What does locking the gimbals in engines do?

[NuclearWarfare]

So I've heard about this a good bit recently. I've never even used this... what does it do? I'm too lazy to start up KSP just to see :I

[Eleven]

Locking the Gimbal prevents the engine from vectoring (steering). When using multiple engines, lock the gimbal on the outside engines, and it shoud save fuel (maybe) and allow for more stability (again, maybe)

[robot256]

When I have a first stage with multiple large engines, I frequently have to lock the gimbal on one or more of them to prevent Mechjeb from wibbly-wobbling the rocket all over the place (it's very easy to excite bending oscillations when you have too much torque at the base). The only trick is remembering to unlock the engines that remain when it's time for the gravity turn.

[El wonso]

Locking gimbals is helpful when controlling big rockets with like 7 mainsails.

[SuperFastJellyfish]

Usually when flying heavy payloads into space you have multiple mainsails running. The vectored thrust the main mainsail provides is plenty for steering. If you set up an action group to turn off all the other mainsails or whatever other vectored boosters you have then your vehicle won't shake/spin so much on ascent.

[N_Molson]

Yes. To sum it up, it avoids engines under ASAS control to fight themselves. Which, on large stacks, can have the catastrophic consequences we know.

I also used that feature as a "trim" (I wish there was a real one !) to control airplanes : you can lock the gimbals in any position. Just hold the controls as you wish and click "lock".

[Flater]

Yes. To sum it up, it avoids engines under ASAS control to fight themselves. Which, on large stacks, can have the catastrophic consequences we know.

I also used that feature as a "trim" (I wish there was a real one !) to control airplanes : you can lock the gimbals in any position. Just hold the controls as you wish and click "lock".

There is a real one... Alt + WASDQE sets the trim, Alt + X resets it.

[N_Molson]

There is a real one... Alt + WASDQE sets the trim, Alt + X resets it.

Thank you for that one, that's going to be put in good use !