Here are a couple of videos to illustrate how fast a parachute can open:
In this video the first jumper deploys at 0:58 and has an open canopy at 1:01. The second jumper deploys at 1:07 and has an open canopy at 1:10.
In this video the jumper deploys at 0:38 and has an open canopy by 0:41.
Now imagine the canoeist throws his pilot chute into a strong head wind as the canoe starts to go over the edge. The canopy would be coming out as the canoe is tipping. It could conceivably inflate and carry him away from the cascade within seconds. It’s possible is all I’m saying.
Okay, it depends on what you define as “arc out”. I never said they “shoot out” as kayaker put it. But they are not buried in the “water center of mass of the falls” either, because otherwise you would’t see them. An experienced chutist has noted its not that hard to get a chute inflate. How clear of a cliff do you think a guy is going to be when he jumps off it with it laying on the ground at the top of the cliff? (the hundred foot cliff :eek: example). Water mist has got to be a bit more forgiving than rock. Keep in mind any kind of chute that manages to inflate that is designed to provide some lift to drag (and IS pointed in right direction) will quickly drive the whole contraption AWAY from the falls.
Now if you can tell me your typical ram air chute provides 30 feet per second of forward speed for every 10 feet per second of decent but your typical large waterfall has a horizontal indraft of 15 feet per second…then yeah there are going to be problems (rough number sorta made up) because the air is gonna suck you in faster than you can fly out. But I’d WAG that folks are overestimating how much horizontal indraft a waterfall has. And of course that would probably be a strong function of how much water is going over the falls. A paddled boat could either be shooting over Niagra Falls or a mere trickle by comparision (which would have virtually no “in draft”).
Back to the OP. Given the importance of the “chute inflating” and it being pointed in the right direction when it does so, something more like those triangular hanglider thingys would probably be better.
And back the OP’s premise in general? Are you going to MacGyver something like this the first time on the fly and have it work? Very likey not IMO. Could you approach this problem like a group of engineers, experts, stunt people, and fighter pilot types would and work up a system that has a decent chance of working? I think so.
Yup. Seconds. Which by that link is maybe 20 or so feet from where they deploy the pilot chute to where the full chute is inflated. During that time the canoe is now pointed straight down at most a few inches from the bulk of the water coming down adjacent to it. IF it is designed to hold the boat horizontal then it will flip one end into the water flow as it levels it out during inflation. If not, well, maybe, there could be some tricky handling to make it possible. And in defense of the concept I’ve at least found video of BASE jumpers jumping next to a waterfall and pulling it off. But again, they seem to be at least ten feet away from the water when they deploy, and another BASE jumper has this caution
The canoeist has an advantage over the BASE jumper because he has forward speed plus a hypothetical head wind so he can deploy before he is next to the cascade. Way upthread I said in real life it might work once in a thousand tries but probably not.
So you agree that it’s remotely possible, or do you still say “No, not possible”?
"If you throw a p/c in the downdraft right next to the waterfall, it may well keep falling with you and never create enough drag to pull your canopy out. "
This part ain’t quite right.
Even if you jump into a serious downdraft you will still eventually gain terminal airspeed in relation to that particular airmass. It can not be any other way. Well, I guess it could be if that airmass can continue to accelerate at 1/2 gt^2 indefinitely (which ain’t really real world)
The main complication is that the downdraft means you need more height to do your stunt than you would otherwise. So, you need to allow for it but a downdraft is not a dealbreaker.
And, again, how much water is going over the falls is IMO going to make a BIG difference in this whole downdraft aspect.
Interesting video. Is it just me or is that guy an idiot for not actually having the drogue chute in his grubby hands when he jumps rather than having to grab and pull it out as he falls? A miss grab or minor hang up and he’d be toast and I don’t really see the advantage of having it stowed away.
Sure, it could. Lots of things could go wrong with your scenario, as people have pointed out. But I maintain that it is physically possible, as you originally asked.
How about this far-fetched scenario: The canoeist throws the pilot chute into an overhanging tree branch just before he goes over. The canopy is out of the canoe when it starts to tip. The pilot chute is attached to the canopy with velcro so it releases and doesn’t leave you hanging there. A strong head wind inflates the canopy just before the canoe goes over. The canoe is never at more than a 45 degree angle.
Alright! It could happen. Not impossible. Highly improbable but not impossible. (Hey the canoe could hit a rock as a take off ramp and get some height …)
I’m curious now. I’m going to dust off my parachute and see if I can borrow a canoe. I’ll have a friend video my adventure and post it on youtube in memoriam to me.
You’re not going to settle down like feather. You’re either going to hit hard and have to do a Parachute Landing Fall (Tuck and Roll) like in the military, or you’re going to have some serious forward momentum, as in sport jumping, either way sounds rather daunting in a canoe.
I agree that it theoretically possible but we’re rapidly running out of waterfalls in the world where all these conditions exist. Remember, our hero is betting his life that this will all come together when he puts his boat in the water somewhere upstream.
What if you used (under incredibly idealized conditions) a parachute to build speed even before reaching the falls? Tricky as hell, but if there is $$ available to fund this, it is a challenge I’d consider! Or a sail-chute conversion type of deal…
I hope I can be forgiven for thinking that sometimes dopers make some of these terms up and then go online to a few websites so as to backfill their cover story for the etymology of these “words.”
Of course how you’re getting into my home and making changes to my copy of the 1965 unabridged Webster’s is still a source of great puzzlement, but rest assured, I will one day figure that part out too. :eek:
