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)

Find drogue Cd

Maydew gives C_{d_0} = .53-.58, D_c/D₀ = .73, and D_p/D₀ = .65 (15).

Clark and Tanner say "It was typically assumed" that D_p/D₀ = 2/3 (12). They do not give C_d 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