Finnish OOB35 Corrections and Suggestions PART 2 -- Units

[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.

[PvtJoker]

Originally Posted by Pibwl

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.

Russian Battlefield gives:

"Наставления автобронетанковых войск РККА. Танк БТ-5", М. Отдел издательства НКО СССР - М.1935 г.
М. Павлов, И. Желтов, И. Павлов "Танки БТ", М. Экспринт 2001 г.
М. Барятинский "Советские танки в бою", М. Яуза 2006 г.

as sources. (I know, the first one isn't available to most people). There is also Mikhail Baryatinskiy's "Light Tanks" in English, which Jaeger Platoon site probably used as source for the background data and development history.

[Pibwl]

Originally Posted by PvtJoker

Russian Battlefield gives:

"Наставления автобронетанковых войск РККА. Танк БТ-5", М. Отдел издательства НКО СССР - М.1935 г.
М. Павлов, И. Желтов, И. Павлов "Танки БТ", М. Экспринт 2001 г.
М. Барятинский "Советские танки в бою", М. Яуза 2006 г.

as sources. (I know, the first one isn't available to most people).

The first one is actually easiest to find, but I don't think that military manual of 1935 would reveal armour thickness and weak points
http://www.farposst.ru/2013/10/16/ta..._sil_rkka.html

The second one may be interesting, in terms of specifications - the last one is rather general source.