Tuesday, 16 July 2019

Upgunning the T-43

"T-43 tank turret with the D-5 system

During installation of the D-5 system into the T-43 tank turret, an insert is welded into the gun port, as the D-5 system is narrower than the F-34. An armoured shield is installed in the upper front part of the turret.

The seats of the gunner and commander are located in the same place as with the F-34. The turret traverse mechanism remains in the same place. The elevation mechanism is lowered by 40 mm relative to the elevation mechanism used on the F-34.

The trigger of the system is electric. The trigger is installed in the handle of the elevation flywheel. An electric trigger also works the coaxial DT machinegun. There is also a backup hand firing mechanism for the D-5 gun.

The sights and observation devices of the turret are installed in the same way as they are when in the F-34 is installed.

The radio is located in the same place as when the F-34 is installed.

50 rounds of ammunition are carried, 29 of which are carried in the floor, 16 in the turret bustle, and 5 on the right side of the turret.

Comparative characteristics of the F-34 and D-5 systems

Weight of the system with mantlet, kg
Caliber, mm
Distance from the trunnions to the rear of the recoil guard, mm
Recoil length, mm
Maximum recoil force, kg
Bore axis height relative to trunnion, mm
88 above trunnion
35 below trunnion
Maximum elevation, degrees
Minimum depression, degrees
Muzzle velocity
Maximum shell mass, kg
Maximum round length, mm
PT-4-7, TMFD
PT-4-15, KT
Mass of the tank with the gun


  1. Hi. I always enjoy viewing your site.

    Btw, I think the weight of F-34 with mantlet is not 1300 kg, but 1500 kg, despite its difficult to read. Intuitively, it seems to that D-5 is far heavier than F-34. But in reality, it is not so much.

    According to service manuals of D-5, the weight of oscillating part (it means without mantlet) is 1235 kg. So, weight of mantlet is around 1600 - 1235 = 365 kg.

    And 1135kg for oscillating part of F-34 (according to service manual 1943). It is likely that both mantlets are almost same in size and thickness, so F-34 with mantlet must be weighted 1135 + 365 = 1500 kg.

    1. Yes, if you look at the total increase in weight of a T-34-85 from a hex turret late production T-34, it is actually not that much. That is why they were able to boost the turret armour quite significantly.

    2. Peter, I have a question for you. IIRC every types of T-34 driver hatch, that's spring loaded hatch. Early T-34 turret (pirozok) also have on top spring loaded hatch. T-34-85 turret have spring loaded hatches. But that is situation in T-34 with gaika (hexagonal) turret? This turret also have spring loaded hatches?

      BTW, if hexagonal T-34 turret have spring loaded hatches, that's mean that in every T-34, every "upper hatches", that's spring loaded hatches.

  2. I'm legit impressed they actually managed to *reduce* the length of the recoil stroke despite nearly a ton more recoil force being involved, and still managed to keep the gun's weight hike to a mere ~200 kg despite a not-insignificant increase in caliber.

    Bit puzzled how according to the table the total mass of the tank went down by fifty kilos tho. Did someone dun goofed their numbers, or was it something like sufficiently fewer 85 mm shells fitting into the hull to result in net savings? According to teh Wikipedia mod. 1943 T-34s were managing to pack a whopping 100 76 mm shells which according to same were a bit over 6 kg apiece while the 85 mm ones were a bit over 9 kg, so with "only" 50 of the latter that would account for ~150 kilos already...

    1. Wait this is the T-43 not -34, derp. That's what I get for posting while eating lunch and only paying half attention. But how much 76 mm *could* that thing pack, anyway?

    2. Probably around the same number, if not more. The T-34-85 with a 76 mm gun prototype could carry 106.

    3. Huh. So assuming, for the sake of napkin maths, 100x 76 mm @ ~9 kg apiece (as per the table, it dawned to me the numbers on teh Wiki are for the shells proper rather than complete cartridges - double derp) for ~900 kg total versus 50x 85 mm @ ~15.5 kg for ~775 kg total... that'd be about 125 kg saved in ammo weight, or almost half of the mass added to the gun.

      Wonder where they shaved off the remaining ~225 kg to get that final net weight saving of 50 kg?