Rocket Attachments - I don't understand why my rocket keeps falling apart!

[Dex Luther]

I have to admit that it's gotten me to the point where I'm so frustrated that I close the game mid launch.

The issue I've been having is building rockets to do anything and progress the game any further. I build a rocket and everything seems to be attached. Take it to the launch pad and parts fall off and my rocket explodes. Alternatively, sometimes I manage to launch the rocket, but spent fuel tanks aren't ditched properly.

I've just unlocked the TT-38k Radial decouplers and those are even more hit or miss than trying to attach tanks to the side of other tanks.

My question is: Is there a way to see what exactly something is attached to or force something to attach to a specific part?

I figured I must be missing something. For example, I put a "Rockomax BACC Solid Fuel Booster" as part of my rocket's body. I needed more lift so I attached 6 more around the first one. I assumed that because it turned green and allowed me to place the part that it was attached properly. Hit the Launch button and as soon as it loads tanks start falling over, exploding, and causing my whole rocket to come down or unable to launch due to lack of lift.

I must be missing something because I can see many players being turned off by the game because they are unable to actually build something that works.

[Hallofo]

Dex,

I'm sorry that you're having so many issues - could you attach a screenshot (F1 in game) and post it?

That being said, about %70 of KSP is "things exploding", followed by refinements to make the explosions less likely.

[hobbsyoyo]

Don't feel bad, I joined the forum today myself to ask Whackjob a similar question. My case is probably a bit more complicated (it's an enormous rocket), but with you its probably that you have either staged incorrectly (pay attention to the order of the staging list on the right side in the VAB) or your machine is too big to hold together without struts. If you are in career mode, stick to smaller rockets until you unlock struts, then use struts to hold everything together. If in sandbox mode, use struts like duct tape - place them EVERYWHERE.

[Johnno]

As already mentioned, struts are your friend. However succesful design is just as much about mass distribution, not having a lot of weight on weaker components or uneven distribution.

Each part attaches to another part by a single point, stuff doesn't get welded together. No matter if you attach 5 tanks on eachother and then use symmetry to put 4 of those around the central original one each stack is only attached to the center stack at a single point. Launch and they'll either crumble or if you lift off they'll start flailing around. This is where struts come in.

And masswise you can test it by putting a small tank below a couple larger ones, the bottom one will promptly be squished when physics load. And that's physics for you, the tanks above are excerting so much force when under effect of gravity that they exceed the smaller tank's structural strength.

KSP has quite realistic physics gamewise, obviously not 100% accurate and some stuff is just placeholders, but basic understanding and application of physics will help you more than hinder you. There's a learning curve though but if you browse the forums and read up on stuff when you get stuck, you'll get there.

[hobbsyoyo]

You can reinforce tanks in a stack by strutting them to each other. Place a strut (or multiples) to a tank at the bottom edge of it. Then run that strut down the top edge of the one below it and place it. They will now be attached to each other with struts, which will greatly increase their strength.

Though I'm not sure structural integrity is really the issue here, he's kind of vague and it sounds like more of a controls issue.

[Dex Luther]

The issue is that there's no way to really tell if things are attached to the right surface or if it's attached to something else. I'll try to get a screenshot or short video up to show what I mean.

Until then I'll try to clarify:

I built a rocket. In career mode you don't have access to much, so everything looks like a derp stick (That's what I aptly name my rockets). I unlocked the radial decouplers and those Rockomax BACC Solid Fuel Booster.

At first I tried upgrading my current derp stick to waste less fuel on launch, so figured those solid fuel boosters would be perfect. I add a new stage to the bottom of the rocket and put some radial decouplers around the outside. The next step is attaching the solid fuel boosters to them. I fiddle with the placement over the radials until they turn green. At that point I assume they are placed correctly. I move the camera around and they do seem to be placed on the radial (the radial face does seem to clip into things sometimes).

Then in launch things can go two ways. Either the tanks just fall over and explode or the ship launches and when I activate the radials I see the parts fly off, but the tanks stay attached some other part of the ship.

There's a bump when the rocket is loaded that doesn't seem to help either lol

[capi3101]

Okay - here's what you need to do. In the VAB, take the part that you want to stick on the 38K and just kinda attach it radially to whatever the 38K is attached to. Don't attach it to the 38K itself; not at first anyway - just get it to stick somewhere. Once it clicks in place, pick it up again and try to put it over the 38K; if it's going to work, it should look slightly further out from where it was when you attached it originally.

It's an old problem with radial decouplers in general. Bit easier to catch with the TT-70 (which is why I pretty much use it exclusively, except for the occasional Hydraulic Detachment Manifold on the end of a Girder; I hate the 38K); your pieces are in fact not sitting on top of the decoupler. So when you hit the decoupler, the tanks stay attached and if you're lucky you'll see the decouplers come flying out the back end of your ship. Happened to me the other day with what was supposed to be a Münshot; wound up being an abort to orbit.

Another thing you should watch is your gee meter as you ascend. If it gets out of the green zone, you've got an enhanced risk of pancaking your stack. All that thrust you had at launch you really don't need by the time you're 30,000m up. Throttle back down into the green and see if that helps a bit.

Also, struts REALLY are your friend. If you've got a rocket that's failing in the same spot over and over again, MOAR STRUTS is the advice you're going to get.

One other thing - when you build your rocket in the VAB, stick the bottom stage engine nozzles into the ground. No, seriously; the game will adjust your rocket so that they're above the pad when it gets out there. If you still have crap falling off after you've strutted everything, add some TT18-As (ground clamps) and see if that helps matters. And if it doesn't, well, then we definitely need to take a look at your ship.

Edited October 23, 2013 by capi3101

[hobbsyoyo]

The game doesnt adjust my rockets height when they are clipping the ground, it spawns the rocket with the engines in the launch pad creating 0 thrust

[SRV Ron]

In career mode, without the launch stabilizers, you will have to be mindful on how a rocket sits upon the engines on the pad. Too much weight on one engine and the whole thing will fall apart on the launch pad. So, if you add a ring of boosters, make sure they are sitting evenly on the pad and not all of the weight on the center engine.

Once you get launch stabilizers and struts, you are good to go on the big designs.

[Taki117]

When I first started Career mode I made kind of a stand off for my rockets. I would place a strut under a decoupler under my engines and set that as stage one (With the engies ready to fire) This prevented any damage to the engines upon launch. As far as thing attaching properly, I use Angle Snap (the button next to Symmetry in the VAB and SPH) so that when I put my Radial Decouplers on they are in the correct spot, and when I attach my boosters I know that they are also on the decoupler.

[capi3101]

The game doesnt adjust my rockets height when they are clipping the ground, it spawns the rocket with the engines in the launch pad creating 0 thrust

Really? That's never happened to me before, and I do the "engines half-buried in the ground" trick a lot.

Go with SRV Ron's advice. If that doesn't work, its time to try SCE to AUX...

[Jean Deaux]

Here's some personal experience I hope may help.

Parts don't hold together very well without struts. It's not so bad in a single stack, but if you branch out at all, the side torque of the lifting is going to shear away at your designs and ensuing explosions usually occur. Again, struts here help to re-enforce the the side torque and help keep the alignment of the side pieces from creating additional stresses.

Staging can be tricky, be sure the engines are out of fuel and have shut completely down. If a firing engine becomes separated, it has none of the weight it was once carrying and will now travel faster than your ship coming up from behind and try to sneak in your back door. Again with this ensuing explosions tending to occur. Best to wait a second after it shuts down to stage than to try and stage at the exact moment the fuel expires.

The higher up your core ship the expended engines are, the farther away from the core of the ship they will need to be. As your ship travels up and the staged engines fall down, you need to be sure that they don't hit one another. If your engines are on the top side of your ship, there's a lot of opportunity there for the two to meet. Put some space between them or use those little ejector engines to shoot those wasted engines farther and quickly away from your ship.

Best of luck to you, pilot!

[ammobake]

A couple things I recommend if you're having wobbliness or parts falling off.

This issue gets much worse with the heavy lift tech when the center of gravity is too high. What can happen is you start to go into a SLOW flat or toppling spin.

Even with S.A.S. enabled you won't be able to recover.

What I usually do - which is especially helpful with the heavy lift stuff... IS what I call reinforcing.

Let's say you have one center fuel tank, 6 fuel tanks out side of that - each attached with a single decoupler.

Typically, after your fuel tanks are attached you can add additional decouplers between the two at different points (above or beneath the previous)

This adds strength and durability to your rocket.

Second, what you can do is add decouplers on either side of each individual fuel tank or above each of the six (in this example).

These decouplers are only there to attach bracing to.

When you decouple the support struts will fall off allowing your main rocket to continue on without the additional weight/mass. But as long as they are in place during launch they will keep everything tied together without needing to directly connect every single piece of fuel tank with supports.

In the past I used to tie steel support bracing in an X pattern between tanks. That works fine for launch but come time to decouple, it can cause problems. Especially if you have engines burning different fuels or at different rates. You want to be able to decouple in sequence after each item burns out so you don't have to carry the added weight/mass for no reason.

If you tie everything together it all falls off at once. It can work but I just think it's unnecessary.

Some of the ring decouplers will also allow you to attach supports to - for example, from a probe to an adjacent tank or between two tanks spaced farther apart than normal. Some of the small white ring decouplers you can tie support bracing between multiple decouplers also. That adds some much needed support too.

If you do go with rockomax with one in the center, six on the outside - it works great but be sure to make the center portion a bit taller and make sure you have fuel crossfeeds to and from the center to each stack. That makes sure everything burns out at once.

-ChriS

[ammobake]

Just wanted to give my two cents for the rockomax fueltanks to limit wobble, tipping & spin.

Ensure fuel crossfeed if you want your liquid fuel engines to burn out at once even though the fuel tanks have different capacities.

Reinforce your rocket with cross-bracing between decouplers. If you use one rockomax tank with six around it. You can add decouplers close together on each tank and add a little much-needed cross-bracing to limit the wobble. You can either attach your decouplers with cross-bracing or attach cross bracing directly from the tank to an adjacent decoupler on each side of the tank. This also works if you want to add bracing on top of the stack to a taller, center rockomax tank stack. The cross-bracing is absolutely key to limiting wobble of each individual stack.

If you want your tanks to decouple in the "Peeled banana" style you will need to make sure your crossbracing is attached to decouplers on either side. Staging is important in this regard.

After you attach your rockomax tanks and make your stacks how you want, you can typically add additional decouplers after the fact (between the two fuel tank stacks). This adds aditional bracing and the trick works between liquid tanks and solid boosters also.

If you find the rocket is still tipping after the stability issues are resolved it just has too much on top (top heavy). Try removing one tank and do some trial and error to see if it goes away.

I recently added one rockomax tank at the top just below my mun lander and it caused ALOT of headaches. It just doesn't work due to the balance issues.

Just trial and error I guess but the stability issues at launch and directly after launch are easily resolved with the cross-bracing reinforcement. You don't have to tie every single item together with crossbracing either. Once you do it a few times you get a feel for what areas might need additional decouplers and cross bracing in-between.

Always use S.A.S. for launch (T) button too. Also, don't be afraid to use RCS thrusters on your upper stage for getting into orbit. It helps immensely when trying to recover if you start tipping at higher altitudes. Just make sure you attach enough mono-fuel for your rocket AND on your command module/probe/lander - because you obviously want RCS while in space for maneuvering.

-ChriS