Thuds won't aim straight

[CosmicCharlie]

I've got a reaction wheel and a drone core. Doesn't help.  I can see the nozzles pointing anywhere but straight. Any ideas?

[Snark]

You have "hold maneuver prograde" turned on in SAS.  Any time you have gimbaled engines and you have chosen any of the "hold <orientation>" options turned on for SAS, it totally spazzes out and starts flicking the gimbal all over the place.  It's particularly bad for the Thud since it has such a big gimbal range.

To stop it, either change SAS so that it's just "hold orientation", or else lock the gimbal on your engines.

...Actually:  you've got MechJeb running, so this could be some sort of MechJeb weirdness.  I never use MechJeb myself, so I can't speak to that.  However, I wouldn't be surprised if it has engine-gimbal issues, too.  Try locking your gimbals-- does that help?

Edited January 10, 2016 by Snark

[CosmicCharlie]

HA! Locking the gimbals did it. Thanks much.

[Matt77]

I have got into the habit of limiting the gimbal range to 15%, if I hope to stay on the node vector. They massively overcorrect.