Design tasks
Write up analysis up until this point
See Parachute Analysis.
Recalculate forces, dynamic pressures, and descent rates for updated rocket
Opening Shock Force (Potvin, 2)
$F=C_k(C_dS)_0\frac{1}{2}\rho v^2$ |
Stress in DGB (Clark and Tanner, 13)
$\sigma t=\frac{F_{design}}{\pi D_{disk}}$ |
Ripstop Nylon MIL-C-7020 (Poynter, 70)
Fabric, oz/yard | t, inches |
---|
1.1 | .005 |
1.6 | .006 |
Find drogue Cd
Maydew gives Cd_0 = .53-.58, Dc/D0 = .73, and Dp/D0 = .65 (15).
Clark and Tanner say "It was typically assumed" that Dp/D0 = 2/3 (12). They do not give Cd anywhere, however they cite a number of papers that my give it.
Lingard has charts with Cd vs M for a number of geometric parameters (55-58). They range from .3-.6 in the subsonic range, .5-.2 in the transonic range, and .3-.5 in the supersonic range. I'm not sure what all of the geometric parameters are or what Cd is with respect to.
Size drogue
As of December 12, the mass budget says the rocket will be about 95lb dry.
Pick geometric ratios
Read Clark and Tanner.
Calculate stresses and forces in components
Pick fell and hem types
Calculate design factors
SRB drogue and main design factors (Maydew et al., 131)
Various DGB design factors (Clark and Tanner, 13)
I think Knacke has some design factor design guides
Calculate required textile strengths
Find most suitable cloths and tapes
Find suppliers and order textiles
See Parachute Suppliers.
Other tasks
Get design reviewed
Draw schematics
Determine proper assembly procedures
Create master list of construction details
Arrange wind tunnel test
Sources
Clark, I., & Tanner, C. (2017). A historical summary of the design, development, and analysis of the disk-gap-band parachute. In
2017 IEEE Aerospace Conference (pp. 1–17).
https://doi.org/10.1109/AERO.2017.7943854 Maydew, R. C., Peterson, C. W., & Orlik-Rueckemann, K. J. (1991).
Design and Testing of High-Performance Parachutes (La Conception et les Essais des Parachutes a Hautes Performances) (No. AGARD-AG-319). ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (FRANCE), ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (FRANCE). Retrieved from
http://www.dtic.mil/docs/citations/ADA246343 Potvin, J. (2009). Updating and Upgrading the World’s Database on the Opening Shock Factor Ck. American Institute of Aeronautics and Astronautics.
https://doi.org/10.2514/6.2009-2905 Poynter, D. (1984). The parachute manual: a technical treatise on aerodynamic decelerators (3rd ed., completely rev). Santa Barbara, CA: Para Pub.