idle thought on active defenses

[gewing]

A long time back, someone posted info indicating that a grenade detonating something like 15 meters (iirc, sorry if I am brain-farting) has a significant possibility of causing enough yaw in a long rod penetrator to either cause a miss or to degrae the penetration significantly.

 

My memory says the notional grenade was something like 2lbs...

 

I had a thought the other day about a possible way to increase the effectiveness of such a defense without significantly increasing the danger to nearby friendlies.

 

 

The Dense inert metal explosive that is being used in the focused lethality munitionk. As I understand it, this incorporates powdered tungsten or some such to basically increase the force of the blast at very short ranges. Because the grains of the powder are so small, they have very little individual mass and so they slow down very rapidly. The bomb casing is something like carbon fiber composite so that it does not create significant heavy fragments either. Thus there is very little fragmentation effect, but the blast effect is severe, but short ranges.

 

Would a similar design in an APS grenade increase its capabilities against projectiles and missiles without increasing the danger area for friendly troops etc?

 

 

Any thoughts?

 

I wish I could afford to patent some of my bizarre thoughts... Maybe one or two would make me $100

[Navck]

Carbon Fiber can still frag, look at Formula 1 cars, they have a significant amount of carbon fiber and fiberglass in them. This is similar to the concept that "a carbon fiber air tank will fracture instead of fragment", which is not necessarily true at high enough pressure and impulse (Imagine prefragmented bits of CF being blown apart.)

BTW on Dense Inert Metal Explosives, the primary effect is you create high lethality to soft targets (People, unarmored vehicles, lightly armored vehicles) within a small area. You'd probably get the same effect if you just had the same amount of explosive. (What happens instead is you're fragging a "cloud" of tungsten in a short range. Might as well stick with the HE detonation causing concussion.)

[gewing]

Any material can frag or spall if you shock it hard enough, the issue is that with plastic, or CF casings is that they don't fly terribly far and they don't hit as hard. The idea here is keeping the same lethality against targets while reducing the lethal range of the device.

 

You most certainly are not guaranteed to get the same effect if you use explosives to launch a flyer or a particle as opposed to just using explosives. You need to sit down and do the impedance calculation. You can almost always hit harder launching a metal into something if explosives quantity isn't a constraint.

 

 

 

so, my idea isn't totally silly?

[Paul Lakowski]

I THink it was a paper I was pushing from 19th ISB. BTW I got the Papers from the 2007 ISB from Spain and there is a paper reporting to suggest deploying airbags to counter incoming missiles rockets etc? I kid you not!

[Guest JamesG123]

Yes the airbags was supposed to stop and contain the RPG warhead without initiating its fuze. It seemed to have some potential. I hope it wasn't dismissed out of hand, but had some insurmountable technical problem that made it unworkable.

 

CF = low mass = low KE.

 

Doesn't the Trophy system's grenades already have a plastic case that produces no fragments?

 

Sorry gewing, no patent millions for you..

[gewing]

Yes the airbags was supposed to stop and contain the RPG warhead without initiating its fuze. It seemed to have some potential. I hope it wasn't dismissed out of hand, but had some insurmountable technical problem that made it unworkable.

 

CF = low mass = low KE.

 

Doesn't the Trophy system's grenades already have a plastic case that produces no fragments?

 

Sorry gewing, no patent millions for you..

 

 

Ah, but does Trophy have DIME in it? (besides, right now I would probably settle for hundreds! )

 

I have been wondering about airbags too, what if an airbag were used to create an "instant standoff" slamming a plate into the path of the projectile, but without an explosive per se?

 

Not practical, I realize(If the incoming weapon could be tracked accurately enough and the munitions/airbags triggered quickly and accurately enough, I would think any number of active engagement techniques would work) , but It was an idea for creating a large enough standoff of a spaced plate to degrade a modern shaped charge.

 

oh well.

Edited November 22, 2008 by gewing

[Navck]

You could use the airbags in a form of something similar to ERA where the plate would induce yaw...

[Guest JamesG123]

Yes, I think that would work quite well at least theoretically. Kind of a hybrid between an APS and ERA.

 

A sensor detects an incoming threat, similar to the APS systems, and triggers a module in the projectile's predicted path to deploy with enough of a delay to meet the incoming. The plate's forward and lateral momentum will induce yaw and will disrupt the "jet". The plate could be attached to the vehicle via the bag or cables to keep it from flying off.

[Navck]

I'd still like to think that when making said APS projectile in a DIME manner wouldn't make it better assuming that you keep mass and volume constant between the projectile. The 2kg HE grenade is going to induce shockwaves onto penetrators, if not set off a shaped charge. The cloud of metallic particles won't do so much againist a kinetic penetrator due to the lack of momentum per particle, more or less. This is like a car driving through rain, whereas large pieces of frag is going to be closer to a sparse amount of hail (Ouch, your windows).

[gewing]

I'd still like to think that when making said APS projectile in a DIME manner wouldn't make it better assuming that you keep mass and volume constant between the projectile. The 2kg HE grenade is going to induce shockwaves onto penetrators, if not set off a shaped charge. The cloud of metallic particles won't do so much againist a kinetic penetrator due to the lack of momentum per particle, more or less. This is like a car driving through rain, whereas large pieces of frag is going to be closer to a sparse amount of hail (Ouch, your windows).

 

 

If the goal is to destroy or disable shaped charges, and yaw kinetic penetrators...

 

 

The way I imagine it MIGHT work out is something like this. NOTE all weights and distances are pure wild Arsed Guesses, pulled out of you know where!

 

if the standard explosive grenade weighs 2kg, has a 2 meter(just for example) radius in which it is likely to cause adequate yawing of the penetrator, and maybe a 5 meter danger radius for exposed friendly troops...

 

 

a DIME based grenade might weigh for instance 3 kg, have a 3 meter radius in which it is likely to cause adequate yawing, but still have the same 5 meter danger radius for exposed friendlies.

 

In contrast, a 3kg conventional grenade might also have a 3 meter effective yaw radius, but have a 6 meter danger radius for friendlies.

 

 

Does that make sense?

[Navck]

I'd like to say that the DIME grenade might just not even induce yaw or damage said incoming penetrator (Again, hail vs rain analogy). Its definitely going to have a lot less effectiveness radius compared to the standard HE grenade.

 

I'd also want to note that the lethality of DIME is pretty high compared to the fading lethality of the HE grenade. What you get is dead soldiers in 3m distance blast wise versus a crippled soldier at 3m. (Depending on the blast + protection worn.)

[Paul Lakowski]

The Airbags were deployed as a part of a APS system and fired at an incomming warhead to deflect it.

 

To read the paper and down load tons of other ballistic research papers from the site go to..

 

http://www.mater.upm.es/isb2007/

 

select "Proceedings"

 

Click on

 

http://www.mater.upm.es/isb2007/Proceedings/PDF/ISB2007.pdf

 

and read the contents select the paper and down load the PDF . The airbag paper is the 8th paper listed , titled... "Application of Airbag Technology for Vehicle Protection and Non Lethal Applications "

 

Some times the site is down due to traffic so you may have to be patient, but their are over 100 papers so there must be something for every one

[gewing]

I'd like to say that the DIME grenade might just not even induce yaw or damage said incoming penetrator (Again, hail vs rain analogy). Its definitely going to have a lot less effectiveness radius compared to the standard HE grenade.

 

I'd also want to note that the lethality of DIME is pretty high compared to the fading lethality of the HE grenade. What you get is dead soldiers in 3m distance blast wise versus a crippled soldier at 3m. (Depending on the blast + protection worn.)

 

 

 

I don't think the original paper was talking about the penetrator being impacted by fragments. I Think it was the blast wave that caused the yaw.

 

Fragments would very possibly be more effective versus CE warheads.

[Special-K]

Interesting idea.

 

I really like the Air bag idea too.

 

I would think that there might be an issue with the toxicity of tungstein effecting either the health of nearby troops or civilians - even if there wasn't much injury per-se.

 

 

 

 

-K

[Navck]

I don't think the original paper was talking about the penetrator being impacted by fragments. I Think it was the blast wave that caused the yaw.

 

Fragments would very possibly be more effective versus CE warheads.

This is exactly why DIME grenades don't work as well as a HE charge, I'm saying that the metallic cloud would be less effective than the concussion causing yaw and shattering... The DIME grenade would turn a lot of the concussion/shock into "frag", microscopic frag in its case.

I have said this through my posts...

[gewing]

This is exactly why DIME grenades don't work as well as a HE charge, I'm saying that the metallic cloud would be less effective than the concussion causing yaw and shattering... The DIME grenade would turn a lot of the concussion/shock into "frag", microscopic frag in its case.

I have said this through my posts...

 

Maybe I am misunderstanding the effects of the DIME "cloud", but my understanding is that the "microscopic fragmentation" has the effect of seriously increasing the concussion effect within the immediate area. I don't think it is acting like fragmentation per se, more increasing the density of the expanding gasses, like a shock wave in water instead of air. I could, of course, be wrong. I am no physicist.

[Navck]

Again, the DIME cloud acts less "gaseous" and more "microfrag", in this case its like a cloud of "dust" blasting you, but with more inertia per particle, I can see such a weapon sandblasting an incoming penetrator, but if you want similar effects as the concussion you have to be closer to the penetrator than you would from a non DIME grenade.

 

AFAIK, DIME = Great on squishy things, not so great if its a penetrator or hard armor.