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- Notably, the chute used in the study (~15 feet diameter) is much larger than our expected drogue parachute (~4 feet diameter)
- Study chute had geometric porosity ~12.5%
- Fabric: 2.0 oz/yd2 dacron
- Shroud lines: 550-lb coreless braided dacron, 15 ft long
- 5.52 lb mass
Most notably, this paper provides a mean empirical curve relationship for parachutes given their geometric porosity. This formula does not take into account atmospheric conditions or parachute type (i.e. disk-gap-band, ringsail):
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\frac{t_{f}}{D_{o}} = \frac{0.65\lambda_{g}}{V} |
In this formula,
We are in the process of conducting a more thorough analysis, as described below:
For the purpose of a simplified analysis, we examined a range of possible main-deployment dynamic pressures (using the chart featured in the Hermes Disk Gap Band Design page as a basis for our analysis). This analysis also made use of 1976 COESA Standard Atmospheric model, as calculated using the MATLAB function atmoscoesa.
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- Altitude: 90,000ft to 150,000ft
- Mach: 0.5 to 2
A Matlab script was written, copied below, to generate a contour plot showing the possible dynamic pressures as a function of both the deployment velocity and dynamic pressure:
TO BE CONTINUED...
Terminology
geometric porosity: the percent of the nominal canopy surface area that is removed due to vents and gaps
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