| Pages:
1
..
37
38
39
40
41
..
68 |
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
floating liner
Here I want to do one more thought. Only one liner functioned flawlessly, perfect. And when it shot through the steel of 10mm. It was the only liner,
which had a floating liner. Thus, as in the diagram. Other liners have been associated with the edge too hard, tight, firmly. After some consideration
I come to the conclusion that the imposition of free disk space is a key structure, point. If the packaging paper, the detail is not important. But
if the packaging is very hard (metal and more), it is important floating liner. It's just my opinion for discussion, it's not 100% confirmed. This
opinion is based only 4 attempts... ...LL
[Edited on 12-1-2015 by Laboratory of Liptakov]
|
|
|
Fulmen
International Hazard
Posts: 1725
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
Idunno... To me the hole looks more like something you'd expect from a SC with less than ideal focus, the dent more like you'd expect from a blunt
projectile. And while it's hard to tell from the pics, the hole seems to be copper coated while the dent isn't. This leads me to believe that you
actually made a SC/EFP combination, the SC being the Cu-tube.
On the other hand, getting that kind of performance from an accidental SC with low VOD explosives seems incredible, and how could this happen without
the jet and penetrator affecting each other? Maybe I'm over-thinking this?
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
pressing
This is a misunderstanding. The scheme is modified, changed. After the molding process should liner little swim, do not touch the pipe......LL
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by Laboratory of Liptakov  | Using polystyrene container is very easy. Production takes 20 minutes. The entire device buries itself in the sand. EFP warhead can be very precisely
adjusted. At the right angle 90x90 deg. Easy, cheap, fast. Safe. For the brave hero (for video) Needless to bury......LL
|
Nice results again LL. You know, I wouldn't say that I was a hero even though I am a little braver than many. I am not a kid anymore, but I still
really do get a lot of pleasure out of a good detonation. As long as the risks aren't ridiculous I don't think there is anything wrong with that.
You're making good progress with your tests, keep it up! 
I have also been trying to decide how well the EFP liner should be anchored, or if anchoring is needed at all really.
Here are a couple mini commercially produced shaped charges that are kind of interesting I think.
Attachment: Mini EBW Inititated Shaped Charge.pdf (29kB)
This file has been downloaded 565 times
Attachment: Mini EBW Inititated EFP.pdf (29kB)
This file has been downloaded 534 times
[Edited on 12-1-2015 by Hennig Brand]
"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
edge
Well, Henning, In the scheme of these PDF attachments can be seen clearly saving liner. The liner is completely on edge. A wrap around is thick. This
confirms the importance of this detail. Especially for EFP......LL
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
I had the same thoughts myself, but at the same time I wasn't 100% sure if these diagrams could be taken as exact representations of the actual
devices. At any rate they do provide a lot of useful information. I think you are right.
"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
confirmed
The assumption idea marginal edge was confirmed. The backing plate is not important. Mechanical or active. That is unimportant. It is important to: 1)
accurate initiation axis. 2) A uniform density of energetic material. 3) The exact and precise liner on the edge. Constructions used for overcoming
the steel is 12 mm on the diagram. Dispersion of the slug is minimal. A force is huge. Attention: on the other side of the steel plate was damaged in
the previous shot. Therefore, it is not a relevant result. But even so, Mythbusters are satisfied.....LL
|
|
|
markx
National Hazard
Posts: 646
Registered: 7-8-2003
Location: Northern kingdom
Member Is Offline
Mood: Very Jolly
|
|
Impressive performance LL! As we see, simplified designs tend to deliver reliable results and it is easier to pinpoint relevant details and causes for
effects...either in a positive or negative direction. I always encourage myself not to overengineer things, even though it is tempting to try a
complicated solution sometimes 
Exact science is a figment of imagination.......
|
|
|
Fulmen
International Hazard
Posts: 1725
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
Impressive indeed. And I agree with you that accurate assembly can make or break the performance. As for the backing I suspect this becomes more
critical as the charge gets smaller. A charge height of 1 caliber seems to provide excellent performance without it, question is what happens if it's
reduced to say 1/3?
When it comes to choice of material for backing I would assume that mass is more important than strength. The hoop stress for a thin walled cylinder
is equal to p*r/t, and with detonation pressures in the 30GPa-range hoop stresses could conceivably be up to 1000 times the yield strength of mild
steel.
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
Catching...
Thank you all for your support. Another attempt will be caught slug projectile. We all know that Slug is a very fast and powerful. As a Kalashnikov,
maybe even stronger. Any suggestions? Definitely will be used 4-5 x bag filled 70x70cm. (50x50) Question: What do fill those bags? Condition 1: Slug
must remain whole. Condition 2: Must be caught......LL
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
I have searched around a bit on the net. This author seemed to have it figured out pretty well.
Attachment: High Speed Bullet Recovery for Analysis.pdf (421kB)
This file has been downloaded 605 times
"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
|
|
|
Dornier 335A
Hazard to Others
Posts: 231
Registered: 10-5-2013
Location: Northern Europe
Member Is Offline
Mood: No Mood
|
|
Phone books or a tall stack of newspapers could probably be used as a first soft filler. Mythbusters used something like 10 phone books to catch a .30
bullet I believe, but I can't remember what shape the bullet was in afterwards. Maybe wood could be used as a last stop for the slug.
I remember reading about how aerogel was used to catch the hypersonic projectiles from light gas guns without damaging them. Considering how most
materials say splat at 7-8 km/s, this is a pretty impressive achievement. But I doubt aerogel would be useful at this scale unless you have
several cubic metres.
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
slug
Slug caught. But only half. Exactly 55%. Liner weight of 3.40g and slug 1.87g. Tried, but it is challenging attempt. Will not be repeated......LL
|
|
|
Bert
Super Administrator
Posts: 2821
Registered: 12-3-2004
Member Is Offline
Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
|
|
I still like water-
Or snow. Soft, fluffy snow is a cheap stand in for the "aerojell" used in the gas gun projectile captures.
When I was a kid, I took a rifle to a very wide frozen lake with fresh snow about a foot deep. Set up a paper target, fired 50 rounds or so on a
nearly horizontal trajectory about a meter above snow level- The projectiles intersected snow surface perhaps 200 m past target as they dropped.
When I walked out on the lake, the bullet path in snow made it easy to get a handful of nearly perfectly preserved fired bullets with nice, clear
rifling marks. These were soft Lead .22 LR bullets, Copper carrots at 10X rimfire cartridge velocity will behave differently, I'm sure!
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
snow
Snow is a good idea. The density of snow can be controlled, modified. First meter light, the second meter medium density, mouthing shovel. 3rd meter
pedaling shoes. Another obstacle water bag. Or very wet snow + water. But there is one problem. Nowhere is snow. If so, very little. OK, I wait for
the snow ......LL
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
I have tons of snow and you can have as much as you like. You have to transport it yourself though.
"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
Henning, you have a lot of snow? Nothing you wait! Hurry up and catch fire! ......LL
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
I hope that means you want me to do a test and not that you are fed up with me and would like for me to spontaneously combust.
I just remembered something from 25-30 years ago. My next door neighbor used to reload and shoot a lot. I remember a couple of times in the spring,
when the large snow banks were melting, finding handgun bullets in the snow in his yard that looked like they had never been fired from a gun. These
were not high velocity rifle bullets, but they were various large caliber handgun bullets cast from wheel weight lead. I remember as a kid marveling
at the perfect condition of the bullets. I remember discussing it with him and he had in fact shot many rounds into the snow banks.
"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
|
|
|
Fulmen
International Hazard
Posts: 1725
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
I agree, snow would be the perfect medium. But water should work as well, even though the velocity is quite extreme a solid copper projectile is
pretty sturdy compared to a regular jacketed rifle bullet.
Also, good job catching the slug Liptakov. I assume it wasn't fired at any solid target? I find the low mass a bit odd, one should think that even a
modestly well shaped liner should produce a single solid projectile.
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
2 top EFP
Snow still not. Here are other (2top) laboratory results. Liner has other outdoor establishment. This change of mind. On the contrary, it is easier to
manufacture. Important dimensions are indicated. Freedom edges of the liner is maintained. This is important ... LL ... university of תל אביב
|
|
|
Fulmen
International Hazard
Posts: 1725
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
Damn impressive work, Liptakov. Seems like you have cracked the code on EFPs, I'd love to see you do it again with a 2m standoff.
|
|
|
Laboratory of Liptakov
International Hazard
Posts: 1405
Registered: 2-9-2014
Location: Technion Haifa
Member Is Offline
Mood: old jew
|
|
EFP m16
Effective range for liner 22mm is 22 meters. For professional device. I suggest shooting at 16 meters, about 75% of maximum distance. Target doors.
Metal or wood. Laser pointer sight. Target will not be thick iron. It is necessary to determine the variance (divergence) to 16 meters. This will be a
challenge. (Oh my God, this task will be) ......LL
|
|
|
Fulmen
International Hazard
Posts: 1725
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
I don't think there is any absolute limits to the range, once formed the projectile should behave like any other ballistic object. Even with the poor
aerodynamic shape it could probably still do serious damage at 100m, but I doubt you could hit the broad side of a barn at that range.
For a DIY device such as this I would be more than impressed with good performance at 100-200 x diameter (2-4m for your 22mm). 16m would blow my mind,
but I have a feeling you just might pull that off.
[Edited on 17-1-15 by Fulmen]
|
|
|
Hennig Brand
International Hazard
Posts: 1284
Registered: 7-6-2009
Member Is Offline
Mood: No Mood
|
|
From what I have read they are normally reasonably aerodynamic. Some of the fancy military grade EFPs are designed to form in such a way so as to
improve accuracy (such as forming fins). Also, the liners are often tapered (thinner closer to the outer edge) which produces a slug that is less
likely to break up and has better aerodynamic qualities. For a homemade device, as long as the slug is reasonably symmetrical and doesn't break up,
the accuracy is likely very similar to an old smooth bore cannon. Since the projectile does not have the stability provided by rotation, as is
provided to a rifle bullet by the rifled barrel, the projectile can sail and drift and even become unstable and flip depending on the symmetry and
length to diameter ratio of the slug. It really depends on the size of the target, but even a reasonably well made homemade EFP should normally be
very effective at 16m (I think). This is just the impression I got from the things I have read in the last few weeks.
"A risk-free world is a very dull world, one from which we are apt to learn little of consequence." -Geerat Vermeij
|
|
|
Bert
Super Administrator
Posts: 2821
Registered: 12-3-2004
Member Is Offline
Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
|
|
If center of drag is 1 caliber behind center of mass, it's likely going to fly stable (like a rocket coasting, or a badminton bird). As far as
accuracy... Who knows, without a lot of testing.
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
|
|
|
| Pages:
1
..
37
38
39
40
41
..
68 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
