Cluster to single engine BP staging

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Tallman

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I've looked at threads here and elsewhere and am trying to figure out the cleanest system for a BT-80 2-stage. Bottom stage is about 6" long, top about 18" with a Phoenix-type Estes cone. I have a three D-engine cluster (triangular arrangement) already done, haven't mounted unit yet in booster. I was going to try having one D12-3 eject a chute and the other two D12-0s funnel into the top stage (which will have an E9 in it - I hope it'll be light if I can give it swept-back fins). Problem is the 2-engine funnel shroud has to sort of bend inward to line up with sustainer engine, and it cramps the proposed D12-3 tube. Rather than stovepipe both items, which is easier said than done, I am wondering if anyone has tried a BT-50-size tube or so in the sustainer, parallel to motor tube, as a parachute holder. Upon staging, the booster falls away and a 14" or so kevlar cord pulls the chute out (I'm going to use one of those "flameproof" ones from Mile High Rocs).

Anyone know if even a slick chute release will knock top stage off track? Is BT-80 staging clean or more prone to veering off course than say a BT-50? Anyone tried this? And lastly, any idea if I basically put Super Big Bertha fins on booster and sustainer, if that's enough to move CP back and compensate for 3-motor cluster in booster?
 

Tallman

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Hmmmmmm...maybe this should be in "Scratch Building" - how do you move it?
 

stevecarr

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I wouldn't put them in a triangle. I'd line them up so I could use one tube to deploy a chute, that booster is going to hit hard without one. The central motor for staging and the out boards for your recovery with a 3 or 4 second delay.
 
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