parasheet shape - Round or Polygon?

[Early Starts]

I am thinking of making some nylon parasheets. I took a look at what I have and the Top Flights are Octagon but the LOC ones are round. I don't need to be concerned with folding the edge since I have access to a serger or overlock sewing machine. What shape should I use?

 

[powderburner]

Short answer: probably whatever you think looks good.

I am no expert on the details of retardation devices, but I have seen lots of reports on "real" parachutes (the kind the big boys use) and don't remember any info given on the best shape for the edges.

For our "toy" parasheets, I would expect to find even less research on this subject. This pretty much leaves you with: whatever is easiest to make, whatever you think looks good, or whatever came with the kit.

Something a bit more important to think about, even for parasheets: how many shroud lines should you use? I like to use at least eight, sometimes ten or twelve. The bigger number reduces the amount of load on each attachment and gives a little redundancy in case one tears out. And the increased number of shroud lines helps even a parasheet pull more into the shape of a true parachute.

 

[Micromeister]

Agree with Powder 100%:
Parasheets are parasheets our flat circles and polygon of the same diameter will produce about the same decent rate.
Number of shrouds and use of a central spill hole are very important considerations. Over time I've settled on 3/4" to 1" spill holes with 6 to 12 shrouds. 6 on sport models always with a spill hole. 12 on competition 1/4mil mylar chute generally without a spill hole since over time and use these mylar 12 shroud chutes stretch a bit into sort of a semi-hemi shape under load.

 

[Zack Lau]

I like polygons--less work to accurately space the shroud lines. Just a attach a shroud line to each corner and you are done!

 

[Handeman]

Come On! Be a Man! Use that sewing machine and make up some 8 or 10 gore hemis!