Summary

The purpose of this test is to test extraction of the main parachute.  Tow testing is a relatively cheap and easy way to test this.

Introduction

The tow test will be performed by tying the parachute bag to the back of an SUV, accelerating up to terminal velocity, and filming parachute extraction.  A line will connect the parachute to a stake in the ground.

Who is needed?

Driver, passenger, observer

Testing locations

Location requirements and weather dependencies: dry conditions, not too windy (<5 mph), at least a mile of runway to perform test

Locations: Berwick, Crow Island

Materials

  1. 3 GoPros with mounts/fancy cameras 
  2. 1000 ft. of line with breaking strength above 200 lbs
  3.  Parachute
  4. Parachute bag
  5. 1/2 in. stake
  6. Big hammer
  7. 16 ft. of webbing (breaking strength > 300 lbs) to mount parachute bag
  8. Camp stand/cardboard box
  9. Printed copy of procedure
  10. Small sand bag
  11. Line to tie parachute for repacking (optional)
  12. 4 quick links
  13. Scissors
  14. Clipboard
  15. Folding table to pack parachute on
  16. Parachute packing procedure - parachute should not be connected to the bag
  17. Tripods for cameras
  18. Traffic cone/markers/stakes at 500 ft. and 1000 ft.
  19. Sewing supplies (especially thread)
  20. Carpenters tape or duct tape

Setup

  1. Contact whoever is in charge of launch/main test about rental cars (make sure the vehicle meets requirements)
  2. Rent car

Packing:

  • Bring parachute packing procedure - parachute should not be connected to the bag
  • At least the night before, pack all of necessary materials
  • Pack parachute on folding table

Selection location

Renting car and vehicle requirements: at least a mid-size SUV, 

People to contact about logistics

What to print before the test: procedure

Procedures

Preparing for the test

  1. Print all necessary procedures
  2. Check cameras (battery level and memory space)
  3. Verify I know how to work slow-mo
  4. Pack all necessary materials

Setting up the test

  1. Use line to measure 200-300 ft. of "runway" (a little under 400 ft is ok)
  2. Drive stake into the ground 
  3. Pack parachute
  4. Mount parachute and camera to back of SUV
  5. Place 2 cameras on tripods at the end of the line
  6. Wind line in figure 8 by stake
  7. Make a loop in the line to tie a piece of thread that is shorter than the line to the parachute 

Performing the test

  1. Start near stake
  2. Drive up to 60 mph (passenger serves as back-up navigator)
  3. Cameras film parachute extraction
    1. 2 cameras outside car- one on side, one from behind
    2. 1 inside car

Conclusion

Analyzing the results

  • Inspect parachute for tears and burns
  • Inspect bag for tears and burns
  • When watching video, see if the lines come out before the parachute, how the unlocking of the locking loop worked, smoothness of extraction

Logging the test and results

  • Make a wiki page

Variations on the test

  • Short blurb about what else we could do with the tow test
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