Don's Weekly, 15 July 2024: Part 5

by Donals Hill & Tom Cooper

(….continued from Part 4…)

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Equipment

Excavators are being used by both sides as close as 1-2 km behind the front lines digging defensive positions in treelines, which they use for cover. The gray excavator has already been sent to the 58th Brigade. The others are undergoing repairs and re-painting.

Russia removed about 300 130 mm artillery pieces from storage. They no longer make 130 mm ammo but North Korea and Iran do.

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Soft Recoil Technology

Early cannons would recoil backwards when fired and had to be pushed back into position. They were then designed to have their barrels recoil, allowing the gun to stay in place and absorb the residual energy. If the gun was self-propelled, then the chassis carrying the gun had to absorb the energy, as well. The next development they are working on is soft recoil, in which the pressurized barrel is set forward in motion the instant before it is fired. That forward motion absorbs 60% of the energy, the recoil of the barrel absorbs some of the energy, and then the residual energy is absorbed by the mount or chassis. With soft recoil, the recoil energy is reduced enough that a much lighter chassis and recoil system can be used to carry and fire the gun.

This technology has been tested with both a 105 mm and 155 mm barrel. Back in April, a 105 mm gun mounted on a HUMMWV was sent to Ukraine to test the system in a combat environment. In addition to the howitzer mounted on the HUMMWV, there is a support HUMMWV that will carry the ammo.

The initial rate of fire is 10-12 rounds per minute and three rounds per minute of sustained fire. If the digitized firing system fails, the weapon can still be fired. The system can be set up, fire two rounds, and displace in three minutes. It has a range of 11.6 km. By comparison, the towed M119 105 mm gun has a range of 17.5 km. It has a crew of 3 and can be operated by a crew of two.

Test firing during development in the US.

In this video, you can see the barrel move forward before recoiling as the US National Guard fired it in 2019.

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UMPKs

The Russians can’t stop claiming, and Pudding-fans abroad can’t stop repeating the Russian claims, that the VKS is deploying UMPK glide bombs based on ‘FAB-3000M-54’ - bombs calibre 3000kg - against Ukrainian positions (especially so in northern Kharkiv, but also in the Chasiv Yar area, and elsewhere).

No doubt, meanwhile, the Russians have managed to refine their UMPK glide bombs to the level where these are having serious effects upon the fighting on the ground. They’re not only terrifying, but where one hits, even if troops are not killed, they are injured, shaken, unable to fight. And the Russians are deploying dozens of UMPKs every single day.

Unsurprisingly considering their effects, the story about ‘UMPKs on FAB-3000M-54s’ is meanwhile bought even by the majority of the Ukrainian media.

Problem: if this is the case, then were are videos showing the Russians actually having an UMPK kit fitting the FAB-3000M-54, and then hanging it on any of their Su-34s, and actually deploying such a weapon?

So far, there were none to be seen. Instead, what the Russians are showing us all the time, are UMPKs based on FAB-1500M-54s - bombs calibre 1,500kg. For example, last year, we’ve been shown the original model:

Essentially, what this video-still is showing is the UMPK-kit strapped on a FAB-1500M-54 - and, so far, that was also what we’ve got to see every single time the Russians have released a new video of ‘UMPK on FAB-3000M-54’, too. So in the latest case, too.

Indeed, in combination with few other photos and videos (see below), this was the most interesting video of this kind, because it’s showing nearly everything relevant. From the fact that the Russians are first installing the bomb on their Su-34s, before strapping the UMPK-kit to it, to the fact that, once released, the bomb first has to ‘flip upside down’ to attain correct attitude for its flight to the target.

But, and despite claims about this being ‘FAB-3000M-54’, there are still strong doubts.

Now, how to recognise a FAB-1500M-54 from the FAB-3000M-54?

That’s not easy. Theoretically, one could estimate by their dimensions.

FAB-1500M-54 is 2.840mm (or 2.8m) long, and its body has a diameter of 640mm (or 64cm, or 0.6m).

FAB-3000M-54 is 3,520mm (or 3,5m) long, and its body has a diameter of 820mm (or 82cm, or 0.8m).

….which means that, if positioned right next to each other, they would look like this:

Sorry for the ‘rusty-black’-painted example in the middle: was a reconstruction of a FAB-1500M-54 released by one of Tupolev Tu-22 bomber of the Libyan Arab Air Force in the course of a strike on a French positions in Chad of 1987, drawn for this book. With other words: yes, I know the Russians are nowadays painting their FABs of these calibres in a darker shade of grey-green, too.

….but, there are no videos or photos showing anybody running around UMPKs with a measuring tape in hands…

Instead, most of the times, what we get to see in terms of (claimed/reported) ‘UMPK on FAB-3000M-54’ are takes like this, where the comparison of dimensions is not easy.

Arguably, no idea about the exact dimensions of Su-27/30/34’s intakes. But, when there are photos or video stills like this one:

…that’s still not looking like 82cm in diameter. Rather the 64cm of the FAB-1500M-54. Plus, the weapon appears ‘too short’ for 3,5 metres.

Arguably, the front party of the part of the UMPK kit holding wings of the weapon in their place on the latest video, is looking different than the same part on the UMPK kit for the FAB-1500M-54 (foremost: it is much longer). But, that detail is ‘not convincing enough’: after all, there are also minor differences in UMPK kits used for FAB-250s and FAB-500s. Probably, these depend on who and where is manufacturing them, or from what batch is the kit in question.

Finally, what we get to see on videos like the one linked above, is still the ‘leaner and shorter’ UMPK on FAB-1500M-54, rather than ‘fat and longer’ UMPK on FAB-3000M-54.

The same is valid for the sequence from which this still was taken:

With other words: pending availability of better evidence, there’s still no clear evidence for the VKS having any UMPKs on FAB-3000M-54 in service.

Of course, we’re looking forward for constructive feedback in this regards.