Asparagus Staging help

[Basicball]

I'm trying to do some asparagus staging, but the last engine/tank of my outer 'circle' keeps blowing off the first engine/tank of my 2nd most outer circle.

Tanks are separated with the help of TT-70 Radial Decouplers, and there is a single center tank as well.

Seen below: The direction my tanks fall off. 1 Blows of 2 when it gets ejected.

Note that the debug tool opened when I took a SS with F12 (Steam shortcut), I was not actually using it for anything, and for some reason this was the first tie it opened when I took a SS.

I would appreciate any help on the subject.

[RexKramer]

I'm guessing you are running into the bug that causes radial decoupler issues. Is the decoupled tank tipping inward and colliding with the rest of your ship? If so, one solution is to use sepatrons to help propel the ejected tank away from the rest of your ship.

Also, see the following thread, which contains more solutions to this issue- http://forum.kerbalspaceprogram.com/threads/97285-KSP-v0-90-Stock-Bug-Fix-Modules-%28Release-v0-1-7d-6-Jan-15%29-Misc-Utilities-%2813-Jan-15%29

[vexx32]

Unless you have more than one type of engine on each layer of the circles, you can just pipe fuel lines from each outer tank to the nearest inner one; they should drain at the same rates unless you've got multiple engine types going.

That's not really the origin of your problem, though. I've found that place decouplers somewhat lower than you might want to, and/or using the Offset gizmo to nudge the outer tanks downward (such that they're attached almost from their top instead of at their middle) can help a great deal. If you still have issues even then, your best bet is to place pairs of separatrons to push the outer stacks away from the center when you decouple.

[TriggerAu]

Is it blowing off as in the decoupler is firing - or the force of tank 1 decoupling is pushing it too hard.

Might be cool if you could pastebin the craft file so otheres can see the design in game

[Basicball]

I'm guessing you are running into the bug that causes radial decoupler issues. Is the decoupled tank tipping inward and colliding with the rest of your ship? If so, one solution is to use sepatrons to help propel the ejected tank away from the rest of your ship.

Also, see the following thread, which contains more solutions to this issue- http://forum.kerbalspaceprogram.com/threads/97285-KSP-v0-90-Stock-Bug-Fix-Modules-%28Release-v0-1-7d-6-Jan-15%29-Misc-Utilities-%2813-Jan-15%29

Well, My fuel tanks Usually tip inwards at the top, and outwards at the bottom. I usually solve this by waiting to stage for anywhere between 1 and 13 seconds. I never thought it was a bug...

It's odd that in this design it only happens fatally when moving to the next ring though.

Unless you have more than one type of engine on each layer of the circles, you can just pipe fuel lines from each outer tank to the nearest inner one; they should drain at the same rates unless you've got multiple engine types going.

That's not really the origin of your problem, though. I've found that place decouplers somewhat lower than you might want to, and/or using the Offset gizmo to nudge the outer tanks downward (such that they're attached almost from their top instead of at their middle) can help a great deal. If you still have issues even then, your best bet is to place pairs of separatrons to push the outer stacks away from the center when you decouple.

Do you mean something like this? I don't really see how that would work the same though. http://i.imgur.com/oVPMKKG.png

If I place my decouplers lower, won't the middle of the ship start sinking in more when I launch, and be more prone to breaking overall?

Is it blowing off as in the decoupler is firing - or the force of tank 1 decoupling is pushing it too hard.

Might be cool if you could pastebin the craft file so otheres can see the design in game

I made a subassembly of the asparagus stage, but have no idea what to put in pastebin.

[TriggerAu]

...I made a subassembly of the asparagus stage, but have no idea what to put in pastebin.

Save the ship and share the .craft file is best - then others can try and fly it (assuming you dont have too many mods in there )

[Basicball]

Only mod on the ship should be Mechjeb.

I'll see if I can find the file

[neamerjell]

Try a mod called "Smart Stage" it is designed for just such a task, which is correctly organizing asparagus staging. My first guess is that your staging is screwed up somehow, which is really easy to do with as few as 6 tanks. Your setup is 3x that!

My second guess is that the first stage is crashing into the interior tank, in which case you need to add separatrons to blow the spent stage away from the rocket. Add on either side of the tank pointed outward at both ends, and it should work.

[Basicball]

I found the file, but don't really know how to share it.

Here are some screenshots to show you instead:

Mechjeb settings (just for testing the rocket) http://cloud-4.steamusercontent.com/ugc/39738595547775402/D234AFC4D9AE0B9748BCD28DA621F473ABC8CE13/

View 1.1 http://cloud-4.steamusercontent.com/ugc/39738595547776009/CD6AE654A43935142DD12FB176C8D365B1C1B7E9/

View 1.2 http://cloud-4.steamusercontent.com/ugc/39738595547776151/813B6F07C75AF61390FF6530F3A9857E9A4AB2E5/

View 1.3 http://cloud-4.steamusercontent.com/ugc/39738595547776280/1C176A7F834AF9EBDED63F89F7F419CF0A5D93EE/

View 1.4 http://cloud-4.steamusercontent.com/ugc/39738595547776880/C0AF4B25EAFBBB833097620DE262F35F00CC54EE/

View 2.1 http://cloud-4.steamusercontent.com/ugc/39738595547777345/3D46889B08A80795571FE5B3A1CB510F9A928790/

View 2.2 http://cloud-4.steamusercontent.com/ugc/39738595547777677/C7B2C597A0E067E0237FD794A924573446E05E6E/

View 2.3 http://cloud-4.steamusercontent.com/ugc/39738595547778178/1E052B72D3B8694E198E6FC76D0C81224C0F164F/

View 2.4 http://cloud-4.steamusercontent.com/ugc/39738595547778846/A1625FC6F9998DC4AF9A872EF9EECE921E63BF20/

[Red Iron Crown]

Unless you have more than one type of engine on each layer of the circles, you can just pipe fuel lines from each outer tank to the nearest inner one; they should drain at the same rates unless you've got multiple engine types going.

That's onion staging, less efficient than asparagus as it is less granular in shedding engine and empty tank mass.

In the OP's situation, I would just add sepratrons to the troublesome tank until it separates cleanly.

[Th3F3aR]

Well as far as i can read your problem i would suggest to use separatrons. With that (i guess 4 each tank would be sufficient) you blow the tanks away from the craft.

I have that "Bug" also and therefore always use separatrons for crafts like this, and i think its not a bug, its gravity

[Janos1986]

Kill your throttle for a couple seconds, trigger the stage to let the tank slide off safely, then burn away from it.

Let the souposphere do its job.

Edited January 16, 2015 by Janos1986

[capi3101]

Let me ask this question real quick - what exactly are you doing with this design? From the 3.91 launch TWR, 4.5 tonne final stage and 9259 total delta-V, I'ma going with Eve launch vehicle - is that a correct assumption?

If it's just to get off of Kerbin, what you've got is some seriously overworked plumbing...

I would second the suggestion to use Seperatrons. If that particular staging event is the only one that's giving you fits, you need only add Seperatrons to that stage. Judging from the size of the stack you're decoupling, I think two should do the trick.

[Basicball]

Let me ask this question real quick - what exactly are you doing with this design? From the 3.91 launch TWR, 4.5 tonne final stage and 9259 total delta-V, I'ma going with Eve launch vehicle - is that a correct assumption?

If it's just to get off of Kerbin, what you've got is some seriously overworked plumbing...

I would second the suggestion to use Seperatrons. If that particular staging event is the only one that's giving you fits, you need only add Seperatrons to that stage. Judging from the size of the stack you're decoupling, I think two should do the trick.

I'm currently just testing out how to use the asparagus staging, but you're correct in the assumption that the final goal is to land the rover and science module, including 2 kerbals on Eve (Single trip).

I'll try using sepratrons as people have suggested, and keep you updated.

- - - Updated - - -

Question: Do I face the sepratrons to push the tanks outwards, or downwards:

Out, 0s delay

Down, 0s delay

Down, 5s delay

Back to 0s, several seconds later

Edited January 16, 2015 by Basicball

[MarvinKitFox]

Bah Humbug Seperatrons!!!

Just spin your rocket, the ejecting tanks will fly off miraculously!

[Basicball]

Bah Humbug Seperatrons!!!

Just spin your rocket, the ejecting tanks will fly off miraculously!

What do you mean? I would assume that spinning my rocket just slams them in harder.

5s delay, no sepratrons

Several seconds later (next stage drop off) ~ 1 ~ 2 ~ 3 ~ 4 ~

- - - Updated - - -

Spinning my ship actually worked somehow. How am I supposed to control the direction if I'm constantly rotating though?

Rotate 1; 0s delay

Next stage

Final stage

[Dispatcher]

Control and delays associated with it are why spinning can be problematic. A good solution, recommended above and one I use when needed, is to add Sepratrons. Their mass and drag (and part count) are negligible compared to the effect of reducing or eliminating damage and control loss to your craft.

[Basicball]

Control and delays associated with it are why spinning can be problematic. A good solution, recommended above and one I use when needed, is to add Sepratrons. Their mass and drag (and part count) are negligible compared to the effect of reducing or eliminating damage and control loss to your craft.

I had no luck with sepratrons (Screenshots previously posted)

[Th3F3aR]

Sepratrons should face outwards, with 4 you can put 2 on the topsides 2 on the bottomsides, should work perfectly, sepratrons should fire on decoupling and it will be fine.

Don't understand that 5 secs delay btw

[Basicball]

Sepratrons should face outwards, with 4 you can put 2 on the topsides 2 on the bottomsides, should work perfectly, sepratrons should fire on decoupling and it will be fine.

Don't understand that 5 secs delay btw

gives the tanks some time to drop and rotate further, making them not hit the other tank. I'll try the 4 sepratrons tomorrow. now=sleepytime