> You will want a tall tree with an excurrent growth pattern—a single, undivided trunk with lateral branches, delicate on top and thicker as you cascade downward.
I had not encountered the word excurrent before. They provide a bit of a definition directly after using it but I was still curious so looked it up. Turns out it is a general botanical term but when used in the context of tree shapes (specifically the crown) it contrasts with decurrent. I found this image [1] which illustrates the different shapes of excurrent vs decurrent trees.
It seems logical that using a large vocabulary impair communication since most people would not know what your words mean. However, up to a degree, it seems like the opposite is the case.
Is there any theory in linguistics for why that is so?
I could see a couple of things that might be at work:
- People are able to figure out what you mean from context and a larger vocabulary allows language that is more aesthetically pleasing.
- People associate a larger vocabulary with greater intelligence and therefore are more likely to listen.
- Access to multiple synonyms allows you to construct more complex sentences without them becoming repetitive or confusing. For example, someone doesn't know what the adjectives you are using mean but they are able to understand that you are making a distinction between two things.
- Due to context, past exposure, an instinctual sense of etymology, etc. people are able to understand a much greater vocabulary than they are able to use.
I think you are just describing jargon, which allows greater specificity when the audience is assumed to have a fundamental grounding in the topic being discussed.
And to all of you who will soon stumple upon excurrent again, maybe multiple times, even though you have never heard about it until now. This is called Baader-Meinhof Phenomenon.
To lay down another level of irony, I just learned about Baader-Meinhof phenomenon an hour ago while watching Stranger Things S03E02. I am now prepared to read about this all over the place.
> Turns out it is a general botanical term but when used in the context of tree shapes (specifically the crown) [excurrent] contrasts with decurrent.
Wow, that's weird. Excurrent is transparent (if you know Latin) as "running out [from something]". But ex- [out] would usually contrast with in- [in]. Contrasting with de- is really unusual, since to a first approximation ex and de both mean "from". (Compare indent/dedent, where de is the opposite of in.)
At a more detailed level, excurrent is "running out [from somewhere]" and decurrent is "running down [from somewhere]", but to me it looks like the decurrent tree branches are running in every direction at once.
The difference is that the decurrent branches fork and decrease in size at each fork from the main trunk, whereas the excurrent branches are all relatively small and mostly branch out from the trunk itself. So I think the term is 'down' in terms of 'down the length of the branches'.
I think there's (at least) one important factor this leaves out. Drag doesn't care what direction you're moving: it will slow you to about 120 mph regardless of whether you're going straight down or at an angle.
This implies that you want to control your horizontal velocity not just to decide where you land, but also to build up as much horizontal velocity as possible. If you can get yourself going at a moderate angle, you can significantly decrease your vertical velocity, which is by far the most dangerous part of a freefall!
The most important thing about approaching at an angle is not to tumble. This strategy would work best if you could slide down or along a loose surface like snow or small gravel, ideally down a hill. This basic strategy is why high speed skiers (who are moving at least 120 mph) can survive crashes.
Stuntman Garry Connery demonstrated the efficacy of what you're describing when he jumped from a helicopter at 2,400 feet (730 metres) and steered himself using a wingsuit onto a runway of vertically stacked cardboard boxes. [1]
> At approximately 200 feet (61 m) over the landing strip, he changed the configuration of his wingsuit so as to decrease the gliding and vertical (falling) components of his velocity to 50 mph (80 km/h) and 15 mph (24 km/h) respectively. [2]
Yep! 15 mph falling is survivable. His total velocity was 52.2 mph on impact - if all that had been straight into the ground it's doubtful that even the thick layer of cardboard boxes would have prevented injury.
Without a wingsuit you're not going to get ratios that good, but every bit helps, and if you can hit a sloped surface with any accuracy your survival chances go up significantly.
Lift generated in the vertical direction is probably a factor worth considering here as well.
If you are able to build up a significant velocity in horizontal direction, you might in the final moments before landing be able to shift posture to an aerodynamic form which converts your horizontal motion to a force in the positive vertical direction with a drag force in the negative horizontal direction, reducing both your horizontal and vertical velocity for a brief period.
The notion reminds me of how helicopters land in the event of an engine failure, a regime of flight called autorotation. After engine failure the main rotor begins to be driven by the airflow. It is set to maximize drag, impart a horizontal velocity (I think? I am not a helicopter pilot, this is not helicopter landing advice), and primarily maintain rotational inertia -- more like a glider with a spinning wing than a rock falling from the sky as one might assume. In the moments before landing the rotor angle of attack is increased, and the rotational inertia is converted to brief surge of lift allowing the helicopter to touch down practically as normal.
The question becomes, what posture should one assume to maximize lift to drag ratio? It seems like something edge on, with the body in a flying wing formation essentially, could come pretty close to offering enough lift to make survival feasible if you could somehow manage to transition to that orientation through what appear to be aerodynamically unstable configurations which would oppose that. And the side-on orientation does not seem like a good posture for the actual impact, so you'd need to quickly shift back to the "shock absorption" posture and if the flying wing orientation had the intended effect you would not have much airflow to maneuver with so it would presumably have to be something more like a zero-g change of attitude (https://youtu.be/960CsCgI6Jg?t=105).
I'll be sure to give it a try if I ever end up falling out of an airplane and let everyone know how it goes, though.
Hmmm...former skydiver here, not sure your point is accurate. I don't understand why increasing your forward momentum from tracking would decrease your fall rate.
I think your assumption that drag will slow you to 120mph is inaccurate - for example, if you fall heads-down your terminal velocity is instead up to ~180mph. Similarly, I'd expect that if you track in a direction your velocity could increase above 120mph while not lowering the speed at which you approach the ground.
Apologies - my physics knowledge and terminology is very limited, but do have some practical experience in the area :)
The trick is that while you can't actually decrease the total amount of energy in your fall, you can get some of that energy to work in your favour.
Think about when you flare a parachute, shortly before landing. What you're doing is trading forward momentum for vertical lift, softening your landing. The more forward momentum you have prior to a flare, the more lift you can get out of it. This is why you see experienced / foolhardy skydivers doing "hook turns" to maximise their forward velocity immediately before landing.
(Of course if you just stayed in the flare position continously, you'd have no forward momentum to trade, and would therefore lose lift entirely, producing the opposite of the intended effect.)
Anyhow, yeah, I doubt that tracking alone would help with survivability. My hunch is that you'd be trading 10mph of vertical momentum for about 40mph of horizontal momentum. Doesn't sound like a good trade. Although maybe -- just maybe -- you could execute a "body flare", whereby you kick your legs forward at exactly the right moment, to kill that forward momentum and trade it for lift. That might actually work (a bit)! But it sounds like an extraordinarily difficult manouevre. You'd certainly never get it right on the first try. Which of course is as many tries as you'll ever get.
You might have to spend your last 10 seconds or so in an orientation that maximizes drag, so as to take advantage of the horizontal velocity you've built up.
I'm familiar with the physics angle, but not the skydiving one. :-) I think to know this accurately we'd have to look at some kind of simulation.
Wikipedia claims glide ratios of 1:1 with efficient tracking. You'll still hit with a 90mph vertical speed, and I suspect you will compromise your ability to land on a soft point target.
Myself, I think landing head-first sounds like the best plan.
”Look around for a proportionate personal vehicle—some large, flat, aerodynamically suitable piece of wreckage.”
Problem: by the time you have dropped from 35,000 to 15,000 feet, such parts will be thousands of feet above you, way out of reach
⇒ if there are such parts, you’ll have to find them before you lose consciousness. Alternatively, you’ll have to construct them (rapidly so) from parts that drop about as fast as you do (could be as easy as opening a suitcase that’s dropping at your speed, if you’re very, very lucky)
You hit the water at terminal velocity. Since water is effectively uncompressible, this is much like hitting concrete, I've read. You are either instantly killed or knocked out, in which case you slip underwater and drown.
I suppose hypothetically your best bet over water would be vertical entry, as opposed to the spread-eagle recommended for a land impact, but at the speeds you'll be going I imagine you're pretty much doomed regardless - even if the impact doesn't shatter you, I believe water rushes into your internal organs through your anus and causes massive damage. I've seen that referenced as a risk for bridge jumps and this is, obviously, as bad a water jump as you can make. I also imagine you'd go deep enough that you couldn't possibly float back up to the surface before drowning, and I imagine the impact and pressure of increasing depth would force all the air from your lungs anyway.
Disclaimer: I am not an expert in any relevant field. I may well have some facts wrong. Just speculating based on what little I know.
Falling from an airplane is basically the same as falling from 1500 feet in terms of velocity. The highest dive ever is approximately 200 feet, and the list of injuries others have taken trying to match that figure is quite impressive. That suggests to me that the odds of surviving, no matter how practiced or proficient you are, would be very low over water.
Of course, there are things you could do to improve your odds. Placing yourself near other people who might assist you would be a big one. If you could somehow make yourself float face up once unconscious that might help as well, although I struggle to see how you would do that given the colossal forces involved. Any kind of crush core would be a huge help.
The horizontal component seems like a red herring when it comes to water. Any advantage you might get from the smaller vertical component would be totally overridden by the horrible death you would suffer due to damage to your internal organs.
Some two decades ago, I remember seeing a news report about a weird tight-knit community of BASE jumpers in the USA who liked jumping from high bridges without parachutes. (The reportage was mainly about how they were addicted to this activity like to a drug, and wouldn’t stop even though several members had died.) In order to make the surface of the water safer to land in, they dropped a heavy object a split second before they themselves jumped, as supposedly once the surface had been broken by the splash of the initial object it was momentarily not concrete-like hard.
Anyone else remember who this group was and has some information about them?
Your best bet would be to hit the water like a needle because you can't reduce the vertical velocity in any meaningful way without a wingsuit. The chance is high that you'll break an arm or leg and lose orientation underwater, so be prepared. Maybe its better to keep your arms straight up but thats just a guess because I never tried. You will probably also need to stick around for a long time until help appears. Good luck!
There's a fascinating story about a fighter pilot named Judkins [1] who survied a free fall above the ocean. There are other similar stories [2]. A lot of luck involved each time.
There was such a case in Russia several years ago. An experienced skydiver was filming his friends and fell out of a helicopter without a parachute. He has landed in a pond and died immediately. It was said that the impact was so hard that it has torn off his jumping suit.
I had not encountered the word excurrent before. They provide a bit of a definition directly after using it but I was still curious so looked it up. Turns out it is a general botanical term but when used in the context of tree shapes (specifically the crown) it contrasts with decurrent. I found this image [1] which illustrates the different shapes of excurrent vs decurrent trees.
[1] http://countrysidelandscape.net/files/2018/10/Branch-pattern...