# Onto what can you fall from 15K feet without a parachute and survive? **URL:** \ **Category:** Factual Questions\ **Created:** [May 9, 2009, 3:27pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852 "2009-05-09T15:27:12Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [May 9, 2009, 3:27pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/1 "2009-05-09T15:27:12Z")
So you suddenly find yourself falling out of your aeroplane and your parachute has failed. Fortunately the WXYZ Corporation has foreseen your trouble and built a large pit nearby filled with a substance into which you can fall safely. What should this pit contain? And how deep should it be? As I see it, there are two main issues: providing a survivable initial impact, and then a smooth and survivable deceleration. Plain water is out, but what about aerated water? Like a huge jacuzzi. What about a pit full of Aerogel? And how many negative G should that deceleration be? ---
**Author:** ![redshift](https://avatars.discourse-cdn.com/v4/letter/r/bbce88/32.png) [@redshift](https://boards.straightdope.com/u/redshift)\ **Post date:** [May 9, 2009, 3:46pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/2 "2009-05-09T15:46:03Z")
Instantaneously, I believe the body can sustain very high G/-G. However, continuously it should not have any more than about maybe -8G? Not sure if negative Gs work the same way as positive ones do, but I know for fighter pilots you start having problems around there and black out at around 12G. Material may not be as important as depth. A very soft, and low decelerating material. A huge pit of jello? ---
**Author:** ![Meurglys](https://avatars.discourse-cdn.com/v4/letter/m/258eb7/32.png) [@Meurglys](https://boards.straightdope.com/u/Meurglys)\ **Post date:** [May 9, 2009, 3:46pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/3 "2009-05-09T15:46:51Z")
Here’s a [few posts](http://forum.keypublishing.co.uk/showthread.php?t=32302) on another message board about a Flight Sergeant Nicholas Alkemade who, during ww2, was shot down at 18,000 feet and jumped without a parachute. He broke his fall in some pine trees and landed in a snowdrift. Oh, a [wiki](http://en.wikipedia.org/wiki/Nicholas_Alkemade) link as well… ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 9, 2009, 3:54pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/4 "2009-05-09T15:54:27Z")
> [@redshift](#): > > Material may not be as important as depth. A very soft, and low decelerating material. A huge pit of jello? A baby fell out of the window We thought that her head would be split But good luck was with her that morning She fell in a barrel of… Shaving cream! ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [May 9, 2009, 3:58pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/5 "2009-05-09T15:58:48Z")
> [@Quartz](#): > > What about a pit full of Aerogel? Despite its appearance, Aerogel is _hard_. You could easily stand on a piece without breaking it. ---
**Author:** ![gaffa](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@gaffa](https://boards.straightdope.com/u/gaffa)\ **Post date:** [May 9, 2009, 4:05pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/6 "2009-05-09T16:05:27Z")
> [@Q.E.D](#): > > Despite its appearance, Aerogel is _hard_. You could easily stand on a piece without breaking it. How about a very deep pit filled with chunks of shredded aerogel? I’m thinking bits the size of packing peanuts. ---
**Author:** ![Annie-Xmas](https://avatars.discourse-cdn.com/v4/letter/a/ecc23a/32.png) [@Annie-Xmas](https://boards.straightdope.com/u/Annie-Xmas)\ **Post date:** [May 9, 2009, 4:06pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/7 "2009-05-09T16:06:28Z")
I don’t know if it would work, but image the sound if the pit were filled with bubble wrap. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [May 9, 2009, 4:54pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/8 "2009-05-09T16:54:03Z")
Get them to work out how to save you from a fall of around 2000 feet and you’ll be covered for anything higher a well. ---
**Author:** ![gaffa](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@gaffa](https://boards.straightdope.com/u/gaffa)\ **Post date:** [May 9, 2009, 5:27pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/9 "2009-05-09T17:27:54Z")
One idea that has been running through my mind is a 2000 foot tall tower. The top would be perfectly vertical, but smoothly transitioning to horizontal so the base of the tower would be 2000 feet wide. The jumper would aim to contact the completely vertical portion of the tower and just ride it down. The whole surface of the tower would be coated with a slick surface like Teflon, but would get less slick closer to the ground. Would this work? ---
**Author:** ![Dervorin](https://avatars.discourse-cdn.com/v4/letter/d/eb8c5e/32.png) [@Dervorin](https://boards.straightdope.com/u/Dervorin)\ **Post date:** [May 9, 2009, 5:31pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/10 "2009-05-09T17:31:46Z")
In general, snow appears to be a good option: [Chuteless Jumps - ParachuteHistory.com](http://www.parachutehistory.com/other/bonusday.html) ---
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [May 9, 2009, 5:33pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/11 "2009-05-09T17:33:43Z")
Stuntmen use mounds of cardboard for their falls from several stories up. I don’t know if that would work well for higher falls. ---
**Author:** ![mswas](https://avatars.discourse-cdn.com/v4/letter/m/e99b99/32.png) [@mswas](https://boards.straightdope.com/u/mswas)\ **Post date:** [May 9, 2009, 5:35pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/12 "2009-05-09T17:35:29Z")
A series of deflating bladders filled with air, like the kind they use for stuntmen in Hollywood films when they jump off of roofs. Isn’t Terminal Velocity, Terminal Velocity? So at a certain point the extra height is irrelevant? You’d drown in a pit of Jello. Does the idea include whether or not the substance might kill you in some other way? What about a pit of down or cotton balls? ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [May 9, 2009, 5:47pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/13 "2009-05-09T17:47:38Z")
> [@gaffa](#): > > One idea that has been running through my mind is a 2000 foot tall tower. The top would be perfectly vertical, but smoothly transitioning to horizontal so the base of the tower would be 2000 feet wide. The jumper would aim to contact the completely vertical portion of the tower and just ride it down. The whole surface of the tower would be coated with a slick surface like Teflon, but would get less slick closer to the ground. > > Would this work? Well, if you don’t mind exiting at the bottom moving at 120 mph in the horizontal direction. Maybe if you put a slight rise over the course of the horizontal surface to decelerate you. And probably some lubricant like a water slide would be advisable to avoid friction burns. The penalty for missing the tower would be severe… ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [May 9, 2009, 5:59pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/14 "2009-05-09T17:59:40Z")
> [@Finagle](#): > > The penalty for missing the tower would be severe… You put a great big funnel on the top of the tower. 🙂 ---
**Author:** ![gaffa](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@gaffa](https://boards.straightdope.com/u/gaffa)\ **Post date:** [May 9, 2009, 6:07pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/15 "2009-05-09T18:07:11Z")
> [@Finagle](#): > > Well, if you don’t mind exiting at the bottom moving at 120 mph in the horizontal direction. That was the idea behind the surface of decreasing slickness. But no, I have no problem with traveling along the ground at 120 mph. > [@](#): > > Maybe if you put a slight rise over the course of the horizontal surface to decelerate you. And probably some lubricant like a water slide would be advisable to avoid friction burns. True. > [@](#): > > The penalty for missing the tower would be severe… Also true. Though nobody ever said that jumping out of planes without parachutes was a sport for _chickens_. > [@Norm McDonald](#): > > “In cliff diving there is only two levels: Grand Champion and…stuff on a rock.” ---
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [May 9, 2009, 6:33pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/16 "2009-05-09T18:33:25Z")
> [@Rick](#): > > You put a great big funnel on the top of the tower. 🙂 Wasn’t there a video game which utilized such devices? ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [May 9, 2009, 10:31pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/17 "2009-05-09T22:31:52Z")
How about wearing a conductive suit, and dropping into a series of magnetic coils? Kind of the reverse of a rail gun. The whole thing could be tuned to supply exactly the right deceleration curve for minimal stress. Another option would be a series of stretchy, breakaway surfaces. high speed parachute drops use that - deploy the first, small chute on a bungee. It applies a progressive force until the bungee snaps, at which point you’re going slow enough for the main chute to deploy. Do the same thing on the ground. Build a giant multi-story frame, and stretch across it materials designed to slow you a bit, then snap and let you fall through to the next layer. Eventually you just stop. That’s essentially what those tree branches did to the guy who fell from 18,000 feet and survived. I like the slope idea, too. [Here’s the story of a guy who survived a 15,000 foot fall this way](http://www.projo.com/news/content/BOMBER_MONUMENT_02-22-09_BQDCSJ1_v39.1a3ff6b.html). He landed on a ski slope. He had streaming parachute remnants slowing him down a bit, which helped. ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [May 9, 2009, 11:40pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/18 "2009-05-09T23:40:47Z")
Really, the only question is what rate of deceleration you want. Creating something which will achieve that isn’t a particularly difficult engineering task. Probably the bigger issue would be whether you could actually hit the target. For instance, I bet you could create thin steel fibers and make a big rat’s nest sort of blanket out of them that can be torn apart like tissue paper, and then have a series of these all down the pit. So…steel even could be a decent fall breaker. The material isn’t so important as the technique ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [May 9, 2009, 11:48pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/19 "2009-05-09T23:48:55Z")
> [@gaffa](#): > > One idea that has been running through my mind is a 2000 foot tall tower. The top would be perfectly vertical, but smoothly transitioning to horizontal so the base of the tower would be 2000 feet wide. The jumper would aim to contact the completely vertical portion of the tower and just ride it down. The whole surface of the tower would be coated with a slick surface like Teflon, but would get less slick closer to the ground. > > Would this work? It worked in **The Empire Strikes Back…** ---
**Author:** ![The\_Seventh\_Deadly\_Finn](https://avatars.discourse-cdn.com/v4/letter/t/6bbea6/32.png) [@The\_Seventh\_Deadly\_Finn](https://boards.straightdope.com/u/The_Seventh_Deadly_Finn)\ **Post date:** [May 9, 2009, 11:51pm UTC](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852/20 "2009-05-09T23:51:44Z")
How about a pit filled with your enemies? You probably wouldn’t live, but at least you’d take a few of them with you. [Next page](https://boards.straightdope.com/t/onto-what-can-you-fall-from-15k-feet-without-a-parachute-and-survive/495852.md?page=2)