Recently I had the opportunity to take a closer look at the skydiving parachute. And I could not explain to my self the reason to use D-Bag and not pack main canopy directly in backpack compartment. I know that the reserve canopy is packed directly into the backpack. And the sequence for deploying reserve canopy is:
- Sky diver pulls release cord, which pulls out the pin that holds the backpack flaps close
- Spring loaded drogue parachute jumps out into the airstream
- Drogue chute pulls out the main canopy which opens
- Sky diver does not flatten him or herself on the ground.
More puzzling is the main canopy assembly. As far as I could understand the main canopy is packed into so called D-Bag. This D-Bag is then inserted into container in the main backpack. Why this intermediate step? The deployment sequence of main canopy is described here: http://adventure.howstuffworks.com/skydiving4.htm
I wonder what happens to the D-Bag after deployment. Does it hang loose? Does it remain close to the canopy on the upper side? As far as I understand the drogue chute remains attached on the back side of the canopy and acts as a sort of stabilizer. But what about D-Bag? Does it just flap around? Why not pack main canopy in separate compartment of backpack directly?