Medusa Drogues
Responsible Engineers: Claire J, Jenna B, Ezra E, Sophia C
Background
Drogue was chosen to be a disk-gap-band parachute which is intended to operate at low dynamic pressures at high altitudes and at supersonic speeds, with better stability than solid flat canopy. See this wiki page for additional research done on parachute selection.
Geometries
See diagram below for parameter matching. Geometries were found using DGB standard of disk, gap, band, and vent areas of 53%, 12%, 35%, and 0.37% of the nominal area (calculated using the selected nominal diameter).
Booster Drogue:
-8 gores
Parameter | Value (in) | Calculation Notes |
Nominal Diameter (Dp) | 54 | |
Nominal Area (S) | 2290.22 | pi*(Dp/2)^2 |
Geometric Porosity | 12% | |
Vent Diameter (Dv) | 3.28 | pi*(Dv/2)^2 = 0.0037*S |
Disk Diameter (Dc) | 38.88 | Dc/Dp = 0.72 *from Phoenix |
Gap Height (h2) | 2.25 | 0.12*S/Band Length |
Band Height (h3) | 6.56 | 0.35*S/Band Length |
Band Length (l=8*e) | 122.145 | pi*Dc |
Suspension Line Length (lr) | 91.8 | 1.7*Dp |
Sustainer Drogue:
-8 gores
Parameter | Value | Calculation Notes |
Nominal Diameter (Dp) | 36 | |
Nominal Area | 1017.88 | pi*(Dp/2)^2 |
Geometric Porosity | 12% | |
Vent Diameter (Dv) | 2.190 | pi*(Dv/2)^2 = 0.0037*S |
Disk Diameter (Dc) | 25.92 | Dc/Dp = 0.72 *from Phoenix |
Gap Height (h2) | 1.500 | 0.12*S/Band Length |
Band Height (h3) | 4.375 | 0.35*S/Band Length |
Band Length (8*e) | 81.430 | pi*Dc |
Suspension Line Length (lr) | 61.2 | 1.7*Dp |
Materials:
Fabric Ripstop by the Roll 1.1 oz Ripstop Nylon, Uncalendared;
Size 46 nylon thread
Kevlar Webbing (check type)
Technora lines (check type)
Manufacturing Steps:
Draw out pattern (we have the paper left over from last time yay!
Cut out octagon and rectangle pieces with extra seam allowance on all sides out of nylon ripstop (seam allowance of ¼ inch)
Cut out Kevlar and seal ends
Reinforce the edges with Kevlar tape (zig zag)
Cut out the radial Kevlar reinforcements and seal the ends - mark where the loops should end and fold
Sew on kevlar using zigzag stitch with nylon thread, make sure to have loops on either end
Finger trap the vent line in place
Cut out 39in of thin Technora for lines → lines should be 30.6in
Tie one end in bowline knot to chute → make sure to make first loop then thread through kevlar loop
Mark 30.6in on all lines
Tie bowline loop on end of thin technora lines and check for length of 30.6
Run around and make sure chute works
References:
https://apps.dtic.mil/dtic/tr/fulltext/u2/a246343.pdf
https://ntrs.nasa.gov/api/citations/19700023573/downloads/19700023573.pdf
