Bronezhilet

Step 1: Be allowed to own firearms

"We want to liberate the country from its oppressive government" >Shells civilians Cunts.

The Ontos used something similar as well.

Might be used as some sort of (veeerrrryyy) crude ranging mechanism. But I seriously doubt the MG-34 had the same ballistic characteristics as le fearsum acht-acht.

We should have picked the T-64, no?

Those are photos of the Dutch Army testing both the Leo 1 and Chieftain to determine the successor to the Centurion. These photos are from around 1968. DBV means "Detachement Beproeving Voertuigen", which translates to "Detachment for testing of vehicles".

So Obsidian is finally going to fix the armour model of the Leo 2. Took them only a few months to fix bugged armour.

Did people die?

I said 6 kg, not .6 kg. At detonation: Highest point:

Wow, damage to the floor like that should not happen like that. Before and after a mine test of an AIFV. 6 kg of TNT directly under the floor. The pressure launched the AIFV over a meter in the air, but the maximum deformation of the floor during the test looked like this: I do not want to be in that BWS when it drives over a mine.

So tl;dr: An Ordnance dude wouldn't even dare to think of moving it. At least not before it sat for, I dunno, a few hours? My guess is that either primer or propellant was slow burning, the shock of ejection ignited properly working primer/propellant, setting off the rest of the propellant I'm not saying everybody should stop shooting cannons, far from that. I really like working, historic guns. But in my opinion this was absolutely preventable. Yes, misfires happen, but the 30 minute rule is present in every single manual of things containing explosives. Even a 'mere' Centurion gunner could tell me about the 30 minute rule. It's not rocket science. I can't stress it enough, it's out there to kill you, treat it as such.

First off, notice the "might" in the title. It is not yet known what exactly happened. What I'll be talking about is something I heard from someone close to the people involved. It might turn out to be not true, or it might be true. To be sure we have to wait for the official report of the investigation. Second, it might seem I am attacking the victims of the accident, this is not the case. But if they made mistakes, I will point them out. So most of you have probably already heard of the accident with the M18 Hellcat. What I have heard from people close, is that the round went off when they opened the breech after a misfire, or slightly after they opened the breech. So, a misfire huh. Nasty stuff when it involves explosives. So, what happened? Well, misfires happen. There's nothing strange about that. I assume a lot of you have experienced misfires with small arms, and you know the procedure of dealing with them. But with misfires like these are handled (completely) differently. I asked around a bit, and apparently the gunner waited a few minutes after the misfire before he opened the breech. This is good, but not good enough. Not by a long shot. If I remember correctly, when your small arms firearm misfires you keep the barrel pointing down range for at least 30 seconds. After 30 seconds you can safely assume the round will not go off by itself. It's different when a proper amount of explosives is involved. You do not wait 30 seconds. You wait at least 30 minutes. But between a misfire and waiting is another step. But I don't know if that step is possible on a Hellcat. More modern tank guns have two firing systems. The normal one, and an emergency one. If there was a misfire you were supposed to try the emergency firing system next, and if that didn't work: Time to wait. After waiting 30 minutes there are two things you can do. The first is to open the breech and check everything. Carry the round to a safe place, and blow it up. This is usually what you can do with normal, proper rounds. But in this case, with more shady ammunition I would go for option two: Call Ordnance. There are multiple things that could be wrong with the round, and I'm go out on a limb here and claim that the gunner did not have Ordnance training. In the military, if something goes wrong, Ordnance immediately becomes the supervisor of everything that happens. There might be Generals running around, but that mere Sarge (or whatever rank they have in the US) is in charge. This is what Ordnance would most likely do: - Establish what round is actually in the gun. Is it an original WW2 round, or is it aftermarket? What primer did they use? What powder? Is it an AP shell, or HE? Does the shell have a fuse? If yes, what type of fuse? - Try to establish what happened with the round before it went into the gun. How was it stored? Did you put it in your shed, or in a bunker with AC? This is all to determine one thing: Is the round stable? In other words: Can I move the round? If the round is determined to be stable, Ordnance can do two things. 1. Open the breech from a safe distance, and making sure the round will be caught before it hits something. Considering an historic piece of equipment is involved, this can result in the best possible ending. Which is a round being ejected without problems. But it is possible that the round will detonate inside the vehicle, destroying the tank and sending shrapnel all over the place. For Ordnance, the problem isn't the tank being nuked, it's the shrapnel. 2. Remove the gun from the turret and move it to a safe place. Ordnance will put at least three shaped charges on the outside of the chamber. One aimed at the primer, one aimed at the propellant and the last one aimed at the shell itself. The whole barrel will then be covered with several tons of dirt and the charges detonated. Voila, another safe ending to a dangerous situation. The gun is properly ruined, but nobody is hurt (except maybe some feelings). I'm assuming that the gunner knew how to handle firearms and various weapons. He had fired the gun before, he knows how it works. He might not have much experience with misfires, but he does know that he should wait a bit before opening the breech. But at this point, it's not a round you have in the gun. It's not a misfired round. It's not a nuisance. It's a faulty round. It's an explosive. It intends to kill. And it intends to kill you. And it intends to kill you immediately. Treat it as such. Don't touch anything. Sod off to a safe place. Call Ordnance.

Are that aftermarket surpressors as well?

Quick, Putin, invade Belarus for becoming westernised! They're even using a capitalist Suburban!!

Shouted GLORIOUS SOVIET COMMUNISM SHALL PREVAIL in front of a mirror three times.

Time to make y'all jelly.

It looks like they are indeed some form of shape stabilisation. But I have my doubts on how effective the stabilisation actually is. Yes, but then your accuracy goes to shit. You cannot rotation stabilise flechettes. If you do try, your shot pattern at a few meters will look like this: Not every effective at longer ranges. So you're stuck with a more elegant version of your every day shot.

If you knew my opinion of the FN P90, you'd probably come after me with one. And I would not be afraid, for the FN P90 is a terrible weapon.

I'm trying to simulate an AR variant, but the original modeler is retarded and couldn't draw for shit.

Solidworks Flow Simulation

Forgot to add, it has about 20% more drag than a rotation stabilised projectile. But considering a rotation stabilised HEAT projectile is about as useful as an AR or AK (only good for throwing it away as far as possible), a shape stabilised HEAT projectile is clearly the better choice.

*cracks fingers* Something that has interested me for a while, are shape stabilised projectiles. As in, projectiles that are stable due to their shape. Everybody has heard of rotation stabilised and fin stabilised projectiles, but shape stabilised is kind of different. I guess most of you here have seen shape stabilised projectiles without actually knowing how and why they work. Geek sidenote: Fin stabilised projectiles are actually fin and rotation stabilised. As I said, shape stabilised projectile have a stable flight path due to their unique shape. Figure 1: A 84mm Carl Gustav shape stabilised HEAT-round Note the slightly ogive front and the stand-off, which are characteristic of shape stabilised projectiles (SSP). Both features are absolutely crucial for the SSP to work. I'm going to throw you guys into the deep end by showing a .gif of the airflow in front of an SSP. Here's a link because I can't embed .gifv apparently The first thing you should notice is the air circulating in some-sort of pocket, and that this airflow is subsonic. Before I continue, here's the airflow in front of a blunt projectile: Clicketyclick While that projectile has a subsonic airflow in front of it as well, it is not circulating. Here's the airspeed of both projectiles as a normal picture: Figure 2: Airspeed in front of an SSP Figure 3: Airspeed in front of a blunt projectile It's clear that an SSP has a ogive-shaped subsonic airpocket in front of the projectile. This basically emulates the ogive of a normal rotation stabilised projectile. In other words, it makes it more aerodynamic. But does that airpocket stabilise the projectile? No it does not. So why is this projectile stabilised? The key is in what happens when it starts to tumble. Right now, there is nothing stopping the projectile from tumbling, and that's the interesting thing. There is literally nothing stopping the projectile from tumbling, except... the projectile itself. Lets take a look at what happens when an SSP starts to tumble. (If I remember correctly, I rotated the projectile 10 degrees) First off, the airflow in front of the projectile. It's fairly obvious that the airflow has changed. Lets check that again, but this time as a picture. Figure 4: Airflow in front of a tumbling SSP Again, it's obvious that the airflow has changed. The subsonic pocket has mainly shifted to one side and the air itself isn't really circulating in the pocket. This change causes a huge change in the Cd of the projectile. Let me show you why. Figure 5: Pressure in front of a tumbling SSP Next, the pressure in front of an SSP flying straight. Figure 6: Pressure in front of an SSP flying straight Please note the approximate pressure in front of both projectiles. The tumbling projectile has, on one side, twice the pressure as the projectile that's flying straight. Very interesting. What's even more interesting is that the pressure occurs on the opposite of the side it's turning to! The projectile is turning upwards, but the pressure builds up at the bottom. This pressure forces the projectile to start turning down again, forcing the projectile in a state where the pressure on all sides is equal. Voila, a shape stabilised projectile. But... why does it work? The subsonic airpocket is created by the stand-off and that little flange, or whatever you want to call it. The dimensions and placement of both are equally important. The stand-off and its side create the airpocket and the flange give the airpocket the required shape. The stand-off size can vary, but the flange size and placement is very important. If the flange is too far forward or too far back, the airpocket will be either too small or too big. Why does the size of the pocket matter? Because of this: Figure 7: Subsonic pocket in front of an SSP I changed the parameters slightly and made all airflow above Mach 1 red. Whatever is not red, is trans- or subsonic. The interesting thing to note here, is the pocket extends to the edge of the projectile (if I made the projectile better it should be exactly on the edge). (Sidenote: Here's the same picture of an SSP at a 10° angle) While the airpocket does not start at the flange, the flange determines where the pocket starts. If, at this velocity, the flange was further back, there would be supersonic flow hitting the front of the projectile, massively increasing drag. If the flange was further forward, the airpocket would be further forward too. This would mean the airpocket would not end at the edge of the projectile, but further out. Creating an airpocket which is wider than the projectile. This would allow the projectile to tumble a bit, because pressures wouldn't change much unless there is supersonic flow hitting the projectile. It is also possible to change the size of the airpocket by changing the front of the projectile itself. If the radius connecting the front and the stand-off is too big, the airflow inside the pocket would disrupt the circulation. The same would happen if the radius is too small. The angle of the front is important as well, but I haven't expermented that much with it so I don't know how important it exactly is, but it has an effect on the airflow. By the way, if the flange did not exist at all, the airpocket would start at around a third to half of the stand-off. Which would completely ruin the airpocket. Without a flange, the stand-off itself would have to be way bigger and longer to create the same kind of airpocket. But Bronezhilet, I hear you cry, if the airspeed changes, the pocket changes as well! I'm glad you brought that up, because you are right. A shape stabilised projectile only works properly within a certain flight envelope. If the projectile is moving too fast, the airpocket would compress allowing supersonic flow to hit the front of the projectile. Which in turns increases drag. By a lot. If the projectile is moving too slow the airpocket widens, allowing the projectile to tumble a bit before it would stabilise. I've been brainstorming with Colli a bit, and we've come to the conclusion that is why some projectiles are both shape stabilised and fin stabilised. When the projectile is moving too slow for shape stabilisation, the fins would keep it pointing in the right direction. And that concludes today's lesson. Thank you for reading.

Thanks mate, I've already talked with Colli and The Man Himself on TS for a few hours about a lot of stuff. Was nice. While looking for pictures for my first proper topic, I realised I had actually deleted my simulations on shape stabilised projectiles. Weellllpppp.

Since I got invited to this forum, I'd figure I make some sort of an introduction topic. So here goes nothing. But because I don't have a lot of time right now, I'll keep it short. I live in beautiful Yurop and I'm currently a mechanical engineering student, professional translator and amateur firearms inventor. I like screwing around with Solidworks Flow Simulation and I absolutely love pissing off both capitalists and commies by claiming the AR and AK are both equally shit. I'm interested in basically anything land-based, everything that flies or floats is a target. My main interest, however, is with the development of small arms, I'm currently working on something that can potentially rock the whole small arms business. (Spoiler: It's better than Hornady's ELD bullshit) To compensate for my horrible shitpoasting, here's a Barrett MRAD flying at supersonic speed: With this picture we can confirm that rails are actually increasing drag, so high-speed low-drag operators need to ditch as much rails as possible. We can also determine that an MRAD at 600 meters per second creates a disgusting amount of mach waves. I have more (serious) simulations, which I will post in a seperate topic soon-ish. Oh, I almost forgot, I've done a thing at a Yurop military weapons research facility.