Launchpad Startup issues

[cyoung_mi]

I'm not sure if it's the physics engine, or I'm not building something correctly..

But when I attempt to launch my vehicle, the launch pad loads, then then physics take over and suddenly parts will sometimes fall off.

( like a rocket booster or something ) even though I have used Struts to brace things as well as launchpad clamps.

It's like that sudden "jolt" when the physics engine takes over.

This is before I even launch.

Any tips or suggestions?

My vehicle is not that complex.. just a liquid rocket with two solid boosters. And again, I put in Struts and use a couple docking clamps.

Thanks for any suggestions, I really love this game.. It's almost addictive.

Edited November 20, 2013 by cyoung_mi
Changed to Answered.

[sal_vager]

Seeing your craft would help a lot, but I'm thinking you need launch clamps here as it's often the case that a heavy craft will buckle under is own mass when on the pad unless all engines and boosters are carefully levelled, and even then it helps if those engines are also strutted

[700NitroXpress]

Sometimes is the craft isn't properly supported, then this will happen a lot. The weight of the craft acting on all the parts will cause structural failure if it's not held in place properly. Usually it's because the craft in the center isn't supported. If you can't put clamps on the center of your craft, you can put a stack decoupler on the bottom of the rocket engine and then put a big metal plate on the bottom of that, then put one docking clamp on the bottom of the plate. When you launch the craft, stage it so the the decoupler releases, but the launch clamp that's holding it stay's attached by putting the clamp in the next stage. This prevents the shrouds from moving and bumping into the engines. If this doesn't work, try using different methods of lifting your payload.

[cyoung_mi]

I'm not really sure, I think it was maybe the construction.

I don't really have an issue when I use prebuilt craft files.

I think perhaps, sometimes when i place a single item, I still have the mirroring on, and it tries to place 2 or more times in that single spot.

When this happens, the connection is not really made, or glitched..

I have tried to pay better attention to my mirror settings, and things have been working much better.

Thanks everyone.

[Kasuha]

In VAB, the ship is in weightless state. When you go to launch it, it is taken in this state, positioned on launchpad, and then gravity is applied on it. If the ship is not ready for the shock, it may break up.

The devil is in proper placement of struts. You need to place them so they don't allow radially mounted parts to wobble along the separator or their other radial anchor point. Notice also that you can always only put a radial part on one separator or girder, if you try to use more (e.g. a radial tank mounted on two separators) only one will be actually used and the rest will be just facing the part. Only the "strut connector" can be used as additional anchor, the whole rest of the ship will always be a "tree", branching out from the first part you placed.

Apart of that there are also some bugs. The ship may start breaking apart on its own if you either shifted the initial part too far from the center where it was initially placed (far enough to not be above the launchpad) or in certain cases when you append complicated parts using symmetry modes.

Edited November 15, 2013 by Kasuha

[capi3101]

Sometimes this happens to me with well-built craft; happened last night with a craft that utilized one of Temstar's Zenith boosters - a design I'd launched a hundred times without flaw alreadty. Of course, I also had the Hell Kraken strike twice last night, so it's possible that my local instance of KSP was simply in a foul mood......

Anyway, couple of things you can try -

1) When you're placing your entire rocket in the VAB, try sticking the engines slightly into the ground. When the rocket goes out to the pad, the game will automatically raise up your rocket so the engines are at ground level; this is a good way to ensure that they are indeed flush with the ground.

2) Before the physics engine releases, try zooming the camera out away from the rocket. No seriously, try this; I don't know why this works sometimes but I can tell you from experience that it does. Zoom back in once you light that candle.

[Alistone]

Sometimes adding decouplers at the bottom of all the parts that touch the ground can add quite a bit of stability on the launchpad. Just make sure they are decoupled as the same time you start your engings.

[Sirrobert]

If it comes off, hit F3 to check the mission log to see where it breaks. Than see if you can fix that point

[cyoung_mi]

Thank you everyone for your help and suggestions.

How do I change this post from [unanswered] to [Answered]?

[capi3101]

Edit your initial post; the tab to change the thread status is there.

[cyoung_mi]

Edit your initial post; the tab to change the thread status is there.

Thanks! found it.. it was on the Go Advanced button.

[SSSPutnik]

On a side note. I note that launchpad instability is MUCH worse if I revert a mission ship to pad rather than to VAB and then Launch again.