Parachute Shock Forces:
- Used OSCALC software to calculate shock forces on parachute during deployment
- Required inputs:
- Air Density at Deployment
- Dry Vehicle Mass
- 80.32 lbs Dry Mass
- Descent Rate
- Drogue: 92 ft/s
- Main: 23 ft/s
- Coeff. Drag
- Estimated Drogue: 0.55
- Estimated Main: 1.6
- Nominal Parachute Area
- Drogue: 15.904 ft^2
- Main: 78.540 ft^2
Parachute | Shock Force (lbf) |
Drogue | 7.282 |
Main | 457.223 |
Drogue Max Drag Force: 80.32 lbf
...
Parachute Materials:
Component | Material | Component | Material |
Canopy Fabric | 1.1 oz Ripstop Nylon, Calendered | Shroud Lines | Vectran, 600 lbs capacity |
Webbing - Main | Type 8 Nylon, 4000 lb Tensile Strength | Risers | Technora, 2,500 lbs capacity |
Webbing - Drogue | Thin Kevlar | Sewing Thread | Nylon 66, Bonded |
Parachute Design - Drogue Sizing:
Diameter (ft) | Area (ft2) | Vent Diameter (ft) | Disk Diameter (ft) |
4.5 | 15.89 | 0.216 | 3.087 |
Gap height (ft) | Band Height (ft) | Suspension Line Length (ft) | # Suspension Lines |
0.36 | 0.509 | 9 | 6 |
Parachute Design - Main Sizing:
- Semi-Ellipsoid Design
- Height to Width Ratio of 0.707
- Parameters from Richard Nakka
Radius (ft) | 5 |
Height (ft) | 3.54 |
# Gores | 12 |
Suspension Line Length (ft) | 10.1 |
Parachute Design - Seams, Lines, Joints:
- Primary Joints (Both Main/Drogue):
- (A) Parachute Skirt to Suspension Lines
- (B) Suspension Lines to Risers
- (C) Risers to Metallic Hardware (swivels)
- Joint Design and Testing:
- Straightforward Insertions joints
- Plan to continue testing to build basis
- Vectran 600 (Suspension Lines: A & B) and Technora 2500lbs (Risers: B & C)
- Use Testing to solidify margins on current design [5” insertion w/ ½” back stitching on each end]
- Hems: 0.79in seam tolerance using zigzag stitch
- Gore on Gore seams: using a turned lapped seam, stitch with straight stitch
- Standard for parachutes, hide possibly fraying edges inside the seam itself
- Lines: sewed on after gore seams are completed, sew onto gore seams with zigzag stitch, locked at both ends
- Testing:
- Tensile Testing Seam Construction
- Machine: Instron 5567 Mechanical Testing Machine (50 kN limit)
