How do you handle radial decoupling?

[Kerbojet]

Even with Seperatrons placed in the middle to push it away I've still had problems. I've had good luck with placing a single Seperatron about center so when it goes off the SRB just spins away. Saves me on parts too. I'm going to have to try all the other solutions mentioned as well.

[worir4]

Two easy steps to decouple radial boosters:

1. Press space.

2. Explode....

[JAFO]

I do like the idea of mounting them on the main stack rather than on the booster. That ... gets rid of the damage the seperatron exhaust causes to the main stack. Good idea that.

in the past I've had problems with sepratrons on the detached part causing damage to the main craft as they pass it

This is easy to avoid. Instead of placing my sepratron pairs opposite each other, ie at 180°, I position them at 120° from each other (and from the radial decoupler), so that instead of pointing at the main craft, they're angled slightly towards the boosters next to them.. there's still more than enough thrust at that angle to push the boosters away, and they don't cause any damage. I only use a pair per booster, mounted at the (empty) CoM point, and angle them up at 30° so they push down as well as away.

Edited March 1, 2015 by JAFO
forgot a comma

[magnemoe]

I just tested with using two seperators on the core, this worked flawlessly even then not using TT-70 but used the one who only left an narrow gap between core and SRB. I put the upper separation a bit farther from the decopler and center of SRB then the bottom one to push the top away more, I think I can reduce the fuel in the seperatron to 50% as they continued to burn after the SRB was well away.

Keeping the SRB close and under the fairing might be smart in 1.0.

[celem]

Been having this issue lately on some of my lifters actually. I tend to use a seperatron, one mounted on top of the tank if its fairly small, a raidal pair just above the CoM if its big. (The one seperaron mounted on top is often not thrusty enough to significantly move a heavy dropped stage).

For what its worth the positioning of the decoupler according to tank CoM to make the stage lean away or towards works fine for me, just remember to empty the fuel in the VAB when you check the CoM, its well low towards the engine on most stacks.

On some launches nothing will stop the tanks hitting my main rocket on ejection, this is usually when i'm blowing a stage mid gravity-turn, the tank 'above' the rocket falls through it's tail before it pulls clear. For these situation I mount a small structural girder onto the decoupler then put the tank on the girder to give more spacing, this girder is also the ideal spot for a seperatron (or pair thereof)

edit: whats the general status of the old bug where some struts could cancel out ejection force? This still around?

[Frozen_Heart]

Really hope this is fixed in 1.0. Quite a few of my lifters broke when this bug was added and I'm keen to get them working again.

Of course, between the new aero, fuel thrust/isp changes, rebalancing, and having to add fairings, I'm pretty sure the decouplers will be the least of my worries!

[Flixxbeatz]

Strategically-placed sepatrons does the job. number of sepatrons attached depends on how huge the part is.

[FlyingPete]

I test the launcher first, and if any boosters rotate inwards on decoupling, fit a sepratron to the top of the booster. Usually, when they then rotate outwards the core rocket clears the boosters. That's normally sufficient for SRB stages. Anything bigger I tend not to stage radially.

[Kip336]

As most of us, I tend to use Sepratons. Depending on how big/heavy the stage is, I use more. I usually put one on top of the stage, angled a bit down and inwards to the core stack. This seems to give (especially the lighter stages) a split second longer to clear the rocket

[PB666]

Claw's Stock Bugfixes are your friend! Radial decoupling that doesn't come back to bite you in the butt

Its not a bug! its a feature. Come on removing that bug takes the fun out designing better rockets.

- - - Updated - - -

Strategically-placed sepatrons does the job. number of sepatrons attached depends on how huge the part is.

I learned one thing from the videos, Kerbals like really annoying creepy space music.

[lajoswinkler]

I use sepratrons placed on the boosters between them and the first stage. Then I tilt them a bit so that they push up and radially away. Also, their center of mass should be at or below the decoupler. Never had any problems with such design and I always get a Korolev cross.

Back when we didn't have offset tool to push them a bit to hide their pointy legs, I'd use Procedural Parts' procedural booster. I'd make a tiny one and save it into subassemblies.

[Laie]

And once more, just because I like that scene so much:

Boosters with minimum fuel will weigh 800kg and can replace a large number of sepratrons. I don't do that often, but so far it seems that boosters will not destroy stuff they're pointed against no matter what; or maybe that's only because they provide so much thrust that they move themselves away quickly.

[lajoswinkler]

Destruction depends on the heat capacity of the part. Tiny strut will blow up faster than those large tanks.

[bigyihsuan]

Just adding sepratrons.

[Miro Beero]

I spin the ship before hitting spacebar.

Centrifugal force pushes them out vs just down.

[TheBeardyMan]

When designing a liquid fuelled booster, I always use the tweaks to remove all fuel to find out where its dry centre of mass is, and place the decoupler as close to that as possible, before tweaking the fuel back up to maximum; sometimes I need to re-start the design with a different root part if I made a wrong guess as to which fuel tank the dry centre of mass would be in.

[Pi_]

You can stop all engines before decoupling and burn slowly after it. So your relativ velocity to the boosters isnt that high.

Not very efficient but it works.

^ that, all day long. Sepratrons... mods... meh

[boxman]

I have never ever needed to use sepratrons. The TT-70 decouplers have never given me this issue as long as they are placed correctly.

I really dont get why people keep using the other ones as they always cause this issue.

[magnemoe]

This discusion made me make an new launcher.

3.75 meter core with 25x4 engine. three large 3.75 meter tank, the top one is the 82 ton dummy payload.

Uses the TT-38K as I assume it will work better to keep the booster close in 1.0, more so at they will be in the drag shadow of fairing.

20 long SRB in 4 groups of 5. aerodynamic top on the srb packs. two seperarons on each pack, one all the way on top and one well done but center of their trust is a bit above center of mass to get the top out more, they clip into the booster and is pushed in more to get away from core.

seperates during start of gravity turn for worst case scenario.

[-Velocity-]

I usually don't use sepatrons. I've tried and successfully gotten them to work before, but I actually found that my rockets always seem to survive being smacked by the ejected boosters, if they get hit at all. Until I have a problem, it's easier (though a bit less realistic, of course) to just not use them.

[hugix]

KW or Novapunch has these lovely SRB nosecones. They have a small solidfuel booster pointed towards the booster angels 45 degrees up. this way th ebooster is pushed from the top up and away from the main core.

[vixr]

What seems odd to me is the fact that every launch is different WRT how the boosters come off... I can launch with no booster issues, revert to launch to fix a staging problem, and the next launch the boosters hit.

[Pixel of Life]

I usually place sepratrons or ullage motors sideways just above the COM of the boosters. Once fired, they push the boosters away and give them just a little bit of rotation to achieve a really clean and nice looking separation.

[Vindaloo]

KW or Novapunch has these lovely SRB nosecones. They have a small solidfuel booster pointed towards the booster angels 45 degrees up. this way th ebooster is pushed from the top up and away from the main core.

Holy crap! That's what those SRB nosecones are for!!?? I was completely confused by those, now I know!

And knowing is half the battle.

[federicoaa]

I place the decoupler near the com of the stage, also having the stage much below the core part to avoid damage.

I also have 2 or more separatrons on each part so they decouple far from the rocket.

Then I fly the rocket, press space and see it explode.