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CV =
πD V
NG
(24)
where NG is the number of gores. CS is then calculated using
CS =
πD
NG
(25)
Using equations 24, 25, and the ratios shown in Table 6Error! Reference source not
found. all relevant construction dimensions and the results are shown in
Rocket Section
Booster
Lower Sustainer
Upper Sustainer
Hazard Detection Payload
Ng
10
10
10
10
CV (in.) CS (in.)
20.56
33.65
23.27
38.09
19.01
31.11
11.02
18.03
h (in.)
32.56
36.86
30.10
17.45
a (in.)
34.17
38.68
31.59
18.31
b (in.)
21.42
24.25
19.80
11.48
Table 7: Nominal parachute dimensions.
Construction
The canopy will be made of MIL-C-44378 0.75 oz. rip stop nylon; the reason this material
was chosen is because the team had success using it last season. The suspension lines
will be made of 1/8th inch nylon para-cord with 400 lb tensile strength. The harness that
connects the suspension lines to the launch vehicle will be made of 9/16th inch tubular
nylon with a tensile strength of 500 lbs, there will be one harness per parachute. There
will be ten suspension lines per parachute as each parachute has ten gores.
To account for the loss of fabric during hemming and sewing the panels together the cut
dimensions must be greater than the characteristic dimensions listed previously. Figure
23Error! Reference source not found. shows the hem layout. The shown dimension H
will be ½ inches, so a total of two inches will be added to the total height of each gore.
Figure 23: Hem layout.
The individual gores will be sewn together in a French felled seam, also known as a
double lap seam, as shown in Figure 24. The shown dimension “S” will be ½ inch so a
total of 1.5 inches will be added to both Cs and Cv for each gore.
| 2013-2014 RCR CDR 33