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OH YOU HAVE NO IDEA HOW THE BLOODY SHITSTORM LOOKS LIKE IN ANOTHER SIDE OF THE OCEAN

The explosive compound in ERA (well, any military explosive compound) will only detonate when a certain pressure is reached. If the impact does not reach that pressure, the explosive will not detonate. As long as the pressure doesn't go above a certain threshold it doesn't matter what's hitting the explosive, it simply won't explode. I suppose there's a way to poke a hole through ERA without setting it off, but I haven't yet figured out how exactly.
 
It is. 
 
If you look at various tests with actual ERA, you'll see that the jet isn't noticeably being yawed/deflected, no matter the ERA angle:

You can however see that the higher the angle of the ERA compared to the jet, the more disturbed the jet is. This is simply because the ERA is capable of feeding more material into the jet, degrading it.
 
Actually, here are a bunch of photos of a shaped charge jets versus NERA at different angles:

 
And again, the more material is fed into the jet, the worse it becomes. 
 
 
However, ERA and NERA do actually deflect the jet, but only very slightly. I'm talking about ~50 m/s down for a 55 degree angle ERA sandwich. 50 m/s might sound a lot, until you realise that these jets move forward at a few thousand meters per second. So the downward velocity is negligible.

 
 
The reason the forwards moving flyer plate caused more damage to the jet is because of... vectors, basically..
 
Or as Kobylkin and Dorokhov put it:
 
Also, this is what the paper says about the pictures you linked:

 
Here are the pictures in higher res by the way, for future use:

The bit I quoted from Kobylkin was directed at your question about why the FMP has a different effect than the BMP, not at whether or not feeding material into the jet lowers penetration.
 
Anyway, yes, the main reason why ERA/NERA works is due to feeding material into the jet. Since a penetrator can only penetrate a finite amount of armour, you can lower the thickness of main armour it can penetrate by feeding material (armour) into its path.
 
The faster a plate moves, the more material it can feed into the jet before the jet has passed the plate. A plate basically looks like this after the jet has gone through it:

And the faster the plate goes, the longer Lslit will be. To be specific, it can be calculated with this formula:
 
The jet will also pass through more material if the angle of the ERA/NERA is increased:

 
And what happens when you increase the thickness of the FMP and BMP?


(Note that the BMP in the FMP test is 8 mm thick while the FMP in the BMP test is 1 mm)
 
Anyway, there's lots more I want to say, but I'm a bit ill at the moment so staring at journals and papers isn't the smartest thing to do, I'm already getting a headache and yet I only have a few journals open:

 
I'll get back to this when I'm feeling better, I'm sorry for not being able to give a concise answer at the moment. Or maybe @Collimatrix can take over, he knows about as much as I do on this subject.
 

I never even took the words "depleted", "spent" or "bleed energy" in my mouth. Maybe you should read carefully?
 
Kobylkin also says this (in the same paper):
 
Mickovic:
 
Hazell:
 
Hazell, again in a different publication:
 
Kobylkin, again:
 
Held:
 
 
Eehhh... hello? Eroding a penetrator is a basic hydrodynamic interaction principle? Unsupported by any research? Fuck me sideways, hydrodynamic interaction between a penetrator and armour is where any decent researcher will start. If someone doesn't understand hydrodynamic interactions it's nearly impossible to understand the penetration mechanics behind APFSDS and HEAT.
 
The penetration formula for a HEAT jet is basically the same fucking formula as the one used for hydrodynamic penetration:

^ HEAT jet penetration formula
 

^ Hydrodynamic penetration formula
 
Both formulas are from Hazell's excellent book called "Armour; Materials, Design, and Theory".
 
Hello again, are you even reading what you type? You're literally giving the answer to your own question: ｖｅｃｔｏｒｓ
 
Do you understand how those work?
 
Evidently not.
 
Hey here's a hint: THE JET IS MOVING TOO
 
LIKE
 
REALLY REALLY FAST
 
Maybe you shouldn't base your rambling on a single source you apparently do not even have access to which is also fully focussed on figuring out a single aspect of HEAT vs ERA interaction. Shit, if you actually properly read the conclusion of the paper you linked you'd have noticed that it starts with "It is proposed that [...]". For some reason you read that as "IT ABSOLUTELY AND TOTALLY IS THIS".
 
Since we're apparently going to sling journals and papers around, here's a thing for you to read (well, multiple things actually): Everything a fellow called Manfred Held has ever written on ERA, since he was one of the people who invented the fucking thing.
 
But anyway, you just stay you and keep claiming that ERA works by magically interfering with the jet. You correctly said that an impact will create a larger crater than the diameter of the penetrator. Which means that if the plates aren't moving into the path of the jet, ERA/NERA will have no effect. As can be seen in the picture I've posted before:

See? No effect on the penetrator what-so-ever. 
 
But guess what, if you angle the ERA/NERA so that the plates will actually intersect the jet, things happen!

 
So no, ERA/NERA does not fucking work if you don't feed material into the jet.

ISIS convoy getting bombed
Video .. Destruction of a large convoy by the Syrian army forces and allies in the countryside of Homs
 

You can watch the rest of the sa80 videos in advance if you use the playlist he made some time ago.

Hello everyone!
 
I've made some videos concerning topics of military, strategy, technology and so on. So far I'm getting pretty good feedback on them so maybe you too would be interested in seeing them.
 
Here's one on Turkey vs Russia: hypothetical air war
 
Or US AMRAAM D missile compared to Russian R-77-1 missile
 
Or UK vs France: hypothetical war
 
So tell me what you think!
 
 

Some Photos of Gripen E production
 
 

 

 

 

 

 

German Army + industry testing Wirkmittel 90:
 
Wirkmittel 90 (Effector 90) is an evolution of the RGW-90. The first series production models are currently being evaluated/validated for standard use with the German Army. It has a range of 1,200 metres (twice that of the currently used PzF-3IT-600 and more than twice that of a RGW-90). It is being used by the special forces of Army and Navy since an unknown amount of time already.
 


 
Like all cool and modern RPG/davis gun in the German Army, it includes it's own fire control system and laser rangefinder. According to one of the guys in the video, it's accuracy is "nearly 100%", which is achieved thanks to a sustainer rocket motor and the projectile gathering wind and acceleration data, which is used for in-flight correction by the projectile. The muzzle velocity is about 200 m/s.
 

 
The development of the Wirkmittel 90 for the German Army started some time after 2005, when the company was test-firing prototypes and invited a member of the German military procurement office to watch them. He was very impressed with the accuracy and range. The weapon can fire four types of ammunition: HE-FRAG (programmable ammo with air-burst option), smoke/fog, IR illumination and training ammunition. The German Army wants to use it to engage MG nests, infantry in structures or on open fields and unarmored/lightly armored vehicles.
 
It is currently in series production for Germany, official introduction will be in a few months with an official handover ceremony.

ISIS made a launcher for S-5 unguided rockets that are used in rocket pods for CAS (helis and planes).

Can't get over how much Yemen looks like Mars.
 
Also these videos show again and again Saudi vehicles being isolated and KO'd. Jesus they are awful at warfare. 
 

Really now?

Please continue, I will compile your complaints and mail them to my alma mater, clearly my engineering education is insufficient to understand ballistics and probability and should have its accreditation revoked.
The theoretical deviation calculations are backed by practical trials. Somehow all the "but the criterion is different!" crowds conveniently ignore those, even without the token "all Soviet trials are rigged" flailing.

The CIA continues to smoke the good weed
 

No, this photograph shows the EGS and not the TTK. The EGS predates the NGP project. It is a testbed, not a prototype; the whole purpose of the EGS was to test if it is possible to create a tank with modular armor package, two men crew in the hull and mobility equal or better than the Leopard 2(A4). The conception of the Panzerkampfwagen 2000 project (from 1989!) already saw the use of a two men crew located in the hull. Just because the NGP had a two men crew, not all prototypes with a two men crew are related to it. The US Army also had tank prototypes with only two men crew, which are not related to the NGP.
 

US tank design from 1993 with two men crew and unmanned turret.
 
Have you noticed that the EGS has no turret and no gun? It doesn't have proper optics and no FCS sensors. It is not a prototype. No prototype of the NGP was ever build, because the concept phase was never finished. Four industry groups (Krauss-Maffei, Wegmann & Co., MaK Systemgesellschaft and a joint-venture of Henschel Wehrtechnik and KuKa Augsburg) were bidding, but none was chosen and no prototype was funded.
 
The Technologieträger Kette (TTK) was a testbed for the crew compartment conception (much like the VT2000), but not designed with armor. It had a front-mounted engine (unlike the EGS), a weight of much less than 30 tons (probably less than twenty - it had only four roadwheels per side). There is no photograph of the TTK, but a drawing showing the vehicle.
 
You can read all of that, and a lot more about the NGP and EGS in the book "Kampfpanzer heute und morgen: Konzepte - Systeme - Technologien" by Dipl.-Ing. Rolf Hilmes, who worked at the German military procurment agency (BWB - Bundesamt für Wehrtechnik und Beschaffung, now integrated into the BAAINBW) as "Referent für Panzertechnologie" and "wissenschaftlicher Direktor". Pages 87-92 contain a sub-chaper on the NGP, while the EGS is mentioned on the pages 180-182.

Title is misleading.

While we are the topic of pole arms, here are some I took photos of the armory in the Doges Palace in Venice. 


 

 

What I meant with lineage is a non stop continuation of evolution if that makes sense. As in evolution of atgeir might have gone "extinct", and later on when the need for polearms came back - some other solution was created or taken. The translation 'halberd' is a bit confusing; did they translate it to that because that's the only polearm they knew and somewhat fit the description? But yeah, whilst I won't try to guess the possible shape of that weapon, I wouldn't be surprised if it was something pretty basic like early voulges, winged-spears and suchlike.
I remember having seen that blog, it is really good!

There is a type of  lineage from the atgeir in the fact that old Norse texts poorly translated atgeir and atgeirsstafir to "halberd".  We really don't have any archaeological evidence of an atgeir, what we have are descriptions from sagas. People have done some experimental archaeology and pieced together what they think the weapon would have looked like.

 

Of course this resembles a bardiche or even a longaxe. 

10th century examples of ax heads, which you can read more about in the blog in the "general archaeology" thread if you have any interest in those. 

I don't completely disagree with Lloyd but I'd like to remind that once again, not all halberds are uniform in shape. Sometimes the cutting blade is canted, other times it's straight, and sometimes the spike/spearhead is long and stubby - other times it has a ability to cut and is short. The halberds Lloyd show in his video are mostly from late 15th century to late 16th century so it could be just a preferred look of the time. I would also like to point out that the shape of the lower part of the cutting portion will probably be a better indicator to if you wan't to do more of a pulling-cut with the weapon. + That chop motion he does when he talks about stab vs chop is way overblown (you don't really have to load up so much with a long polearm to inflict damage).
h

Axes: someone is gonna get hurt.

Few more of those funky axes

 
But yeah, some proper testing would be nice.

Patton and the Panzers: An Interview with Steven Zaloga