So, got some new stuff to post.
Supposedly test data from a declassified paper about the 120mm gun used on PTZ-89, which itself is embedded in a post about soviet armor.
original post:
http://www.fyjs.cn/thread-1898527-1-1.htmlI'll translate the relavant part, there are mainly 2 things to note. FIrst being obviously the 120mm gun itself and secondly the setup used for such tests.
the relevant pics:
I'll mainly translate the first one and comment on the second one.
Here we go.
There are 2 data columns, the left is the design requirments and the right is the tested results.
Design requirments:
- Gun caliber: 120mm smoothbore
- Ammo type: APFSDS, HE, HEAT
- Penetration power: At 1500m it needs to penetrate a type 681 composite target angled at 68° (90% pen on average), direct fire range exceding 2000m.
- Muzzle velocity: 1680-1700m/s, velocity decay per 1000m smaller than 80m/s
- Chamber pressure: 431Mpa under normal temperature. High temperature single shot abnormal pressure mustn't exceed 539Mpa
- Accuracy spread at 1000m target: Strive for 0,3mx0,3m at 1500m
- Operating enviroment temperature: -40 to +50°C
- Gun elevation: -8 to +18°
- Recoil force: smaller or equal to 494,3KN
- Recoil distance: smaller than 450mm
- Barrel endurance: No requirement
- Gun weight: Less than 3000kg (including shield)
- Maintenance: Barrel change without dismounting turret
Tested result:
- Gun caliber: 120mm smoothbore
- Ammo type: Only APFSDS tested, HE untested, HEAT development delayed due to funding issues
- Penetration power: Type 681 composite target plate terminal penetration velocity is 1422m/s; 150mm RHA plate angled at 65° terminal penetration velocity is 1441m/s, extrapolated penetration dstance are all above 3000m
- Muzzle velocity: Average muzzle velocity for 3 sets is 1698m/s, velocity decay per 1000m less than 60m/s
- Chamber pressure: 465Mpa under normal temperature. High temperature single shot abnormal pressure 553Mpa
- Accuracy spread at 1000m target: 0,12mx0,27m at 1000m
- Operating enviroment temperature: -40 to +50°C
- Gun elevation: -8 to +18°
- Recoil force: Maximum recoil is 563KN
- Recoil distance: smaller than 410mm
- Barrel endurance: No overall endurance tests conducted, after the trial the chamber wear already exceeded 3mm.
- Gun weight: Less than 3000kg (including shield)
- Maintenance: Specific tank chassis and layout were not taken into consideration
I think the most interesting is the pen power stuff, in the second pic the type 681 composite armor plate is given a thiccness at 204mm@68°, which is around 544mm at 0° the same number most people will find for the PTZ-89. However consider the target plate is not a steel block but a composite armor block, the true RHA is unknow.
Funny enough aside from the successful test against the composite target, the thiccest RHA target is just a 150mm plate at 65° (354mm RHA). The difference of the two is pretty obvious, and i think this is one of those quirks when it comes to PLA giving those target plates as the max pen power. It's confusing. Now imagine this sort of thing is very likely to apply to RPG and other HEAT weapons too.
The rest of pic too is just a overall comparison to other guns, pen power for NATO stuff and usually given using the NATO standard triple layer heavy target (10/20/80mm RHA plates). I think the numbers are selfevident enough, so i'll slkip translating.
Consider at the test table the HEAT round is still not finished i would assume the whole thing is from 1989 or a bit earlier. Anyway, thought this is interesting and shed some more light onto the test setup for PLA AP stuff and somehow also justifies the AP number eugen did for game balance purposes.
