Rocket tilting over when previously it didn't.

[ZeGamingCuber]

So, I was trying to send a probe to Jool with a rocket that I used to send a probe to Duna, but once I separated two of its stages at ~10,000m in Kerbin's atmosphere it started spiraling out of control. It never did this when I was going to Duna, which makes no sense at all. Does anyone know what I'm doing wrong?

[Snark]

Hello, and welcome to the forums! 

38 minutes ago, ZeGamingCuber said:

So, I was trying to send a probe to Jool with a rocket that I used to send a probe to Duna, but once I separated two of its stages at ~10,000m in Kerbin's atmosphere it started spiraling out of control. It never did this when I was going to Duna, which makes no sense at all. Does anyone know what I'm doing wrong?

I'll move this over to Gameplay Questions, since this is more a matter of "how to design a rocket"-- technical support is more to do with technical issues with the game.

Could you post a screenshot of your rocket?  Would help us to provide specific advice.  Rockets flipping is a common problem in KSP, and usually comes down to the design of the rocket.  The general solution is "put fins on the back, make the front pointy and streamlined, and have the CoM as far forward as possible.".  But we'd need to see a picture to be able to give more specific advice than that.  (To post a screenshot:  just host it to an image-sharing website like imgur, then right-click on the image there and choose "Copy Image Location". Then paste that URL here and it'll get automagically converted into an in-line image.)

As to "why does this rocket have problems now when it didn't have problems previously", could potentially be any one of a number of things, such as:

• If you've changed the design in some way (e.g. put a different payload on top)
• If you're flying it differently somehow (i.e. your ascent trajectory)
• If it's an old rocket that you were flying in an older version of KSP and you're using it now with a newer version where the aero may have changed

...but really, we need to see a screenshot to be able to help. 

[ZeGamingCuber]

22 minutes ago, Snark said:

Hello, and welcome to the forums! 

I'll move this over to Gameplay Questions, since this is more a matter of "how to design a rocket"-- technical support is more to do with technical issues with the game.

Could you post a screenshot of your rocket?  Would help us to provide specific advice.  Rockets flipping is a common problem in KSP, and usually comes down to the design of the rocket.  The general solution is "put fins on the back, make the front pointy and streamlined, and have the CoM as far forward as possible.".  But we'd need to see a picture to be able to give more specific advice than that.  (To post a screenshot:  just host it to an image-sharing website like imgur, then right-click on the image there and choose "Copy Image Location". Then paste that URL here and it'll get automagically converted into an in-line image.)

As to "why does this rocket have problems now when it didn't have problems previously", could potentially be any one of a number of things, such as:

• If you've changed the design in some way (e.g. put a different payload on top)
• If you're flying it differently somehow (i.e. your ascent trajectory)
• If it's an old rocket that you were flying in an older version of KSP and you're using it now with a newer version where the aero may have changed

...but really, we need to see a screenshot to be able to help. 

[Snark]

Yeah, the problem with that rocket is that it's got that huge, draggy, probably lightweight fairing up front, and the heavy stuff back behind.  It's going to be aerodynamically unstable.

The first thing to try is, put some fins on the bottom.  Steerable fins would be best (e.g. the AV-R8 winglets), but even non-steerable fins would help, if they're big enough.  Put them as low down as you can manage.

The other thing is to start your gravity turn fairly early and keep pointing precisely as you fly-- that will also help flipping.

[ZeGamingCuber]

4 hours ago, Snark said:

Yeah, the problem with that rocket is that it's got that huge, draggy, probably lightweight fairing up front, and the heavy stuff back behind.  It's going to be aerodynamically unstable.

The first thing to try is, put some fins on the bottom.  Steerable fins would be best (e.g. the AV-R8 winglets), but even non-steerable fins would help, if they're big enough.  Put them as low down as you can manage.

The other thing is to start your gravity turn fairly early and keep pointing precisely as you fly-- that will also help flipping.

Thanks, adding fins worked.