Uncontrollable Roll

[Tiron]

and for the record, in my experience, gimbaled engines can't really control roll at all, so in atmo you need some kind of controllable fins to be able to manage roll in any meaningful way. I tend to use Standard Canards rather than Winglets though, as they're lighter and have more lift... >.>

[TheHengeProphet]

I agree with this greatly. I've been contemplating attatching the long SRBs, just to help it get in the air, but at this point, I think that would be unneccessary. All I really want to do is solve my rotation problem, which has been a major problem in getting this to reach orbit.

When I get some time, today, I'm going to add support to the landing stage and throw in an ASAS in a lower stange, and pray to Kerbod it doesn't explode. Adding SAS near the pod causes some very strange stuff, though I would like to have it for the lander, so I'll just have to make do without.

[edit]Tiron, you are correct, and in my later versions of the craft -- which I have not posted here -- there are canards; however, the important time for controlling roll is once I make my gravity turn, where atmosphere is not nearly an issue, being around 16km up.[/edit]

Edited October 6, 2012 by TheHengeProphet

[Ekku Zakku]

Usually uncontrollable turns are when objects are colliding somehow, and it's likely your upper stage, being quite complex. It's definitely going to be that colliding problem/bug if it happens with the engines completely cut (idk if you've mentioned this at all). Usually the only way to fix it is to remake the whole thing, but it's often the only way to fix persistent problems like these =/

[animalcross]

Uh... That much SAS is just plain DANGEROUS.

[vexx32]

No, I find that much SAS to be rather useful. If you start using multiple ASAS modules, things start to get hairy xD

[TheHengeProphet]

Uh... That much SAS is just plain DANGEROUS.

As far as base SAS goes, I've used that much to keep rockets stable with great degrees of success, before this rocket. SOMETHING about this rocket makes SAS go insane. This is a problem I have never encountered before.

On that note... I've never had a rocket that launches the pod inverted, before this.

[Khiro]

I think I know what's going on with your SAS. It's something that I've been meaning to doing some research on, to report as a bug.

I first noticed it when I started using the 3-man capsule in .16 . That capsule has its hatch at some funky angle in the back, so before I'd build my rocket, I'd always spin it around to face front, and then build my rocket as normal. Everything seemed fine until I got into orbit and killed MechJeb. To hold me steady while prepping for transit, I'd flip on the SAS... and my rocket would start flipping like mad. Like, full force. Never figured out why.

Then the other day, I made a different rocket, using the black 3-man capsule from I think Sunday Punch. It's called Odin or Thor I think. Its ladder is directly in the back, so again I spun it around, exactly 180 degrees, and built my rocket as normal. Same thing... when I got orbital and turned on SAS, I went into a flat spin... directly planar with my yaw. I racked my brain for what might be going on until I made the connection. Going back to the VBA, I popped the whole rocket off the capsule, turned it around the "way it came", and launched again. The killer roll? Completely gone.

The TL;DR version: the SAS determines left, right, etc based on its own orientation, not that of the capsule. The game, however, determines the rocket's orientation (and the nav ball) based on the orientation of the capsule. If the two are not in agreement, wacky things happen. As an experiment and proof of theory, I made a rocket and put two SAS modules on it, one of which had been rotated 180 degrees. When you turn them on, both SASes will completely max out their force reading, but the rocket does nothing: They are fighting against each other because they have differing opinions on what is left and right.

If you flipped your capsule upside down, try flipping your SAS unit upside down in the same orientation. Play with it to make sure they agree on up, down, left, right, back, and foward, and I'll bet you'll find that your issue has gone away.

[TheHengeProphet]

Actually, I have tried orienting my SAS with my pod, and it just spins it the other way.

On a side note, I am getting the same spin when I use my sky crane... So, I'm going to re-build that without the fancy cone adapter and see if that fixes it. I've noticed that the cone adapter does not behave normally, where attatching radially is concerned.

[edit]Okay, I've pretty much fixed it. Turns out that the cone I had the crane engines attatched to was angling one or two of the engines. I present the PP3-LV2 (Planet Pod 3 - Launch Vehicle 2)! No pictures, because I'm lazy. Note: If you want to use this, you may wish to add fuel lines from the engine nacelles of the skycrane... I forgot to do that before uploading the file, and I'm feeling lazy.[/edit]

Edited October 6, 2012 by TheHengeProphet