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There are four inputs to the design process: parachute parameters, rocket and environmental parameters, the force correction factor, and design and safety factors.
The parachute parameters are derived from past flights and from the scientific literature. There are difficult to measure and our conditions do not quite match those in the literature. The error in the measurement Cd stems from only having a single axis velocity measurement, the drag of the rocket body, and from difficulty in measuring air density. These are confounded by data loss, poor recording of ambient conditions at launch, and that Cd is generally recorded without context (data sources, parachute diameters, and ambient conditions are not listed.
The rocket and environmental parameters encompass the estimated mass and the predicted air density.
The force correction factor (Cx) is coefficient in the deployment force calculations that is interpreted by the designer from tables in the literature.
The design factors encompass the joint efficiencies, abraision losses, etc. and the safety factors. and My intuition tells me that the design is too conservative. I feel this way because I am biased from anchored on the original design and the swivel suggests that the measured force was roughly 50% of the predicted force.
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