RocketFeller
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- Sep 15, 2009
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I am building a large (12.75" x 10') rocket with a group of my students. The rocket should weigh in at around 40-45 pounds loaded, maybe a little less. This is the first rocket of this size we have built, the largest previous being a 4" all-fiberglass rocket.
The rocket will be a 4.9x upscale of the Binder Design Dragonfly and will have elliptical fins with a 10.85" root chord and a 23" span. Because of these long fins and a rocky launch site I want to set it down gently. This is definitely going to be a low-and-slow rocket, but even so it will be going up 5000'+ on a full L or higher on a small M. All this makes me think that we definitely want dual parachute deployment. In order to keep things lightweight and simple, I would like to deploy both parachutes from the main compartment.
It seems that a fairly "standard" recovery sequence might go something like this:
Rocket separates at apogee with a 12-pound rated parachute attached to the nosecone (nosecone should weigh just a bit under 12 pounds).
Nosecone is attached to a deployment bag (containing main) which is attached to airframe via a Tender Descender or similar release mechanism.
Release mechanism is triggered at main altitude and nosecone pulls out deployment bag.
Parachute is pulled out and nosecone and airframe recover separately.
One worry I have (someone brought this to my attention) is that the large compartment (12.625" x ~22") will allow the deployment bag to move around too much while falling. It was suggested that I use a 6" or 7.5" stuffer tube to hold the parachute - I am reluctant to do this because of the weight. Should I be concerned? How might I mitigate this?
I would love to hear people's opinions of the "best" way to go about recovering a rocket of this size and shape! What would you do?
The rocket will be a 4.9x upscale of the Binder Design Dragonfly and will have elliptical fins with a 10.85" root chord and a 23" span. Because of these long fins and a rocky launch site I want to set it down gently. This is definitely going to be a low-and-slow rocket, but even so it will be going up 5000'+ on a full L or higher on a small M. All this makes me think that we definitely want dual parachute deployment. In order to keep things lightweight and simple, I would like to deploy both parachutes from the main compartment.
It seems that a fairly "standard" recovery sequence might go something like this:
Rocket separates at apogee with a 12-pound rated parachute attached to the nosecone (nosecone should weigh just a bit under 12 pounds).
Nosecone is attached to a deployment bag (containing main) which is attached to airframe via a Tender Descender or similar release mechanism.
Release mechanism is triggered at main altitude and nosecone pulls out deployment bag.
Parachute is pulled out and nosecone and airframe recover separately.
One worry I have (someone brought this to my attention) is that the large compartment (12.625" x ~22") will allow the deployment bag to move around too much while falling. It was suggested that I use a 6" or 7.5" stuffer tube to hold the parachute - I am reluctant to do this because of the weight. Should I be concerned? How might I mitigate this?
I would love to hear people's opinions of the "best" way to go about recovering a rocket of this size and shape! What would you do?