Combined Staging & Clustering

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JoeLaunchman

Launching since 1975
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My 10 year old son’s idea. He asked if we could combine staging and clustering so we came up with this. Four 18mm motors in 2x2 configuration. I devised the split booster stage to guard against non-simultaneous upper stage ignitions. BT-60, 41”, 4.5 oz. Any predictions on performance or choice of motors?22A070EF-B5BC-4E54-8D10-E9EFD9DAD07E.jpg70B947E1-05DE-4FE2-8C60-4E1DB84B178F.jpg8CA93756-2BEE-4A12-B1A9-CB8EEC73B59D.jpgD80DFA94-48A0-42F0-8ED6-86767F319D26.jpg02E0C5E1-43F0-4C7D-BCE3-77F908304321.jpg18760454-2A69-4D77-A7F2-CE12D8A6E30E.jpg
 
I love the fact that your son came up with this idea, and I like the two-part booster. Maybe I'm missing something, but how do you envision keeping it together during flight?

I have successfully flown a clustered booster to a single-motor sustainer before, and it works great. I designed the booster in a way that the hot gasses from the booster motors would be ducted together to light the sustainer.

IMG_1233.jpgImageUploadedByRocketry Forum1487376893.681764.jpg

I'm not sure that you will light both of the sustainer motors simultaneously, but it's worth a shot. Definitely a heads up flight, but I think the risk is worth it, if for none other reason than to encourage your son to keep innovating!
 
Neat ideas guys!!! Thanks for sharing!

[EDIT] Oh, I should add... DO NOT ASK ME TO SIM THESE!!! (for a while yet) It's well beyond OR's abilities at this time. When and If OR will support angled body tubes (relative to the centerline), I will give it a try.
 
I've done 3 to 1 gap staged, and 3 to 3 direct staged. Both performed well, never had an issue with no-lights on the direct staging with all 3 in the same booster. I always use a pad relay for lighting clusters, but especially so when adding staging to the mix.
 
Holding the boosters on will be the tape on each of the engine stacks. Whether the sustainers ignite at the same moment or not should not affect the performance much. I'll let you know.
 
Four engines in the tail (lot of weight), may be a stability issue as pushes CG back. I theeeeenk you are okay, as you have a pretty long rocket. May need a bit of nose weight, though.

May ESPECIALLY be a factor if only one of the boosters ignites. Will one booster engine be enough for a stable flight?

Definite heads up flight, also be extra cautious if there are dry grasses or bushes around.

Good luck, I like the split booster design, good thought for if one boosters burns out a bit behind the other to make sure both sustainers light.
 
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