External Booster Separation

[AlamoVampire]

Okay, I know how to make a rocket that stages and can dump external stages, BUT, my question is about those external stages and how to make them kick away from the rocket as they depart. See, when I dump my boosters they just sorta stay together and slow down as the parent ship flies away not really doing much more than sliding off like a glove. What I am after is like this:

how do you make them kick away like this, or like this:

Edited August 15, 2013 by AlamoVampire

[astropapi1]

There's this thing called "sepratrons".

[capi3101]

Best way in stock is to set a couple of Sepratrons on the outboard stages, aim them to fire inboard (and slightly upwards) and set them to ignite when you stage the radial decouplers. You can kinda see the Shuttle SRBS doing that sort of thing in that pic you've got there.

EDIT: Ninja'd, sorta.

[AlamoVampire]

i do not recall seeing sepratrons in the stock stuff...

[astropapi1]

Yep, been here since .16 IIRC.

They're little radial SRBs.

[AlamoVampire]

will take a look, thanks guys!

[arq]

IRL the drag is probably enough to push them away. But with KSP drag (omnidirectional) that doesn't happen. I usually add a sepratron at the top or bottom of radial stages, on the outside side. Point it upward (and possibly 5-10deg inward, if it does not clear the inner stage well enough), so that it will spin the stage away after release.

[AlamoVampire]

SUCCESS!!!! THANK YOU ALL!!

[AlamoVampire]

now I look all official like I know what I am doing!

[astropapi1]

Now stick 'em to a rover seat!

[AlamoVampire]

Now stick 'em to a rover seat!

stop giving Jebediah ideas! He has cost the Kerbals enough money already

[AlamoVampire]

I would consider this now answered but have no idea how to change the prefix so, um yeah lol

[Epic DaVinci]

Edit the original post and change the prefix, i think you may need to "go advanced"

[John FX]

yes, change to `answered` please, I came to answer...

[KrazyKrl]

For my fattest launches, I like to put several sepmotors on the tank I'm jettisoning. It keeps the tanks from "pinching" the center main engine, they fly out and away.

(30 second MSPaint jobs are worth about 20 words.)

[annallia]

Aditionally if you can get away without strutting your SRB's to your main tank the normal radial decouplers will do the job.

[Tiron]

Aditionally if you can get away without strutting your SRB's to your main tank the normal radial decouplers will do the job.

Oh so the struts manage to exert some force before they break huh...well that explains a lot...

[Kerbart]

You might want to put them top and bottom. I had some wonderful launch failures because the boosters ripped out the main engine after separation, because they angled out too steeply and their nozzles banged off the main engine. That was after a few launches where they ripped off tail fins, but that is usually survivable. Your main stage having no engine makes getting into orbit... challenging.

Just put the top ones horizontal as KrazyKrl pointed out (at 45° angle unless you want to see the occasional fuel tank blow up) and the bottom ones pointing 30° upwards as well, so they (a) push down the booster and ( don't deliver as much horizontal thrust, resulting in the "peeling off" that you want to see.

For comic effect you can add a single separatron to small stuff that you decouple and see it go wild like a balloon set loose

[rdfox]

KrazyKrl's drawing shows how *all* my radial boosters are set up.

I also, even though it's not really necessary, put a ring of forward-facing Separatrons around my vertically stacked lower stages, set to fire with the decoupler, to guarantee a quick, clean separation. (NASA does that, too; the Saturn V had eight small solid rocket separation engines on the first stage alone.) Helps make sure that when I jettison the lower stage, it does nicely clear the upper stage's engine before upper stage ignition.

It also makes it so that when I jettison my last stage after reaching orbit, there's a good chance that it will deorbit itself and thus help clean up my debris...

(edit)

Kerbart, I used to do that, but then I realized that if I put the Separatrons near the booster's center of mass, it wouldn't pitch the booster significantly and they'd separate cleanly. (Granted, now they tend to roll after jettison, but only after they're far enough away that they're clear of the core stage and it won't be a problem.) The weight saved on Separatrons makes up for the weight I now spend on extra RCS to help with ascent guidance...

Edited August 13, 2013 by rdfox

[annallia]

Oh so the struts manage to exert some force before they break huh...well that explains a lot...

Something like that... They more or less negate the effect of them regardless of the decouple force and the struts sheering strength.

This works well for SRB's (stock ones anyway) but not so much for asparagus staging as they tend to weigh more + have more thrust than the SRB requiring struts to keep everything stable.

[AlamoVampire]

I found the change of prefix under the advanced thingy in the edit post. As to the 'asparagus' staging, I found the little sepratrons work just fine, even if I strut the snot outta them. I use a huge heavy lifter with 6 mainsails under the orange tanks as my boosters with a central lift stage of yet another mainsail and orange tank. its freaky to watch them peal away now rather than slide down.