|
Free FallThe Free Fall Research Page |
|
|
Free FallThe Free Fall Research Page |
We occasionally receive questions about falling. Here are some examples, along with our response. If you would like to have your question answered, send an e-mail to Jim Hamilton.
|
My teacher wants to know why Joe Kittinger didn't burn up when he jumped through the atmosphere. Was it his clothes? |
He didn't burn up because he didn't re-enter the atmosphere in the way a space capsule would. He was high up but he wasn't that high up. Burning up was not his concern, the cold and lack of oxygen were his problems. He did have a special suit, but that was designed to keep him warm and provide breathable air. During one point he lost a glove and injured his hand, but he survived without serious injury. | Note: The Wikipedia entry on Joe Kittinger is pretty good if you are looking for more information on him. | By the way, some guy was trying to beat Kittinger's record in the summer of 2007. He was going to jump from a balloon in Canada but it didn't happen. Now it looks like it's off until 2008. (See the April or May issue of the New Yorker for a good article on this.) |
Can you explain how to compare various speeds? |
Given the nature of this web site, there are frequently times when a speed figure is given in miles per hour, kilometers per hour, feet per minute (or second), or meters per minute (or second). This is why we've created the Free Fall Research Page Speed Conversion Table. This is a device that allows you to see comparable values in miles per hour, kilometers per hour, feet per minute (or second), or meters per minute (or second). Two quick conversions are worth keeping in mind: (1) multiply miles per hour by 1.61 to get kilometers per hour and (2) multiply kilometers per hour by 0.62 to get miles per hour. |
Could the article by David Carkeet really help someone? |
This question came with the following explanation: “I was reading your articles and stories after I found "Survival Tips for an Unplanned Freefall" by David Carkeet. I am in Grade 8 and am interested on doing a speech using this articles and some of your stories. I have a question: Could the article by David Carkeet really help someone? I know that it is meant for humour and that it it mising some things (ie. how would you see without goggles?) but if I wanted to make my speech funny AND helpful, could I use it? You see, I want to use humour and tie in some mystery and fate and was hoping to use the article. I just don't want to have a hilarious speech that actually wouldn't help someone a little bit-speeches have to have SOME research and information in them!” It was signed “Sincerely, A Speech Writer” | The quick answer to your question is “no.” If someone were really falling from thousands of feet, there is not anything in that article that would help the person to survive. You could remind them to carry goggles every time they get on a commercial airliner so that if they fell they would have a better view on the way down, but all in all that’s not very helpful. | Even so, I would encourage you to speak on the topic anyway because if you can give an interesting and funny speech, that in itself is very helpful. People like to be entertained. In addition, it is a true gift to be able to make people laugh. Why not take this opportunity to find out if you have that gift? I wish you good luck with your presentation no matter which topic you choose. |
Approximately what percent of people actually survive a freefall? |
The survival rate can only be guessed at, but it is certainly well under one percent. Here is one way to look at it. In World War II there were a lot of people jumping or falling out of damaged airplanes, probably tens of thousands of them. Unless these people had a working parachute, they almost certainly fell to their deaths. I know of a handful of cases where the person miraculously survived without a working parachute. If there were 10,000 such cases of people thrown out of planes without parachutes (and this is a guess), then maybe three survived. That would make the chances about 3/100ths of one percent. | In the U.S. 8th Air Force during World War II, more than 26,000 men died. To assume that a few thousand of them fell unconscious or without a parachute when their aircraft was destroyed is not too far-fetched. In addition there were many other allied and enemy airmen in other regions who may have died that way. Those who survived are part of a unique and fascinating club, but we should not forget the many others who died. |
I was talking with a friend recently about the World Trade Center jumpers. I would’ve thought they would’ve lost consciousness prior to hitting the ground. Would this be true or would they have been alive and conscious up until impact? |
I suppose they might have fainted from fright, but I think it’s likely they were conscious. The fall itself wouldn’t make them pass out. Skydivers fall much further and are still conscious and able to pull their ripcords. | The choice that the people in the World Trade Center had to make was really the same one that faced Nicholas Alkemade (see the Freefallers page). He chose death by falling over death by fire, but through an odd combination of circumstances, he survived. None of the WTC jumpers had that kind of luck. |
What are the different names for parachutes? For example, what do you call the old World War II style round parachutes and what are the rectangular, wing-like ones called? |
Note: This answer comes from skydiving instructor Jim Phillips. Thanks Jim! | There are two main types. The most common reference to either is “round” or “square.” Rounds are still used by quite a few outside of the regular sport. Most pilot’s rigs contain rounds. The military of course. The sport started phasing them out in the 1980s. The biggest reason for the change was directional control. A round is much more susceptible to the winds and far more difficult to be accurate with. Where you get out over the ground had to be much more precise or you might not land where you wanted to. | It may not have been a design goal, but another large difference in the square and round is the ease of packing. A round required much more space and sometimes different tools to pack. I don’t need anything to pack a square but the space in my living room and a shoestring. You can pack a square, using care and doing it safely, in less than 10 minutes. | So now we have squares, or to be technical, ram-airs. They are not actually square though. They were close to square in the first few prototypes but now are mostly straight on the leading edge and tapered on the tail. The leading edge is open. | This open edge allows the parachute to pressurize and become more solid which in turn enables the chute to take on the shape of a wing and be able to produce lift. This lift has allowed the soft landings we now have as opposed to hitting the ground like a sack of rocks the way the military does. | There are many models and dealers to choose from. The largest difference between models is the size and how tapered the tail is. The larger the parachute and straighter the cut of the tail, the more docile and safe a canopy is. The smaller and more tapered you go, the more responsive, fast and controllable a wing gets. The choice should foremost be made by your experience level but rarely is. To fly safely and conservatively, it is recommended that you have 1 square foot of canopy per pound of your exit weight. They recommend that you don’t fly a heavily tapered wing, which is called elliptical, until you have at least 500 jumps. As you get more experienced, you desire more speed and performance. To date, the smallest parachute landed was 39 square feet. |
Why does the military still use round chutes? |
This is a follow-up to the previous question and again is answered by Jim Phillips. | There are a couple of reasons the military still uses the round chutes. I don’t know their official stance but I would imagine the main reason is the altitude at which they exit. Combat jumps are made around 800 feet. Even with a static line, a square takes more time to open than a round. These jumps are also made with a lot of gear on. It would take a much larger canopy and quite a bit more training to handle a square that quickly with everything else going on. Another thing is, if you were to put out hundreds of jumpers over a field on squares they would have numerous collisions under canopy. Under a round a canopy collision is often uneventful. Under a square a collision generally ends in collapse. Perhaps with extreme proficiency you could manage a square in that kind of traffic, but military jumpers often don’t have many jumps under their belts. To get 50 jumps in a four year career would be a lot. The cost of a round is also much less than a square which to our government is surely a factor. Now special forces types do use squares. They are in much smaller groups and have considerably more training. They also tend to exit much higher. | Dave Sterling wrote in with the following additional point: "One key reason that the military uses round chutes is because that type's relative lack of maneuverability significantly increases the chance that the 'stick' will land close together. That's important as the time it takes to get organized once they are on the ground can easily mean the difference between life and death in a combat situation. (Note: A stick is the group of jumpers who leave a plane during a single pass over a drop zone. This could be the entire planeload or a part of it depending on how big the drop zone is and how many troops can exit at once without some of them missing it.)" |
What is an unbounce anniversary? |
An unbounce anniversary is like a re-birthday in a sense, it’s the annual celebration of the day that the person survived the long fall (rather than bouncing, I suppose, though it seems that you could do both…) |
Why am I alive? |
This is the question from an e-mail to this site: "I have been waiting for over 7 years to find out some answers about why I am alive. I think you are the most qualified to tell me. Could you help me answer some questions?" | This question comes from a man who jumped (or fell, it’s not really clear) from the 14th story housekeeping balcony of the Bonita tower of the Disneyland Hotel in February of 1998. He fell about 110 feet and landed on the roof of the lobby entrance. He survived with a dislocated left shoulder, a collapsed right lung, and facial injuries. He didn’t break any bones. He wanted to know why he was alive, and specifically how fast he fell and what contributed to his survival. He had heard from security guards that nine people had committed suicide from that balcony. He wanted to know why he had survived and they did not." | Here's how I responded: “Someone falling from that height will be going 50 to 60 miles per hour by the time they reach the ground. That's fast but survivable depending on how they hit the ground. If they fall head first they die. If the fall feet first they break a lot of bones and may die. If they fall on their sides, as it looks like you did, their shoulders and chests absorb the worst of it. Maybe the worst of the fall gets distributed even further from knees to hips to shoulders. It may also be better to take some of the hit on your face, as opposed to busting the back of your skull.” | “As for the other nine people, who knows? You did fall an awfully long distance but I have seen at least one other story like yours (eighteen stories I think). I'm sure most people who fall that far die, but a few (one in ten or one in a hundred) will survive for one reason or another.” |
There are some other interesting points in regard to his question:
|
If you fell out of a plane could you really see anything? |
Thanks to Travis Brown who wrote the following, presumably after having read David Carkeet's The Unplanned Freefall: "Something you never mentioned is that if you are falling unexpected you will not have any eye protection. I know it was mostly meant to be humorous, but if you really were in a plane that broke up midflight you would not be seeing very much on the way to the ground unless you happened to have some goggles hanging around your neck. Think of it like riding 120 mph on a motorcycle with nothing to shield your eyes from the wind ..." | I countered with the following: " It's an interesting point but I suppose you could look up. You'd have a nice view of the sky at least." | Travis, a skydiver and a realist, wrote back: "Flying on your back is easier said than done..." |
My high school physics teacher told me that theoretically a person could survive a free fall by diving head first straight toward the ground, and at the last second tipping his hands up slightly. This would cause the diver to curve past the ground and actually rise up momentarily before falling again, sort of like a piece of paper. If timed perfectly the person could land feet first unharmed. He said that German skydivers had experimented with this technique (at altitude of course), and got some encouraging results. Have you ever heard of this? |
I've never heard this story, but there are some bits and pieces that sound a little familiar. There were barnstormers called Batmen who jumped out of planes in special suits with fabric between the arms and legs. They were able to use those outfits to swoop around a little, but they still needed parachutes. There is also the story (see below) about the Russians dropping soldiers from planes into snow banks without parachutes. We are also investigating a story about a Russian guy who fell out of a helicopter and used his coat like wings to slow his fall. It’s the point about reversing direction that is particularly bothersome. Seems to me like your teacher was pulling your leg. |
This is my web site so I am going to submit my own question: I get a surprising number of e-mails from people who take David Carkeet's The Unplanned Freefall seriously. Engineers write to question his math. Scientists scoff at his physics. College students from foreign countries ask serious questions about his discussion of "five-point" landings. My question is this: Is there a group of people out there wandering the Internet for whom humor is a foreign language? |
The sampling of e-mails I have received suggests that there are a lot of humor-deprived human beings in the world. David's article is one of the funniest things I've ever read, which is why I was so happy that he agreed to let me post it here. If you are bothered by the math or physics or whatever, get a hold of yourself. If you want to write me an e-mail, fine, but just remind yourself that it's a humorous piece. Okay? | By the way, the "guy" who said "Failure is not an option" was Gene Krantz, flight director for Apollo 11 and 13. He wrote a book by the same name, which if you go by reviews on Amazon.com is a must-read. |
Why isn’t Joe Kittinger’s lengthy free fall included somewhere on this web site? Note: On August 16, 1960, Joseph Kittinger, then an Air Force Captain, rode a helium balloon to an altitude of about 100,000 feet. He jumped and fell for more than four minutes. His parachute opened at about 14,000 feet. His jump showed that astronauts in pressure suits with oxygen could survive an ejection from a very high altitude. |
It wasn’t included it on the site (until now) for one simple reason: his parachute worked. The stories that are included on the Free Fall Research page generally involve someone who fell with no parachute, or, someone who fell with a parachute that failed. | There are a couple of exceptions to this rule. These are stories of people whose parachutes worked, but who had something else bad happen to them. (See the bottom of the Unlucky Skydivers page.) Fortunately for Kittinger, his jump went exactly as planned. |
Did the Russians ever make soldiers jump out of low-flying planes without a parachute? I don't know. I really doubt it, but there are some who state that they did. These stories show up on the Internet with no sources quoted. |
Here is how the story goes: When Leningrad (now St. Petersburg) was under siege by the Germans in World War II, the Russians planned an airdrop of soldiers and supplies, but (imagine this) they were out of parachutes! The situation was so desperate that they asked for volunteers to test whether a reasonable number of soldiers could survive a jump from a slow-moving, low-flying plane into a snow bank. According to the story, they did such a test and found that about half survived the jump in good enough condition to fight. (Another version notes that the Russians didn't have enough rifles for everyone anyway, so it didn't matter if some percentage were killed or injured.) Yet another story notes that the Russians dropped soldiers with no parachutes during the Russian invasion of Finland. The Finns, however, had some inkling that the Russians might try this and painted the rocks white in suitable landing areas. | If someone can confirm whether there is any truth to this story, I'd be interested in hearing from them. The story seems to me like a combination of a joke, a myth, and an anti-Russian slur. I just don't see how a commander would make such a decision given other possible options. There certainly must have been somewhere within a couple of hundred miles of St. Petersburg where they could have landed solders and then marched them to where they were needed. Also, the story about the Finns painting the rocks white only makes sense if they knew the Russians had done this in the past. The problem is, the siege of St. Petersburg happened after the invasion of Finland. Were the Russians supposed to be so desperate about invading Finland that they would throw lives away to do it? |
How far can someone fall and still survive? Someone could trip and fall and die. On the other hand, Chisov, Alkemade, and Magee all fell 18,000 feet or more and survived. David Carkeet references a relevant statistic in The Unplanned Freefall. Here is what he says: Much will depend on your attitude. Don't let negative thinking ruin your descent. If you find yourself dwelling morbidly on your discouraging starting point of seven miles up, think of this: Thirty feet is the cutoff for fatality in a fall. That is, most who fall from thirty feet or higher die. Thirty feet! It's nothing! Pity the poor sod who falls from such a "height." What kind of planning time does he have? |
Have any of these people jumped again after surviving one of these accidents? Quite a few of the Unlucky Skydivers have jumped again, including Arch Deal, Dragan Curcic, Glenn Hood, Joan Murray, and Michael Cox. However Arch Deal may be the recordholder in this category. He has jumped thousands of times since his accident. |
What is the Caterpillar Club? The Caterpillar Club was founded in 1922 by the Irvin Air Chute Company. Its name refers to the insect's role in producing the silk used in early parachutes. To become a member one's life had to have been saved by a parachute of Irvin design. A few of the incidents described in Other Amazing Stories relate to members of the Caterpillar Club, including Joe Herman and Ken Wright. Herman's story is interesting because he left his plane without a parachute and it was someone elses' parachute that saved him. Wright's story is interesting because his parachute did not open fully, but the Caterpillar Club determined that it still contributed to his survival and so they approved his membership. See the Recommended Reading page for information on two great books about the Caterpillar Club. |
Jim, are you a skydiver? No, I'm not. I got interested in this through some research I had done on World War II. I ran across a bunch of these stories: Nicholas Alkemades, Joe Jones, I.M. Chisov, and Alan Magee, and so I thought it would be an interesting project to see how many there were. For more information on "The Writing 69th" and other projects I am working on, visit the Green Harbor Publications web site. |
Could a trained cliff diver survive a fall if he/she maximized drag in a spread-eagle until right before impact assuming a perfect dive position? I don't think that cliff divers jump from high enough to get to speeds of much more than 60 miles per hour. Someone falling without a parachute from more than 2,000 feet or so would be falling quite a bit faster than 100 miles per hour, and although varying their position could increase or decrease their speed, I'm afraid it wouldn't do them much good. The folks who have survived falls into water have had streaming parachutes above them, which probably slowed their falls to the 60-mph range. Having a streaming parachute helps in another way because it aligns the body in a position where the feet enter the water first. |
| There are a few well-documented falls into water. See Unlucky Skydivers for Lois Frotten, Klint Freemantle, and Brett Shabey. See also Cliff Judkins under Other Amazing Stories. |
Can you die from free falling? The problem isn't the falling, it's the stopping. Seriously though, people are not harmed by long free falls. If they start from above 30,000 feet or so, they may lose consciousness due to the lack of oxygen at those altitudes, but they usually come to when they get closer to earth. |
| When parachutes were first being developed, people wondered whether someone would survive a long fall, or even be able to remain conscious long enough to activate the parachute. That is why the first parachutes opened automatically. However it soon became clear that a skydiver could fall a great distance and still remain conscious. |
| It seems natural to think that someone might have a heart attack when faced with the prospect of a lengthy free fall without a parachute, but unless someone's heart was already weak, there is no reason to believe that something like that would happen. |
What role does the surface tension of water play? This question requires a little additional explanation: Assuming that the surface tension of water would make it about as hard as falling on solid ground, what would happen if the surface tension of the water one fell into was broken first, perhaps by a breaking wave or an explosion that churned up the water. Would that help? |
| In response: Perhaps there is an expert on the physics of surface tension who can tackle this one from a more scientific perspective. However one thing is clear after looking at enough of these incidents: There aren't a lot of freefallers or wreckage riders who have survived falls into water. The couple of cases where this has happened, the people have had streaming parachutes that slowed their falls to some extent. Others fell into mud or swampy areas where surface tension probably did not play much of a role. |
| The point is this: If falling into water turned out to be a good survival technique (if you didn't have a parachute), then it's likely that a few World War II aviators would have miraculously survived that way. Some may well have had wreckage or waves to break the surface tension, but for one reason or another (perhaps drowning) few of their stories have come our way. |
| A number of folks have written with comments about the compressibility of water in regard to this question. Here is what a correspondent named Matias had to say: "I doubt surface tension matters at all, what *does* matter is a simple fact about water: it's an incompressible fluid. Even plain earth will compress when hit by a falling body, and if you add grass, etc, it's even 'bouncier'. Basically, falling on water at high speed is like falling on concrete, except concrete won't swallow you after breaking your bones and rendering you unconscious." |
Are these miracles? You will see many religious web sites that point to these events and call them miracles. The American Heritage describes a miracle as "an event that appears unexplainable by the laws of nature and so is held to be supernatural in origin or an act of God". By this definition, these stories are miraculous, but only because they appear to be unexplainable. I think if you look at the circumstances and do the math, then it is not too surprising that a very small percentage of people who fall from such great heights survive. I don't see any divine intervention. Some survivors of such incidents started out as atheists or skeptics, and remain so afterward. People say that these folks should thank the Lord each day that they survived, but really, anyone who believes in God should give thanks each day, whether they survived a lengthy free fall or not. |
Are cats able to survive long falls? Cats have survived some surprisingly long falls, mostly as it turns out, from high-rise building windows. In 1987 two doctors from Manhattan, Cheryl Mehlhaff and Wayne Witney, published a landmark study involving 115 cats who fell anywhere from two to thirty-two stories. A significant number (104) survived for more than 24 hours after the fall. If you'd like additional details, see if you can find the Journal of the American Veterinarian Medical Association. If you find it, please share a copy with us! |