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I recently posted a new build thread in the HPR category "Warp Test #1" Build Thread, and one very observant rocketeer asked about my recovery setup so I have decided to post my new recovery system here to get some feed back.
A little while back I met with my father to discuss formalizing and prototyping an ejection system he flown in a rocket he recently launched at LDRS. I have since designed a few versions of this idea both for deployment on opposite ends of an avionics bay and single ended deployment with a tender descender or cable cutter. The versions pictured are the two options I want to prototype for use in my 2” rocket with single end deployment. The upper design was may original design and would be lighter, more compact, less expensive, and also stronger due to the coupler on the left having a thicker ring near the end and the one on the right being reenforced by the airframe. The downside is that it has an additional reduction in ID which could be a problem particularly in a 2" rocket.
2 inch single sides deployment assembled.
2 inch single sides deployment separated.
The yellow tubes on both ends are the airframe, the drogue chute is in nose section on the left, the main is in the tube on the right. The system consists of an aluminum coupler set with shelves to support 2 loose fitting plates with the parachute tethers joining the two end through the plates. The ejection charge(s) are placed between the plates which are held apart by a loose fitting tube and the couplers are locked together with shear pins (I have four 1/16” pins shown in this setup). When the charges a fired the plates are pushed apart shearing the pins and separating the rocket, the parachute tethers then pull the plates out and the chutes come out as normal. The idea is to provide several benefits over other systems, which use a combination of products to address each of these issues.
1. The system provides a small fixed volume for ejection which makes the necessary charges smaller and easier to handle.
2. The plates will be forced against their shoulders, like a check valve, sealing of the parachute and avionics from the ejection blast.
3. The system provides a metal to metal machined interface for a better joint fit (a significant problem in my dad’s rocket that used couplers).
4. The metal to metal interface provide an ideal place for shear pins.
5. The metal couplers should be much more resistant to zippering. In larger diameters where the constriction isn’t as large an issue the wall can be even thicker.
6. The couplers will have a significant smooth rounded edge on the end which won’t cut shock cords like glass tubes can.
I would eventually like to develop and sell these for all common airframe sizes. I also designed a setup putting one of these on each sides of an avionics bay for a two ended deployment with a bulletproof av bay. Any and all thoughts and comments would be appreciated.
A little while back I met with my father to discuss formalizing and prototyping an ejection system he flown in a rocket he recently launched at LDRS. I have since designed a few versions of this idea both for deployment on opposite ends of an avionics bay and single ended deployment with a tender descender or cable cutter. The versions pictured are the two options I want to prototype for use in my 2” rocket with single end deployment. The upper design was may original design and would be lighter, more compact, less expensive, and also stronger due to the coupler on the left having a thicker ring near the end and the one on the right being reenforced by the airframe. The downside is that it has an additional reduction in ID which could be a problem particularly in a 2" rocket.
2 inch single sides deployment assembled.
2 inch single sides deployment separated.
The yellow tubes on both ends are the airframe, the drogue chute is in nose section on the left, the main is in the tube on the right. The system consists of an aluminum coupler set with shelves to support 2 loose fitting plates with the parachute tethers joining the two end through the plates. The ejection charge(s) are placed between the plates which are held apart by a loose fitting tube and the couplers are locked together with shear pins (I have four 1/16” pins shown in this setup). When the charges a fired the plates are pushed apart shearing the pins and separating the rocket, the parachute tethers then pull the plates out and the chutes come out as normal. The idea is to provide several benefits over other systems, which use a combination of products to address each of these issues.
1. The system provides a small fixed volume for ejection which makes the necessary charges smaller and easier to handle.
2. The plates will be forced against their shoulders, like a check valve, sealing of the parachute and avionics from the ejection blast.
3. The system provides a metal to metal machined interface for a better joint fit (a significant problem in my dad’s rocket that used couplers).
4. The metal to metal interface provide an ideal place for shear pins.
5. The metal couplers should be much more resistant to zippering. In larger diameters where the constriction isn’t as large an issue the wall can be even thicker.
6. The couplers will have a significant smooth rounded edge on the end which won’t cut shock cords like glass tubes can.
I would eventually like to develop and sell these for all common airframe sizes. I also designed a setup putting one of these on each sides of an avionics bay for a two ended deployment with a bulletproof av bay. Any and all thoughts and comments would be appreciated.
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