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Historical Accuracy, or why listening to WoT can be bad for you


Life_In_Black
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So, two days ago on Status Report it was mentioned that the top speed of the Action X Centurion was historical, that it was based on the South African Olifant (no relation to that BabyOlifant fellow from the WoT forums):

 

 

- The improved 53 km/h of Action X is historical, this speed was achieved during tests in South Africa (Olifant suspension)

 

Naturally, this made me curious and so I started digging into the history of the Olifant and the upgrades South Africa made to their Centurions.

 

Project Skokiaan began in 1972, with the goal being to replace the always unreliable 650hp Meteor engine. The replacement was the 810hp V-12 AV-1790 gasoline engine, which had seen service in the early variants of the M48 Patton, which was coupled to a new three speeed automatic transmission. In 1974, Project Semel was undertaken to further improve both the engine and tranmission, and it was under Project Semel that the Centurion reached a power to weight ratio of 16.5 hp/ton and a top speed of 50km/h, up from the 35km/h it got with the 650hp Meteor engine, and effectively doubling the vehicle's range.

 

Now here's where it gets interesting. Under Project Olifant in 1976, the engine was replaced with a 750hp V-12 AVDS-1790 (used on the M60, and Israeli Centurions and M48s) and possibly a new transmission, which lowered the power to weight ratio to 13.4hp ton, and the top speed down to 45km/h, however the range further increased due to the diesel engine and fuel efficiency. With some other improvements, this became the Olifant Mk. 1

 

Near as I can tell, it took the Olifant Mk. 1A to finally replace the 20-pdr with the 105mm L7, but it's the Mk. 1B that's interesting. The engine on the Mk. 1B was repalced again with a 900hp engine, but apparently this was later superceded by a V12 950hp engine, possibly an American engine by way of Israel. In addition, the entire suspension was comprehensively rebuilt with individual torsion bars for the roadwheels rather than the outdated Horstmann suspension.

 

So having researched all of that, I went back and looked at the engines of the Centurion Mk. I and Centurion Mk. 7/1 in-game, of which the elite form of the Centurion Mk. I is the Centurion Mk. III, and the elite form of the Centurion Mk. 7/1 is the Mk. 9. The Centurion 1 starts out with a 600hp Rolls-Royce Meteor engine, upgrades to a 650hp Rolls-Royce Meteor engine, which near as I can tell pretty much all of the Centurions in British service used for the entirety of their service, and finally as an elite engine it gets a 750hp Meteor engine that may or may not have existed, and certainly wasn't mounted on any mark of Centurion even close to a Centurion Mk. III, which with its historical 650hp engine, went a whopping 35km/h. In-game however, the top speed of the Centurion Mk. I is 40km/h,

 

The Centurion 7/1 on the other hand, starts out with the 650hp Meteor engine, gets the aforementioned (and possibly fictional) 750hp version, and then gets a 950hp Rolls-Royce Griffon engine, that I can only find a single source as to ever being fitted to a Centurion. What's incredible however, is that the top speed of the Centurion 7/1 in-game is still 40km/h, even though the South Africans managed to get 50km/h with the 810hp AV-1790, and 45km/h with the 750hp AVDS-1790 and a lower power to weight ratio.

 

However, it doesn't end there, as I came across something very interesting along the way. Namely that the Olifant Mk. 2 has a 1040hp diesel engine, also possibly of US origins via Israel. I even found an article from 2005 detailing that BAE had won the contract to upgrade more of the Olifant Mk. IBs to Mk. 2 standard, which includes 1040hp engine. So having found this, I decided to go back and look at the stats for the Action X Centurion on Status Report and something jumped out at me:

 

 

Engine: 1040 hp

 

Makes you wonder just what was meant by that statement regarding the Action X and Olifant, huh?

 

Sources:

http://www.secretprojects.co.uk/forum/index.php?topic=9088.235

http://www.secretprojects.co.uk/forum/index.php/topic,9088.240.html

http://www.pmulcahy.com/tanks/south_african_tanks.html

 

Anyway, I figured this could be a thread for instances like this, effort posts detailing just what Wargaming got wrong or might be fucking up in some way, either knowingly (as I believe to be the case here with the Action X being given some South African upgrades to make it competitive), or ignorantly, because they couldn't be bothered to do basic research. Hell, maybe I should try sending this into Status Report, get my name in all the papers or some shit. ;)

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Advocatus Diaboli here; the top speed of a tank can be limited in two ways.  It can be limited by RPM availability or it can be limited by power availability.

 

If you took a stock centurion and plopped a more powerful engine in it, it might not go any faster, because you might be limited by the maximum RPM of the engine and the maximum gearing ratio of the transmission.  The additional power would improve acceleration, but not top speed.

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Advocatus Diaboli here; the top speed of a tank can be limited in two ways.  It can be limited by RPM availability or it can be limited by power availability.

 

If you took a stock centurion and plopped a more powerful engine in it, it might not go any faster, because you might be limited by the maximum RPM of the engine and the maximum gearing ratio of the transmission.  The additional power would improve acceleration, but not top speed.

 

Funnily enough, Daigensui brought up the same thing over in the T110 thread when I first mentioned the Semel's top speed in relation to the Action X. While I don't doubt the British probably couldn't get a much higher top speed out of the Centurion, the fact the Centurion Mk. I gets an unhistorical engine and a corresponding boost to top speed means they could give Centurion Mk. 7/1 a boost to its top speed as well. But really, this deals mainly with Action X and the justification for its top speed using the Olifant, in which case, why can't the Centurion 7/1 get the South African upgrade of an 810hp AV-1790 and an increase in top speed to 50km/h?

 

EDIT:

 

Well on WOWS, they Iowa class only goes 30 knots when it was capable of 33, and did more than that in the 80s.  Not sure if you want to cover WOWS here though.

 

Why not start a thread for it over in Naval Discussion?

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As far as I know, pretty much all variants of the Oliphant use some version of the AVDS-1790 diesel engine.  It comes in several different power levels, as it's been upgraded over the years.  The original version, the AVDS-1790-2 series was 750HP.  It came in a few different versions depending on the size of the alternator.  The original version is called the AVDS-1790-2A.  Those that were built specifically for use in the Centurion were called AVDS-1790-2AC.  Later versions also had a "C" added to the end of the name if they were intended for use in a Centurion.  Later on, Teledyne Continental Motors  introduced the AVDS-1790-5 series.  These engines are commonly listed at 900 HP engines, but in reality they are 908HP.  These went into the Merkava I.  Israel wanted more power so TCM was able to provide a slightly better model called the AVDS-1790-6 with 950 HP.  After that came the AVDS-1790-8 series.  This engine has 1050HP.  I suspect this is the 1040hp engine mentioned in the sources you listed for the Oliphant.  The AVDS-1790-8 is still in production to this day for the US Army M88A2 Hercules ARV.  After that, the next version is the AVDS-1790-9.  This engine produces 1200HP and is in the Merkava 3 and the Namer APC.  The model used in the Merkava is specifically designated AVDS-1790-9AR.  While an "R" in a AVDS-1790 designation usually stands for "recovery vehicle", in this instance it stands for "Renk", since the Merkava uses a Renk transmission.  There is also a version that has been prototyped but not put into production called the AVDS-1790-1500.  The 1500 stands for 1500 HP.  So yes, and engine that started out as 750 HP is now capable of twice that amount, 1500hp.  

 

Unfortunately for the AVDS-1790, Israel decided to go with the MTU 883 1500HP diesel for the Merkava IV.  I doubt the 1500HP AVDS 1790 will ever see production.  From a marketing perspective, it's hard to convince customers that an engine that has its roots in the 1950's is as good as the shiny new designs coming from MTU.  Also, the aircooled AVDS-1790 looks so much bigger and bulkier than the German watercooled jobs on paper.  Of course, when you look at the total size of the powerpacks, cooling systems included, the difference is much less.  Also, it's a fairly long engine, too long to be mounted transversely, as is the fashion for some of the newer tanks out there.  

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As far as I know, pretty much all variants of the Oliphant use some version of the AVDS-1790 diesel engine.  It comes in several different power levels, as it's been upgraded over the years.  The original version, the AVDS-1790-2 series was 750HP.  It came in a few different versions depending on the size of the alternator.  The original version is called the AVDS-1790-2A.  Those that were built specifically for use in the Centurion were called AVDS-1790-2AC.  Later versions also had a "C" added to the end of the name if they were intended for use in a Centurion.  Later on, Teledyne Continental Motors  introduced the AVDS-1790-5 series.  These engines are commonly listed at 900 HP engines, but in reality they are 908HP.  These went into the Merkava I.  Israel wanted more power so TCM was able to provide a slightly better model called the AVDS-1790-6 with 950 HP.  After that came the AVDS-1790-8 series.  This engine has 1050HP.  I suspect this is the 1040hp engine mentioned in the sources you listed for the Oliphant.  The AVDS-1790-8 is still in production to this day for the US Army M88A2 Hercules ARV.  After that, the next version is the AVDS-1790-9.  This engine produces 1200HP and is in the Merkava 3 and the Namer APC.  The model used in the Merkava is specifically designated AVDS-1790-9AR.  While an "R" in a AVDS-1790 designation usually stands for "recovery vehicle", in this instance it stands for "Renk", since the Merkava uses a Renk transmission.  There is also a version that has been prototyped but not put into production called the AVDS-1790-1500.  The 1500 stands for 1500 HP.  So yes, and engine that started out as 750 HP is now capable of twice that amount, 1500hp.  

 

Unfortunately for the AVDS-1790, Israel decided to go with the MTU 883 1500HP diesel for the Merkava IV.  I doubt the 1500HP AVDS 1790 will ever see production.  From a marketing perspective, it's hard to convince customers that an engine that has its roots in the 1950's is as good as the shiny new designs coming from MTU.  Also, the aircooled AVDS-1790 looks so much bigger and bulkier than the German watercooled jobs on paper.  Of course, when you look at the total size of the powerpacks, cooling systems included, the difference is much less.  Also, it's a fairly long engine, too long to be mounted transversely, as is the fashion for some of the newer tanks out there.  

 

Interesting, and not at all surprising given what I found out looking at the Olifant, and the Israeli tanks too for that matter. Was the version used to upgrade the M48s given a special designation too, like the Centurions?

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 Also, it's a fairly long engine, too long to be mounted transversely, as is the fashion for Soviet tanks since the mid 1940s.  

 

There, fixed a small mistake.

 

Looking carefully at pictures in the Merkava thread, I think that part of the reason for going to the liquid-cooled engine is that it frees up more space for secret-sauce armor arrays about the front of the tank.  The original air-cooled engine was taking up quite a bit of space; enough so that it left a noticeable bulge in the hull on Merk I-III.

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Some things that come to mind in regards to Soviet Tanks:

  • Depression of the IS-7 is 7 degrees and not 3 (or 1.5) degrees.
  • All guns on the ST-I are unhistorical along with weight and engine horsepower
  • 122mm on KV-4 and KV-3 are not historical.
  • T-62A turret armor is incorrect and has 5 degrees depression instead of 7.
  • Depression of the Object 140 should 5 degrees not 6
  • Turret and gun options on the LTTB are unhistorical,  D-10-85 was only ever mounted on a SU-85.
  • Object 261 model and gun is wrong
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Interesting, and not at all surprising given what I found out looking at the Olifant, and the Israeli tanks too for that matter. Was the version used to upgrade the M48s given a special designation too, like the Centurions?

No, the versions used for the M48 were the same as what was put in the M60.  That said, there were several different versions used in the M48 and M60, although the differences are relatively minor.  All version used in either vehicle were 750HP, therefore they were all AVDS-1790-2.  The original version was AVDS-1790-2A.  Later on, they created two new versions of the engine, the AVDS-1790-2C and the AVDS-1790-2D. These are what is known as the "RISE" engines.  They were improved reliability versions basically.  The -2C had a more powerful 650 amp alternator, which was required to run the fire control system of the M60A3.  The -2D had the older 300 amp alternator and was intended as the replacement in older vehicles.  A few years later around 1975, they started having issues with engines suffering from severe dust gutting.  After much arguing with Chrysler and the Goverment, Continental got permission to redesign the air induction system.  To quote my dad, "With Chrysler Defense opposing, our analysis was that they had a shitty air cleaner system."  Continental got permission from the M60 Program manager to redesign the air induction system and rolled out the new "clean air" variants of the engine.  These are designated with an additional "A."  So, the final version of the 750hp engine are AVDS-1790-2CA and AVDS-1790-2DA.  As I understand it, many of these "clean air" engines were not new manufacture but rather upgrades done with kits provided by Teledyne Continental. 

 

To the guys in the field, a RISE engine often meant 650 amp generator.  This is not technically accurate as I understand it, but it was how the soldiers often understood it.  Also, sometimes 650 amp engines got put into older vehicles, not just M60A3.  The extra electrical power proved very popular regardless of the vehicle type.  

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No, the versions used for the M48 were the same as what was put in the M60.  That said, there were several different versions used in the M48 and M60, although the differences are relatively minor.  All version used in either vehicle were 750HP, therefore they were all AVDS-1790-2.  The original version was AVDS-1790-2A.  Later on, they created two new versions of the engine, the AVDS-1790-2C and the AVDS-1790-2D. These are what is known as the "RISE" engines.  They were improved reliability versions basically.  The -2C had a more powerful 650 amp alternator, which was required to run the fire control system of the M60A3.  The -2D had the older 300 amp alternator and was intended as the replacement in older vehicles.  A few years later around 1975, they started having issues with engines suffering from severe dust gutting.  After much arguing with Chrysler and the Goverment, Continental got permission to redesign the air induction system.  To quote my dad, "With Chrysler Defense opposing, our analysis was that they had a shitty air cleaner system."  Continental got permission from the M60 Program manager to redesign the air induction system and rolled out the new "clean air" variants of the engine.  These are designated with an additional "A."  So, the final version of the 750hp engine are AVDS-1790-2CA and AVDS-1790-2DA.  As I understand it, many of these "clean air" engines were not new manufacture but rather upgrades done with kits provided by Teledyne Continental. 

 

To the guys in the field, a RISE engine often meant 650 amp generator.  This is not technically accurate as I understand it, but it was how the soldiers often understood it.  Also, sometimes 650 amp engines got put into older vehicles, not just M60A3.  The extra electrical power proved very popular regardless of the vehicle type.  

 

Thank you. I'm going to need to look into this further for the Israeli tech tree I'm working on. As we all know, Wargaming loves giving modules different designations for the exact same ting, even better when it's historical.

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Some things that come to mind in regards to Soviet Tanks:

  • Depression of the IS-7 is 7 degrees and not 3 (or 1.5) degrees.
  • All guns on the ST-I are unhistorical along with weight and engine horsepower
  • 122mm on KV-4 and KV-3 are not historical.
  • T-62A turret armor is incorrect and has 5 degrees depression instead of 7.
  • Depression of the Object 140 should 5 degrees not 6
  • Turret and gun options on the LTTB are unhistorical,  D-10-85 was only ever mounted on a SU-85.
  • Object 261 model and gun is wrong

 

 

fist-slide.jpg

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