I understand the installation we’ve seen on Abrams so far is only for testing purposes. The operational systems are supposed to be more streamlined and better integrated into the turret.
Based on images we have seen of it in European deployment.
Photos released on July 10 ahead of the second phase of the Army's Defense Europe exercise show an M1 Abrams main battle tank rocking an Israeli-made Trophy Active Protection System (APS)
I think that the bulky form is the final form. Early artist concept images that showed a more integrated form, I think failed to materialize due to the number of changes needed to be done to the A2 Turret. I mean it had the phased array Radar panels in the frontal armored plate. The countermeasure launcher was in the middle of the turret. It just wasn’t realistic.
Mar 4, 2022 - This Pin was discovered by SUSAN OZAN. Discover (and save!) your own Pins on Pinterest
That is not a knock against Abrams it’s one of the MBT that can easily hold the top tank of the world trophy (Not knocking any other Modern MBT either, it’s just that right now most of the Tanks you can name are pretty much tied and it becomes a question of your perspective on what you feel is more relevant a feature vs the others). But it seems likely Merkava 4’s modular armor in particular the side armor of the turret was used to host the system.
This slide image source Merkava Mk 4 Tank - Fighting-Vehicles.com
image Source File:Merkeva Mk 4M - Israeli Tanks 2019-04-21 IZE-42.jpg - Wikimedia Commons
The above image Slide the armor of the Merkava 4 Turret in exploded view. The two frontal armor sections we see on 4M but the side sections are where the Trophy system lives. As seen in the second image. It seems like they cut into the spaces of the sides to house a lot of the machinery. Abrams Turret wasn’t designed in that manor. Most modern NATO tanks have been extensively modified with new kit and armor modifications not to the degree here where in the turret was totally replaced
Though it does have side armor it’s not in that configuration of large sections that could easily be swapped out like that. Only a handful of modern tanks are built like that Leclerc I think could do that, Leopard Revolution too. But it generally would need a new armor system and or Turret for a tank of Abrams design era.
As such the most convenient solution thus far was it seems to mount the system along the side racks. As an external module. This allowed the system the space for its automatic loader, radars, launcher and the like. It means that at least in theory more Abrams can also be retrofit with the system fairly rapidly. Considering the Number of the type available or stored that’s a good advantage. Although a heavy one. It makes a already heavy tank, “chunkier”.
This makes things interesting for the Challanger. Challanger II turret has to be replaced for this upgrade. If that’s the case than depending on build an APS added to the system could be more streamlined into the new turret. If the final architecture resembles the current Challanger than the side mounted system would make sense. If they give the armor package a total overhaul then more integrated. The Artists concepts for Rheinmetall's Challanger II redux make me think bolt on as it “ looks” like the old turret, Yet that’s subjective and not based on the final product.