Spacecraft starts flipping when taking off from the mun.

[Sublight]

I can get to the moon and land just as easy as pie.  I mine ore on the moon and replenish my fuel/mono and do science stuff.  Then I wanted to take off, and go to another spot, and farm the science from there also.  But for some reason every time my craft takes off it will just suddenly start flipping, and it wont stop.  Is this a bug on the Xbox?  I have checked and all of my engines are firing at 100% and they all work.  The problem happens with im at about 75% fuel and 6k meters high.  Ill have to send a craft to retrieve Peter, Lulu, and Joliene.  Any ideas why this happened?  I want to farm the entire moons science, but as it is, i dont know what to do.

[Bluarc]

Just now, Sublight said:

I can get to the moon and land just as easy as pie.  I mine ore on the moon and replenish my fuel/mono and do science stuff.  Then I wanted to take off, and go to another spot, and farm the science from there also.  But for some reason every time my craft takes off it will just suddenly start flipping, and it wont stop.  Is this a bug on the Xbox?  I have checked and all of my engines are firing at 100% and they all work.  The problem happens with im at about 75% fuel and 6k meters high.  Ill have to send a craft to retrieve Peter, Lulu, and Joliene.  Any ideas why this happened?  I want to farm the entire moons science, but as it is, i dont know what to do.

Try redoing the mission without landing legs. It's usually a problem with the hit-box for the suspension. See if that helps. Also, I would recommend establishing a space station in orbit around the moon, as it can prove very useful for rescues. I like to have escape pods in very low orbits for easy accessibility.  But, it requires patience and time. It's not feasible unless you don't like rescuing the rescue mission.

[Sublight]

I have no landing legs. My engines sit on the ground.  

Edited August 18, 2016 by Sublight

[FyunchClick]

Perhaps the fuel is draining unevenly, which can happen with misaligned fuel ducts. And are you using SAS to track a particular direction? If so, check if it's not accidentally set to Target. I'm on pc myself so I can't say if it's an Xbox thing. A picture of the Lander would help if you can grab it somehow.

[foamyesque]

If it's on the Mun, it can't be aero. Most probable culprit is misaligned thrust somehow; pictures and/or craft files would help a lot.

[Sublight]

1 hour ago, foamyesque said:

If it's on the Mun, it can't be aero. Most probable culprit is misaligned thrust somehow; pictures and/or craft files would help a lot.

It landed with no problems. 

It flies perfectly for the first 1500 feet then abruptly turns

[Sublight]

I shut off the bottom tank and it stopped. Took me hours to find that

[Rath]

How complex is the fuel duct system?  One tank may be draining after another runs out of fuel, but not the other ones placed in symmetry with it.  

Did you try and do asparagus staging?  

[Hotel26]

Assuming that you are flipping because one or more engines shutdown due to fuel starvation (which you haven't explicitly said)...

you would then find the following fuel rules helpful to understand.

The key point in these rules is under the heading Common Errors: "If the ship is symmetric, it will draw fuel symmetrically".  If tank A supplies tank D via two paths, through B and C, one of B and C will begin to drain earlier (as if not fed by A).  I doubt your lander is this complex, but bear it in mind and the above article is essential to the design of any complex craft, particularly those using asparagus staging.

[foamyesque]

18 hours ago, Sublight said:

It landed with no problems. 

It flies perfectly for the first 1500 feet then abruptly turns

 

Does it do this if you don't mine? Turn on infinite fuel. Do you still have electricity to power reaction wheels?

 

Without a .craft or screenshots of the problem though I'm just guessing in the dark. Help me help you.

[Sublight]

Video

This is a video of what it WAS doing.  I turned off the fuel tanks in the center which was supposed to just feed fuel to the 3 outside engines.  Apparently that was a problem.  I turned them off and diddnt use any more fuel from those tanks.  I traveled all around the Mun and collected enough science to unlock everything.  I even brought the kerbals back to Kerbin orbit, and sent a rescue ship for them.  So they are not national heroes on in our nation, because they were in space for a total of 5 years doing research and sending it home.

But when they got home the cat jumped on one of them and she died. You know.... brittle bones from all the time in space.  Crushed her head with a dead mouse.  Tragic.

[foamyesque]

8 hours ago, Sublight said:

Video

This is a video of what it WAS doing.  I turned off the fuel tanks in the center which was supposed to just feed fuel to the 3 outside engines.  Apparently that was a problem.  I turned them off and diddnt use any more fuel from those tanks.  I traveled all around the Mun and collected enough science to unlock everything.  I even brought the kerbals back to Kerbin orbit, and sent a rescue ship for them.  So they are not national heroes on in our nation, because they were in space for a total of 5 years doing research and sending it home.

But when they got home the cat jumped on one of them and she died. You know.... brittle bones from all the time in space.  Crushed her head with a dead mouse.  Tragic.

 

One of your engines stops thrusting, hence the flip. Which one and why I can't say based on that video, not enough info, but on the right-side front stack there's a very clear change in the exhaust right before the flip.

Edited August 20, 2016 by foamyesque

[magnemoe]

12 hours ago, foamyesque said:

 

One of your engines stops thrusting, hence the flip. Which one and why I can't say based on that video, not enough info, but on the right-side front stack there's a very clear change in the exhaust right before the flip.

If you run the ISRU while the engines is running its an good chance for uneven trust because of some bug. Solution is to not do this, you produce so little in the few minutes of trust it don't matter anyway, once in orbit start the isru again to refill the tanks. 
 

[Sublight]

Thanks everyone, the problem is solved.  Thanks for helping out!