Uncontrolled flipping in space

[Syrius]

I have about 770 hours logged into KSP already and I have not come across this issue before and I for the life of me cannot figure out what the F is going on. I have already checked out videos, the KSP tutorials and am no closer to sorting it out.

The issue is stability and uncontrolled flipping in space. I launch with the SRB's and I am fine I shoot up like an arrow, I decouple and roll my rocket into position and leave atmo and this is where the problems occur. If I fire up the liquid rocket past 25% it starts to flip and lose trajectory. I have used RCS to aid... no go. Reaction wheels, nothing. I even thought hell maybe the rocket is to long, so I decouple the next stage and have a nice smallish craft and that will spin once it hits around 30-40% thrust. If I decouple my probe and small engine.... same thing.

I have checked and my Center of Thrust is always under my Center of Mass. My Aerodynamic Overlay point is ever right next to my CoM or when I decouple to the top above it. 

At this point I am getting so frustrated I am tempted to shelf the game. Can someone please help me.

 

Current Mods in Use

X Science                                                      Kopernicus                                      OPT Spaceplane                                                  Karbonite and Karbonite Plus
Ablative Airbrake                                           KSPWheel                                       OPT Legacy                                                         Karibou
Alcor Landing Capsule                                  KW Rocketry                                   Orbital Survery Plus                                             Konstruction
B9 Aerospace                                               Infernal Robotics                              Planetary Base Systems                                      Kontainers
Chatterer                                                      Mark 2 Expansion                            Planetshine                                                          Life Support
Coatl Aerospace                                           Mark 3 Expansion                            Portrait Stats                                                        Malemute
Comorant Aeronology                                  Mark 4 Systems                               SCANsat                                                               Service Pack
Distant Object                                              Mechjeb                                            Ship Manifest
DM Orbital Science                                      Mining Expansion                             Simple Construction
Infernal Robotics                                         Mod Pods                                          Smokescreen
EVA Transfer                                               Modular Flight Integrator                   SpaceY Expanded
Extraplanetary Launchpads                        Konstellation HLV2                             SpaceY Lifters
Field Training                                               Space Plane Transport                     Shadow Space Technologies Unlim (SSTU)
Flexible Docking                                          Near Future Construction                  Station Parts Expansion
Ground Construction                                   Near Future Electrical                        Station Science
Interstellar Fuel Switch                                Near Future Props                            Surface Lights
Transparent Pods                                        Near Future Propulsion                    Stock Visual Terrain
Kerbal Attachment System                          Near Future Solar                             Tarsier Space Tech
Kerbal Engineer                                          Near Future Spacecraft                     Tweakscale
Kerbal Reuseability Expansion                    Handrails                                           Universal Storage
Kerbaltek                                                     Final Frontier                                     Akita Rover
Kerbnet Controller                                      Docking Camera                                Asteroid Recovery Tech
Kerbal Inventory System                            Outer Planets Mod                             Freight Transport Technologies
 

 

IMAGES OF THE ROCKET IN VARIOUS STAGES

 

Edited April 2, 2017 by Syrius

[The Aziz]

Recently I started having problems with asymmetrically placed mechjeb module, it caused my rocket to flip. I can't see if you have it, but if you do, remove and try again.

Also maybe try different payload? Something more... Round and simple?

[FullMetalMachinist]

1 hour ago, The Aziz said:

Also maybe try different payload? Something more... Round and simple?

@Syrius that would be my suggestion. Try to isolate what is causing the issue first. I find that an ore tank with the contents adjusted so it masses the same as your original payload works well. 

From there you should be able to work out if the problem is with the payload, the transfer stage, or the booster. If it's not obviously caused by one of those things, I would suspect a bug, most likely from one of your mods. 

[linuxgurugamer]

Why not post the craft file so we can try it outselves?

[bewing]

Extended wheels inside fairings are sometimes a problem. There is a button on the context menu for the wheels for exactly this purpose, about "extend when stowed", or something like that. Also, wheels that are very near the outer surface of a fairing have caused problem interactions in the past. Your rocket is very sleek and nice as it is, but I think you may need to expand the fairing a bit, to get it farther away from those wheels. I'm not sure if you've tried discarding your fairing when you are in space, as part of your testing -- but that's what I'd test first.

 

Edited April 2, 2017 by bewing

[Razorforce7]

It probably seems to easy to be overlooked.

but,

You might have SAS on with autopilot set to anything other then kill rotation i.e. pro/retrograde, anti/radial, and/or anti/normal.
So you may be constantly fighting the SAS autopilot.
Either put SAS off or switch to kill rotation.

[Snark]

Hi @Syrius, and welcome to the forums! 

Not sure what's the issue, but your screenshots above aren't working-- I'm just seeing some standard imgur "sorry, no such image" error images.  Could you fix them up?  Lots easier to offer advice when the ship is visible. 

[steuben]

A blind suggestion:

Assuming you're using a probe core as the control point, the core is facing the right way?

[Syrius]

Hmmm I am not sure why the images broke but here are the links...


Steuben - Yes I am using a probe core for a rover I am taking to Mun and yes it is upside down so when it deploys it will be right side up.

Razorforce - I do have SAS on but it has been set to holding course, I do not have it set to pro, retro, etc.

Bewing - The wheels look deployed because the rover is upside down, they are in the stowed position.

Linuxgurugamer - I can do that but would you not need the same mods, or at least the same mods supplying parts to the craft to test it?

The Aziz - I do have a mechjeb controller on one side only... I will give that a try.

Full Metal Machinist - So I had originally checked the payload and it was not the issue, although I have changed the payload so maybe something is different. I used much the same design so I did not recheck it.


UPDATE - Okay the payload seems to be the issue, although I cant sort out what about it is the issue. It is symmetrical for the most part, and is attached with a decoupler, and reinforced with medium struts (groan).

Thank you everyone for helping with responses and feedback. If any of you want to continue to help with why this payload is creating this issue that would be awesome. I will post a close up of the rover to maybe get some feedback.

http://imgur.com/a/x90L1

http://imgur.com/a/yK2i9

 

Edited April 2, 2017 by Syrius

[FullMetalMachinist]

2 hours ago, Syrius said:

Yes I am using a probe core for a rover I am taking to Mun and yes it is upside down so when it deploys it will be right side up.

Is there a chance that the upside-down rover probe core is the only probe core on the craft? If so then that is likely the problem. Any slight deviation and the probe core will use SAS to try and correct it, but since it's upside-down it 'corrects' in the opposite direction, making the problem worse. 

A fix would be to put a second core on the transfer stage somewhere, and then use the re-root tool to make it the root part. (you don't necessarily have to make it the root part, but if you don't you'll have to remember to right click on it and select 'control from here'.) 

[bewing]

4 hours ago, Syrius said:

If any of you want to continue to help with why this payload is creating this issue that would be awesome. I will post a close up of the rover to maybe get some feedback.

The first thing I would try is doubling the size of the fairing around the rover, and see if the problem goes away. If it does, then you know the problem is an interaction between the fairing and the payload.

Additionally, you said the problem only happens when you get above the atmoshpere? You can stage your fairing at 55km in the atmosphere, and then the problem might go away.

 

Edited April 3, 2017 by bewing

[Syrius]

2 hours ago, FullMetalMachinist said:

Is there a chance that the upside-down rover probe core is the only probe core on the craft? If so then that is likely the problem. Any slight deviation and the probe core will use SAS to try and correct it, but since it's upside-down it 'corrects' in the opposite direction, making the problem worse. 

A fix would be to put a second core on the transfer stage somewhere, and then use the re-root tool to make it the root part. (you don't necessarily have to make it the root part, but if you don't you'll have to remember to right click on it and select 'control from here'.) 

I will give that a try and see what happens.

1 hour ago, bewing said:

The first thing I would try is doubling the size of the fairing around the rover, and see if the problem goes away. If it does, then you know the problem is an interaction between the fairing and the payload.

Additionally, you said the problem only happens when you get above the atmoshpere? You can stage your fairing at 55km in the atmosphere, and then the problem might go away.

 

I am not sure the fairing is to blame but it is worth experimentation. Once outside atmo I decoupled the fairings and was still having an issue but I can expand the fairing and see if that fixes the issue.