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I've been playing KSP since about 0.22. I've been having a bunch of problems since 1.0 though, where I cannot even get into orbit.

The major issue is that with every rocket design, when it comes to gravity turn, the rocket goes into an uncontrollable spin in that direction- the command pod torque seems to do nothing now. I tried adding several reaction wheels (like, 10 at the top of the rocket), but it had no measurable effect. I added some of the wings, which seem to help keeping the craft stable but only when it's going up- when trying to stably turn the rocket in-atmosphere they don't seem to help.

It seems somewhat to me like the controls just aren't working properly. If you're going straight up, and you push left or right, the whole craft wobbles tremendously because 10 consecutive reaction wheels are not a good structural element and you're applying a lot of torque. But when the craft is spinning, there's no wobbling at all and pushing the keys has absolutely no effect.

What's the cause of this huge change in stability mechanics and how can I adapt my older rocket designs?

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The model for atmospheric drag has been replaced. Where previously atmospheric drag was solely determined by mass, it is now a more accurate physics model where the cross section (and therefore, the orientation of your craft) actually matter.

If the rocket is not aligned in the direction of travel, drag on each component will induce a torque. On components ahead of the center of mass, this torque will induce a rotation away from the direction of travel, destabilizing the craft, while on components behind the center of mass, drag will induce a rotation towards the direction of travel, stabilizing the craft.

Therefore, my preferred solution to stabilize the craft are tail fins, as shown on this suborbital tourist rocket:

enter image description here

(The fins in the middle are for stabilizing the rocket after separation of the first stage)

Reaction wheels are far weaker than atmospheric drag (they are designed for navigation in space, after all). Therefore, if atmospheric drag makes your rocket unstable, reaction wheels won't help.

  • So effectively, you cannot turn more than a few degrees away from your current heading, else atmospheric drag will rapidly overcome your torque? And wings can help with this but they need to be on both the tail and the tip... – DeadMG Jun 14 '15 at 22:03
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    @DeadMG: Wings are very often the way to stabilize a rocket, yes. But don't put them at the tip, just the tail. The additional wings in the middle here are used to stabilize the second stage after separation. You might need to use larger fins on the bottom stage(s) and smaller fins on the middle/upper stage(s); of course, only for those stages that are actually fired in the atmosphere. – DarkDust Jun 15 '15 at 8:32
  • I would recommend to replace the fixed fins with control surfaces ("winglets") as soon as they are available because they make the rocket a lot easier to rotate for the gravity turn. Using AIRBREAKs is also an option because they also act as control surfaces. They have the advantage that they create far less drag when not actively steering the rocket (but even more when they do). – Philipp Jun 15 '15 at 12:10
  • I did, and that was a start, but it's not enough to just go back to the old days- clearly I simply need a new technique. – DeadMG Jun 15 '15 at 22:47
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    @DeadMG if you'd like to see how it's done (to get the hang of the gradual turn), Scott Manley (Youtube) has done a very wonderful tutorial series (updated for the release of KSP). Just vrey gradually turn and you should be fine. Maybe try with a smaller rocket at first to get the hang of it. – Flater Jun 16 '15 at 8:07
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Winglets way at the back. The center of lift should be behind (i.e., below) the center of mass, otherwise it's aerodynamically unstable. That's jargon for "any maneuver is likely to overshoot," what you've seen. An airplane is the same: moving its CoM aft (by adjusting ballast, easier and safer on a model than on something you sit in) makes it twitchier and more agile, but once the CoM moves aft of the CoL, the airplane becomes uncontrollable.

If stages after the first are still in atmosphere, sure, give them winglets too, but not so large as to destabilize the first stage.

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Alternate solution: Increase available delta V by 1.5x, add verner engines, turn on RCS, and start your gravity turn at 35k.

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