Toxotis Self-Propelled Howitzer

Okay, so we have our new MBT, and our new Heavy IFV. Now we’ll outline our self-propelled howitzer. Again, we’re going to make logistics and crew safety a priority. We’re going to push the envelope a bit, but not too much. This will of course be a 155mm howitzer. Can we add another standard item, our stock heavy vehicle engine?

We might think no, at first. 1,500 horsepower is an awful lot of horsepower. But we’re getting pretty heavy. The Panzerhaubitze 2000 and 2S35 Koalitsiya-SV are both about 55 tonnes. That’s pretty close to the weight of our tank, and we can always govern the engine down a bit. So it will be a heavy vehicle, to no one’s great surprise. It will be able to keep up with an armored thrust, of course. The powerpack is rear-mounted.

Heavy is good though. It lets us haul plenty of ammo, which lets us sustain proper fire missions. If there’s one thing I’ve learned from watching The Great War’s wonderful week-by-week of World War One on youtube, it’s that there’s no such thing as enough artillery shells. Artillery does the killing. Artillery is the key to success.

But, a good load of artillery shells (which are, of course, explosive) and the charges needed to launch them (more explosives, duh) is going to be dangerous in the event of an armor penetration. To maximize survivability, we will take a page out of our MBT design and completely separate the crew from the ammunition.

This means a reduction in crew, because we can’t have human loaders. We’ll need to handle loading shells and charges automatically. This is a little harder than it was in the Myrmidon, since tanks use convenient one-piece ammo. So the projectile and cartridge and primer are all in one relatively easy to handle piece. Great. But artillery is different. Artillery has a much larger range spectrum than an MBT gun, because it’s an indirect fire weapon. To make accommodating this easier, charges come separate from the projectiles, and in different sizes. Recently, rather than dealing with a whole bunch of different size charges, some have developed modular charge sets, to let you build a full charge from smaller, easier to handle bits. To no one’s great surprise, we’ll go with this. Specifically, the Bofors Uniflex-2 Modular charge system, since it’s already developed. As a bonus, Uniflex-2 charges are insensitive munitions, so they’re harder to accidentally detonate. Which is great for reducing how bad an accident gets. Electrical fires suck. Electrical fires setting off your stowed ammo load sucks more.

To maximize the potential of the Uniflex 2, we’ll have a chamber volume of 25 L on our 155mm/L52 howitzer. This is a bit bigger than the NATO standard of 23 L, but that’s not really a big issue for us. We can still use NATO standard projectiles, which is the more important bit, since that saves us some R&D money if we can just buy/license existing things like the wonderful GPS-guided Excalibur round. More on exotic and cool 155mm rounds later in this piece. Also, since I know you’re curious, it requires 6.5 Uniflex-2 charges to fill the chamber completely. There are both “full” and “half” size charges, and you need six full-size charges and one half-size charge to fill the 25 L chamber to capacity.

Speaking of capacity, you’re probably wondering how many rounds are carried. The Toxotis carries 60 rounds and associated charges (390 equivalent charge loads total) in two 30 round/195 charge magazines. The magazine subdivision, with corresponding roof blow-off panels, is designed to try to reduce the chance of one hit igniting everything. Ammunition handling, charge loading, fuze setting, and primer handling are all fully automated.

Automatic loading and a modern, computerized fire control system allows for nine-round MRSI1 capability. Toxotis can come to a halt and fire the first shot within thirty seconds of receiving a fire mission. It can get moving again in under thirty seconds.

Electronically, the Toxotis has a fully-computerized fire control system, and our standard friendly unit tracking system. It also has a highly precise navigation suite, which can compute position based on inertial references, from satellite data, or pull in positional information over the tracking system. Fire missions may be computed internally or sent via secure datalink. The radios are designed to facilitate communication with nearby infantry, armor, and aircraft to coordinate support and fire mission requests. So while it can use a fire direction system, this is not required for a fire mission. Like on the Myrmidon, the three-man crew of the Toxotis are all in the front of the hull in an armored capsule. There is, of course, less armor than on the Myrmidon. NBC protection is, of course, standard. There’s also provision for direct fire missions, with a thermal viewer and laser rangefinder mounted on the roof.

To resupply, troops can manually load projectiles and charges into loading hatches at the rear on each side of the turret. These automatically stow the munitions appropriately. For more rapid resupply, the companion reloader vehicle, the Hypaspist, can be used. This is built on a nearly identical chassis to the Toxotis, but it lacks the gun, the rotating turret, and only has a crew of two. In place of the gun is an enclosed resupply conveyor to reload the Toxotis through a hatch on the back of its turret. From here, both magazines can be reloaded. The Hypaspist carries a double-load, or 120 rounds plus associated charges and primers. All ammunition handling within the Hypaspist is fully automated.

Both the Toxotis and the Hypaspist come equipped with a Trophy active protection systems, an array of smoke-grenade dischargers, and a 12.7mm M2A1 heavy machine gun in a remote weapons station on the roof. They are designed for the highest paced shoot-and-scoot missions in mobile warfare. Each weighs approximately 60 tonnes, and the production cost for the pair is $6 million.

Let’s also talk about some off-the-shelf artillery rounds. A standard HE round weighs 43.5 kg, and carries 11.3 kg of HE filler. There’s the M549A1 rocket-assisted HE shell, which has 6.8 kg of HE filler and a rocket motor for extra range. The M110A2 White Phosphorus round, which can be used for incendiary effects or producing smoke, weighs 44 kg, of which 7.1 kg is white phosphorus filler. We have projectiles that can be used to scatter small mines. The antipersonnel variant weighs 46.7 kg, and holds 36 antipersonnel mines. Each mine weighs 0.54 kg, and contains 21.9 g of high explosive. The anti-vehicle variant also weighs 46.7 kg, and holds 9 anti-vehicle mines. Each of these mines weighs 1.8 kg and contains 0.6 kg of high explosive. There’s also a couple submunition variants available. The standard version holds 88 dual-purpose (antipersonnel/antimateriel) submunitions. The extended range version has a base-bleed shell, and holds 72 dual-purpose submunitions. The submunitions are similar to the US DPICM submunitions.

In terms of smart rounds, several more are available on the market at present. There’s the long (1.4 m), heavy (62.4 kg) M712 Copperhead, which uses laser guidance. This provides useful capabilities against quickly identified point targets, including armor. Also available for the anti-armor mission are the very similar Bofors BONUS round and the Rheinmetall SMArt 155 round. Both have a pair of smart submunitions that fall slowly in a spiral pattern. Multispectral infrared sensors and a millimeter wave radar are used to detect armor targets. If one is detected, the submunition fires an explosively-formed penetrator at the target. Finally, there’s the aforementioned M982 Excalibur, which is GPS guided. For fixed targets, this is easier to use than a laser-guided round like the copperhead, since it doesn’t require a designator, but it is not useful against moving targets.

1.) Multiple rounds, simultaneous impact. So the Toxotis can fire up to nine rounds at a target and have them all hit at the same time, totally ruining someone’s day.

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