Why is my rocket tipping?

[jonahk3]

Why is my rocket tipping?

 

OK so I know this a commonly asked question, but I cannot figure out why my rocket is tipping. Immediately after launch (less than 5 secs) it begins turning in a random direction (different each time), until its facing down.

The purpose of the rocket is to bring some mining equipment to the surface of Ike.

Here are some pictures

 

 

I have removed the fairing that would be at the top usually.

 

The first is a pic of the whole rocket, the second the mining part with the hinge inward (where it would be for takeoff), and the third the hinge outward (Where it would be for mining)

Here is the craft file - https://easyupload.io/deijvl

All help is appreciated, thanks.

If you also need the LoadMeta file for the craft (I am new to this), I can edit the post just tell me.

I am using the Breaking Ground DLC

[Ben J. Kerman]

Hmm, is it bending, or just flat out falling over while remaining rigid as a whole? If it is bending before falling, then you just might need to use autostrut on some of the parts. If it is just falling over, then it could be a weight distribution issue, or much more likely, something else I don't know about. Sorry if this is no help at all, but check if this works (Unless you already used autostrut or normal struts.)

[Guest]

Looks like too much mass at the bottom end. Those SRBs seem overkill for that payload so I’d downsize those first. Second I’d ‘bulk up’ the upper stage with more fuel to push the CoM up. Finally I’d ditch the fins on the upper part as drag higher up is undesirable. Plus I’d stick to just 1 fin per side as 3 just adding more mass. 

If it’s still not playing nicely, stay vertical for as long as you need before doing a gravity turn. You’ll use more fuel but it should resist flipping higher up.

PS make sure there’s plenty of reaction wheels as well. 

[OHara]

15 hours ago, jonahk3 said:

If you also need the LoadMeta file for the craft (I am new to this), I can edit the post just tell me.  I am using the Breaking Ground DLC

We do not need the .loadmeta file to try your craft, but we do need to have all the mods for parts you use (KOS for the KAL9000) .  I have used KOS so I reactivated it to try your craft, but you might want to upload a version with the KAL9000 removed so more people can try it.  Letting people try the craft is a very good idea, because otherwise people are just guessing.

For me, the rocket flew fine with SAS off, but it turned off course with SAS on.  As you uploaded it, the control point is the Probodobodyne in the miner probe, which is upside down, so it would steer backwards.  You can set an option to have the Probodobodyne look up when it is steering the booster.