Separate Recovery

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jmasterj

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Question: Under what circumstances would you recover a rocket in multiple pieces? The nose cone under one chute and the airframe under another, for example. I've seen this done (on a huge rocket, though) and recently read about someone doing it with a heavily-weighted nose cone. What kind of conditions would make you consider this?

Background: I'm building a short stubby Rocketry Warehouse Flying Pumpkin (5.5" diameter, 20" long airframe, elliptical nose cone) and it needs lots of weight in the nose: maybe 4lbs in a rocket that would otherwise weigh 6ish lbs without nose weight. Having read at some point (though I can't remember where) that a very heavy nose was a contributing factor to recovering it separately, I started thinking about it. Am I overcomplicating things for this class/size of rocket?

Thanks!
 
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The only rocket I recover the nose cone separately "kind of" is my Performer 150. I did that to simplify and make the recovery system more reliable.
The nose cone is attached to the pilot chute that pulls the d-bag out of the BT and off the main parachute. The pilot was sized to drop the nose cone at a slightly slower speed than the main drops the rest of the rocket. They aren't actually separate. I have about 100 ft. of 150 lbs. Dacron line that connects the inside of the d-bag to the top of the main chute so the pilot stays above, but connected to the main.
 
I've done the tether deployment freebag method a number of times (everything out the top). The nosecone under its chute comes down at about the same speed as the rest of the rocket, and tend to land relatively close to each other.
 
My GLR Nuclear Sledgehammer uses a free bag setup on the nosecone and main chute, the nosecone weighs ~18lbs so it has its own 60" chute which is also the pilot for the main chute deployment bag. Size both chutes for the same approximate descent rates and both pieces should land fairly close together. In your case/IMO you should be able to use a single main and keep everything together
 
I have seen it done when a team has a payload that they want get data from.
 
If you do head end deployment (two out the top) it is often advantageous to let the nose separate and come down on its own chute, so you don't risk entanglement with the main chute when it opens. On the other hand, in that scenario the nose will come down on its own "slow" chute from apogee and likely end up drifting a long way from the rocket dropping fast under drogue. So, separate tracking of the nose would be a must.
 
If you do head end deployment (two out the top) it is often advantageous to let the nose separate and come down on its own chute, so you don't risk entanglement with the main chute when it opens. On the other hand, in that scenario the nose will come down on its own "slow" chute from apogee and likely end up drifting a long way from the rocket dropping fast under drogue. So, separate tracking of the nose would be a must.
If you do HED the NC should be shear pinned to the upper tube, only the booster separates at apogee and the booster and upper with NC attached come down together on your drogue to whatever you main charge is set to, then the NC blows off the upper airframe and everything comes down together on the main.

Big heavy NC’s can become chute bombs very easily, separating them From the rest of the bird can help eliminate this from happening, typically anything I have over 8” the NC will come in under it’s own chute
 
If you do HED the NC should be shear pinned to the upper tube, only the booster separates at apogee and the booster and upper with NC attached come down together on your drogue to whatever you main charge is set to, then the NC blows off the upper airframe and everything comes down together on the main.

Big heavy NC’s can become chute bombs very easily, separating them From the rest of the bird can help eliminate this from happening, typically anything I have over 8” the NC will come in under it’s own chute
Sorry not upper the coupler e-bay I meant
 
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