Aircraft rolling in high g pitch maneuvers

[SpaceToad]

Whenever I pitch up in particular aircraft, the aircraft rolls right out of control when hitting high g's. Any ideas?

[Snark]

A screenshot would help.

[T-Bouw]

Are your elevators perpendicular to the hull-surface?

A V-tail for instance introduces some forces other than pitch when commanded to move as such.

[RizzoTheRat]

IRL I'd say you're stalling one wing and spinning. Push the stick forward to the stops and then mash the rudder until it stops rotating.  Not sure KSP's aero model is that that detailed though.

Is the craft symmetrical and does it stay that way?  It only a takes a minor cock up with a fuel line to lighten one side faster than the other.

[AeroGav]

Perhaps if you pitch up aggressively with some yaw on, one wing will generate more lift than the other, causing a roll.  This would  point to insufficient vertical stabilizer.

However,  it might be worth eliminating the really simple first.     All of my aircraft had minor handling issues,  they'd all deviate in random directions flight to flight and need constant correction - I could never leave them to fly hands off or go with time acceleration.   This was despite using gull-wing dihedral,  high wing design,  generous vertical stabilizers and very aft CoL etc etc.     Then one day I forgot to plug my joystick in and was forced to fly on keyboard - suddenly,  my aircraft handle perfectly.   They actually work better with SAS off,  slowly return to level flight of their own accord, and can simply be left AFK with SAS off and 4X time acceleration to fly to distant destinations. 

So, try with joystick unplugged to make sure your stick isn't generating a roll moment when heaving it all the way back.  From a human point of view, it's difficult to keep dead centred anyway when tugging hard like that.

Back in the 80s/90s,   computer peripheral standards came and went like the changing of the seasons,  generally if you could physically plug it in it wasn't that old and bound to work fine.   I just realised i can't remember when i bought this USB logitech stick.  It might be over 10 years old?  

[Snark]

All of this is useful advice, but @SpaceToad, seriously, post a screenshot.

Planes are complex beasties, there are many potential design issues that could be causing you problems, and if you just post a screenshot, there's a high likelihood that it will be instantly obvious to folks in this forum what your problem is, and they can immediately give you short, to-the-point advice that will directly address your actual issue.

Otherwise, you're just going to get reams and reams of generally-useful advice that will have a low signal-to-noise ratio for you, because it will all be "maybe your problem is this, maybe it's that" rather than directly addressing your actual issue, which no one can know until you post a screenshot. 

[SpaceToad]

Yeah. I guess it might be good if I, you know, POST A SCREENSHOT. I'll have one for you this afternoon.

[SpaceToad]

Problem solved. Combination of slight adhedral wing angle and V tail seemed to be the issue.