My rockets lose stability when trying to launch

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?

Solution 1:

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:

(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.

Solution 2:

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.