Russian Paratroop Deployment Tactics

[yuvuphys]

According to

http://en.wikipedia.org/wiki/Diving#The_effect_of_height_on_the_dive

Falling 100 feet is 50% lethal, falling 200 feet is nearly 100% lethal. As before I noted the lowest velocity you'd get based on minimum stall speeds and heights is equivalent to a 160 foot fall. Thus, the falls will be ~75% lethal, and those who aren't killed probably won't be feeling too good. Also, as noted before, snow isn't all that fluffy and soft after it's been on the ground for over several days.

So, yeah, I'm sure a few people tried it at some point. But there's not change that a unit did such a jump into combat, and did anything effective afterwards.

[jacobs_ladder2]

Originally posted by John D Salt:

Well, clearly, if the 'plane is low and slow enough, the fall is eminently survivable. Let's say 10 feet and 10 knots, that's what's used for helocasting...

What you are describing is a far cry from what would have been possible in WWII or even up until recently. We have come a long way from the original argument to arrive at modern day extreme sports.

What I know is this: I have buddies who jump from a rail bridge every year as some kind of life affirmation thing. They leave their chutes almost hanging open and throw themselves off. At a hundred or so feet, if the chute doesn't open, and open fast, you splat. Most of them have broken something or ended up in the hospital even after the chute opened. Why? Usually because of a change in the wind that made it hard for them to control their landing. If you don't hit the ground moving more or less forward, you end up in bad shape.

Cliff divers regularly jump into water from heights that produce impact speeds of 60 mph...

You know how many street kids go up there in Acapulco and break their knecks doing that? The tourists get to see the few guys who survive their first few jumps. They don't get to see the noobies getting pulled from the bay farther down the coast.

Snow, you know, snow, that white fluffy stuff you see on Xmas cards, is compressible.

I live in Canada, have lived pretty far north, and I have rarely seen the kind of powder being described here except for on a mountain, at high altitudes (often produced by a machine) or in a beer commercial. Snow may look white and soft and cute and cuddly, but if it is wet and has had a few hours to harden you would not want to fall into it.

The fluffier the snow, the more it gets moved around by the wind. Everything ends up looking white, but the depth of the drifts can vary dramatically.

In fact, without prior knowledge of the landing zone and without having the area very well marked, I find it impossible to imagine a pilot ever finding the right spot to jump.

...but to assert that it is all instant death is just silly.

OK, maybe not instant death , but that is a moot point. The end result is so far beyond your control that it doesn't matter. In fact, unless you can reduce all of the variables down to almost zero, which is impossible, you are effectively committing suicide. No matter how good you are at falling out of an airplane, you are still spinning a roulette wheel.

In other words, I agree with you, that a fall is survivable, but so are a lot of things I would not try (i.e. swimming with sharks, getting hit by lightning, playing golf with drunken Canadians, etc.)

Cheers

Paul

p.s. That was a well-constructed post, btw. Interesting reading and some nice links.

[PzTwt]

Originally posted by jacobs_ladder2:

The snow idea was the best one. I am still laughing at the image of dozens of men splashing into snow and stopping WWII era tanks advancing through the same deep powder.

LOL - Nice to know I'm not the only one...

[John D Salt]

Originally posted by jacobs_ladder2:

</font><blockquote>quote:</font><hr />Originally posted by John D Salt:

Well, clearly, if the 'plane is low and slow enough, the fall is eminently survivable. Let's say 10 feet and 10 knots, that's what's used for helocasting...

What you are describing is a far cry from what would have been possible in WWII or even up until recently. We have come a long way from the original argument to arrive at modern day extreme sports.

</font>

[Andreas]

Originally posted by John D Salt:

Did I ever tell you about the ex-SBS man I used to work with, same birthday as me, and his definiiton of a "hard man"?

Someone who could finish his pint while I am still handing out the round to the rest of the lads?

[jacobs_ladder2]

Originally posted by John D Salt:

Tom Wintringham, writing in "New Ways of War", gave a percentage (based on his experience of the Spanish Civil War) of losses from air attack that he would take before considering moving to a new position. The figure he gave was 50%. I can't see anyone thinking that a remotely acceptable guideline these days, and most people would regard a unit attrited to half that extent as combat ineffective. But 50% is what he wrote. There were some hard men about in those days.

Did I ever tell you about the ex-SBS man I used to work with, same birthday as me, and his definiiton of a "hard man"?

All the best,

John.

That's a good one. Hard to believe how some of these people view life, isn't it. My Grandfather was in the war for 4 years, then worked in sewers for 35. He drank four or five times a week and never missed a days work. When he retired he had 3 years worth of sick days he had never used. Some days I find it to be a pain in the ass to mow the lawn. Generation gap I suppose.

Hard men or not, these guys are still subject to the forces of nature. I agree that they are probably rocky enough to try this sort of thing, but also human enough to quickly find how ridiculous it is.

My point about the bridge jumping thing was to say that you need to land in just such a way to avoid injury. It is extremely easy to foul up a landing, even with a parachute and light to moderate winds, and twist an ankle.

What I don't understand is your argument. I am under the impression you are trying to validate something, but I am no longer clear on what that is. No sarcasm intended, but is your point that the Russian airdrop into snow story is simply a possibility that we should accept as unlikely but not reject out of hand? If so, then we are in agreement.

Jumping into water or snow at stall speeds is something I can accept as being "possible". In the case of water I can see it even being an enjoyable experience. However, doing it into snow with any kind of regularity or dependability is something I cannot accept. If it happened and these men survived, it is the kind of thing that should go in the books as freakish (like the stories of people surviving drops from altitude).

I have heard stranger stories. Ever heard the one about the scuba diver they found stuck in a tree after a forest fire?

Cheers

Paul

[76mm]

Whoa! Now we're firmly in urban-myth territory--the story about the scuba diver in the tree is just BS.

After reading the rather interesting back and forth on the topic of Soviet jumps sans parachutes, what is the consensus? To me it sounds like:

1) the Soviets probably--almost certainly--conducted some experiments on deploying airborne infantry without parachutes (maybe using sleds or other protective gear);

2) the Soviets might have done a couple of combat jumps without parachutes, but this seems pretty unlikely; and

3) it seems pretty much inconceivable that combat jumps without chutes were a regular practice.

76mm

[Andreas]

Originally posted by jacobs_ladder2:

I have heard stranger stories. Ever heard the one about the scuba diver they found stuck in a tree after a forest fire?

Cheers

Paul

Lots of people have.

Scuba Doobie Doo!

[John D Salt]

Originally posted by Andreas:

</font><blockquote>quote:</font><hr />Originally posted by John D Salt:

Did I ever tell you about the ex-SBS man I used to work with, same birthday as me, and his definiiton of a "hard man"?

Someone who could finish his pint while I am still handing out the round to the rest of the lads? </font>

[jacobs_ladder2]

Originally posted by 76mm:

Whoa! Now we're firmly in urban-myth territory--the story about the scuba diver in the tree is just BS.

Exactly.

Cheers

Paul

[Dandelion]

Originally posted by jacobs_ladder2:

I live in Canada, have lived pretty far north, and I have rarely seen the kind of powder being described here except for on a mountain, at high altitudes (often produced by a machine) or in a beer commercial. Snow may look white and soft and cute and cuddly, but if it is wet and has had a few hours to harden you would not want to fall into it.

Paul

Snow cannot reach density beyond 0,10. The crystals won't compress any further (but turn into glacier instead, or melt). Snow is normally around 0,01-02, even in thaw. It is at it's hardest in severe dry cold, when hardened surface layers are formed. That's how they build igloos. Such surfaces will not affect a person falling into snow very much in terms of impact (brittle), but it can cut him up severely with sharp ends. Other than that a falling human body can always be softly collected by snow covered ground. Theoretically.

The actual problem with the theory is depth. It needs to be pretty darn deep to softly collect a guy falling from the sky. Simple application of Newton's law I believe. Mass multiplied by speed squared, divided by 2, to have the impact of the guy. Given the impact absorption and rate of breaking the fall of a ground with the mass of snow and - say - 0,05 density, we're at a minimum three meter snow cover right?

Anyway. Never been in a place with a 3m snow cover.

Cheerio

Dandelion

[Pirx]

I have also lived in frozen Canada for a good part of my life. Therefore, although I am not a military history expert, I do have a good lay understanding of snow. I would like to make 2 points about snow:

1. Snow may seem really fluffy when you see it on TV or in the movies, but that doesnt mean it will feel soft when you hit it at >100 miles per hour. By analogy, water feels extremely soft (more so than snow!) when you put your hand in it at <1 mile per hour, but if you were slammed into it at >100 miles per hour then you would be killed.

2. As Dandelion pointed out, snow cover is less than what a lot of people have assumed. Underneath the snow is very hard and pointy stuff, like rocks.

Bottom line is that propelling a fragile human body into snow at >100 miles per hour is going to cause severe injury or death in the vast majority. Likewise for anyone in a crude protective device, notwithstanding what some of the more gullible forum members may have concluded by watching "Indiana Jones and the Temple of Doom" too many times.

[76mm]

Hmmm, maybe I'm one of the "more gullible forum members" cited by Pirx, but I really don't see why it is so hard to believe that under controlled (ie, non-combat) circumstances and at a very small scale, soldiers could survive experimental jumps into snow without parachutes (certainly with a fairly high proportion of broken limbs).

First, these jumps would presumably have occured at a very low altitude--tens, rather than hundreds of feet--from prop planes, even biplanes, with relatively slow prop planes.

Second, these jumps would not necessarily have to occur into open, rather shallow, fields of snow--presumably the pilots (and jumpers) would aim for extensive drifts, where--under certain circumstances--snow could easily be 3 or more meters deep. I suspect that someone who knew what they were doing could pick out such drifts from the air, or (again, under controlled circumstances) the drifts could have been marked or even built up by "pathfinder" type crews.

Given all of the presumptions and favorable circumstances required, this kind of undertaking would seem to have virtually no practicable use, but I don't see why it should be considered impossible on an experimental basis.

76mm

[John D Salt]

Originally posted by Dandelion:

[snips]

It is at it's hardest in severe dry cold, when hardened surface layers are formed. That's how they build igloos. Such surfaces will not affect a person falling into snow very much in terms of impact (brittle), but it can cut him up severely with sharp ends.

I don't follow this. I should have thought that brittle failure would have done a fine job of dissipating energy. Recall that one of the terminal-velocity fall survivors mentioned earlier had his fall broken by glass.

Originally posted by Dandelion:

Other than that a falling human body can always be softly collected by snow covered ground. Theoretically.

The actual problem with the theory is depth. It needs to be pretty darn deep to softly collect a guy falling from the sky. Simple application of Newton's law I believe. Mass multiplied by speed squared, divided by 2, to have the impact of the guy. Given the impact absorption and rate of breaking the fall of a ground with the mass of snow and - say - 0,05 density, we're at a minimum three meter snow cover right?

Please show your working. How do you get from the assumed density to the figure of 3m?

FM31-70, otherwise known as CATP 9-1, the Basic Arctic Manual of October 1951, says on page 226:

"A rifle bullet fired from 100 yards loses its killing power in unpacked snow, after penetrating 3 to 6 feet depending on the type of snow".

I don't understand why snow capable of taking the killing force out of a rifle bullet's flight shouldn't be able to do a comparably good job of taking the sting out of a person's fall in the same thickness.

Originally posted by Dandelion:

Anyway. Never been in a place with a 3m snow cover.

My Dad told me he'd seen snowdrifts higher than a double-decker bus in the Winter of '47, and that was in England.

All the best,

John.

[ June 25, 2005, 03:00 PM: Message edited by: John D Salt ]

[John D Salt]

Originally posted by Pirx:

I have also lived in frozen Canada for a good part of my life. Therefore, although I am not a military history expert, I do have a good lay understanding of snow.

Believe it or not, there are actually parts of the world outside Canada that have snow. Some non-Canadians do have experience of snow other than what they have seen on TV and Xmas cards.

Originally posted by Pirx:

1. Snow may seem really fluffy when you see it on TV or in the movies, but that doesnt mean it will feel soft when you hit it at >100 miles per hour. By analogy, water feels extremely soft (more so than snow!) when you put your hand in it at <1 mile per hour, but if you were slammed into it at >100 miles per hour then you would be killed.

The fact remains, though, that water is incompressible, and snow is compressible. Which do you think would be better to fall into?

Originally posted by Pirx:

Bottom line is that propelling a fragile human body into snow at >100 miles per hour is going to cause severe injury or death in the vast majority.

Where did you get the impact speed of >100 mph from? That's dam' near terminal velocity.

Originally posted by Pirx:

Likewise for anyone in a crude protective device, notwithstanding what some of the more gullible forum members may have concluded by watching "Indiana Jones and the Temple of Doom" too many times.

I thought "gullible" meant accepting things without evidence.

If someone can come up with some convincing figures for the retardation effect of snow on a falling body, and these show that it does a lousy job, then I might alter my current opinion that such experiments may indeed have been carried out by the Red Army.

If people are going to keep offering their own personal opinion as if it were unchallengeable truth, then I am afraid I am going to become very bored.

All the best,

John.

[Dandelion]

Originally posted by John D Salt:

I don't follow this. I should have thought that brittle failure would have done a fine job of dissipating energy. Recall that one of the terminal-velocity fall survivors mentioned earlier had his fall broken by glass.

I quite agree. My comment was referring to the risk of fatal impact damage. The rate at which the kinetic energy leaves the body and transfers into the snow could reach fatal speed if the surface is too hard, killing the person. My comment merely wanted to clarify that the mere existence of a crisp surface did not in itself entail such a risk.

We have people from Australia, Florida, Canada and such snowless places here so I just wanted to be perfectly clear on that point

I don't understand why snow capable of taking the killing force out of a rifle bullet's flight shouldn't be able to do a comparably good job of taking the sting out of a person's fall in the same thickness.

Well it is almost the same thickness

In the Bundeswehr, 2000mm packed snow was considered enough protection against standard enemy assault rifle calibres. Considered roughly equivalent to about 1cm steel, in that respect.

Nothing advanced about the maths, nor an extremely serious attempt at it. I simply halved the falling speed with the impact absorption, assuming no maximum depth. In real life of course as you know, snow will increase resistance with every centimeter because a) snow below surface is increasingly packed and the ground presents a terminal limit for compression. But that seemed too arduous to calculate. Regrettably, I omitted the spread of weight and calculated a human the shape of an average spear, landing on his head.

But nonetheless. I believe we need some kind of appreciation of what speeds energy can safely leave a human body, to find a minimum snow cover for high altitude drop survival. If a bullet lose killing power (stops?) after travelling through 2 meters of packed snow, we might have the problem of a human body being destroyed if it experienced the same loss of speed at the same rate?

Another, more practical problem would be angle of the body. Wouldn't want to fall head first, or with any limbs in the way, so to speak. One would need to know the impact absorption of human bone - at what energy does a spine snap?

A thought that occured to me also, as I was walking last night, was the size of the hole in the snow. Given powdersnow, it might prove a serious problem getting up from a 2 meter hole (especially if it collapsed and buried you).

My Dad told me he'd seen snowdrifts higher than a double-decker bus in the Winter of '47, and that was in England.

My grandfather and his brothers had similar experiences in the Soviet Union five years earlier. Myself I haven't seen these depths, except in alpine terrain of course but even there only when gathered in depressions. But unpacked snow for 3 meters will certainly cushion the fall - even if spearshaped, landing on ones head

Sincerely

Dandelion

[Pirx]

Where did you get the impact speed of >100 mph from? That's dam' near terminal velocity.

Given that the drop would occur at an extremely low altitude, the speed of the aircraft relative to the ground would most be the major contributor to the impact speed of the falling body, not acceleration due to gravity. I guessed that a plane would be going around that speed while making a drop, although possibly it could be done at lower speeds.

One wonders how risky these alleged non-parachute drops would be to the pilots, given that they would have to fly as low as possible at as low a speed as possible. It might be easier just to land the plane on skis, discharge the troops, and take off again.

I don't understand why snow capable of taking the killing force out of a rifle bullet's flight shouldn't be able to do a comparably good job of taking the sting out of a person's fall in the same thickness.

I ABSOLUTELY think that snow would cause a very rapid deceleration of a human body traveling at high velocity. That's why it would cause injury! Crash injury is related to the rapid deceleration, not how hard or soft the impact material is. (Although hard substances would tend to cause more rapid deceleration because they tend to be less compressible or displacable).

I dont have any formulas or calculations for you, and my search of the internet didnt reveal any experiments where humans or animals were shot at high velocity toward snowbanks. Possibly such experiments have been deemed unethical.

Have any of the non-parachute enthusiasts found any official documentation by the Soviet army on their use of non-parachute drops, either experimental or under battle conditions?

[flamingknives]

25g is a good figure for human resiliance to acceleration. Up to this acceleration the chance of injury is low. Survival is likely up to 60 g. This is assuming a reasonable level of support.

A body travelling at 50mph (22.2m/s), decelerated at 25g will come to rest in the space of 1m. It will require a decellerative force of 19620N distributed over the body surface. (2 metric tons)

[Dandelion]

Ah, I had a faint hope some engineer would come along, attracted by the seemingly impossible maths in this equation

Stay with us some more please Flame, I can't make this out myself.

It is known that in terms of pure weight, dry snow weighs about 0,1Kg per litre (0,01 density m.). Dry snow, we also know, has about 40% porosity. The latter figure is assuming unconfined compression space. I feel we can leave it at that, and disregard the increasing density/decreasing porosity with depth.

Given that - how many N can snow provide as reaction to the action of a falling body? And as a consequence, at what depth would said body reach absolute stop?

Sincerely

Dandelion

[76mm]

Have any of the non-parachute enthusiasts found any official documentation by the Soviet army on their use of non-parachute drops, either experimental or under battle conditions?

In 1987 when travelling in Russia I bought an official Soviet history of their airborne forces (in Russian). This volume described these experiments (which struck me as being so crazy that I've never forgotten). I've moved many many times since 1987 and doubt that I still have this book but I will rummage through the basement and see if I can find it...

76mm

[yuvuphys]

Well, for snow of infinite depth (all snow pushed downward via impact giving linearly increasing density as the fall progresses) with initial density of 1g/cm^3, and a 200lb man with cross-sectional area of .38 m^2, hitting the snow at 60mph I get you'd have to have 13.8m of snow. [L=ln(v)/(2*alpha), alpha=crosssectional area man*density snow/mass of man]

So I'd conclude compressibility and depth of snow, as well as the process of melting and refreezing into ice, is an important factor, as would be the ground. Otherwise, you have one big mother of a hole to dig yourself out of...in short, what's most likely to happen is you'll cut through the soft snow rather quickly, it won't slow you much, then you'll hit something hard at a slightly reduced speed, which will stop you quickly. That's where the injury will occur.

Obviosuly experiments could still have been done; you can do experiments with strapping a man into a 380mm rocket to deliver him miles behind enemy lines if you wanted to; they just wouldn't be very successful. The question is whether any experiments that might have been done were successful. In the sense that a decent number of the participants survived (or were prisoners from the a gulag), probably so...the fact that the method never saw actual use indicates that the method failed in some manner, most likely from injury to the test subject which removed his combat capacity.

[Dandelion]

Hm. You're right. We can't ignore the dynamics of the snow.

Freshly fallen, dry snow has the lowest density (the 1kg per cubic metre as above). Mean density of a snowlayer in mid winter is actually some 2-3 kg per cubic metre, depending on the freeze/refreeze cycle. At extreme pressure, snow can reach 5kg per cubic decimetre (I think the theoretical maximum is 5.5kg, found only in the polar regions). There's the range of impact resistance of snow.

As for the placing a ground level as an absolute stop - the average snow depth for most of Canada (they started this insane debate, so lets remain there) is between 30 and 99 cm. Depths do not get deeper the farther North one goes, it is New Foundland and the Eastern coastal region who have the deepest snow covers. A tiny area close to Alaska does have an average of 300cm or more. (For comparison, mean snow cover in Siberia is highly similar, and most ground is really only covered by some 40cm - so Canada is a very snowy country).

Lets say depth of snow cover is 100cm. Lets say the top layer of snow has a density of 1kg/m^3 and the lowest layer already has the 5kg/m^3, and thus will not compress. Five equally deep (20cm) layers of snow. What speed would the falling human have when actually reaching the ground?

Er, right, I'm more of an ideas person. We wouldn't have an engineer or grad stud actually willing to undertake this excercise, around here, would we?

A hopeful

Dandelion

[jacobs_ladder2]

Originally posted by Dandelion:

As for the placing a ground level as an absolute stop - the average snow depth for most of Canada (they started this insane debate, so lets remain there)

LOL...true enough, but remember, how often is it that a Canadian gets to offer cultural expertise on anything relative to the world at large?

is between 30 and 99 cm. Depths do not get deeper the farther North one goes, it is New Foundland and the Eastern coastal region who have the deepest snow covers.

Eastern Coastal Regions, or simply the East Coast, Canada's Ocean Playground for the tourists, is a pretty snowy place. Nice in the summer though.

I just wanted to say that 90cm, although it may not seem like a lot, is a crapload of snow. That kind of depth pretty much shuts things down until the roads can be cleared over a period of days to a week or more. Lightly-armed troops in skis might be able to move around, but any heavier equipment would be a real drag.

90cm as an average would produce some pretty deep drifts, btw. 300cm is incomprehensible to me. That kind of snow would bury entire towns.

Lets say depth of snow cover is 100cm. Lets say the top layer of snow has a density of 1kg/m^3 and the lowest layer already has the 5kg/m^3, and thus will not compress. Five equally deep (20cm) layers of snow. What speed would the falling human have when actually reaching the ground?

Er, right, I'm more of an ideas person...

Me too, but I'll offer something. Two years ago we had a big snowstorm. My nephews spent the day throwing themselves off our roof (about 12 feet) into drifts a little higher than themselves (say four or five feet). For them it was a blast, but what I now know from experience is that adults require much more snow to break their fall. Even from a modest height, that much snow is still not enough to stop you from getting to the ground. My brother, who is shorter than me, buried himself up to his neck and needed to be helped out. I went straight through.

And, as a side note, the snow would need to be pretty powdery for your impact to create an explosion of any kind. Most often, that kind of powder comes from a machine. Snow, at least the kind we get here, is not powdery at all. In fact, I can't remember ever seeing any depth of snow that I would describe as powdery.

Cheers

Paul

[flamingknives]

Originally posted by yuvuphys:

Well, for snow of infinite depth (all snow pushed downward via impact giving linearly increasing density as the fall progresses) with initial density of 1g/cm^3, and a 200lb man with cross-sectional area of .38 m^2, hitting the snow at 60mph I get you'd have to have 13.8m of snow. [L=ln(v)/(2*alpha), alpha=crosssectional area man*density snow/mass of man]

I'm going to take issue with this.

1g/cm^3 = 1000kg/m^3 = water.

Snow is much less dense than water, therefore Dandelion's 0.1g/cm^3 to 0.5g/cm^3 is more likely. Switching units is a good way to get very confused very quickly. Far better to stick with what you're familiar with and convert easily.

Using consistant units and the same values, bar the density, I get 3.93m of snow from that equation.

Water would take 0.4m to bring the body to rest and densely packed snow would take 0.79m. I'm not familiar with that equation though, so it might be wrong. That said, the distance for water seems feasible.

[jacobs_ladder2]

But I think the density of snow can vary quite a bit depending on atmospheric conditions (i.e. humidity, temperature, etc.). Snow can be quite hard, usually nearer the surface, up to as hard as ice. On the other hand, if the air is dry and cold, snow can be fluffy (you can blow it off your hand).

Cheers

Paul