Finnish OOB35 Corrections and Suggestions PART 2 -- Units

[PvtJoker]

Finnish (OOB 35) corrections and suggestions:

NOTE! A lot of armor stuff is applicable to Soviet OOB as well!

Unit 2 FT-17: This tank was called FT-17 "female" in Finland (Translated to English, since the OOB does not use Finnish words elsewhere, either). Since Jan 1938 main weapon was a Maxim M/09-31, which had a rate of fire of 900 rounds per minute. A TMG for that gun should be added to weapons as well. HE Kill would probably be 8. Last availability should be Oct 1943, since a few tanks survived the Winter War and used for training. No radios, so radio code should be 1.

Unit 3 FT-18: called FT-17 "male" in Finland. No APCR ammo was available, so Weapon 12 (37mm Puteaux) should be modified to have an AP Penetration of 1 and the Sabot rounds transferred to AP. Correct total number of rounds was 233. No radios, radio code 1.

Unit 004 Vickers 6s: the Coaxial MG was the Maxim M/09-31 mentioned above. Ammo load 35 HE, 15 AP. No Sabot!

Unit 005 T-26 M31: Turrets' armor was less than 10mm all-around, so SP armor value for turret should be 1 for all faces. No radios, so radio code should be 1 (actually this tank was pretty common in Finnish use in 1941, so radio code could be also 0, but that's up to you).

Unit 006 T-26 M33: I would give this one radio code 2, since it was the most common of T-26 variants in Finnish service. Only command tanks had radios in any case, so no chance for others to get them.

Unit 007 T-26 (OT-130): probably radio code 1 would be suitable. The numbers of these conversions is unknown, but it could not have been very significant.

Unit 008 T-26 M37: radio code could be changed to 2, because this variant was pretty common since summer 1941, although not quite as common as Unit 006 above.

Unit 009 T-26 (OT-133): probably radio code 1 as per unit 007.

Unit 010 T-26E: radio code 0, no radios except in some command tanks.

Unit 011 BT-5: my sources give it turret side armor of 15mm (2) and front hull armor of 30 mm for lower front hull. The 13mm upper hull front is also well sloped (http://www.jaegerplatoon.net/BT5_2.jpg), so the penetration path at 90 degrees would surely be at least 20mm. Therefore I would give it a total hull front armor value of no less than 3. Max speed on road with tracks about 50 km/h (Speed 17). Last ones were retired from Finnish service in Spring 1942, so end date should be no later than June 1942. Radio code should be 1; despite fairly large numbers captured, the Finnish army never used the BT tanks much.

Unit 012 BT-7: hull side armor 15mm (2). The hull front was well sloped (http://www.jaegerplatoon.net/BT7_2.jpg) with 15-20mm of armor, so I would give it armor value 3. Radio code and availability as Unit 011.

Unit 013 T-50: turret side armor was 37+14mm (the applique was not installed on all Soviet T-50 tanks). Hull sides also 37mm.

Unit 014 T-28: turret front and side and rear armor was only 20mm. You may want to add something from the gun mantlet and rounding, but at least the current TF value of 5 is excessive. Upper hull front 15mm, but well sloped and lower front hull 30mm with some slope. HF value 6 is still clearly too much. Hull sides and rear 20mm. Top armor was less than 25mm on average, so top armor value should be 2. Machine gun turrets 20-22mm. 70 rounds for the main gun. Max. road speed was 45 km/h (15). The optics were half-decent for aiming the gun, so I would give it FC value 2. All tanks had a radio, so radio probability should be 50+.

Unit 015 T-28E: turret front and sides 80mm, turret rear 40mm. Upper hull front 58mm (+slope), lower 30mm, driver 80mm (the current HF value 8 is probably OK otherwise, but the thinly armored machine gun turrets are a problem). Hull rear remained at 18-20mm. Machine gun turrets 30-32mm. Top armor was not upgraded. Top speed 33 hm/h (11). Otherwise as Unit 014.

Units 016, 017, 018: harmonize unit data with the current Soviet OOB. Currently they differ especially in armor. Move Sabot ammunition to regular AP, since practically no APCR was available to the Finns. Radio probabilities should be higher. More than half of the Finnish T-34/76 tanks had a radio, since the ones bought from Germany all had a radio.

Unit 019 T-34 M44: change name to T-34/85, which was the most common designation used for this tank by the Finnish Army. Harmonize other data with current Soviet OOB. Move Sabot ammunition to regular AP.

Unit 020 KV-1c: Harmonize data with Soviet OOB unit 023. Move Sabot ammunition to regular AP. Finnish designation was KV-1A, if you want to confuse people even more (possibly KV-1A (M1942) would be acceptable?)

Unit 020 KV-1e: Harmonize data with Soviet OOB. Finnish designation was KV-1B, if you want to confuse people even more (possibly KV-1B (KV-1E) would be acceptable?)

Unit 022 Panssar IVJ: all had a radio, so radio code should be 92. Turret skirts were still in place in 1944, so turret armor should be harmonized with German unit 745. Icon should also be 1301 in 1944. Later turret skirts were removed. It happened some time in spring 1945, so Jan 1945 is probably as good time as any. A second unit identical to the current Unit 022 should be created for that.

Unit 024 ISU-152: harmonize data with Soviet OOB unit 038.

Unit 024 BA-10: replace with BA-6 (currently missing) from Soviet OOB unit 311. Keep the current availability start (Feb 1940), extend end to Dec 1946.

Unit 025 BA-10+: rename to plain BA-10, available since Apr 1940 until Dec 1946. Harmonize other data with Soviet Unit 041 BA-10, except ammo total 43 rounds (should probably be corrected to the Soviet unit as well). As recon vehicles the BA-10 usually had radios, so radio chance should be much higher than 20. (The radio chance of 10 is quite low for the Soviet unit as well, although late production examples after the German invasion often did not have a radio).

Unit 111 BA-3: no radios.

Unit 112 BA-20M: all had a radio at least in pre-invasion production. (Applied to earlier BA-20 as well in case you want to adjust the Soviet OOB). Max speed 70 km/h (23).

Unit 113 FAI: no radios (radio code 0).

Unit 301 Turret Bunker: change weapon, FC, RF and turret armor as per unit 2.

Unit 302 Turret Bunker: should have same turret armor and FC/RF as Units 2 & 3, no Sabot but regular AP as Unit 3. ROF 8 (where did that 6 come from?).

Units 304-315: change name to Casemate, since a word with common etymology (kasematti) is also used in Finnish (both come from Italian casamatta).

Suggest addition of MG units with 7.92mm Maxim MG-08. Import weapon 122 from German OOB (While pondering why it has a higher HE Kill than other 7-8mm Maxim MGs and MGs with similar cyclic rate of fire and belt feed ). About 1,000 of these weapons were used by the Finnish coastal troops and fortification units.

Changes to artillery and AAMG units were recommended already in the Weapons post (PART 1).

Sources: mostly Jaeger Platoon website: http://www.jaegerplatoon.net/MAIN.html

The Jaeger Platoon site contains some incredible research, including lots of digging into primary sources like war diaries and field manuals, which are not available on-line. I suggest it for anyone interested in WW1/WW2 Finnish and Soviet equipment (some German stuff as well). For Finnish Army WW2 weapons and vehicles it is the best single source that exists anywhere.

[Mobhack]

Unit 3 FT-18: called FT-17 "male" in Finland. No APCR ammo was available, so Weapon 12 (37mm Puteaux) should be modified to have an AP Penetration of 1 and the Sabot rounds transferred to AP. Correct total number of rounds was 233. No radios, radio code 1.

Why does everyone assume that a sabot round has to be a superior anti-tank round over any plain AP???

This gun is the precise opposite. It was deliberately given a short-range special round so it can only penetrate armour at minute range, but still have a decent range for its (primary) HE round.

Note the range for the sabot - the only AP round for the Puteaux 37mm! - is 4 hexes... it is not a tungsten-carbide HVAP!. (If you gave it an AP round with 1 AP value it would be able to plink armoured cars etc with 1 armour at its maximal range of 1.5 km on occasion.)

And we have been saying that for as many years as this game has been out but still somebody comes along, does not look at the basic game data, and assumes its a super-hot "silver bullet" round that the 37mm Puteaux has because its a "sabot"!.

In fact - due to the rapid pull-down in AP value over a range of merely 4 - its optimal anti-tank performance is in the 1- or perhaps 2 hexes range. Look at the figures in APCalc for that gun and generally ignore the "best" result as that is the once in a blue moon case.

The 37mm Puteaux is one of the few (or only?) cases where AP round #2 (commonly called 'sabot') - is an especially slugged item. Its there for throwing HE and if you want to kill tanks - then you'll have to waddle up and place the muzzle against the enemy tank's paintwork, basically...

Andy

[PvtJoker]

Originally Posted by Mobhack

Why does everyone assume that a sabot round has to be a superior anti-tank round over any plain AP???

This gun is the precise opposite. It was deliberately given a short-range special round so it can only penetrate armour at minute range, but still have a decent range for its (primary) HE round.

Note the range for the sabot - the only AP round for the Puteaux 37mm! - is 4 hexes... it is not a tungsten-carbide HVAP!. (If you gave it an AP round with 1 AP value it would be able to plink armoured cars etc with 1 armour at its maximal range of 1.5 km on occasion.)

Andy

Okay Andy, I understand what you mean and what's the rationale behind the short range "Sabot" round, but my point is that such external ballistics are quite unrealistic for the kind plain jane AP shot the gun actually fired (basically a big bullet). The shot was a heavy steel slug with fairly high sectional density and low muzzle velocity.

Without knowing the projectile shape one can't fully estimate its ballistic coefficient, but chances are the V(drop) was not very high. In other words, penetrating 20mm at 50 meters and less than 5mm at 150 meters is not how the physics work for such projectiles. It is, however, pretty much how they work for high velocity but relatively light and odd-shaped APCR projectiles, especially early ones, which were quite unstable.

I added the AP Pen 1 as I suggested, looked at the results of APCALC, and frankly the penetration numbers of the AP look much better and more realistic to me. AP Pen is 1 and Best AP is 2 until 150m. After that you get best AP 1 until max range (1500 meters), which is not that unrealistic if the likelyhood of Best AP occurring is really only 0.1 percent as the WW2_APCalc_Help.TXT file indicates. Even if it's one magnitude higher, plinking an armored car at 1500 meters with a 1% chance does not sound bad at all -- after all, most of those ACs and tankettes with armor value 1 in SP had only 5 to 9 mm of armor in reality.

There is one final point to this discussion: the French actually developed a real APCR round for the 37mm L/21 SA18 gun in the mid-1930. It was issued to modern light tanks with that gun (R-35 and H-35) and was used in 1940 with good effect against German PzKw I and II light tanks. Armor penetration was really about 30mm at 100 meters and useful range about 500 meters (that means penetration was equal or better than the 19th century vintage AP shot up to 500 meters). I see it is even modeled in the French OOB as Weapon 12 37mm SA18 m.37, although as much more expensive round it never fully replaced the old shot in real life.

[Mobhack]

Perhaps - but that weapon was set up that way after much discussion on the old Yahoo! forum for the DOS edition 10+ years back.

I'd thought it was in the Mobhack help file as a counter-example, but it looks like that was never done. It will be added this update cycle though. (The technique was later applied to field guns that needed an AP shot but that have extremely long HE ranges).

Andy

[Pibwl]

37mm SA-18 couldn't be all that rubbish, if Polish armoured cars wz.29 recorded several destroyed armoured cars and light tanks, including Pz-I with 13mm armour (http://derela.republika.pl/wz29.htm ). Most probably they had standard AP shots, and I doubt, if all cases were point-blank.

I've just read a Polish source, that steel 37mm bullet pierced 15 mm of cast iron at 1000 m (which is of course not armour, though). All in all, I feel, that range 4 should be increased a bit, maybe doubled.

[PvtJoker]

Originally Posted by Pibwl

37mm SA-18 couldn't be all that rubbish, if Polish armoured cars wz.29 recorded several destroyed armoured cars and light tanks, including Pz-I with 13mm armour (http://derela.republika.pl/wz29.htm ). Most probably they had standard AP shots, and I doubt, if all cases were point-blank.

I've just read a Polish source, that steel 37mm bullet pierced 15 mm of cast iron at 1000 m (which is of course not armour, though). All in all, I feel, that range 4 should be increased a bit, maybe doubled.

The material properties of (grey) cast iron are quite different from any quality armor steel, most notably its tensile strength and toughness are much lower even though it's pretty hard.(White cast iron is very hard, but I doubt they used it for testing). So I can't even guess what that penetration might be against armor steel plate of any hardness.

As for the combat experience, it is of course undeniable. Yet even that web page mentions that penetration was only 12mm at muzzle. Are you certain that the Polish Army did not develop an improved AP round for the gun some time in the late 1930s? The original French AP was late 19th century design and probably some improvement (e.g. something like 30% better penetration) could have been had just by developing a more up-to-date AP or APC ammunition.

[Pibwl]

Originally Posted by PvtJoker

Unit 011 BT-5: my sources give it turret side armor of 15mm (2) and front hull armor of 30 mm for lower front hull. The 13mm upper hull front is also well sloped (http://www.jaegerplatoon.net/BT5_2.jpg), so the penetration path at 90 degrees would surely be at least 20mm. Therefore I would give it a total hull front armor value of no less than 3. (...)

Unit 012 BT-7: hull side armor 15mm (2). The hull front was well sloped (http://www.jaegerplatoon.net/BT7_2.jpg) with 15-20mm of armor, so I would give it armor value 3.

Of course, if we change armour, these tanks should be first modified in the Soviet OOB. However, as for BT-5, Russian Bronyekollektsya 1/1996 about BT-2/BT-5 indicates armour 13 mm at hull front, without special mention on its lower nose hull plate (which was very small and difficult to hit, BTW). A nose was well sloped indeed (apart from a driver's hatch), but is it enough to make armour 3 out of 13mm?
Sides were vertical 13mm, so it's up to choice if it is 1 or 2 in game terms. Rear hull was 10mm indeed.
Also 13mm is given for turret front and sides (not excluding rear).

As for BT-7, there is a scheme attached from Bronyekollektsya 5/1996. With reluctance, I'd agree with 3 at hull front. Sides were 15 mm, so they deserve 2 (now 1).

[PvtJoker]

Originally Posted by Pibwl

Of course, if we change armour, these tanks should be first modified in the Soviet OOB. However, as for BT-5, Russian Bronyekollektsya 1/1996 about BT-2/BT-5 indicates armour 13 mm at hull front, without special mention on its lower nose hull plate (which was very small and difficult to hit, BTW). A nose was well sloped indeed (apart from a driver's hatch), but is it enough to make armour 3 out of 13mm?
Sides were vertical 13mm, so it's up to choice if it is 1 or 2 in game terms. Rear hull was 10mm indeed.
Also 13mm is given for turret front and sides (not excluding rear).

Russian Battlefield:

http://www.battlefield.ru/bt5/strani...tvo-tanka.html

Confirms that both 13mm and 15mm plate was used on BT-5, but unfortunately does not detail where. It does say that the driver's plate was 20mm thick and the upper part of the lower hull was actually 40mm. No mention about turret front being thicker, so probably that is incorrect at Jaeger Platoon site.

All in all I am still thinking Armor Value 3 for the front hull. 2.5 would probably be closer to the "truth", but since we can't have that, 3 it should be. I am also considering the fact that highly sloped armor will very often make small projectiles like ATR bullets ricochet, which increases the practical protection over the penetration path required to punch a hole through the armor. On the other hand we do know that the Lahti ATR was effective against the BT-5 even through frontal armor, but I have no data about the combat record of the Maroszek wz. 35 or the PzB 39 against the BT-5, although both were still used by the Germans in summer 1941.

[PvtJoker]

Originally Posted by PvtJoker

All in all I am still thinking Armor Value 3 for the front hull. 2.5 would probably be closer to the "truth", but since we can't have that, 3 it should be. I am also considering the fact that highly sloped armor will very often make small projectiles like ATR bullets ricochet, which increases the practical protection over the penetration path required to punch a hole through the armor. On the other hand we do know that the Lahti ATR was effective against the BT-5 even through frontal armor, but I have no data about the combat record of the Maroszek wz. 35 or the PzB 39 against the BT-5, although both were still used by the Germans in summer 1941.

An addition to above: I measured the glacis plate slope from images at the Russian Battlefield site and it is no less than 60 degrees (the same as BT-7 and T-34, so really no surprise there). That makes the required penetration path 26mm and so the front hull armor should definitely have Armor Value 3 in the game.

In addition, Russian Battlefield says in the BT-7 article:

Броневая защита танка - противопульная, выполненная из броневых катаных листов толщиной 6,10,13,15 и 20мм. Броневая защита машин первых лет выпуска находилась на уровне танка БТ-5.

Which to me, knowing that 15mm plate was used with the BT-5, suggests that it had 15mm in the turret front and sides just like BT-7.

[Pibwl]

Originally Posted by PvtJoker

An addition to above: I measured the glacis plate slope from images at the Russian Battlefield site and it is no less than 60 degrees (the same as BT-7 and T-34, so really no surprise there). That makes the required penetration path 26mm and so the front hull armor should definitely have Armor Value 3 in the game.

(...)

Which to me, knowing that 15mm plate was used with the BT-5, suggests that it had 15mm in the turret front and sides just like BT-7.

You may be right, that BT-5 should have front hull 3.
As for turret: the mentioned Bronekollektsya says 13 mm, but J. Magnuski wrote in his book 15 mm. It's strange, but I can't find any other detailed Russian monographs on this tank.