The video I saw showed the ballistic testing was completed first, IIRC. Of course, I might be mistaken in this regard as it has been a while since I saw the video.
The environmental test was from -60F to 130F to simulate the conditions of a long-route C-130 or other non-heated cargo plane flying at cruising altitude and then landing in Baghdad to sit in the sun for a bit before getting unloaded. Pretty reasonable testing IMO as this happens all the time in the military.
I feel the lack of the sport chutes also reflects the differing requirements of a basic Airborne drop which is simply getting your personnel down fast from a rapid mode of transit that happens to fly. You don't need some crazy stunt chutes to get your boots on the ground with the gear they require to light fires and blow stuff up. Spec Ops, on the other hand, often have additional Airborne schooling than the line Airborne troops and often have to land in more difficult wind conditions and in much smaller drop zones so they will be much more likely to need and use the modified versions of the sport chutes.
Full Version: How safe/controled are parachutes?
QUOTE (Kerenshara @ Jun 15 2009, 01:02 AM) 
Don't be dense. *thbbbbbt*
I assume the equivalent of at LEAST the 6.5 Grendel or 6.8 SPC cartridge, given the way they seem to be portrayed. And take a look at what even a hollow-point 9mm Parabellum does to any single layer of Kevlar. That's with the fibers not being pre-stressed to any great deal. Put them under direct tension and then hit them with the same force. THAT was my concern. A much higher caliber projectile with a lot more mass hitting pre-tensioned fiber. That is why I wondered aloud about things like a tendency to re-seal as opposed to blowing open. I just don't have enough information on the characteristics of the material underr those conditions. And I DIDN'T actually make a "ruling". Besides, there is the question of ABSOLUTE weight of simple nylon vs. Synthetic Spidersteel. Plus the added weight of the camo polymers, and how THEY would affect the strength of the resultant material under fire.
I assume the equivalent of at LEAST the 6.5 Grendel or 6.8 SPC cartridge, given the way they seem to be portrayed. And take a look at what even a hollow-point 9mm Parabellum does to any single layer of Kevlar. That's with the fibers not being pre-stressed to any great deal. Put them under direct tension and then hit them with the same force. THAT was my concern. A much higher caliber projectile with a lot more mass hitting pre-tensioned fiber. That is why I wondered aloud about things like a tendency to re-seal as opposed to blowing open. I just don't have enough information on the characteristics of the material underr those conditions. And I DIDN'T actually make a "ruling". Besides, there is the question of ABSOLUTE weight of simple nylon vs. Synthetic Spidersteel. Plus the added weight of the camo polymers, and how THEY would affect the strength of the resultant material under fire.
I am not talking about Kevlar...instead I am thinking of spidersteel and extrapolating for 60 years down the road. As far as the tension, and I have no math to back this up, but I would guess that a canopy of spidersteel would in fact do a better job of remaining in tact.
Your points about camo polymers and the weight issues are good ones, and I have no idea.
In regards to calibers of projectiles and how a fabric reacts to an impact without a backing and how ballistic clay deforms and retains the wound cavity really are apples and oranges. The reason that I bring this point up is that I have a feeling that the child's fist analogy is a merging of those. My line of thought is that if the fabric fails the hole is going to be much smaller than say an impact on a person.
You seem to have taken my last post as something of an attack on you. It really wasn't, when I put a smiley in a post it means that I am exceedingly light hearted about the matter. The ruling bit is simply my way of saying is that while we may disagree I don't consider this a matter of hard science and fact.
(still whimsically inclined)
QUOTE (psychophipps @ Jun 15 2009, 08:36 AM)
The video I saw showed the ballistic testing was completed first, IIRC. Of course, I might be mistaken in this regard as it has been a while since I saw the video.
The environmental test was from -60F to 130F to simulate the conditions of a long-route C-130 or other non-heated cargo plane flying at cruising altitude and then landing in Baghdad to sit in the sun for a bit before getting unloaded. Pretty reasonable testing IMO as this happens all the time in the military.
I feel the lack of the sport chutes also reflects the differing requirements of a basic Airborne drop which is simply getting your personnel down fast from a rapid mode of transit that happens to fly. You don't need some crazy stunt chutes to get your boots on the ground with the gear they require to light fires and blow stuff up. Spec Ops, on the other hand, often have additional Airborne schooling than the line Airborne troops and often have to land in more difficult wind conditions and in much smaller drop zones so they will be much more likely to need and use the modified versions of the sport chutes.
The environmental test was from -60F to 130F to simulate the conditions of a long-route C-130 or other non-heated cargo plane flying at cruising altitude and then landing in Baghdad to sit in the sun for a bit before getting unloaded. Pretty reasonable testing IMO as this happens all the time in the military.
I feel the lack of the sport chutes also reflects the differing requirements of a basic Airborne drop which is simply getting your personnel down fast from a rapid mode of transit that happens to fly. You don't need some crazy stunt chutes to get your boots on the ground with the gear they require to light fires and blow stuff up. Spec Ops, on the other hand, often have additional Airborne schooling than the line Airborne troops and often have to land in more difficult wind conditions and in much smaller drop zones so they will be much more likely to need and use the modified versions of the sport chutes.
Considering the backing material is susceptible to heat degradation it seems completely reasonable to test for that. While I have tried to follow the information released concerning Dragon Skin, I can only base the information on what has been released that I have seen. It seems that I have in fact missed some information that would be crucial to making an informed decision. In a perfect world I would be allowed to setup a Myth Buster lab and have the chance first hand to test such things (dream job).
Now, with all that said. I have dealt with government engineers and contracts (for non-military projects). The amount of corruption is directly proportional to the amount of money involved. This may not be the case with Dragon Skin (as you have raised a number of valid points) but...there is a Modus Operandi in corruption and there are some disconcerting trends with what I have seen.
You certainly have reignited my interest in the subject though.
QUOTE (Dumori @ Jun 14 2009, 10:08 PM)
Surely then a soultion to this problem will be found quickly, also from my Reading it only failed at 77c quite an extrem in most places.
I'm told daytime temps in Iraq reach 55C in the summer. Temperature in a conex in the sun gets a lot higher.
Very true for desert combat the armor needs improvement however for most areas it is very good. Hopefully a new backing metiral can be found fixing this flaw.
QUOTE (Bob Lord of Evil @ Jun 15 2009, 07:14 AM)
I am not talking about Kevlar...instead I am thinking of spidersteel and extrapolating for 60 years down the road. As far as the tension, and I have no math to back this up, but I would guess that a canopy of spidersteel would in fact do a better job of remaining in tact.
Your points about camo polymers and the weight issues are good ones, and I have no idea.
In regards to calibers of projectiles and how a fabric reacts to an impact without a backing and how ballistic clay deforms and retains the wound cavity really are apples and oranges. The reason that I bring this point up is that I have a feeling that the child's fist analogy is a merging of those. My line of thought is that if the fabric fails the hole is going to be much smaller than say an impact on a person.
You seem to have taken my last post as something of an attack on you. It really wasn't, when I put a smiley in a post it means that I am exceedingly light hearted about the matter. The ruling bit is simply my way of saying is that while we may disagree I don't consider this a matter of hard science and fact.
(still whimsically inclined)
Your points about camo polymers and the weight issues are good ones, and I have no idea.
In regards to calibers of projectiles and how a fabric reacts to an impact without a backing and how ballistic clay deforms and retains the wound cavity really are apples and oranges. The reason that I bring this point up is that I have a feeling that the child's fist analogy is a merging of those. My line of thought is that if the fabric fails the hole is going to be much smaller than say an impact on a person.
You seem to have taken my last post as something of an attack on you. It really wasn't, when I put a smiley in a post it means that I am exceedingly light hearted about the matter. The ruling bit is simply my way of saying is that while we may disagree I don't consider this a matter of hard science and fact.
(still whimsically inclined)Personal attack? *laughs* I figures the raspberry would have clued you in that I was ammused if only slightly vexed. Worry not, Bob.
The reason I mentioned Kevlar is because it's already a mature technology AND it's already demonstrate a tensile strength greater than steel. Many people think of it being bulletproof without realizing that trait is derived from the rediculous tensile strength of the material. Watched a test once where they actually braded a Kevlar rope, and it was literally mind boggling watching how much they managed to load on before it broke (quite spectacularly).
The bit about "self sealing" was more my wondering if (since I don't know either) the material would simply yeild across the limited surface area of the bullet and remain a tight weave, or if the energy WOULD transfer far enough out in a radius to help unravel the weave and allow pressure diferentials to force the hole open. And a child's fist is a LOT smaller than the exit wounds the Grendel or SPC cartridges are supposed to be yeilding on human tissue. *grin*
It's a good discussion, and you raise good ideas/issues, which I try to analyze and either accept, modify or reject based on supporting evidence.
So there. *thbbbbbt*
QUOTE (Dumori @ Jun 15 2009, 01:09 PM)
Very true for desert combat the armor needs improvement however for most areas it is very good. Hopefully a new backing metiral can be found fixing this flaw.
So being heavier, bulkier, and not stopping the round it's supposed to be rated for counts as "very good" to you? I have immediate access to a bunch of "very good" cars that I would love to sell you for $3,000-5,000, my friend...
QUOTE (Snow_Fox @ Jun 13 2009, 11:12 AM)
They reported on the news that Bush the elder celebrated his 85th birthday by skydiving, again, and he already is planning to do it again when he's 90. It was a tandem jump when he is strapped to a guide but it still makes me ownder.
In the 1940's the parachutes looked much bigger and still did damage if you landed badly. In the 1990's I had a friend in the army who said in parachute training a man he knew broke both legs on a jump.
Today, not only do you see tandem jumps it seems like stunt diverts can actually land on their feet, runnig to break mommentum and not have to do the whole tuck and roll thing, so the question is, has the tech level really improved that much?
In the 1940's the parachutes looked much bigger and still did damage if you landed badly. In the 1990's I had a friend in the army who said in parachute training a man he knew broke both legs on a jump.
Today, not only do you see tandem jumps it seems like stunt diverts can actually land on their feet, runnig to break mommentum and not have to do the whole tuck and roll thing, so the question is, has the tech level really improved that much?
Hmm.
There's very different technologies and ideas at work in military parachutes and skydiving parawings.
I have limited experience (5 jumps) with parawings. While I was sitting through my 8 hours of instruction before anyone kicked me out of a perfectly good airplane, and after having seen a group of skydivers swoop, flip, and soar to perfect landings, I asked the instructor (he of 3000 jumps), "So why doesn't the military use square, very steerable parachutes?"
And he said, "Because the Army doesn't want several hundred adrenalin-pumped, weapon-laden teenagers and 20-somethings trying to steer to dramatic, bullet-dodging landings when they're kicked out of airplanes at 500ft." Skydivers kill themselves under perfectly deployed parawings when they flip or crash into the ground at the last instant. In a crowded military sky? No, you want a chute that keeps each of hundreds of troops on a predictable ballistic arc.
Fully trained skydivers usually jump at ~10,000 feet for 2 minutes of freefall, followed by a couple minutes under canopy. Their Rogallo-wing parachutes (parawings) are great for individuals and small groups of people steering into clearly lit, open fields. The only time my novice ass got dumped on the ground in a rough landing was my very first jump, when I didn't know how to spill air from my parawing after it hit the ground. A breeze filled the chute, yanked me over, and dragged me a bit. My next four jumps I didn't take more than 2 or 3 steps on landing - as you made your final approach, you flared, dropped lightly to the ground, turned and yanked on one riser to deflate the parachute, and were done.
The parawing is very much a glider - as you fall, you trade altitude for horizontal speed until you can pick up some serious ground speed. Skilled (and/or dumb) skydivers use this for high speed, daredevil approaches to thrill spectators. Novices like me use the speed to spiral around the landing field toward the designated landing point and, at the last minute, yank on both risers (normally used for steering), which is effectively like deploying the flaps on an airplane. Your lift and drag both spike, so your fast approach turns into an upward curve, the parawing stalls, and you slowly drop to the ground on one toe. In precision landing skydiving contests, victors are determined by matters of centimeters - there's no running or stumbling, just a neat flare and drop at the end.
Large airborne military units aren't interested in spiralling approaches, steering, flares, or even full loops (which small, highly loaded parawings can manage). They want to shove several hundred troops out to the ground, at a designated location, get them down quickly, and do so with minimal broken legs. My father, who served in the 101st Airborne, managed to suffer proportionally more misjumps in 30 jumps than any civilian skydiver I met - he dropped atop another parachute in midair and had to scootch off of it before his chute and the other guy's collapsed, and landed in trees and atop a barn. Throw in highly steerable parawings and you have a recipe for disaster in those crowded military drops.
Good stuff above.
I'll add that the high-speed/low-drag types are trained to jump fully loaded with parawings and air masks from 30-35,000 ft so they can land as far as 30 miles in perfect conditions from their release point for insertion. The black bag types also train often to jump from unmodified commercial aircraft so they can add another layer of protection to their insertion method.
I'll add that the high-speed/low-drag types are trained to jump fully loaded with parawings and air masks from 30-35,000 ft so they can land as far as 30 miles in perfect conditions from their release point for insertion. The black bag types also train often to jump from unmodified commercial aircraft so they can add another layer of protection to their insertion method.
QUOTE
And he said, "Because the Army doesn't want several hundred adrenalin-pumped, weapon-laden teenagers and 20-somethings trying to steer to dramatic, bullet-dodging landings when they're kicked out of airplanes at 500ft."
Pfft, maybe the real Army doesn't, but I can see that sort of shit goin' over hugely well in Desert Wars sim-broadcasts and tridshows.
QUOTE (Kerenshara @ Jun 15 2009, 09:15 PM)
Personal attack? *laughs* I figures the raspberry would have clued you in that I was ammused if only slightly vexed. Worry not, Bob.
The reason I mentioned Kevlar is because it's already a mature technology AND it's already demonstrate a tensile strength greater than steel. Many people think of it being bulletproof without realizing that trait is derived from the rediculous tensile strength of the material. Watched a test once where they actually braded a Kevlar rope, and it was literally mind boggling watching how much they managed to load on before it broke (quite spectacularly).
The bit about "self sealing" was more my wondering if (since I don't know either) the material would simply yeild across the limited surface area of the bullet and remain a tight weave, or if the energy WOULD transfer far enough out in a radius to help unravel the weave and allow pressure diferentials to force the hole open. And a child's fist is a LOT smaller than the exit wounds the Grendel or SPC cartridges are supposed to be yeilding on human tissue. *grin*
It's a good discussion, and you raise good ideas/issues, which I try to analyze and either accept, modify or reject based on supporting evidence.
So there. *thbbbbbt*
The reason I mentioned Kevlar is because it's already a mature technology AND it's already demonstrate a tensile strength greater than steel. Many people think of it being bulletproof without realizing that trait is derived from the rediculous tensile strength of the material. Watched a test once where they actually braded a Kevlar rope, and it was literally mind boggling watching how much they managed to load on before it broke (quite spectacularly).
The bit about "self sealing" was more my wondering if (since I don't know either) the material would simply yeild across the limited surface area of the bullet and remain a tight weave, or if the energy WOULD transfer far enough out in a radius to help unravel the weave and allow pressure diferentials to force the hole open. And a child's fist is a LOT smaller than the exit wounds the Grendel or SPC cartridges are supposed to be yeilding on human tissue. *grin*
It's a good discussion, and you raise good ideas/issues, which I try to analyze and either accept, modify or reject based on supporting evidence.
So there. *thbbbbbt*
LOL! Coolio good to know!
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.