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When browsing various papers and publications I usually stumble on quite interesting information every so often, but it's usually not enough to warrant a whole topic or linking the complete paper. So this is a topic where I'm going to dump all the things I find exciting or interesting. I'll post a small explanation on why it's interesting/exciting as well. I usually save all the paper I read or skim through, so if you want the full paper just gimme a yell. ------------------------------- So yesterday when I was checking papers for the sandbag topic I was also looking at shaped charge penetration in concrete, and I stumbled upon this: If you ever wondered why anti-bunker shaped charges use aluminium liners, compare Test #1 with #2 and #3. While the aluminium liner has quite a bit less penetration than a steel or copper liner, it makes a much bigger hole. Which is handy if you want to drop a secondary charge through the hole you just punched. The after armour effect on tanks might be enough to disable it completely, but with a bunker you most likely need a secondary charge to effectively neutralise everyone inside the bunker. And bigger hole = bigger secondary charge. ------------------------------- While thinking about @roguetechie's question about a focal point in shaped charges I remembered a paper which had some simulations about the penetration capabilities of a segmented HEAT jet. Sadly I can't find the paper anymore, but the advantages of segmented penetrators are fairly well known. So I was wondering whether you can control the breaking up of a HEAT jet, which should be possible by making weaker points in the jet on purpose. And when looking for a good introduction to shaped charges I found this: Turns out you can totally make a jet that breaks up at predetermined points, and you can probably also engineer it in such a way it breaks up at predetermined times. Looking at this, it's totally possible to make a segmented HEAT jet, but it's probably very expensive to make. ------------------------------- A while ago we were having a discussion about whether or not a long rod can ricochet. Today I went looking for data on it and lo and behold I found a whole bunch of data on it. I haven't found a formula to use (that I can understand), but as it turns out the minimum ricochet angle is about 3-4 degrees for steel penetrators with an L/D of 10.7 (modern long rods have an L/D of over 35), depending on target strength: If you look at different L/D numbers, the ricochet angle should change, according to Tate: However Tate's formula seems to be inaccurate when you compare it with real data: Rosenberg's formula is more accurate, but it doesn't include neither L/D ratio nor target thickness, which is probably why Rosenberg's model is shifted up compared to real life data. What the relation between the real life data and Rosenberg's formula is, is unknown to me at the moment. ------------------------------- ...speaking of L/D and segmented long rods... This is why segmented long rods work: The higher the L/D ratio, the lower the penetration efficiency. When you check the actual penetration values of different constant diameter (0.3 cm) L/D ratios, you'll see this: The L/D 6 has a penetration of about 1.8 cm, which is exactly right for a 1.8 cm long rod. Remember, an L/D ratio of 6 has an efficiency of close to 1. If the L/D effect wasn't a thing, the L/D 30 should have a penetration of 1.8 cm * 5 = 9 cm. But it only has a penetration of ~6.2 cm. Which is due to it's lower efficiency of only 0.69 (9 cm * 0.69 = 6.21 cm). So the point of segmented long rods is to create multiple shorter penetrators instead of one long one. This means you're basically stacking multiple high efficiency penetrators instead of using one long inefficient penetrator. With the above numbers, a long rod with 5 L/D 6 ratio rods will have 9 cm penetration while a single L/D 30 rod (which is the same length) has only 6.2 cm of penetration. ------------------------------- More to come.

You know, turn around is fair play. We all remember all those shootings of Democrats perpetrated by whack job right-wing extremists during the Obama years..... Oh wait.

Turns out the Javelin doesn't give a shit if a mid-wing* is damaged: (The percentages after the CEP are seeker failures) But if a mid-wing is missing or not deployed, its largely screwed, except if the missing wing is a vertical one: I thought ATGMs could deal fairly well with wing failures, but this research suggests otherwise. * Wing numbers:

For those that wondered how wave shapers (like in the Panzerfaust 3) actually change the detonation wave:

That's weird, I didn't see a single picture of a mallet.

The devil protects his own creatures.

For comparison: by taking the same 30kW beam and pulsing it (1ms pulse followed by 4ms rest, 100 pulses, spot size of 5mm) you can drill a neat hole about 2cm deep into a solid block of aluminium. This would work quite nicely to punch a hole in a drone or similar, but would also need a fairly big mirror and advanced optics to pull off. The 200kW beam would drill through 12cm of solid aluminium, while the 1MW beam would do the same but with a 1cm spot size. Graphite is still effective as armour, but will only completely stop the 30kW beam (~1mm hole depth). The 200kW beam will still manage about 7mm of drilling, while the 1MW beam can do about 1cm with a 1cm spot size, and 4cm with a 5mm spot size.

Yup, but only by staring at them for a good long while, and only where the shell/rocket is pretty soft-skinned. Slap a carbon coating on it and make the casing thicker and suddenly your truck-sized laser setup will struggle to shoot it down in time. My guess is that improvements in power storage et al will mean that 200kW becomes doable much sooner than anyone expects, and a proper (ie: solid-state or fibre rather than chemical or gas) 1MW beam might be possible in the near future with some serious money and effort. For reference, the LaWS takes about 2 seconds to shoot down a baby drone (scaneagle) with its 30kW beam and what I'm assuming is a near-infrared frequency. According to the calculator I keep referencing; the difference between a 30kW laser zapping a drone for 2 seconds and a 200kW laser zapping it for one is that the former manages to get a 10cm spot up to melt temperature, and the latter melts through its casing entirely (to a depth of about 3mm). A 1MW beam doing the same will burn a relatively neat hole right through the drone. When faced with a graphite body, however, the 30kW beam doesn't do much more than leave a smoking scorch mark on the outside. The 200kW beam, meanwhile, cooks off the outside to a depth of a fraction of a millimetre. Even the 1MW beam doesn't get you too much love: about 1mm of graphite gets blasted off. The 1MW beam can, however, widen its focus and just set the whole drone alight. So a bit of suitable protection goes a long way.

http://www.dtic.mil/get-tr-doc/pdf?AD=ADA469696 This is a goldmine for snippets of really interesting information on shaped charges. It has all sort of interesting information from tons of different papers, all in one neat package.

Yes. These sorts of things happened basically all the time during the Cold War. There was a bit of a slump after the breakup of the USSR, but now that the US has decided to go for Cold War, round 2 (playing the villain this time), these sorts of missions are back to normal rates. SU-27 remembering the Alamo:

Unfortunately, because WT tracks information from it's players game clients differently than WoT, there's a lot more cheating/hacking. One of the technical merits of WoT is that it is extremely difficult to cheat in a way that significantly impacts gameplay. It simply isn't possible to have a mod that reveals the location of enemy players if you don't already know that information. It is similarly impossible to have a mod that causes your shots to penetrate when they should have ricocheted. In WOT, if you don't have line of sight to the enemy, the server simply doesn't give you the enemy's location, and the server performs all the penetration calculations on its own and then tells your client what the results were.

I just got Flying Wings and Radical Things, a very nicely illustrated book on all of Northrop's actual aircraft and paper projects until they merged with Grumman. There are all sorts of wonderful things in here, from this twin-engined Black Widow derivative: To this carrier-based flying wing: To this stealthy cruise missile:

The image I made above is a little big, I had no idea it was THIS big though! 109 inches by 94 inches! Wall decoration anyone?

Yes, I agree. Beating down old misconceptions is fun, though. I liked Shad's coverage of education during the Middle Ages.

Historians really don't debate the dark ages anymore. That term has been out of favor for a while. Only folks that seem to perpetuate that the myth of a "dark age" is Hollywood. The period is already typically divided up into Early, High, and Late Middle Ages. There was a lot going on and in Europe it was an especially tumultuous time. Germanic Migration period was between 500 and 700. Slavic migrations around the same time. Merovingian period probably 480 to 774? Carolingian period was really only 775 to 900. The Viking age was 792 to 1066. Byzantine Empire was at it's high point. The rise of Islam. Rurikid Dynasty sprung up in Kiev and Novgorod around 800. Crusades, end of migrations, consolidations of what would become modern states. It's a bit difficult to pack all this into 500-1000 was X and 1000-1500 was Y.

I got to ride in a Bronco once when I was like 12. The local air museum had just got one which was still flight rated at the time they got it and a former Ov-10 pilot on the museum staff took me up in it one afternoon for a half hour or so. I wasn't a large child so they stuffed my helmet with t shirts out of the gift shop so that it kind of almost fit because the pilot knew that buckling me in wasn't going to keep me particularly safe LOL.

Moosered again A moose tried to pick a fight with an An-26 with expected results.

Started reading The Walking Dead comic. Holy shit, the TV show is miscast and mis-edited.