Binary93 65 #1 Posted December 14, 2020 Had a discussion with a friend, haven't done any testing and didn't find any information on this so asking here. When a same person jumps the same canopy of two different sizes (say 170ft and 100ft), does one (as a rule) open faster/slower/harder/softer/other than the other? And if so, how would this difference be compared to the differences in openings for two different canopies of the same size (e.g. pulse and katana)? We can assume packing is identical, etc. Not asking about the skill required to fly the openings (harness, etc.) but only about the speed/strength of the opening. Quote Share this post Link to post Share on other sites
flyingwallop 7 #2 December 14, 2020 (edited) At the same loading, as in this case, I'd say the bigger canopy has the stronger stopping/breaking power. So I'd bet my money that it opens faster. Although I am sure it's alot more complicated, and probably, how fast it opens is more influenced by the volume of the air needed to inflate fully and how quickly the air can get into the canopy. Edited December 14, 2020 by flyingwallop Quote Share this post Link to post Share on other sites
riggerrob 643 #3 December 15, 2020 On the rare ocassions when I have jumped tandem canopies by myself, they opened so softly and flew so slowly that I had to look up a couple of extra times to re-assure myself that they were inflated properly. Hah! Hah! For comparison, I have made more than 4,000 jumps with tandem students strapped to my chest, so tandems are my "normal." Quote Share this post Link to post Share on other sites
Quagmirian 40 #4 December 16, 2020 Could you ask a more simple question, like 'what's the meaning of life?' There are so many factors that go into how a canopy opens that it's really difficult to compare like for like and just pluck out a factor like size. 1 Quote Share this post Link to post Share on other sites
Deimian 43 #5 December 16, 2020 Also harder and faster are not the same. "Hard" depends on time to decelerate and the speed difference (freefall vs under canopy). "Fast" depends on time to inflate. It is a subtle difference, but an important one. A grocery bag can open much faster than a Sabre 1, but for sure it won't slam you. Quote Share this post Link to post Share on other sites
Binary93 65 #6 December 16, 2020 2 hours ago, Quagmirian said: Could you ask a more simple question, like 'what's the meaning of life?' There are so many factors that go into how a canopy opens that it's really difficult to compare like for like and just pluck out a factor like size. Fair point, and I agree. I know there are folks around here who did lots of both design/development and testing of different canopies (also for cargo IIRC), so I thought they might have some insight and data regarding this. I'm hoping for some data and experience here :) "No" is also a valid answer (i.e. size doesn't affect the opening characteristics in a predictable way), but as I said, it would be awesome if there was some data or experience supporting it. Quote Share this post Link to post Share on other sites
sfzombie13 324 #7 December 16, 2020 On 12/14/2020 at 9:02 PM, flyingwallop said: At the same loading, as in this case, I'd say the bigger canopy has the stronger stopping/breaking power. So I'd bet my money that it opens faster. Although I am sure it's alot more complicated, and probably, how fast it opens is more influenced by the volume of the air needed to inflate fully and how quickly the air can get into the canopy. but as op has put the question, it is a much different loading that is presented if the same jumper is using the canopies op has suggested. from the few conversations i have followed regarding hard openings, i am certain there are many more variables and that we may never get the full data set to explain them. Quote Share this post Link to post Share on other sites
