Modelling > Engineering Dept.

Mineclearing Flail Tanks for Ukraine

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apophenia:
I wanted to discuss the Ukrainian use of mineclearing flail tanks. To facilitate that, I am first going to describe the minefields currently faced by the ZSU and then give an overview of mineclearing flail technology since the early 1990s.

I'd intended this to be short but have inadvertently dropped back into analyst mode ... making my preambles quite lengthy. If you would prefer to avoid such overviews and go straight to 'Options', click this link :
-- https://beyondthesprues.com/Forum/index.php?topic=10845.msg211575#msg211575

RU Minefields in Occupied Ukraine

As the sub-title suggests, I am separating the issue of military minefield breachings from longer-term, postwar mineclearance activities. It is not that latter are easier or safer to perform but, of necessity, civilian demining activites must be much more thorough. Military minefield-breaching operations, on the other hand, must be done at speed and generally under hostile fire. Indeed RU forces have made attacks on breaching vehicles a top priority on the frontlines.

A recent RUSI report notes that "Russian minefields had been doctrinally set down as 120-metres deep prior to the offensive. Following the early clashes, it was noted that this depth of mines was breachable by MICLIC and UR-77 to a sufficient depth to enable infantry to get into Russian defensive positions." [1] According to a Forbes article by David Axe, the Russians have now quadrupled the depth of their minefields in Ukraine. [2] Worse, Ukraine has only received 15% of demining and other combat engineering materiel requested from Western nations for this counteroffensive.

In the past, we've discussed options for additional, tank-based line charge launchers - like NATO-standard M58 MICLIC and Soviet-era UR-77 Meteorit. Actually, AEVs are being supplied (or promised) to Ukraine in fairly good numbers. Many are relatively modern Leopard 1-based vehicles, some are Leopard 2-based. One of the first Western mineclearing tanks delivered to Ukraine were a pair of ex-Finnish Leopard 2R ploughs. Most of the other tank-based mineclearing vehicles in (or heading to) Ukraine will also be fitted with mine ploughs/rakes - such as the 15 x FFG Wisent 1MC conversions being delivered by Germany. So that brings me to the first big question:

Q - Are flail tanks considered relevant on the modern battle field?

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[1] Stormbreak: Fighting Through Russian Defences in Ukraine’s 2023 Offensive, Dr Jack Watling & Nick Reynolds, The Royal United Services Institute, 04 Sept 2023, pg. 15.

-- https://rusi.org/explore-our-research/publications/special-resources/stormbreak-fighting-through-russian-defences-ukraines-2023-offensive

[2] To Slow the Ukrainian Counteroffensive the Russian Army Quadrupled the Size of its Minefields

-- https://www.forbes.com/sites/davidaxe/2023/09/05/to-slow-the-ukrainian-counteroffensive-the-russian-army-quadrupled-the-size-of-its-minefields/?sh=65d3030569e8
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apophenia:
Are Flail Tanks Still Relevant?

Most of the online 'answers' to this question that I have seen are of the 'not according to established practices' sort. But such they-don't-because-they-won't tautologies aren't useful to anyone. Perhaps a better way to put the question would be: What Western truisms on assault breaking techniques need to be re-examined in light of the experiences of the Ukrainian 2023 counter-offensive? In other words, are donated mine ploughs and line-charge launchers the only arrows needed in the ZSU's assault-breaker quiver?

There are a number of mineclearing flail systems in current Ukrainian use. On the lightweight side are remote-controlled systems like the Croatian DOK-ING MV-4 (including the US Army M160 variant) and GCS-200s (provided by Canada); Slovakian Bozena 4; and, soon, the Digger D-250 (promised by the Swiss). These are useful vehicles but were developed during the past decades of asymmetrical warfare - essential for postwar mineclearing, but obviously ill-suited to the well-defended frontlines that ZSU units now find themselves facing.

Reviewing the technology, it seems that flails generally began to lose their appeal in the 1990s. The downsides were well-know. Mine flails are heavy, mechanically complex, and, in operation, they are extremely noisy while kicking up a debris/dust cloud that instantly gives away vehicle positions. Otherwise, the cause for flail losing favour in the 1990s seem to have been two-fold:

- First, humanitarian demining became the priority rather than military route-clearing. This meant an emphasis on thoroughness at the expense of speed of operation. For practical reasons, 'civilian' demining also required greater economies, leading to much smaller systems. Vehicles lighter than tanks had reduced fuel consumption while making trailered delivery by road much simpler (assuming that civilian de-mining vehicles could not self-deploy on their own tires).

- Second (and still related to those humanitarian demining emphases), the technological preference shifted to tungsten-tipped tiller wheels over 'old-fashioned' flail systems. It helped that many of the experimental deminer developers and manufacturers already had experience with soil tiller machinery for farming equipment.

Despite 'transport issues', mineclearing tiller systems were still applied to tank hulls - at least experimentally. One example was the FFG Minebreaker 2000/2 with a mineclearing width of 3.69 m. Here, in part, Flensburger Fahrzeugbau Gesellschaft mbH was trying to find second lives for its collection of retired Leopard 1 hulls. [1] Around the same time, Bofors Defence AB produced its improbably-name Mine-Guzzler tiller system beginning with two Leopard 1-based prototypes. (Bofors then moved on to adapting its tiller system to civilian crawlers with mineclearing widths reduced to 3 m.)

Neither of those tank-based systems caught on for obvious reasons. The biggest drawback is the sheer size and weight of these systems. But tillers have their own pitfall. While they are incredibly sturdy, the tungsten tips do get damaged. To maintain uniform tilling, operations must be stopped until the damaged tips can be unbolted and replaced. Tricky in the field but impossible under fire. Of course, flails also get damaged during operations. But replacing a damaged chain (or hammer 'ball') is a much simpler endeavour.

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[1] Many of those potential 'donor' hulls are now being converted into FFG Wisent 1 AEVs (including Wisent 1MC mine clearing variants fitted with the now-ubiquitous Pearson mine ploughs).

apophenia:
On-Going Mine Flail Development Efforts

As mentioned above, where flail technology development did continue, it was skewed towards much smaller machines (sometimes remote-controlled or fitted with aft-mounted armoured operator cabs set high and out of the blast zone). One approach that broke that pattern were the Scanjack 3500 prototypes. Based on a well-established Finnish forestry vehicle 'prime mover', the Scandinavian Demining Group's Scanjack 3500 took an interesting dual-flail approach. [1] A variation on that theme is DOK-ING's MV-10 which combines a primary flail with a secondary tiller system.

Another early 1990s military mine flail effort resulted in Aardvark Clear Mines' Rapid Area Clearance Equipment (RACE). One variant - RACE C - followed the contemporary trend of mounting the flail system on a front-end loader. This armoured cabbed Volvo L90 was unremarkable - other than in its flail drum being hydraulically-driven. Another variant - RACE A - was intended for use on APCs. The FV432-mounted prototype carried an auxiliary diesel engine in a box slung off the rear of its hull. That separate diesel was dedicated to powering the hydraulic system. [2] A remarkable feature of the RACE A system was that its drum was articulated. Folding at that joint, the drum formed a more compact 'V' shape for transport.

-- https://beyondthesprues.com/Forum/index.php?topic=10826.msg211261#msg211261

Probably the best-known mineclearing flail system of the 1990s was the British Aardvark JSFU which has seen fairly widespread military service ... again, for humanitarian mine clearance operations. However, an Aardvark-style flail system [3] was adapted to the Leopard 1 hull. In early 1999, Norway's Hägglunds Moelv AS teamed with two US firms [4] to produce the AMCV (Armoured Mine Clearing Vehicle). A Leopard 1 hull had its turret replaced by central, fixed 'doghouse' for the flail operator. The flail system itself, pivoted from a mount on the forward portside of the hull. [5] When in their stowed position, the flail booms surrounded the 'doghouse' (with the flail drum to starboard).

Norway's Hæren intended to procure seven AMCV conversions as their Minerydderpanservogn (MRPV or minesweeper armoured vehicle) but that never happened. The sole prototype was tested operationally with Norway's KFOR deployment but the MRPV project was cancelled in 2002 - budgetary and floor-space priorities having shifted to Hägglunds Moelv's conversion of 22 x Leopard 1 hulls into NM189 Ingeniørpanservogn AEVs (three of which have now been donated to Ukraine).

This leaves us with one type of tank-based mine flail vehicle currently in service with a major European army - the M48-based MiRPz Keiler which entered Bundeswehr service in 1997. Four of these Minenräumpanzer have now been transferred to Ukraine. However, since the MiRPz Keiler is the basis for our first flail-tank 'Option', I'll leave further discussion of this vehicle for Post #?.

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[1] The SDG Scanjack 3500 had tandem flails of different diameters. Normally, these flails were rotated clockwise but they were reversible (and could be counter-rotated). The shorter front flail chains cleared to a depth of 20 cm - removing most vegetation and detonating anti-personnel. The larger-diameter second flail cleared down to 40 cm, dealing with anti-tank mines. The flails were driven by a dedicated 550 hp Scania DSI 14 turbo-diesel V8 separate from vehicle propulsion.

See: https://www.files.ethz.ch/isn/26723/MDE_Catalogue_2002.pdf

[2] If I understand the system correctly, a diesel engine drove a hydraulic pump which, in turn, provided the hydraulic energy need to turn hydraulic motors. Those hydraulic motors then turned that hydraulic energy back into the mechanical energy needed to spin the flail drum. AFAIK, the Volvo's diesel drove the hydraulic pump via a power take-off. The FV432 did the same with its separate, auxiliary engine.

[3] I have said "type" because the flail system was original to Hägglunds. Some online sources claim that an actual Aardvark unit was mounted on the AMCV/MRPV. That is clearly not the case - consider the Norwegian vehicles complicated folding mechanism alone.

[4] Much of the AMCV/MRPV development work was actually done in Alabama. Those American firms were Summa Technology, Inc. and Quality Research, Inc. - then both of Huntsville, AL (Quality Research has since relocated to San Antonio, TX).

[5] Rather than trying to accurately describe the mechanism, see images attached (based upon Hägglunds Moelv drawings).

apophenia:
Current Breaching/Mine Clearing Efforts in Ukraine

Prior to 2022, the ZSU relied upon Soviet-era UR-77 Meteorit line-charge launchers [1] and KMT-7 mine-roller systems. In theory, any Soviet tank can mount KMT-series rollers but the ZSU has specialized mine-clearing vehicles fitted with the KMT-7 system. These are the old Soviet BMR-2 [2] and the domestic BMR-64 engineering vehicles. (The latter is perhaps best-known for a ramming attack where the trawl gear was used to take out an RU BMP-2.) One BMR-2 has recently been destroyed while attempting a breach - although most observers were distracted by the knocked-out M2 Bradleys arrayed in front of it.

Mine-rollers are a tried-and-tested technology dating back to post-WW1 experiments. They work but there is a big disadvantage to using Soviet-era KMT-series rollers. The Russians still use them too and are quite aware of any weaknesses. That, in part, explains the current RU techniques of stacking 3 x TM-62M anti-tank mines. The object is to 'kill' the de-mining vehicle, not to just disable its rollers. An alternative RU technique is placing a TM-62 on top of a buried FAB aircraft bomb. [3] Such mine stacking techniques have proven equally effective at knocking-out vehicles fitted with dozer blade/rakes and the flat 'mine-plates' of Pearson ploughs.

Those Pearson Full-Width Mine Ploughs equip most Western tank-based AEVs committed to mineclearing in Ukraine. [4] These include the Leopard 1-based FFG Wisent 1MC dedicated mineclearers [5] and AEVs such as Dachs 2 and the Norwegian-designed NM189 Ingeniørpanservogner. Then there are the Leopard 2-based AEVs - Dachs 3 and Finnish Leopard 2Rs (3 x confirmed lost). [6] This is not to say that losses of such vehicles are all attributable to stacked mines - eg: the Oryx-confirmed Wisent 1MC loss was hit by an RU ATGM - but fitted with scrapers and Pearson ploughs, even the heavier-armoured Leo 2-based vehicles are vulnerable.

Are Flail Tanks Less Vulnerable than Mine Plough AEVs?

It turns out that there is a Russian phrase for 'overkill' - izlishneye ubiystvo ... I looked it up - but you'd never know it by the way the RU army lays minefields. We've seen that AEVs and other tanks fitted with rollers and ploughs are vulnerable to stacked mines. Like line-charge layers, once disabled, those mineclearing AEVs become top priority targets for RU artillery. Lancet loitering munitions and Krasnopol laser-guided 152 mm shells are held back especially for such targets. The subject of combating drones providing laser targeting is off-topic. But laser-guided artillery will be slightly less dangerous to moving vehicles.

So, another take on our question might be: Would flail tanks be any less vulnerable to stacked AT mines than plough-fitted AEVs? That ends up being a rhetorical question because I do not know the answer. With a large enough explosion, any armoured vehicle will become a mobility kill awaiting fires. But are the jibs and spinning drum of a flail tank far enough in front of the armoured vehicle's hull to avoid mobility kill-level damage?

Just as germane is whether that drum is far enough off the ground to avoid damage to itself. Likewise, will stacked mines tend to damage chains or hammer 'balls'? After all, if the flail ceases to function properly, the flail tank has no option but to retreat. And, as that flail tank must retrace its steps back through the minefield, its path of retreat will be a highly predictable one. Helpful for RU gunners and Lancet controllers, not so good for Ukrainian sappers.

Alas, the answers to the above questions will probably not become apparent until the only tank-based mine flail in Ukraine sees action and its efficiency (or losses) are made public knowledge. Four ex-Bundeswehr MiRPz Keiler flail tanks were delivered to Ukraine in January 2023. But, so far, there is no public record of their combat use.

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[1] The UR-77 hull is similar to that of the 2S1 Gvozdika SP howitzer (also in ZSU service). Accordingly, the UR-77 is lightly armoured (20 mm fwd arc, 8-12 mm elsewhere) like the shared-parent MT-LB APC. So, despite having been designed to operate near the frontline, Meteorit is too poorly-armoured to survive long in that environment.

[2] The BMR-2 is a fixed-superstructure conversion of T-54B tanks. That superstructure mimicked the shape of the old BMR-1 - a 'defrocked' SP-122-54 - which, until quite recently, also remained in the ZSU inventory. A similar modification of the T-64A tank was done in Kharkiv to produce the domestic BMR-64. Two of the latter are confirmed knocked-out by Oryx, with one captured.

[3] The resulting explosion would be very powerful. Each TM-62M mine has an HE filling of only 7.5 kg. But, stacked with an aircraft bomb, the modest TM-62M blast is also acting as the fuse for a FAB-50 (24 kg filling) or FAB-100 (38 kg filling). Effective ... but also revealing the current RU mine shortage created by deepening 1,450 km of frontline minefields.

[4] Many of the AEVs mentioned can also mount M58 MICLIC to act as launch vehicles for those line charges - indeed, MICLIC is a simple bolt-on for the Norwegian M189.

[5] Germany has promised or delivered 36 of these dedicated mine-clearing tanks.

[6] Ex-Finnish Leopard 2R AEVs - like their Leopard 2A4 and 2A6 MBTs - can also mount Soviet KMT-5 mine roller systems (which date back to when the Maavoimat still operated T-55 tanks).

apophenia:
Tank-Based Mine Flail for Ukraine? - Option #1

It is risky but, in the absence of experience-based answers, I am going to assume that flail tanks might be a another useful arrow in that mineclearing quiver. The Russians have, at least partially, gotten the measure of AEVs and tanks fitted with mine-rollers and Pearson ploughs. Are flail tanks sufficiently different in their method of operation to avoid countermeasures tailored to the rollers and ploughs? If we assume that they are, for the moment, what is the best option for providing flail tanks to Ukraine?

The obvious candidate is easy ... the German MiRPz Keiler is the only flail tank in current service with a NATO army. This Minenräumpanzer - with its sophisticated  flail system - was to be procured for the Bundeswehr in large numbers [1] but, in the end, only 24 MiRPz Keiler were ever built. Germany sent four of those vehicles to Ukraine in Jan 2023. That means that another 20 x German MiRPz Keilers are now available for immediate transfer to Ukraine.

Option 1 - MiRPz Keiler Pros & Cons

Advantage: Obviously the quickest option for getting mine flail tanks to Ukraine.

Downside : Involves time-consuming Bundestag decision-making & BWB procurement policy. [2]
-- Over the course of the full-scale RU invasion, neither of the above seem to be improving.

Advantage: Commonality (training/parts) with MiRPz Keilers already delivered to UA.

Downside : Based on M48 tank; no parts commonality with any other vehicle in UA service.

Downside : All MiRPz Keilers going to UA robs DE of its only heavy mine-clearing vehicles.

Advantage: Provides the Bundeswehr with an opportunity for 'standard hull' replacements.

As mentioned, availability is the major benefit of sending more MiRPz Keilers to Ukraine. The single biggest obstacle to implementing Option #1 is Bundestag decision-making time.

Even with only 4 x Keilers deployed by the ZSU, these vehicles will be tested in combat. If proven valuable in Ukraine, Berlin need only order their stablemates shipped east. The BWB and the Bundeswehr have an opportunity. Rheinmetall now owns the rights to the Keiler flail system. [3] New flail sets could be ordered and fitted to refurbished Leopard 2A4 hulls.

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[1] Original plans were for 245 x flail tanks. The MiRPz Keiler concept dates all the way back to 1971 but other BWB priorities delayed production for a quarter century. It was only the minefields of the Balkan conflict that drew attention back to the programme. Keiler production finally began in 1996.

[2] I know that the proper acronym is now BAAINBw. But Bundesamt für Ausrüstung, Informationstechnik und Nutzung der Bundeswehr is even more unwieldy than the old Bundesamt für Wehrtechnik und Beschaffung ;p

[3] The original Keiler competition was won by construction machinery firm Kaelble GmbH of Backnang (near Stuttgart). Kaelble was responsible for the design and creation of the complex, folding mine flail system. Integration and prototype building fell to lead contractor Krupp MaK. Since Keiler production ended, Krupp MaK has became Rheinmetall Landsysteme GmbH and Kaelble went out of business. The Keiler mine flail system is now the property of Rheinmetall.

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