Stabilizing a Docked Ship for Flight

[Project Pluto]

I've finally managed to dock in orbit! So, time to take Kerbals to another planet. Problem is, when I throttle up to escape Kerbin, disaster strikes…

Here are the docked ships:

And here is what happens when I throttle up:

The clamp-o-tron docking ports don't provide as much rigidity as I assume/hoped. I like playing stock, so am hoping to not have to use any mods.

Thanks for any help!

Edited January 24, 2014 by Project Pluto

[WhiteKnuckle]

1. Pull, don't push. (put your interplanetary engine at the front, then dock everything behind that section)

2. If all of your sections have RCS, use that get everything moving, then slowly feed in your main engine power.

[vetrox]

You can always use half throttle or quarter throttle.

EDIT: is that 5 mainsails? thats alot of thrust lol 1500kn each if memory serves your TWR must be insane!

[Cerberus738]

Those engines cause a lot of stress on a ship. Try throttling up slower or don't go full throttle. It looks like you need a couple of struts to hold the sections that are separating together. The docking ports will always wobble a bit. I've used horizontal mounted landing legs as clamps before but the construction ends up fairly large.

[Mobjack]

Use the large docking ports.

A little hack you can do is to put the ship quickly in warp for a few seconds when it starts getting out of control. This will stabilize it for you.

[iStickyDuck]

First off... Mainsails are not the best for an interplanetary mission. Despite their immense power the ISP on them is awful so the nuclear engine is the one you want to use for these kind of mission because although they are very low power they are ridiculuosly efficient.

To solve your problem you have two main options:

- Rebuild it with large docking adapters, engines at the front and use more effecient engines

- Take it slow and increase the engine power slowly using RCS to keep you stable

[theend3r]

Your engines are insanely overpowered. With the fuel (mass) I see in your picture, few nuclear engines would be enough. One mainsail = 25x LV-N. You have 5 mainsails

[Project Pluto]

Thanks for the help folks!

Back to the designing board (or VAB that is…)

[Tank Buddy]

Option 1: Use Clamp-o-tron Sr.

Option 2: Pull your payload

Option 3: Give up

[I_Killed_Jeb]

1. Pull, don't push. (put your interplanetary engine at the front, then dock everything behind that section)

this is the most important thing. even sr docking ports won't stay rigid enough with orange tanks, you need a puller

[Jordanpumah]

option 3 is best option.

[Skorpychan]

Thread hijack!

I'm pulling my craft, with Sr docking ports and two nuc engines. No thrust is hitting the structure anywhere, and it's all pretty much radially symmetrical. However, it wiggles when under thrust. Enough that I have to keep dialing down physics warp to correct it.

I have reaction wheels all over the craft. Would that be causing it? Do I need to enable RCS to stabilise it, like back in the ASAS days?

[I_Killed_Jeb]

Thread hijack!

I'm pulling my craft, with Sr docking ports and two nuc engines. No thrust is hitting the structure anywhere, and it's all pretty much radially symmetrical. However, it wiggles when under thrust. Enough that I have to keep dialing down physics warp to correct it.

I have reaction wheels all over the craft. Would that be causing it? Do I need to enable RCS to stabilise it, like back in the ASAS days?

there you go

[Skorpychan]

It wiggles even without x4 physics warp. Just slower.

[SpaceGremlin]

Disable extra reaction wheels, if you have multiple reaction wheels spaced far apart (particularly if they are on both sides of a docking connection) they will bend your ship.

[Pecan]

More struts.

My first pull tractor (when I didn't realise how well-recommended they are and thought I was being clever ^^) had the same problem - the nukes were on I-beam girder outriggers and oscillated moderatley badly even without a load. Strutting the engines to the tractor body damped it all out and now (Mk II) there's no movement at all.

Thanks again to everyone who was actually clever in the first place, unlike me, and has posted so many tips here.

[Vanamonde]

Your problem, as others have noted, is not in the docking arrangement, but in your engine choice. Much more fragile ships than that do just fine as long as you're not blasting them with umpteen Gs.