So I'm building a multipart ship...

[rockbloodystar]

...and i'm wondering how accurate i need to be with weight disrtibution, so that when i turn on my engine i will not get unwanted torque.

Any ideas?

(also my account vanished in the forum outages so i'm posting to get up to five messages - sorry for what looks like spamming)

[Volodyuka]

first problem with multipart ship is wobbling of it, so u need mods or make a multiport docking system.

[georgexiro]

yes. They need to be pretty accurate. if they are not then without proper ASAS systems and a lots of RCS your ship will probably start spinning its guts out..

[ThatBum]

It's not too much of an issue once you're in space I guess, but you could put the parts together in the VAB and look at where the center of thrust is relative to the center of weight. They shouldn't be offset from each other.

[Eric S]

Each individual section should be balanced, otherwise you'll have problems getting them into orbit and rendezvoused before you even have to worry about how they balance together.

And yes, wobble will probably be an issue as well. Personally, I recommend the Common Berthing Modules addon to help with that. There's also a Docking struts addon and the Quantum struts addon.

[rockbloodystar]

Hmm, if i load one of those mods, will i have to redo the launches that already make my station?

[Malaugrym]

You won't have to re-launch your station. Part mods that simply add new things generally don't affect craft that already exist.

[Noticeably FAT]

New parts won't affect anything you have already launched, but you may have to relaunch any modules you want to have the new parts.

The aforementioned Quantum Struts are awesome for station building, but there are a few things to watch for you might find helpful. First, assign them to an action group so you can turn them on and off. I've found that with bulky modules they will activate before the docking node magnetism settles, so the nodes and struts will fight each other and tear things apart. Having them off before you dock, then turning them on after everything stops moving seems to help. Second, in the VAB rebuild the part of your station you will be docking with so you can correctly aim the struts. Don't assume that you have them aimed right, there's nothing quite like the frustration you get when you finally dock only to find that the struts are trying to lock to the cold vacuum of space.

ETA: Try to not face the struts down on the ship you are launching. They occasionally seem to attech themselves to the launch pad, and surprisingly enough have enough strength to hold your rocket on the ground. I've had a 2.8 TWR rocket hover 50' over the pad at full throttle due to quantum struts. Also, if you do want to toggle them make sure you have them on an action group. You can right click them, but not fast enough that the first one you activate won't pull your module sideways before you can get the rest.

Edited April 23, 2013 by Noticeably FAT