Trigger dependent decoupling (when solid rocket boosters reach 1%)

[addman16]

Hey guys,

What Im trying to accomplish is having my solid rocket boosters decouple while they are still firing so that they slowly drift apart before going out. NASA uses this technique if you look at the space shuttle launches you can see that the SRB's are detached before they run out completely giving a star shaped pattern as they drop away.

Is there a way, a mod or setting that the decoupling can take place when the solid rocket boosters reach 1% of their fuel. Right now they only decouple after all the fuel is gone.

 

Thanks guys

[Foxster]

Well, they don't decouple automatically in the stock game. So, unless you are using MechJeb to control staging, there is nothing to stop you manually staging your SRBs before they are empty. 

[Harry Rhodan]

5 hours ago, addman16 said:

NASA uses this technique if you look at the space shuttle launches you can see that the SRB's are detached before they run out completely giving a star shaped pattern as they drop away.

Yeah, but real SRBs slowly lose thrust while KSP SRBs have full thrust until the very end of their burn. So if you decouple them at 1% they would still fly in front of or right into you rocket.

[addman16]

33 minutes ago, Harry Rhodan said:

Yeah, but real SRBs slowly lose thrust while KSP SRBs have full thrust until the very end of their burn. So if you decouple them at 1% they would still fly in front of or right into you rocket.

How do I get the the SRB to behave that way? I'm using mechjeb btw. So far I tired changing the thrust limiter and the mass of three rocket so that when the SRB has some fuel left the rest of the ship is accelerating faster. However it's really not elegant like in this video. 

 

[DrLicor]

@addman16, unless you have some kind of thrust curve installed in the SRB config. (RO) You can just time them right.

[Harry Rhodan]

21 minutes ago, addman16 said:

How do I get the the SRB to behave that way?

The last one.

[Spricigo]

I'm not totally aware of the capabilities of  MJ in how it can time staging.  But I risk to say vou need KoS, kRpc or Smart Parts for staging when [fuel%] is left on [part]. The later mod is much simpler.

In any case you don't need any of this to make your boosters drif away. If the decoupler is a bit over the CoM of the booster, the later will be ejected with a small rotation that point it away from the craft, with a good aerodynamic shape it willl drift away nicely and not collide with the main craft or another booter

 

Edited October 4, 2017 by Spricigo

[Snark]

1 hour ago, Spricigo said:

In any case you don't need any of this to make your boosters drif away. If the decoupler is a bit over the CoM of the booster, the later will be ejected with a small rotation that point it away from the craft, with a good aerodynamic shape it willl drift away nicely and not collide with the main craft or another booter

^ This.

Another technique that I've seen people use:  Put some Basic Fins on your SRBs, mounted near the top and angled slightly outwards, so that they produce an aerodynamic force away from the centerline of the ship.  It's astonishingly effective, given the high speed & aero forces that usually pertain to the moment of SRB separation.  As soon as you decouple, they tug the front end of the booster away from your ship, then the aero force hits the long side of the booster and whump it's peeling away to the side.

[Draalo]

I often build things just for the view.

 

You can add some sepatrons to the booster.

Use 1x symetry, add a decoupler and a booster. Now switch to 4x symetry, add sepatrons at the bottom of your booster - slightly tilted outwards - and maybe one sepatron above the decoupler, facing towards the rocket.

Grab the decoupler (and consider saving it as a subassembly), switch to 2x or whatever symetry, mount the decoupler again.

 

After decoupling the booster will still have some thrust - enjoy the view

[Alacard]

On 10/3/2017 at 9:05 PM, addman16 said:

Is there a way, a mod or setting that the decoupling can take place when the solid rocket boosters reach 1% of their fuel. Right now they only decouple after all the fuel is gone.

Smart Parts mod does this