparagus Rockomax setup regardless of it's intentions to go into orbit or interplanetary.

[KerbMav]

Different though - have you tried strutting the quadupler to the ships core?