Rear engined types for the tanks.
Front engined types for the TBMP/TBTR vehicles.
Koalitsiya is not an "Armata".
It has already been stated that the photos of Coalition currently show it in a T-90/72/80 or whatever chassis as a test bed and that the final vehicle will be based on the armata chassis. there is also a truck based version and I would ask the obvious... if Coalition is going to operate 70km behind the armata division it is supporting then WTF does it need to be based on armata chassis for? There is lots of evidence of the truck based version which should be much cheaper to buy and to operate and should offer the same artillery performance... why bother lightening the armata chassis when they already have a lighter and much cheaper truck chassis version?
We are not talking about "non-MBTs"; we are talking about a very long-ranged SPG. Koalitsiya would be deployed way to the back with respect to the tanks and the IFVs.
Coalition would be part of the division that includes all the vehicles from MBT, IFV, rocket and tube artillery, missile and missile/gun air defence, recon, command, anti tank missile, ambulance, engineer, bridge laying, mortar carrier, and possibly BMPT too. All those vehicles will be armata based, with two types of armata chassis... front engined and rear engined.
All are with the same level of armour and similar engines for similar levels of mobility.
And let's not bring the fiction and forum-talk related to an internal antiterrorist action into a logical discussion about an SPG for use as part of mechanized groupings.
They have already stated there will be two SPG variants of Coalition.. armata based and truck based.
I rather suspect there will be engine and transmission unification between that truck based version and the Boomerang wheeled medium vehicle family and probably the Kurganets family because apart from the difference of tracked vs wheeled they will be the same weight and both amphibious and unified crew stations and weapons...
65 tonnes would not be nearly enough. Do the calculations.
MSTA at 42 tons is slightly lighter than the T-80 tank it is based upon... I rather doubt the T-72 engine it is fitted with changed the weight that much.
Assuming the armata mbt is 52 tons, that means the turret could be 13 tons heavier than the turret fitted to the MSTA and the final weight would still be 65 tons... sounds reasonable to me.
I have never read anywhere that the MSTA has reduced hull armour.
This is a very inaccurate statement. With the level of technology the Russians would make public with this generation of vehicles, to give the SPG tank-like passive armor, would take the SP out of the SPG.
If the Coalition at 65 tons can't move with a feeble 1,400hp engine how the hell does the Abrams move... it is 5 tons heavier and only has an extra 100hp?
Some idiots even claim the Abrams can move around quite rapidly... silly them I guess.
But most importantly, there would "never" be a Koalitsiya within the range of an enemy 0.50'' rifle. Koalitsiya wouldn't intermingle with tanks and IFVs. Koalitsiya would have a range of over 100 km, and its range performance is superior to a 2S5, which was an army-level SPG.
There may not be any discernible front line and likely range is more likely to be closer to 70km max... which is plenty with GLONASS guided shells, it certainly will try not to mingle with enemy tanks and IFVs, but enemy anti tank units dropped behind enemy lines or ambush attacks can occur almost anywhere on a modern battlefield... helicopter or jeep mounted troops with TOWs or similar will try to surprise your forces from all sorts of directions.
What you are asking is like asking why MiG-31 wouldn't have the passive armor protection of a T-90.
No. More like asking why the MiG-31 has a self defence suite and chaff and flares is most of the time it will be shooting down B-52s and cruise missiles. the self defence avionics and flares and Chaff and capacity to use jammer pods means it can be used for other things like wild weasel roles and anti AWACS and and JSTARs purposes.
Exactly, Koalitsiya will have similar armor protection to that of ZSU-57-2; that's all they need; they are both vehicles to provide support. An SPG's armor protection requirement is less than that of BRDM-2. The armor is there to stop shrapnels (after all it has to deal with shrapnels, not with 50 cal bullets) and to provide a monocoque structure for the vehicle.
The purpose of unified vehicle families is to shorten the logistics tail by having one vehicle type with one transmission type, one type of track, one type of wheel, one type of engine with the same parts.
If paper thin armour was all that was needed then why bother with an armata based version?
A truck based model would be much cheaper... use the same engine and transmission as the armata family and just base it on a truck. With a 70km range you could just drive down nice hard roads, or make it a 10 wheel truck with excellent cross country mobility... it would still be cheaper to buy and cheaper to run than any track layer.
The reason for the armata based SPG is to have a vehicle that can operate on the front line if needed. Doesn't mean it will spend all or even any of its time there, but having the same mobility and protection as all the other vehicles in the unit is important.
The fact that the turret could be penetrated... or that the turret of the MBT or the turret of the 120mm mortar carrier or the turret of the air defence vehicles or the rocket artillery vehicles is not important... the purpose is not to create super armoured invincible super vehicles... the point is to make as sure as possible that if any of the vehicles are hit and taken out that the crew has the best chance of walking away and that goes for all vehicles in all weight classes.