Levi

There were two types of power train for GTD-1250 equipped T-80s. First - for domestic use, and it wasn't different from any other version of T-80 (with no steering, see below). And the second one (posted above) was marketed for international customers.

Regardless of the choice of steering, BKPs on all T-80 tanks were different from those used on T-64 and T-72.

Reverse works pretty much the same way it does in your road car (see ZF transmission above for example) - by locking one of the carriers onto the case. Only it has to be turned on on both sides here. BKP is essentially not very different from any automatic transmission - it's a planetary gearbox with 4 planetary gearsets and 6 wet clutches. The only two things it lacks to become a proper automatic transmission are torque converter and governor - walve box is already there.
It's small size is mostly the consequence of each gearbox transmitting only the half of the summary power output. This, plus the fact that there is no steering mechanism.

I must also add that T-80 wasn't very different from T-64 and T-72 in this department. It also didn't have neither any differentials, nor steering. It's BKPs were slightly smaller with 3 gearsets instead of 4 (it had 4 ranges instead of 7). Probably along with the fact that gas turbine doesn't have many auxiliaries reciprocating engines require and occupies less space, this was the motivation behind the idea to equip T-80 with hydrostatic ivt steering. The system was developed (see schematic below), tested, but never went into production.

Not sure if what I'm writing now is needed (or wasn't posted before), but I'll make a little contribution of my own.
I always thought of Russian 2nd gen MBTs having "very special" transmission arrangement as a well known fact, but constant confusion and numerous gaffes (like wikipedia articles claiming T-72 transmission to be a synchromesh, or Al-Khalid being equipped with SESM ESM500, which are both garbage) drove me to write this.
I do not have much time and haven't been able to find any decent articles, so I'll be brief. Long story short - Soviet/Russian tanks from T-64 through T-90 (and Ukrainian T-84) do not have a transmission per se. All the shifting is done in final drive assemblies instead - so called BKPs - "half-gearboxes". There is no main clutch - when clutch pedal is pressed, clutches in both BKPs are disengaged, and there is also no steering mechanism. Steering is done by switching one of the half-transmissions to the lower gear, or braking with disengaged clutch if it already was in the first gear. It's easy to deduce that this way you get a unique turning radius on each gear.
Here's an excerpt with description from T-72A manual:





And a gorgeous picture from Rolf Hilmes' "Kampfpanzer Heute und Morgen". Unfortunately I don't have a scanner, so the quality is medicore to say at least.

The interesting part is why did they come up with such a system to begin with. BKP was originally designed as a part of Object 430 tank's powerpack, and later used on it's successor - T-64. In both of those tanks BKPs were coupled each to a different end of the "briefcase engine's" crankshaft. One of crankshafts actually, since briefcases (both 5TD and 6TD) are horizontal transversely mounted opposite piston engines. The simple schematic of this:

(and here's why 6TD-equipped Al-Khalid couldn't possibly have a SESM transmission)
All of it was done in favor of saving space - T-64 was and is easily the most compact main battle tank ever produced. And the tradeoffs were considered acceptable. The obvious downside to this is a principal inability to insert a torque converter in such a power train, attempts to introduce hydrostatic steering also didn't produce any viable results. None the less BKPs were carried onto many subsequent Soviet MBT designs, in favor of both uniformity and space saving. Here's an example of North Korean Chonma tanks model 215 and 216 I've made some time before. Transition from synchromesh to BKP was most likely made because of latter ability to handle more torque, but difference in engine compartment size is also obvious:

1, like I said before, though we did try to make a tank engine based on MTU in 1978, but it failed. So maybe Type99 tank's engine still has some German tech, but that's not the major part.
2, in 1990s, a lot of Chinese  military fans worship German tech (even still today), so they hope our engine is also made by German tech, that's why the "99 engine is copyed from MTU" rumor keeps spreading.
3, 120V150ZLC engine (type 80/88/96, 730hp, also called as "730" by our old tank enginers and designers) is basicly a turbocharged V-2-54, here are 2 early photos of it:
prototype engine under test:

test tank ( looks like a Type69, maybe "68 revolution", according to WZ123's deputy chief designer's memoir, "68 revolution" is the frist test bed for 730 engine, it's a tank designed by a worker, yes, worker, not tank enginer, basicly a ordinary type 59/69 with some improvements, no detail info or photo ) with prototype engine under test:

4, Type99 (before 99A)'s engine is C12V150ZAL (1200hp, or 150HB), like I said before, it is basicly a new engine (with some tech from British CV12 much more than German MTU), and that's also why it's so unreliable for a very long time (unlike Type80/88's 730 engine based on V-2). Here are some photos of it:
.
(the photo above could either be 150X or 150HB, I'm not sure, sorry, I'm not good at engine. BTW, in case you don't know, 150X is another engine designed for WZ123, like F100/F110 for F-15/F-16 , but it's canceled before completed)


I have to work now, I'll answer your rest questions later.
 

Didn't see this one before, hence many thanks!
So, as we now have seen the vehicle's engine compartment, I assume it was to be powered by the same engine the final Type 99 version ended up with, wasn't it? Is it actually based on MTU MB 873 design as many articles suggest, or is it just a rumor?
I also have couple photos of WZ123 running prototype, more advanced design than what this mockup represents, but still inferior to the final Type 99:


Note that it is armed with 2A46 gun instead of ZPT-98, lacks commander's panoramic sight, and turret's cheek armor has visibly less los thickness than production variant.
Another interesting thing - unknown Type 80 prototype armed with D-10:


And another bunch of my questions:
-What were the factory codes for Type 80 and Type 85 family vehicles? Not all of them were developed out of factory's own initiative.
-What is the difference between Type 85-II and Type 85-IIA? Was Type 85-IIA ever made? I have seen no photos.
-What engine and transmission did Type 85-III have? Some sources claim it was equipped with 1000hp V-2 derivative and BKPs. If yes, then are we to assume these originated from Poland?
-Can you give a rundown of Chinese V-2 derivatives and transmissions Type 80 and 85 tanks had?

Not sure if what I'm writing now is needed (or wasn't posted before), but I'll make a little contribution of my own.
I always thought of Russian 2nd gen MBTs having "very special" transmission arrangement as a well known fact, but constant confusion and numerous gaffes (like wikipedia articles claiming T-72 transmission to be a synchromesh, or Al-Khalid being equipped with SESM ESM500, which are both garbage) drove me to write this.
I do not have much time and haven't been able to find any decent articles, so I'll be brief. Long story short - Soviet/Russian tanks from T-64 through T-90 (and Ukrainian T-84) do not have a transmission per se. All the shifting is done in final drive assemblies instead - so called BKPs - "half-gearboxes". There is no main clutch - when clutch pedal is pressed, clutches in both BKPs are disengaged, and there is also no steering mechanism. Steering is done by switching one of the half-transmissions to the lower gear, or braking with disengaged clutch if it already was in the first gear. It's easy to deduce that this way you get a unique turning radius on each gear.
Here's an excerpt with description from T-72A manual:





And a gorgeous picture from Rolf Hilmes' "Kampfpanzer Heute und Morgen". Unfortunately I don't have a scanner, so the quality is medicore to say at least.

The interesting part is why did they come up with such a system to begin with. BKP was originally designed as a part of Object 430 tank's powerpack, and later used on it's successor - T-64. In both of those tanks BKPs were coupled each to a different end of the "briefcase engine's" crankshaft. One of crankshafts actually, since briefcases (both 5TD and 6TD) are horizontal transversely mounted opposite piston engines. The simple schematic of this:

(and here's why 6TD-equipped Al-Khalid couldn't possibly have a SESM transmission)
All of it was done in favor of saving space - T-64 was and is easily the most compact main battle tank ever produced. And the tradeoffs were considered acceptable. The obvious downside to this is a principal inability to insert a torque converter in such a power train, attempts to introduce hydrostatic steering also didn't produce any viable results. None the less BKPs were carried onto many subsequent Soviet MBT designs, in favor of both uniformity and space saving. Here's an example of North Korean Chonma tanks model 215 and 216 I've made some time before. Transition from synchromesh to BKP was most likely made because of latter ability to handle more torque, but difference in engine compartment size is also obvious:

Not sure if what I'm writing now is needed (or wasn't posted before), but I'll make a little contribution of my own.
I always thought of Russian 2nd gen MBTs having "very special" transmission arrangement as a well known fact, but constant confusion and numerous gaffes (like wikipedia articles claiming T-72 transmission to be a synchromesh, or Al-Khalid being equipped with SESM ESM500, which are both garbage) drove me to write this.
I do not have much time and haven't been able to find any decent articles, so I'll be brief. Long story short - Soviet/Russian tanks from T-64 through T-90 (and Ukrainian T-84) do not have a transmission per se. All the shifting is done in final drive assemblies instead - so called BKPs - "half-gearboxes". There is no main clutch - when clutch pedal is pressed, clutches in both BKPs are disengaged, and there is also no steering mechanism. Steering is done by switching one of the half-transmissions to the lower gear, or braking with disengaged clutch if it already was in the first gear. It's easy to deduce that this way you get a unique turning radius on each gear.
Here's an excerpt with description from T-72A manual:





And a gorgeous picture from Rolf Hilmes' "Kampfpanzer Heute und Morgen". Unfortunately I don't have a scanner, so the quality is medicore to say at least.

The interesting part is why did they come up with such a system to begin with. BKP was originally designed as a part of Object 430 tank's powerpack, and later used on it's successor - T-64. In both of those tanks BKPs were coupled each to a different end of the "briefcase engine's" crankshaft. One of crankshafts actually, since briefcases (both 5TD and 6TD) are horizontal transversely mounted opposite piston engines. The simple schematic of this:

(and here's why 6TD-equipped Al-Khalid couldn't possibly have a SESM transmission)
All of it was done in favor of saving space - T-64 was and is easily the most compact main battle tank ever produced. And the tradeoffs were considered acceptable. The obvious downside to this is a principal inability to insert a torque converter in such a power train, attempts to introduce hydrostatic steering also didn't produce any viable results. None the less BKPs were carried onto many subsequent Soviet MBT designs, in favor of both uniformity and space saving. Here's an example of North Korean Chonma tanks model 215 and 216 I've made some time before. Transition from synchromesh to BKP was most likely made because of latter ability to handle more torque, but difference in engine compartment size is also obvious:

Didn't see this one before, hence many thanks!
So, as we now have seen the vehicle's engine compartment, I assume it was to be powered by the same engine the final Type 99 version ended up with, wasn't it? Is it actually based on MTU MB 873 design as many articles suggest, or is it just a rumor?
I also have couple photos of WZ123 running prototype, more advanced design than what this mockup represents, but still inferior to the final Type 99:


Note that it is armed with 2A46 gun instead of ZPT-98, lacks commander's panoramic sight, and turret's cheek armor has visibly less los thickness than production variant.
Another interesting thing - unknown Type 80 prototype armed with D-10:


And another bunch of my questions:
-What were the factory codes for Type 80 and Type 85 family vehicles? Not all of them were developed out of factory's own initiative.
-What is the difference between Type 85-II and Type 85-IIA? Was Type 85-IIA ever made? I have seen no photos.
-What engine and transmission did Type 85-III have? Some sources claim it was equipped with 1000hp V-2 derivative and BKPs. If yes, then are we to assume these originated from Poland?
-Can you give a rundown of Chinese V-2 derivatives and transmissions Type 80 and 85 tanks had?

Didn't see this one before, hence many thanks!
So, as we now have seen the vehicle's engine compartment, I assume it was to be powered by the same engine the final Type 99 version ended up with, wasn't it? Is it actually based on MTU MB 873 design as many articles suggest, or is it just a rumor?
I also have couple photos of WZ123 running prototype, more advanced design than what this mockup represents, but still inferior to the final Type 99:


Note that it is armed with 2A46 gun instead of ZPT-98, lacks commander's panoramic sight, and turret's cheek armor has visibly less los thickness than production variant.
Another interesting thing - unknown Type 80 prototype armed with D-10:


And another bunch of my questions:
-What were the factory codes for Type 80 and Type 85 family vehicles? Not all of them were developed out of factory's own initiative.
-What is the difference between Type 85-II and Type 85-IIA? Was Type 85-IIA ever made? I have seen no photos.
-What engine and transmission did Type 85-III have? Some sources claim it was equipped with 1000hp V-2 derivative and BKPs. If yes, then are we to assume these originated from Poland?
-Can you give a rundown of Chinese V-2 derivatives and transmissions Type 80 and 85 tanks had?

Not much, I know sth about what we have in that era ( specific armour and weapon performance, but it is still classified info, so I can't told you the detail, what I can share is in 1989, the lowest Chinese composite armour is a copy of early T72's UFP armour, 200mm at 22  degree, which resist 320mm VS AP and 425mm VS HEAT; the best one is also 200mm/22 degree, which can resist 400mm+ VS AP and 600mm+ VS HEAT. So we may assume that's what the first prototype has ), but not WZ123's original design's detail info.
All I have about it, is another photo of its early model, this is declassified:

Reverse works pretty much the same way it does in your road car (see ZF transmission above for example) - by locking one of the carriers onto the case. Only it has to be turned on on both sides here. BKP is essentially not very different from any automatic transmission - it's a planetary gearbox with 4 planetary gearsets and 6 wet clutches. The only two things it lacks to become a proper automatic transmission are torque converter and governor - walve box is already there.
It's small size is mostly the consequence of each gearbox transmitting only the half of the summary power output. This, plus the fact that there is no steering mechanism.

I must also add that T-80 wasn't very different from T-64 and T-72 in this department. It also didn't have neither any differentials, nor steering. It's BKPs were slightly smaller with 3 gearsets instead of 4 (it had 4 ranges instead of 7). Probably along with the fact that gas turbine doesn't have many auxiliaries reciprocating engines require and occupies less space, this was the motivation behind the idea to equip T-80 with hydrostatic ivt steering. The system was developed (see schematic below), tested, but never went into production.

There were two types of power train for GTD-1250 equipped T-80s. First - for domestic use, and it wasn't different from any other version of T-80 (with no steering, see below). And the second one (posted above) was marketed for international customers.

Regardless of the choice of steering, BKPs on all T-80 tanks were different from those used on T-64 and T-72.

GTD-1250 transmission on tanks in Russian inventory is not different from GTD-1000 transmission. At least not fundamentally, probably the ranges are slightly different, I'm not entirely sure about that. Again, I should strees it that transmission with hydrostatic steering was never produced - Russian military was not interested in it, and no foreign customers have been found.

Neutral steer is possible with BKP mechanically wise, but iirc control system does not have this option.

Oplot has pretty much the same transmission setup as T-64, but with external gearset for reverse, so that the vehicle can move backwards on any range.
There is also a bizzare version with hydrostatic steering, that doesn't have any links between BKPs other than engine's crankshaft. It has two IVTs each paralleled to the mechanical part of respective BKP so that reduction can be made continuously without shifting down. But it is forever in development and was never produced. No schematics available.

GTD-1250 transmission on tanks in Russian inventory is not different from GTD-1000 transmission. At least not fundamentally, probably the ranges are slightly different, I'm not entirely sure about that. Again, I should strees it that transmission with hydrostatic steering was never produced - Russian military was not interested in it, and no foreign customers have been found.

Neutral steer is possible with BKP mechanically wise, but iirc control system does not have this option.

Oplot has pretty much the same transmission setup as T-64, but with external gearset for reverse, so that the vehicle can move backwards on any range.
There is also a bizzare version with hydrostatic steering, that doesn't have any links between BKPs other than engine's crankshaft. It has two IVTs each paralleled to the mechanical part of respective BKP so that reduction can be made continuously without shifting down. But it is forever in development and was never produced. No schematics available.

Reverse works pretty much the same way it does in your road car (see ZF transmission above for example) - by locking one of the carriers onto the case. Only it has to be turned on on both sides here. BKP is essentially not very different from any automatic transmission - it's a planetary gearbox with 4 planetary gearsets and 6 wet clutches. The only two things it lacks to become a proper automatic transmission are torque converter and governor - walve box is already there.
It's small size is mostly the consequence of each gearbox transmitting only the half of the summary power output. This, plus the fact that there is no steering mechanism.

I must also add that T-80 wasn't very different from T-64 and T-72 in this department. It also didn't have neither any differentials, nor steering. It's BKPs were slightly smaller with 3 gearsets instead of 4 (it had 4 ranges instead of 7). Probably along with the fact that gas turbine doesn't have many auxiliaries reciprocating engines require and occupies less space, this was the motivation behind the idea to equip T-80 with hydrostatic ivt steering. The system was developed (see schematic below), tested, but never went into production.

There were two types of power train for GTD-1250 equipped T-80s. First - for domestic use, and it wasn't different from any other version of T-80 (with no steering, see below). And the second one (posted above) was marketed for international customers.

Regardless of the choice of steering, BKPs on all T-80 tanks were different from those used on T-64 and T-72.

Not sure if what I'm writing now is needed (or wasn't posted before), but I'll make a little contribution of my own.
I always thought of Russian 2nd gen MBTs having "very special" transmission arrangement as a well known fact, but constant confusion and numerous gaffes (like wikipedia articles claiming T-72 transmission to be a synchromesh, or Al-Khalid being equipped with SESM ESM500, which are both garbage) drove me to write this.
I do not have much time and haven't been able to find any decent articles, so I'll be brief. Long story short - Soviet/Russian tanks from T-64 through T-90 (and Ukrainian T-84) do not have a transmission per se. All the shifting is done in final drive assemblies instead - so called BKPs - "half-gearboxes". There is no main clutch - when clutch pedal is pressed, clutches in both BKPs are disengaged, and there is also no steering mechanism. Steering is done by switching one of the half-transmissions to the lower gear, or braking with disengaged clutch if it already was in the first gear. It's easy to deduce that this way you get a unique turning radius on each gear.
Here's an excerpt with description from T-72A manual:





And a gorgeous picture from Rolf Hilmes' "Kampfpanzer Heute und Morgen". Unfortunately I don't have a scanner, so the quality is medicore to say at least.

The interesting part is why did they come up with such a system to begin with. BKP was originally designed as a part of Object 430 tank's powerpack, and later used on it's successor - T-64. In both of those tanks BKPs were coupled each to a different end of the "briefcase engine's" crankshaft. One of crankshafts actually, since briefcases (both 5TD and 6TD) are horizontal transversely mounted opposite piston engines. The simple schematic of this:

(and here's why 6TD-equipped Al-Khalid couldn't possibly have a SESM transmission)
All of it was done in favor of saving space - T-64 was and is easily the most compact main battle tank ever produced. And the tradeoffs were considered acceptable. The obvious downside to this is a principal inability to insert a torque converter in such a power train, attempts to introduce hydrostatic steering also didn't produce any viable results. None the less BKPs were carried onto many subsequent Soviet MBT designs, in favor of both uniformity and space saving. Here's an example of North Korean Chonma tanks model 215 and 216 I've made some time before. Transition from synchromesh to BKP was most likely made because of latter ability to handle more torque, but difference in engine compartment size is also obvious:

Not sure if what I'm writing now is needed (or wasn't posted before), but I'll make a little contribution of my own.
I always thought of Russian 2nd gen MBTs having "very special" transmission arrangement as a well known fact, but constant confusion and numerous gaffes (like wikipedia articles claiming T-72 transmission to be a synchromesh, or Al-Khalid being equipped with SESM ESM500, which are both garbage) drove me to write this.
I do not have much time and haven't been able to find any decent articles, so I'll be brief. Long story short - Soviet/Russian tanks from T-64 through T-90 (and Ukrainian T-84) do not have a transmission per se. All the shifting is done in final drive assemblies instead - so called BKPs - "half-gearboxes". There is no main clutch - when clutch pedal is pressed, clutches in both BKPs are disengaged, and there is also no steering mechanism. Steering is done by switching one of the half-transmissions to the lower gear, or braking with disengaged clutch if it already was in the first gear. It's easy to deduce that this way you get a unique turning radius on each gear.
Here's an excerpt with description from T-72A manual:





And a gorgeous picture from Rolf Hilmes' "Kampfpanzer Heute und Morgen". Unfortunately I don't have a scanner, so the quality is medicore to say at least.

The interesting part is why did they come up with such a system to begin with. BKP was originally designed as a part of Object 430 tank's powerpack, and later used on it's successor - T-64. In both of those tanks BKPs were coupled each to a different end of the "briefcase engine's" crankshaft. One of crankshafts actually, since briefcases (both 5TD and 6TD) are horizontal transversely mounted opposite piston engines. The simple schematic of this:

(and here's why 6TD-equipped Al-Khalid couldn't possibly have a SESM transmission)
All of it was done in favor of saving space - T-64 was and is easily the most compact main battle tank ever produced. And the tradeoffs were considered acceptable. The obvious downside to this is a principal inability to insert a torque converter in such a power train, attempts to introduce hydrostatic steering also didn't produce any viable results. None the less BKPs were carried onto many subsequent Soviet MBT designs, in favor of both uniformity and space saving. Here's an example of North Korean Chonma tanks model 215 and 216 I've made some time before. Transition from synchromesh to BKP was most likely made because of latter ability to handle more torque, but difference in engine compartment size is also obvious:

Not sure if what I'm writing now is needed (or wasn't posted before), but I'll make a little contribution of my own.
I always thought of Russian 2nd gen MBTs having "very special" transmission arrangement as a well known fact, but constant confusion and numerous gaffes (like wikipedia articles claiming T-72 transmission to be a synchromesh, or Al-Khalid being equipped with SESM ESM500, which are both garbage) drove me to write this.
I do not have much time and haven't been able to find any decent articles, so I'll be brief. Long story short - Soviet/Russian tanks from T-64 through T-90 (and Ukrainian T-84) do not have a transmission per se. All the shifting is done in final drive assemblies instead - so called BKPs - "half-gearboxes". There is no main clutch - when clutch pedal is pressed, clutches in both BKPs are disengaged, and there is also no steering mechanism. Steering is done by switching one of the half-transmissions to the lower gear, or braking with disengaged clutch if it already was in the first gear. It's easy to deduce that this way you get a unique turning radius on each gear.
Here's an excerpt with description from T-72A manual:





And a gorgeous picture from Rolf Hilmes' "Kampfpanzer Heute und Morgen". Unfortunately I don't have a scanner, so the quality is medicore to say at least.

The interesting part is why did they come up with such a system to begin with. BKP was originally designed as a part of Object 430 tank's powerpack, and later used on it's successor - T-64. In both of those tanks BKPs were coupled each to a different end of the "briefcase engine's" crankshaft. One of crankshafts actually, since briefcases (both 5TD and 6TD) are horizontal transversely mounted opposite piston engines. The simple schematic of this:

(and here's why 6TD-equipped Al-Khalid couldn't possibly have a SESM transmission)
All of it was done in favor of saving space - T-64 was and is easily the most compact main battle tank ever produced. And the tradeoffs were considered acceptable. The obvious downside to this is a principal inability to insert a torque converter in such a power train, attempts to introduce hydrostatic steering also didn't produce any viable results. None the less BKPs were carried onto many subsequent Soviet MBT designs, in favor of both uniformity and space saving. Here's an example of North Korean Chonma tanks model 215 and 216 I've made some time before. Transition from synchromesh to BKP was most likely made because of latter ability to handle more torque, but difference in engine compartment size is also obvious:

Not sure if what I'm writing now is needed (or wasn't posted before), but I'll make a little contribution of my own.
I always thought of Russian 2nd gen MBTs having "very special" transmission arrangement as a well known fact, but constant confusion and numerous gaffes (like wikipedia articles claiming T-72 transmission to be a synchromesh, or Al-Khalid being equipped with SESM ESM500, which are both garbage) drove me to write this.
I do not have much time and haven't been able to find any decent articles, so I'll be brief. Long story short - Soviet/Russian tanks from T-64 through T-90 (and Ukrainian T-84) do not have a transmission per se. All the shifting is done in final drive assemblies instead - so called BKPs - "half-gearboxes". There is no main clutch - when clutch pedal is pressed, clutches in both BKPs are disengaged, and there is also no steering mechanism. Steering is done by switching one of the half-transmissions to the lower gear, or braking with disengaged clutch if it already was in the first gear. It's easy to deduce that this way you get a unique turning radius on each gear.
Here's an excerpt with description from T-72A manual:





And a gorgeous picture from Rolf Hilmes' "Kampfpanzer Heute und Morgen". Unfortunately I don't have a scanner, so the quality is medicore to say at least.

The interesting part is why did they come up with such a system to begin with. BKP was originally designed as a part of Object 430 tank's powerpack, and later used on it's successor - T-64. In both of those tanks BKPs were coupled each to a different end of the "briefcase engine's" crankshaft. One of crankshafts actually, since briefcases (both 5TD and 6TD) are horizontal transversely mounted opposite piston engines. The simple schematic of this:

(and here's why 6TD-equipped Al-Khalid couldn't possibly have a SESM transmission)
All of it was done in favor of saving space - T-64 was and is easily the most compact main battle tank ever produced. And the tradeoffs were considered acceptable. The obvious downside to this is a principal inability to insert a torque converter in such a power train, attempts to introduce hydrostatic steering also didn't produce any viable results. None the less BKPs were carried onto many subsequent Soviet MBT designs, in favor of both uniformity and space saving. Here's an example of North Korean Chonma tanks model 215 and 216 I've made some time before. Transition from synchromesh to BKP was most likely made because of latter ability to handle more torque, but difference in engine compartment size is also obvious:

WZ is for vehicle which requested by PLA, like WZ120, WZ121, etc, that's what Chinese army asked first, then the plant start the project.
BK means "BaoKe" (In Chinese,"包科"),
"Bao"("包") means BaoTou ( "包头", a city of Inner Mongolia,  the city where plant 617 located),
"Ke"("科") means Keyan ( "科研", means "research" in English).
So BK means plant 617's own research project (not some stuff requested by PLA).
So they have no connection to each other,  a BK vehcile is not for the Army, so it won't have any WZ number.

The real "1st Chinese welded turret" ( built in 1979 or 1980. some parts are cast made, I think it means the hatchs and the part around mantlet) of type 80 tank, which is used as a ballistic test target, there is a project ( maybe a 122mm HE? ) right in front of it.

Plant 617's testing ground, there are 2 WZ122s in the right, and a T72 (T72B?) in the left.

 
You asked me about the different between 2 sets of photos of "Type80's welded turret" before, I just found out why:


This tank is not the "Type80 with test welded turret" at all, it is BK1851 as wrote on its turret. It's much later than "Type80 with test welded turret", it is a project started in 1985 which meant to use steering wheel driving and western engine & transmission parts.
Another unkown tank, maybe still BK1851:

I'll post BK1871 ( a early prototype of Type90-II tank, more like VK3601 to Tiger but not VK4501) 's photo later.

Didn't want to sign up, but it seems I have no choice but to step in to clarify some things. All of the questions were mine.
Hello, everyone, by the way!
That's a shame. I was wondering if there are more photos of those specific vehicles, sitting in the 617 plant's museum, where these came from, not any photos in general. Specifically, I am interested in seeing engine decks of 122 vehicles. But you have already partially provided this, thanks a lot.
This is golden.
It's a good thing you have gathered I was asking about WZ-122, not WZ-111
But I've made a mistake. The vehicle standing behind WZ-122-6 is WZ-122-2, not WZ-122-1. It can be easily identified as Three-Mechanical, but for some reason I thought that Three-Mechanical was built first, and Three-Hydraulic after, not the vice versa. I was wrong. So it is WZ-122-2 aka WZ-122B in the museum. And of course I was asking about never-seen-before photos (such as from this museum), not those two we all have surely already seen.
No, the turret it not original either, It just was installed earlier than the gun. It is clearly evident that this turret was built to house 2A46, since it has large round opening for commander's cupola on the right side (1) and typical gunner's hatch on the left (2). This constitutes for the crew of 3 (autoloader is present). And if this is not enough, it also has the case ejection window (3). This kind of setup is unsuitable for 105mm.


Here it is, sitting next to WZ-111 hull:


There is a name plaque in front of it, but nobody bothered to make a photo of it yet.
I suspect that this may be pre-1969 WZ-121, but it's only a hunch.

Didn't want to sign up, but it seems I have no choice but to step in to clarify some things. All of the questions were mine.
Hello, everyone, by the way!
That's a shame. I was wondering if there are more photos of those specific vehicles, sitting in the 617 plant's museum, where these came from, not any photos in general. Specifically, I am interested in seeing engine decks of 122 vehicles. But you have already partially provided this, thanks a lot.
This is golden.
It's a good thing you have gathered I was asking about WZ-122, not WZ-111
But I've made a mistake. The vehicle standing behind WZ-122-6 is WZ-122-2, not WZ-122-1. It can be easily identified as Three-Mechanical, but for some reason I thought that Three-Mechanical was built first, and Three-Hydraulic after, not the vice versa. I was wrong. So it is WZ-122-2 aka WZ-122B in the museum. And of course I was asking about never-seen-before photos (such as from this museum), not those two we all have surely already seen.
No, the turret it not original either, It just was installed earlier than the gun. It is clearly evident that this turret was built to house 2A46, since it has large round opening for commander's cupola on the right side (1) and typical gunner's hatch on the left (2). This constitutes for the crew of 3 (autoloader is present). And if this is not enough, it also has the case ejection window (3). This kind of setup is unsuitable for 105mm.


Here it is, sitting next to WZ-111 hull:


There is a name plaque in front of it, but nobody bothered to make a photo of it yet.
I suspect that this may be pre-1969 WZ-121, but it's only a hunch.