Lots of people note that hard kill APS rarely have more than 2-4 rounds available on each aspect, ever wondered why? A(nother) thread!
When you look at projectile APS, most have 2-4 rounds (either ready rounds like an Iron Fist, or reloads like a Trophy). There are some exceptions, QuickKill had 8+ but that single pod covered all aspects, versus 2 or 3 per aspect on more traditional systems. So, 2-4 is the norm.
Even non projectile systems tend to trend around here. StrikeShield/ADS has 2 per pod with adjacent pods able to defend one another, so again in the 2-4 window, give or take.
Some people say that’s not enough, but in reality the maximum number required is somewhere between 1.5 and 4, and very much weighted to the lower end of that estimate.
How that figure is reached varies, and most of the work to inform it is classified, but there was a rare example of public facing data in a brace of TRADOC papers in 2000/2002 that show some of the rationale behind it
There are two key factors that drive this ammunition capacity – SwaP limits, and survivability of the system, the latter being the key one.
First though, SWaP – Space Weight and Power. The outside of a turret or hull is a busy place, and space claims are very limited. Finding unobstructed areas to put radars, EO sensors, launchers and all the cabling and boxes to go with them is not simple.
Finding those locations that also do not impede the vision of sights and crew stations, nor interfere or are interfered by communications systems, jammers and other emitters/receivers/sensors again is not a simple ask of the designers.
It also needs to be as light as possible. Systems like Trophy add as much as 2.2 tonnes to a vehicle, and all of that is up high on the turret, impacting CoG and other vehicle dynamics. Often (as with M1) you have to counterbalance the APS with yet more weight and space claim.
And in the case of M1, CR3 and Leo2A7A1 you have to add further structures to the vehicle to mount all this on, with all three using new sponsons on the sides of the turret to mount their Trophy systems.
That’s more weight on the turret and stabilisation, more weight on the suspension and powertrain, more volume for logistical concerns. Its just more everything. So the goal has to be the smallest and lightest possible, nothing more than required. So what is required?
Here is the modelling bit. Manufacturers and users conduct their own assessments, I’ve seen a few, and all mirror the broad approach of the TRADOC papers. Essentially it comes down to how long an APS is actually going to stay working in combat.
Because even if everything works perfectly, when an APS defeats an ATGM or RPG, a large volume of fragmentation and debris is projected over the vehicle. Whilst the marketing videos often show APS as a forcefield, they obviously are not.
That frag cloud will wash over the vehicle as that was the path of the projectile and will impact exposed systems. APS is not a behind armour system, it is located on the surface of the vehicle and even the wiring is typically in exposed conduits on the surface.
Things like radars and EO sensors cannot be readily armoured, and the mechanisms of the effector turrets similarly are vulnerable to damage.
So, assuming the APS works, and a threat is defeated c.50m from the vehicle, a fragmentation and debris cloud will still hit the vehicle. In very broad generalisation, this will be about 110 fragments.
For a typical Trophy-like APS around 11 to 33 of these will hit an area that contains a critical APS component – radars, EO sensor, effector, munition, or cabling. Depending how many fragments, you get a probability that a critical system is hit and the APS degraded or destroyed.
You can then model out the likelihood across repeat engagements using a Markov chain approach, and it becomes increasingly likely the system is damaged beyond function and rendered inoperable, much moreso as fragmentation density increases.
Assuming the lightest end of the fragmentation estimate – 10 – then there is a possibility that the system could survive to 3.41 engagements before it is rendered inoperable.
However at the more credible fragmentation density that number falls radically, with 1.55 being the most likely figure. So whilst statistically unlikely, you’re looking at 2 engagements and the system is dead.
Ah but you could make the system smaller, then its less likely to be hit. Well, not really. The model shows that a typical APS has a presented area of c.2.5ft2. That would need to drop to between 0.2ft2 and 0.039 ft2 to achieve >95% survivability against 4 consecutive engagements
In essence, it is statistically unlikely for an APS to remain functional for more than one or two intercepts, and so designers and users have agreed that a safety net of three to four (however unlikely such a high figure may be) is a good maximum number of engagements required
Any more than this is overwhelmingly unlikely to be needed, and in fact is likely to mean a shorter effective life as the components will be larger and more likely to be hit by fragmentation and debris in the first place. So, 2-4 rounds is the norm.
There are a lot more factors, and this is just one of them, but shows within public domain some of the broad thinking that informs these sorts of decisions, which are far from arbitrary /end #AFVDesign#tanktwitter#miltwitter#AFVaDay
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A brief summary🧵of the Manned Ground Vehicle (MGV) element of the aspirational US Army Future Combat Systems (FCS) programme. A bit of a "what they almost got" for the US Army of the late 90s and early 00s.
MGV was a common family of AFV that were bold in their vision - baseline 24 ton hull (later upped to c.30t) with hybrid drive & CRT track, loads of data & sensor fusion, a lot of automation (most variants were 2-man crews), with less passive armour and more smart solutions.
A few more details of the core base platform that the family would build on. Lots of bold capabilities that many 2020s AFV still lack, and all with the strategic benefits of a single common platform across an entire Army fleet, which are substantial.
A long-requested (long) overview of the UK’s wheeled vehicle strategy – the Land Mobility Programme (LMP) and Boxer Strategic Pipeline (BSP).
Its actually rather good as a plan, being well considered, framed in reality and funded. Well done Army!
So, broad strokes. LMP and BSP form a full spectrum of wheeled vehicle capability for the Army. LMP comprises three strands – Light Utility, Light Protected Mobility, and Medium Protected Mobility. Boxer sits above as a de-facto Heavy Protected Mobility of sorts
In all we are talking a 20-year pipeline of >12,000 vehicles with a combined budget likely well over £7Bn. This is also the big test whether MoDs new Integrated Procurement Model is all talk or not – buy simple and fast, iterate and export, or not.
1/ 2024 is shaping up to be a bit of a year of the Leopard, a brief summary of plans afoot to make even more Leopard 2 users and variants a reality, which is always a good thing.
An open-ended, non-exhaustive list of actual & speculative users going on as of February 2024:
2/ 🇮🇹 Italy: Leopard 2A8
The Italians are looking at a medium-term successor to the Ariete (pictured), despite that tank still being in the midst of an MLU, with long term aspirations to join MGCS (or whatever emerges when it finally gives up).
3/ They plan to do a lot of the work domestically, building at a Leonardo production line in La Spezia and fitting with Italian industry components including sights, radios, C2 suite and potentially domestic manufactured barrel for L55A1 gun.
Anticipated production run: 130x 2A8.
1/ Japan's Future Amphibious Technology Research (FAT-R). The oft-overlooked work to really push the envelope of AAV tech that is actually making some great strides in the background.
A short summary 🧵
2/ A quick background of Amphibious Assault Vehicles (AAVs). Since the DUKW and LVT in the 1940s, there has been a niche for AFV capable of swimming when afloat and transitioning to land movement seamlessly to transport and support an opposed landing and inland movement.
3/ In the contemporary space the only meaningful example is the AAV7 (previously LVTP7), in service since 1972 and still the only vehicle of its type (ack that there are some peripheral amphibious AFV like ACV/SUPERAV, AMV and others, but nothing that was from the outset an AAV).
1/ A short summary of 🇪🇸's Leopard 2E upgrade plans.
Spain bought 219 Leopard 2E (local name Leopardo 2E), which are broadly speaking a 2A6 analogue with the Strv 122/2A6HEL roof armour and some unique to Spain C4 gear (LINCE BMS, Indra licence-built TI optics etc)
2/ The initial plan was to manage obsolescence and reduce some of the maintenance burden - in recent years the training has been curtailed simply because funding for spares and consumables wasn't there, so they are rather keen to minimise outdated elements.
3/ However, some money has been found somewhere, and so the upgrade plan has expanded into a multi-phase approach. Phase 1 will result in the Leopard 2E M1, and remains on the original plan - obsolescence management and sustainment efficiencies. IOC is planned for 2029.
1/ UKs Challenger 3 prototype now a real steel bit of kit, going into trials within the next few weeks. Imagery from #IAV2024 courtesy of @Janes own @Rivet_Counter
A few of the usual objections/critiques/comments flying around on twitter this week - a mini thread of responses to
2/ The design remains unchanged at the overall design level from that which I summarised 3 years ago at contract award in this thread:
3/ Critique: "Its not got APS". Yes it does, we've seen pics & videos of Trophy tested on mock turrets. Remember CR3 is "fitted for but not with" APS so prototype not having it means v little. This kind of testing would not be expected to have more than ballast to simulate APS