Tag Archives: militariana

Handicapping the FFG(X) Contenders

Big Navy announced the finalists for the FFG(X) program a few days ago. Let’s have a look.

In the interest of spicing things up a bit, I’ve assigned some moneyline odds to each competitor.

FFG(X): buying 2012’s frigate in 2020

The Navy ended up a little behind the eight ball after its insistence on buying the all-but-useless Littoral Combat Ship, which we’ve trashed on several occasions1. Rather than build a frigate as the Perry class was running out of lifespan, they built a weird fast corvette with no striking power and found themselves paying $700 million a pop for effectively useless ships.

FFG(X) is a stopgap measure to take care of the actual business of naval combat while the LCS contractors get their collective acts together, in which the Navy will spend $20 billion to buy twenty actual, effective combat ships.

LCS variants: Less Crappy Ships

The two contractors for the LCS have each assembled a bid using their LCS as a base for a real fighting ship. Both have unrefueled ranges of less than 4,500 nautical miles.

Austal Frigate: -300

Austal’s entry is based off of their trimaran Independence-class, a design I like aesthetically and for a few practical reasons (that giant flight deck among them). The Austal Frigate cuts a few feet off of the flight deck to add a stern platform to hold twin- or quad-pack Harpoon launchers (or other SSM launchers), as well as a towed sonar. Earlier Austal Frigate proposals put the VLS in the superstructure, on either side of the main mast, but someone must have realized what a terrible idea that was in practice; in the final proposal, one VLS 8-pack is forward of the superstructure, and one is at the aft end of the flight deck.

I was going to gripe about how 16 VLS cells seemed a little light, but it appears that’s the fit most of these frigates have, sadly. At least the ESSM can be quad-packed; 32 ESSM and 8 fancy Standard Missiles is an acceptable combat load, I guess.

Freedom Frigate: -400

The Freedom Frigate is the LockMart-brand LCS frigate, with very little to differentiate it from the Austal Frigate beyond its more conventional design. Same armament: 16 Mk. 41 VLS cells and a gun. Similar aviation capacity, although it has a smaller hangar. (Both only ship one MH-60 in normal circumstances, though.) I think the basic Freedom-class has less to recommend it than the basic Independence-class, which is why I give them a lesser chance here.

Not-invented-here options

Various European navies have interesting frigate choices. Two of them made it to the final round.

FREMM: -1000

As much as I like the FREMM, I don’t think it’s a very likely choice for the US Navy. The VLS system is wrong, and I have no idea how easy it is to plug a Mk. 41 system into the Sylver A43 hole in the FREMMs.

Too, it also depends on the FREMM version. The French FREMM is well-kitted for anti-air and anti-surface-unit warfare, with 32 VLS cells in all, Exocet launchers, and even support for land-attack missiles in the larger 16 VLS cells. It only has one helicopter, and only the anti-submarine versions carry a towed sonar.

The Italian FREMM has a faster cruise speed, a faster top speed, two helicopters, an improved radar, two guns, and (in the anti-submarine fit) anti-submarine missiles, but it has fewer cruise missiles and is only fit with 16 Sylver A43 VLS cells.

Both have long range, north of 6,000 nautical miles. Both are expensive, between 600 and 700 million euro per unit.

Keeping in mind the various incompatibilities which would have to be addressed, and the fact that the ship is built by ‘Fincantieri Marine Group’ no matter how much they claim they’re from Wisconsin, I think the FREMM is one of the less likely options.

F100: -450

The F100/Álvaro de Bazán class of Spanish frigates came as a bit of a surprise to me; I hadn’t heard much about them, but clearly I should have been paying closer attention.

The F100 is an Aegis frigate. Yes, you heard me right; besides the related Fridtjof Nansen class, they’re the only frigate-size ships to carry the Aegis setup. Fittingly, the Spaniards did not skimp on missiles. The F100 carries a full 48 cells of Mk. 41 VLS, for a standard combat load of 64 ESSMs and 32 SM-2s.

Its anti-ship capability is a bit more suspect, at only eight Harpoons, but those are in deck launchers and easily retrofit should the Navy come up with an actual decent sea attack missile.

It carries decent anti-submarine weapons and a torpedo decoy, along with a single helicopter, but does presently lack a towed array, a missing feature which could come back to haunt General Dynamics. I don’t know if it would be an easy retrofit, but it’s certainly something the Navy would want addressed.

Beyond that, though, the F100 strikes me as the blindingly obvious choice from the final competitors. There’s zero reason to complain about its anti-air fit, and its anti-ship fit is no worse than most of the other competitors. (Eight Harpoons seems to be enough for the Navy.) A helicopter is more important for modern anti-submarine warfare than a towed array, and one presumes that the F100 could probably ship one if it comes to that, given that a variable depth sonar and a towed array are on the requirements list and General Dynamics still entered the F100. It has 4,500 nautical miles of range, and doesn’t cost any more than the other options on the list.

Why do I not make it the favorite among the options, then? Because the Navy has already plowed a ton of money into the LCS, so they aren’t canceling it, and if they buy a non-LCS-based frigate, then they have to pay both to buy the new frigate and eventually turn the LCS into one. I expect political concerns to hamper the European designs, despite the fact that both the F100 and the FREMM are objectively better in every useful dimension than either LCS or LCS frigate conversion.

The Coast Guard rides again

But wait! There’s a dark horse contender.

Legend-class/National Security Cutter: -2500

While the Legend-class cutters are the right size, have superb range (it’s reduced to 8,000 nautical miles for the bid), and, as Coast Guard cutters, have tons of internal room for weapons and whatnot, selecting a cutter as a base for a frigate design would require the Navy not only to admit the Coast Guard exists, but also to admit that the Coast Guard built a better ship than they did. Not going to happen.

Program canceled or delayed beyond the point of usefulness: +250

I’m not a pessimist by nature, but this really does seem like the most likely outcome to me.


  1. It’s one of our favorite punching bags. If we’re missing a segment for the podcast, I’ve been known to say, “Have we beaten up on the LCS lately?” 

What’s In a Bradley?

Let’s take a look at what’s in a Bradley, courtesy of Hunnicut’s excellent work on the vehicle. Some of the information below is a little old (it’s from back when the M60 was the US Army’s squad support weapon), so I’ll make estimates for more modern systems as appropriate.

–Equipment for Vehicle Subsystems–

  • Fuel: 175 gal.
  • Engine oil: 26 qt.
  • Ready 25mm rounds: 300
  • Stowed 25mm rounds: 600
  • Ready 7.62mm rounds: 800
  • Stowed 7.62mm rounds: 1,4001
  • Ready TOW missiles: 2 missiles
  • Stowed TOW missiles: 5 missiles (Or 3 TOW missiles + 2 Javelin missiles, see below)

–Equipment for Dismounts–

  • Stowed 7.62mm rounds: 2,2002
  • Stowed 5.56mm rounds: 5,3203
  • Stowed AT4 Rockets: 3 rockets
  • Stowed ATGMs: 0 or 2 Javelin missiles

Curiously, in the tables in Hunnicutt’s book, both AT4 and M72 LAWs are listed as carried. In the text he mentions that AT4s were carried instead of LAWs and stowage was altered accordingly. I’ve gone with the latter here. We can also see that the Bradley is absolutely loaded with ammo.


  1. In Hunnicut’s table, ammo for the coax M240C is noted separately from the ammo for the M60 that’s to be deployed with the squad. I have preserved the distinction here (See also note 2) 
  2. These might also be used in the coax gun, since they’re still linked 7.62x51mm. Alternatively, this space should hold about 3,300 rounds of 5.56mm belted ammo for M249s, which is the current squad automatic weapon of the US Army. 
  3. Originally these were separated out for the M239 Firing port weapon and the infantry’s M16s, but the M239s didn’t work very well, and later versions of the Bradley plated over the firing ports. In any case, the M16 and M239 use the same magazines, so I haven’t split the ammo out here like Hunicutt does. 

What Does a Puma Carry?

Here’s a list of stuff that a Puma carries, at least according to Tankograd’s wonderfully photo-laden book on the vehicle.

–Equipment for Vehicle Subsystems–

  • Fuel: 900 L
  • Ready 30mm ammo: 200 rounds
  • Stowed 30mm ammo: 161 rounds (in seven-round boxes)
  • Ready 5.56mm ammo: 1,000 rounds
  • Stowed 5.56mm ammo: 1,000 rounds
  • Ready ATGM: 2 missiles
  • Stowed ATGM: 0 missiles
  • Grenade Launcher, Ready Rounds: 12 76mm Grenades -OR- 24 40mm grenades

–Equipment for Dismounts–

  • Stowed 5.56mm ammo for dismounts: 1,500 rounds
  • Stowed 40mm grenades: 36 rounds
  • Stowed frag grenades: 30 grenades
  • Stowed smoke grenades: 7 grenades
  • Stowed signal rounds: 20 rounds
  • Stowed rockets: 4 Panzerfaust 3 rockets and 2 launchers
  • Stowed Water, 1.5 L bottles: 32 bottles

The Tankograd volume doesn’t make mention of how much of the 5.56mm ammo stowed for the dismounts is in magazines and how much is linked for the dismounts’ MG4. 1,500 rounds doesn’t seem like all that much for six men, but perhaps the Germans trust their supply. It’s nice that Tankograd notes how much water the Puma usually carries.

Resurrected Weapons: XM307

Here’s yet another attempt to replace the Mk. 19 GPMG and/or the venerable M2 HMG. The XM307 was part of the same program that gave us the XM29 OICW, and later the XM25 once the OICW failed. The program itself emerged from a 1980s study saying that weapons development had reached a plateau, and that the next breakthrough would come with the integration of airburst-fused high explosives into the US Army’s weapons. They had tried to schedule a breakthrough in the late 1960s with SPIW. They failed. Now, a new generation of engineers would try their hand.

The XM307, or Advanced Crew Served Weapon (ACSW), had the same airburst principles as the XM25 and XM29. The gunner would use an integrated fire control system to get the range to target with a laser rangefinder, set an airburst distance, and then shoot rounds at the target. Except now with automatic fire. Let’s look at a quick size comparison chart:

XM307M2Mk. 19
length52.2″65.1″43.1″
barrel length25.1″45.0″16.25″
weight50 lbs.83.78 lbs.77.6 lbs.

It’s definitely lighter. Plus, it’ll bring a flatter trajectory than the 40mm grenades of the Mk. 19, so it should be easier to score hits with. Those are pluses. And, the M2 doesn’t pack an explosive punch. All good things so far for the XM307. So let’s talk lethality.

From autocannons, we know that autocannon ammunition makers don’t think a 25mm autocannon shell holds enough explosives to make an airburst fuse option worthwhile. We know there are lots of deployed 25mm systems, so there’s plenty of incentive to try. Big market, but nobody’s bothered. This isn’t a perfect comparison, of course. Sizes may vary, but if there’s a difference, the autocannon has the bigger projectile. A 40mm Bofors fires a much bigger round than the 40mm Mk. 19. Still, it’s cause for concern.

More concern comes from the test deployment of the XM25. In Afghanistan, while there are plenty of accounts of airburst rounds scaring Taliban fighters away, there are no accounts of it actually killing anyone. And this should be its best chance for success: taliban fighters don’t wear any kind of protective gear. None. If it can’t get kills there, what about when it encounters troops wearing actual modern armor? At least the Mk. 19 has a long history of being effective against unarmored opponents. It starts somewhere. Also note that lots of comparisons with 40mm grenades make a comparison between 25mm Airburst HE-Frag and 40mm HEDP, which is going to be less effective in the pure-antipersonnel role than 40mm HE/HE-Frag.

Now, the XM307 has automatic fire capability, and a belt feed, unlike the XM25. We’re not limited to a one round for one round comparison, which means we’re going to get into “stowed kills” type computations. Clearly, the XM307 holds more grenades in a box than the Mk. 19, so we can try to come up with some notion of relative effectiveness. Or we could, if we had a lot of ammo and a proving ground. Unfortunately I don’t, and I don’t know if the US Army tried this computation. The XM307 was cancelled in 2007.

Another obvious option is to integrate the airburst fusing and targeting system into existing 40x53mm grenade systems. So you’d still have the option of using existing grenades that work, plus you wouldn’t have to develop an entirely new round and ammo system. Someone at DoD actually thought of this, and the Mk. 47 was born. It’s lighter than the Mk. 19, fires the same 40x53mm grenades, and is equipped with a targeting system to set the fuses of airburst grenades. In US Service, that would be the Mk. 285. It’s in limited use in the US Military, and has seen export success with Israel and Australia. So let’s go with that, because it’s way less cost and risk.

Verdict: Funding Denied by the Borgundy War Department Ordnance Procurement Board

Resurrected Weapons: The LWMMG

Around 2010, General Dynamics independently1 developed what they called the Lightweight Medium Machine Gun. This weapon was designed to fill the “capability gap” between the M240/MAG-58 GPMG, chambered for 7.62x51mm and the M2 Heavy machine gun, chambered for 12.7x99mm. The idea was to be able to “overmatch” enemy PKMs in a weapon that was still man-portable like an M240.

The cartridge chosen was the .338 Norma Magnum2. This cartridge was designed to fire the excellent 300 grain HPBT .338 projectiles from rifles that had actions too short to accept the .338 Lapua Magnum cartridge. It was chosen for this application for its excellent ballistic performance at range, to really allow the LWMMG to stretch it’s legs.

Clearly, the .338 Norma Magnum has a lot more recoil energy than the 7.62x51mm round used in the M240. But General Dynamics wanted to maintain portability, and their goal was to maintain the “footprint” of the M240. So it couldn’t be too much heavier or larger. To accomplish this, General Dynamics used the same recoil system they had developed for the XM806. Having the barrel, gas system, and bolt recoil together meant they could distribute recoil forces easier, and not have to use as much weapon mass to do so. The LWMMG ended up being able to use the same tripods as the M240, and is three pounds lighter than the US Army standard M240B. Later versions of the LWMMG cut two more pounds off the weight.

The US Military opted not to procure the weapon, and I don’t really blame them. While the weapon is about the same weight as the current GPMG, the ammo is heavier, round-for-round. And, frankly, the extra range over 7.62×51 is usually wasted, because of line of sight considerations or target discrimination considerations. If you are in PKM range, he is in M240 range. Or range of vehicle weapons. Or mortar range. There are lots of other ways to deal with that sort of opponent. And you’d be adding another round type and spares type to the logistics trail. The use of other weapon systems is an even better idea if the enemy comes with modern body armor.

Let’s get some numbers on the ammo weight side, since this ends up being pretty significant. We’ll look at the weight of 100 linked rounds of 7.62×51, .338 Norma Magnum, and .50 BMG. 100 rounds isn’t a basic load, but it’s a nice round number to work with. Your basic load/vehicle load will probably be some multiple of that.

  • 7.62x51mm NATO — 6.625 lbs.
  • .338 Norma Magnum — 12 lbs.
  • 12.7x99mm BMG — 29 lbs.

Can it replace other weapons? I wouldn’t use it to replace existing 7.62x51mm GPMGs, because of ammo considerations and because that range is really not needed in general. It’s wasted on the regular infantry and the training and optics available to them, plus it’s almost twice as heavy. The .338 Norma Magnum round is also entirely too powerful for a semiautomatic or select-fire Marksman’s rifle, so 7.62x51mm would stay in the inventory. The LWMMG also isn’t going to replace the M2, because you’re giving up some range and a lot of soft target terminal performance with the smaller, lighter round. To be fair, General Dynamics never proposed it as such. It’s a marvelous technical solution in search of a problem. Cool, but I’d rather spend the money on other things.

Verdict: Funding Denied by the Borgundy War Department Army Ordnance Board


  1. I.e. without a solicitation or RFP from the DoD 
  2. Not to be confused with .338 Lapua Magnum, which is a bit longer. 

Red Flag 18-1 Kickoff

It is on like Donkey Kong.

This year’s first iteration of the USAF’s aerial war games, Red Flag, kicks off today. There will be day and night exercises. There will be tons of the best simulated combat we can set up. Two things make this year’s Red Flag a little different than most.

First, the guest list. Red Flag is always an invitation only affair. For this one, it’s Diamond Super Platinum members only. Which means Australia and the UK, in addition to America. That’s it. Nobody else.

Pretty hardcore, right? You may be wondering why. There’s likely going to be some testing of sensitive capabilities. Also, let’s look at some interesting notifications for aircraft operating in Los Angeles Center airspace and flying in and out of airports in the Las Vegas area.

Arrivals and departures from airports within the Las Vegas area may be issued non-Rnav re-routes with the possibility of increased traffic disruption near LAS requiring airborne re-routes to the south and east of the affected area. Aircraft operating in Los Angeles (ZLA) center airspace may experience navigational disruption, including suspension of Descend-via and Climb-via procedures. Non-Rnav SIDs and STARs may be issued within ZLA airspace in the event of increased navigational disruption. Crews should expect the possibility of airborne mile-in-trail and departure mile-in-trail traffic management initiatives.

Huh.

Among other things, the US DoD is cranking up a bunch of high powered GPS jammers in the Nevada Test and Training Range, and this might interfere with nearby civilian traffic. Consider yourself warned.

It’s about time we did some training in a no-GPS environment. See how we cope and develop TTPs. That’s what Red Flag is for.

Resurrected Weapons: XM806 Heavy Machine Gun

The Browning M2 is nearly 100 years old, and it is still a very effective weapon. It is heavy and made with decidedly old-school manufacturing techniques. The XM806 was an effort to replace it with a newer, lighter machine gun, still chambered for the classic 12.7×99 mm BMG round. The XM806 was a development of the cancelled XM312, which was a prospective heavy machine gun that could be easily converted to fire 25×59 mm airburst grenades.

The XM806 preserved the recoil system of the XM312 (and its grenade launching sibling, the XM307). This system had the barrel and bolt move forward when the trigger is depressed, forcing recoil forces to overcome the forward momentum of both the bolt and barrel.

The XM806 weighs only 40 lbs (18 kg), less than half the weight of the M2. It has less recoil than the M2, and it’s also easier to disassemble. On the other side, it has about half the rate of fire of the M2. For present uses, a reduced rate of fire probably isn’t a huge deal. We’re long past the days of expecting a heavy machine gun to be an effective antiaircraft gun.

While the weight savings are eye-popping, one might question the point. 40 lbs is still too heavy to easily manpack, and the weapon is still very bulky. And 12.7mm BMG ammo is big and heavy. It’s going to be a bother for a team of light infantry to deploy, and they’re probably going to be better off with GPMGs supplemented by antitank weapons, not least because of the weight of the ammo. As for vehicles, the difference between 40 and 84 lbs is basically immaterial. We can mount M2s on dune buggies. We can mount M2s on aircraft and helicopters. The weight savings really don’t get us much in terms of more usability in the roles that we normally find ourselves using a heavy machine gun. And (again) we still have the weight and bulk of ammo to deal with either way, which is a much more significant issue for small vehicles.

Probably a depressing way to look at it. But the biggest thing here would be cost, and it’s really hard to compete with an established system. When the US Army cancelled the project, they diverted funds into improving the venerable M2, and I can’t fault them for it. At least the XM312 added a new capability.

Verdict: Funding Denied by the Borgundy Army Ordnance Development Board.

A Cruiser By Any Other Name

I’ve discussed before that the Arleigh Burke-class is the best destroyer afloat today. It’s got a good radar, plenty of missile capacity, and comes at a pretty reasonable price due to its large production run. Competitors like the Daring class cost entirely too much and deliver entirely too little. Let’s look at a a follow on. Nothing lasts forever, and something newer, with newer systems, will be fun to sketch. This will be my version of something like the Zumwalt class. Though, because I prefer things evolutionary, it will be rather less ambitious. Admiral Zumwalt would have wanted it that way, anyway.

We’re not going to compete directly with the Burkes in terms of size, because that makes it really hard to justify the changes. And we’ve already sketched smaller. In case the title didn’t give the game up, we’re going bigger.

As always, we must first define our mission. Being a large cruiser, we’d like it to focus on air defense and air control, with plenty of land attack capability (i.e. plenty of missile tubes). We’d also like reasonable antiship capability and some antisubmarine capability, though this last is negotiable. I’ll pencil in some nice, off-the-shelf sonar systems now, with the understanding that designers can make adjustments as needed for cost reasons there.

On to the sketch! First thing to do is to forget about the stealth nonsense baked into the DDG-1000 design. Some low-observability features are a good thing, but the excessive stealth optimization of the Zumwalts with their special superstructure and ridiculous tumblehome hull is silly. A more normal hull design, bow raked forward, has far better seakeeping, and that’s much more important. Not only is it a patently obvious ship if one bothers to look out their windows, but we’d expect it to be able to handle Air Defense and Air Control, which means the radars have to be on, which means it will be pumping out electrons like the Las Vegas strip. And if we don’t turn on the radars, what exactly is protecting the carriers? Accepting that not every new design has to be a ghost’s shadow will help keep costs down. We need to limit the use of new technologies in new designs so the costs don’t explode. Nobody bats 1,000 with new designs. Some will fail, and we need to be resilient about this. Also, a more conservative design means we’ll be able to reuse some things from existing designs. Or, test out some new stuff elsewhere. Like we used to.

There you have it. Some gentle angles, avoid corner reflectors, keep the nice clipper bow. As a side effect, that’s a lot prettier.

Next: radars. I really like the original, un-neutered suite planned for the Zumwalts, namely the SPY-3 and the SPY-4. The SPY-3 is an X-band AESA radar, optimized for best tracking accuracy. The SPY-4, deleted from the DDG-1000s to save costs and still fitted on the Ford-class Carriers, is an S-band AESA radar optimized for high volume search. This split of functionality mirrors what NATO testing found to be best in the late 90s. These were integrated into a dual-band array system, which is some pretty revolutionary stuff. I’m fine with that as one of the key new technologies embarked, though the emitters could also be separated. The overall concept is right though. And, of course Aegis-type integrated fire control and combat management systems.

As a bonus, from an emissions perspective, a cruiser with a dual band radar looks a lot like a carrier with a dual band radar. Or maybe that other contact is another cruiser and the carrier is somewhere else. Or has its radars off. Emissions doesn’t tell you. With the right ECM and radar signature management, your active radar won’t help you either at range. Better go look, and hope you can radio your buddies back before you eat a missile.

On to missiles, and the tubes that launch them. The Mk. 57 can handle a greater volume of exhaust gasses than the Mk. 41, but the sheer number of deployed Mk. 41 tubes means missiles will be developed for that. Also, while the Mk. 57 is a bigger tube, it’s not much bigger, and there’s no missile around that would not fit in a Mk. 41 but would fit in a Mk. 57. Plus, the Mk. 57 modules are rather bulkier than those of the Mk. 41. So Mk. 41 it is! And we’d like to pack her with missiles. To hell with 80 missiles on nearly 15,000 tons. If we can’t do better than the 128 cells of a Ticonderoga, we should go home. Ideally we’d fit four of the big 64-missile clusters off the Ticonderogas for a total of 256 missile tubes. This gives us plenty of space for SAMs, including ballistic missile defense capable ones, LRASMs, Tomahawks, and VL-ASROCs.

Now, let’s talk about the gun. DDG-1000 originally had an ambitious vertical gun with guided shells, but this was shelved. The impact of development costs remains on the final design. I am not sold at all on ambitious gun projects that aren’t railguns, and those are nowhere near ready. The best estimates on the range of the Advanced Gun System put the ships entirely too close to shore. I’m fine with 155 mm, but 155 mm without being able to share shells (and shell development projects) with the army is patently absurd. And I’m still not entirely sold on the need these days, given how many other options there are for getting firepower on the beach, and how nasty coastal defenses can be. For my design, I’m quite satisfied with the 127mm/64 LW gun from Oto Melara. 127mm is a pretty standard naval gun caliber, and there are plenty of guided shells in that caliber under development.

There’s no need for extra antiship missile launchers given plenty of VLS cells and LRASM, so we don’t need to worry about those.

Point defense duties will be handled by at least two Rolling Airframe Missile launchers, mounted, well, wherever there’s room. Possibly amidships. Possibly fore and aft, which is rather more traditional.

Since we’re not obsessing over stealth, we can throw in some remote weapons stations and pintle mounted heavy machine guns to hose down any suicide bombers. Who will have no trouble finding a stealth boat because they use their eyeballs, not radar.

For propulsion, we’re going to go for Integrated Electric Propulsion, which has also been done on the Zumwalts. And could have been tested somewhere else. There’s no reason why it should be hard. Generators are run by diesel engines and gas turbines, and electric motors drive the screws. I’d like to take some time on a demonstrator to explore steerable propulsion pods for the electric motors in a military context, specifically focusing on cost, agility, and noise.

Helicopter fit is the usual hangar for two SH-60-size birds and beartrap-equipped deck. No reason to change it. Though, given the size, we should probably expand the hangar a bit to accommodate several drones.

Antisubmarine warfare is not our focus, but we should make a bit of effort to be prepared. A nice bow sonar and variable-depth towed array will do nicely, as will the usual pair of triple 325mm torpedo tubes amidships. Something like the Thales UMS 4110 CL sonar for the bow and a Captas 4 in the towed role.

M1 CATTB

The Component Advanced Technology Test Bed was another late 80s American test program to investigate new systems for future tanks. As we’ll see, it looked quite a bit different from the TTB, and where the TTB was testing a very specific change (namely the unmanned, low profile turret) the CATTB tested a variety of new technologies in a more conventional layout.

CATTB

CATTB shared an Abrams hull, but the turret was new, and came with a bustle-mounted autoloader. The autoloader was very similar to the one on the Leclerc or K2. A new gun was tested, the XM291, which came in both 120 mm and 140 mm versions. The 120 mm version provided a lower-risk alternative to the 140 mm. The turret had rather large forward armor arrays, plus reasonably thick side arrays and a decent amount of roof protection. And I have no idea why they decided to mount so many smoke grenade launchers on there, but they did. This was before the advent of soft-kill active protection systems, but might not go amiss on a tank today with the right cueing system.

CATTB Rear view

As you can see from this rear view, the CATTB also came with a new engine: the XAP-1000 diesel. The Cummins/Allison XAP-1000 was based on the advanced Cummins XAV-28 V-12 diesel, a low-heat rejection engine. It used only oil coolant and has no water in the cooling system at all. Higher temperature exhaust gasses were tapped to run the APU. I don’t know a ton about this engine, but the US Army has a history of backing highly advanced diesel engines that end up being problematic. I would suspect similar things with the XAP-1000. Again, the project went nowhere. Later in the 90s, the Abrams was going to get a new engine as an offshoot of the Crusader project, but the proposed engine was not the XAP-1000. Instead, a gas turbine was chosen.

CATTB is a lot more of a conventionally designed tank. I do really like its lines. The project which was supposed to lead to the Block III MBT ended up leading nowhere due to changing priorities. Though, it is not at a museum. It is in the long term storage section of the Sierra Army Depot in Hurlong, CA. Make of that what you wish.