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We will conduct research into the deployment sequence to mitigate possible failures, ensure a stable descent, and help inform our camera choices.
Chute Inflation
To inform our choice of camera, we need to gather information on chute deployment and inflation rates.
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- Avionics system apogee detection response time
- Webbing lengths (example: if the drogue parachute is loosely held in the booster section, full line extension will draw it out)
- Deployment event energy (example: after a non-energetic deployment event, such as we saw in ground tests 1 and 2, the bodies may need more time to achieve sufficient distance from one another to pull the drogue parachute out)
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- Line Snatch: occurs upon line extension right at the start of parachute inflation; forces during inflation outweigh the snatch force (Potvin and Peek)
- Note that this source relates to skydiving applications which include sliders that affect the deployment sequence. Thus, things may be different for rocketry.
Main Parachute Release
Our main parachute will be released at an altitude of approximately 2,000 ft. We will use two Tender Descenders for redundancy. There are two configuration options, series and parallel:
Parallel Configuration
There are many advantages to a parallel configuration. Notably:
- Saves a lot of space vertically in the cup, which in turn will reduce the likelihood that the main parachute's deployment bag is in the airstream prior to descent.
- Reduces mass (fewer quicklinks)
One disadvantage is that you have to be sure that the Kevlar line (or another type of line if you so choose) will not abrade.
Series Configuration
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Terminology
geometric porosity: the percent of the nominal canopy surface area that is removed due to vents and gaps
Resources
Potvin and Peek, Parachute Opening Shock Basics
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