3x3 Screamer

[11bravo]

Messing around with my nephew and came up with this.
Three stages, 3 engines each stage; D12-0's for the six booster engines and E's for the sustainer.
At first the different colors of the sections was just to keep them straight while designing, now I kind of like the looks. The second stage is actually black, but here is grey for visibility in the sim.
I think this is one that I deffinately would like to build.
Anyone have staging experience that could lend anything?
For instance, how do you keep the staging engines from just ejecting and not taking the stage with them?
Is there anyway to add a streamer to the stages so they are easier to see while they fall free?

Thanks,
Greg

 

[Elapid]

but, when they burn through, a shower of sparks goes forward to ignite the other motors, if there's a gap, you make a hole in the body tube so that the force doesn't separate the booster early.

looking at the sim file, you'll want to make sure to use a 50" launch rod or longer to assure flight speed.

looks like a fun design!
clusters are cool!

 

[11bravo]

the booster motors don't have an ejection charge

Oh yeah, I forgot that part, he says beating his head on the desk.
BAM! BAM! BAM! Ouch.
Any other words of wisdom, Oh Great Wriggly One?
Or anyone else for that matter.

Thanks,
Greg

 

[xenon]

you will need to get a waiver to fly this thing with all the motors even though it is black powder because the propelant weight is <125gms. You probably already thought of this anyway..........

 

[xenon]

oh yea, it sounds realy cool even though I don't have RocSim on this computer. Good luck with it

 

[Fore Check]

Originally posted by xenon
you will need to get a waiver to fly this thing with all the motors even though it is black powder because the propelant weight is <125gms. You probably already thought of this anyway..........

That's interesting....

You're probably correct about the waiver and the propellant weight (I don't know the propellant mass restriction off the top of my head)

But -

When I was getting ready for NSL, I contacted the guy in charge to make sure I could launch a 4 x E (estes) bp cluster without needing any special certifications. He said that I could launch a cluster of 8 or 9 Estes E engines without needing any special certifications or paperwork. Perhaps he wasn't thinking of the waiver in regards to net propellant mass.....

 

[gerbs4me]

nice design,
I think he would need a waiver

 

[Fore Check]

As far as your question regarding a tracking device or streamer for the booster(s), check out this plan (in *.pdf format) for the Centuri Uni-Bird published in American Rocketeer.

https://plans.rocketshoppe.com/pubs/Centuri/American_Rocketeer/plans/CRP172_Uni-Bird.pdf

This plan is of a 2 stage rocket that is set up like a CHAD staged bird (the fins on the sustainer are large enough that no fins are put on the booster). There is a small diameter body tube mounted on the outside of the sustainer airframe near the bottom. This tube holds a streamer that is attached to the booster.

This will make more sense as you download and check out the plan.

 

[xenon]

The total propelant mass would be 234 grams with all the motors, so you would need a waiver since it is over 125 grams.
You would not need to be certified though because it is only 187.5ns. Although it is an H class, you can cluster and stage rockets up to 320ns.