View source for BT-42

{{Short description|Finnish assault gun}}
{{Use dmy dates|date=January 2018}}
{{Infobox weapon
|is_vehicle = yes
|name = BT-42
|image = Bt42 parola 2.jpg
|caption = BT-42 at the [[Parola Tank Museum]]
|origin = [[Finland]]
|type = [[Assault gun]]
<!-- Service history -->
|service = 1943–1944
|used_by = Finland
|wars = [[Continuation War]]
<!-- Production history -->
|designer =
|design_date =
|manufacturer =
|unit_cost =
|production_date = 1942
|number = 18
|variants = [[BT-43]]
|crew = 3
|length = {{convert|5.7|m|ftin|abbr=on}}
|width = {{convert|2.1|m|ftin|abbr=on}}
|height = {{convert|2.7|m|ftin|abbr=on}}
 <ref>{{cite web | url=https://www.jaegerplatoon.net/ASSAULT_GUNS.htm | title=Finnish Army 1918 - 1945: Assault Guns }}</ref>
|weight = 15 tonnes
|armour = 6-16&nbsp;mm
|primary_armament = [[QF 4.5 inch Howitzer|114 mm (4.5-inch) howitzer]] (50 rounds)<ref>Thank you for your message and question. We have some material here in the museum relating that one survived example of BT-42 Ps 511-8 which we have on display. We have for example its driving and maintenance books and user and gun manuals. It is written on the manual that the BT-42 can hold 50 rounds for its 114 mm main gun. It sounds quite big amount, but that is how the manual says.

BR,

Jari Saurio

Museum curator

The Parola Armour Museum

Finland</ref>
|secondary = 
|engine = [[Mikulin M-17]]T V-12 gasoline engine
|engine_power = 500&nbsp;hp (370&nbsp;kW)
|suspension = [[Christie suspension|Christie]]
|clearance = 0.31 m
|speed = {{convert|53|km/h|mph|abbr=on}}
|pw_ratio = 33.33&nbsp;hp/tonne
|vehicle_range = {{convert|375|km|mi|abbr=on}}
|sights = Recycled 76 K/02 (76 mm field gun model 1902) field gun sight
}}

The '''BT-42''' was a Finnish [[assault gun]], constructed during the [[Continuation War]]. It was constructed from captured [[Soviet Union|Soviet]] [[BT-7]] light [[tank]]s and British [[QF 4.5 inch Howitzer|4.5-inch howitzers]] (114&nbsp;mm-calibre light howitzer, model 1908) from 1918, which had been donated during the [[Winter War]]. Eighteen vehicles were constructed, yet only 1 survives to this day, housed at the [[Parola Tank Museum]].<ref>Parola Armour Museum: [https://www.panssarimuseo.fi/wp-content/uploads/2017/11/Rynn%C3%A4kk%C3%B6tykki-BT-42_esittelytaulu.jpg BT-42 information board] {{Webarchive|url=https://web.archive.org/web/20211203184943/https://www.panssarimuseo.fi/wp-content/uploads/2017/11/Rynn%C3%A4kk%C3%B6tykki-BT-42_esittelytaulu.jpg|date=3 December 2021}}</ref><ref>Second Lieutenant Stig Holmström: Separate Armored Company [https://www.rul.fi/gw-storage/v3/container/404/node/5253/original/Erillinen_Panssarikomppania1.pdf Vänrikki Stig Holmströmin tie Äänislinnasta Karjalan Kannakselle ja Lapin sotaan] {{Webarchive|url=https://web.archive.org/web/20220608231310/https://www.rul.fi/gw-storage/v3/container/404/node/5253/original/Erillinen_Panssarikomppania1.pdf|date=8 June 2022}}, Lecture notes in the Finnish Reserve Officers Federation website</ref>

==Development and use==
As the Second World War progressed, the [[Red Army]] were fielding better and better tanks. The [[Finnish Army]], on the other hand, had to make do with a large number of captured tanks, which were for the most part lightly armored and armed.<ref>{{Cite book |last=Murphy |first=David |url=https://books.google.com/books?id=jcY4EAAAQBAJ&dq=The+Finnish+Army+had+to+make+do+with+a+large+number+of+captured+tanks&pg=PA5 |title=The Finnish-Soviet Winter War 1939–40: Stalin's Hollow Victory |date=2021-09-16 |publisher=Bloomsbury Publishing |isbn=978-1-4728-4394-4 |language=en}}</ref>

The Finns decided to redesign the [[BT tank|BT-7]] Model 1937 tank. They constructed a new turret fitted with 76 K/02 gun sights and armed it with British-made 114.3&nbsp;mm [[howitzer]]s that had been supplied by the British during the [[Winter War]] (Q.F. 4,5&nbsp;inch howitzer Mark II, also known as ''114 Psv.H/18'' in Finland).<ref>{{cite web |title=Finnish Army 1918 - 1945: Assault Guns |url=http://www.jaegerplatoon.net/ASSAULT_GUNS.htm#BT-42}}</ref> Eighteen BT-42 were built between 1943-1944.<ref>https://www.jaegerplatoon.net/ASSAULT_GUNS.htm#BT-42</ref>

These converted vehicles quickly became very unpopular with their crews.<ref name=":0">{{Cite book |last=Tucker-Jones |first=Anthony |url=https://books.google.com/books?id=t_rLDwAAQBAJ&dq=The+BT-42s+were+used+in+the+defence+of+Vyborg.&pg=PT63 |title=Armoured Warfare and Hitler's Allies, 1941–1945 |date=2013-07-19 |publisher=Casemate Publishers |isbn=978-1-78346-899-7 |language=en}}</ref> The weaknesses could mainly be attributed to the new turret, which apart from giving the tank a high-profile also added significant weight to the vehicle, stressing the suspension and the engine.<ref>https://tank-afv.com/ww2/Finland/BT-42.php</ref>

The BT-42 was used for the first time in 1943, at the [[Svir River]], where it was used against enemy pillboxes. The design worked reasonably well against soft targets but was completely unsuitable for [[anti-tank warfare]].<ref name=":0" />

The BT-42 ultimately failed in its original goal of establishing a domestic armor production to combat the Soviet tanks—this being realized when the tank proved ineffective in tank-to-tank combat<ref name="AFV BT-42">{{cite web |last1=Bocquelet |first1=David |title=BT-42 |url=https://tank-afv.com/ww2/Finland/BT-42.php |website=tank-afv.com |access-date=21 October 2023}}</ref> and later replaced with the German [[Sturmgeschütz III|Stug IIIs.]]

To counter this, the Finns copied a German-designed [[High explosive anti-tank warhead|HEAT]] round for the gun and it was initially thought that it would be effective against the [[sloped armour]] of the [[T-34]]. Testing showed that it could penetrate 100mm of steel plate at 50 or 60 degrees, and should be able to penetrate 110-115mm armor sloped at a 70 degree angle, but this was proven incorrect at the [[Battle of Vyborg Bay (1944)|Battle of Viipuri]] where it was shown to be incapable of taking down even medium tanks. 2,000 shells were ordered but this was cancelled after 500 had been delivered.<ref>https://www.jaegerplatoon.net/TANK_GUNS.htm#114H18</ref> Supposedly one of the main issues was with the copied HEAT shells fuses, which apparently did not arm themselves correctly after firing, due to the different muzzle velocity and round spin rate of the 4.5-inch howitzer compared to the original German guns{{Citation needed|date=February 2023}}.

The BT-42s were used again during [[Fourth strategic offensive|the major Soviet offensive in 1944]]. Nine BT-42s were deployed in the defense of [[Vyborg]].<ref name=":0" /><ref name="Finnish Army BT-42">{{cite web |last1=Moore |first1=Craig |title=Surviving Finnish Army WW2 Tanks |url=http://tank-photographs.s3-website-eu-west-1.amazonaws.com/finnish-army-BT-42-assault-gun-parola.html |website=Tank-Hunter.com |access-date=31 December 2023}}</ref><ref name="AFV BT-42" /> In one encounter, a Finnish BT-42 hit a Soviet T-34 eighteen times, failing even to immobilize the enemy vehicle.<ref name="AFV BT-42" /> During this battle a BT-42 was destroyed by a T-34 tank shell.<ref name="Finnish Army BT-42" /> Seven of the BT-42 tanks were also lost due to mechanical failures, resulting in eight of the nine deployed being destroyed.<ref name="Finnish Army BT-42" /><ref name="AFV BT-42" /> At the time Finnish armoured units were still composed mostly of older designs such as the [[Vickers 6-Ton]], [[T-26]] and [[T-28 (medium tank)|T-28]] tanks, and all of these suffered losses.

Emergency supplies of [[Panzer IV]] tanks and [[Sturmgeschütz III|StuG III]] self-propelled assault guns from Germany made it possible for the Finns to replace their losses with more effective vehicles. The BT-42 was retired soon after the Vyborg battles, replaced in their role with German-made StuG IIIs. Finland also used captured [[T-34]]s, as well as receiving more of these vehicles from Germany's stock of captured enemy kits.<ref>{{Cite book |last1=Jowett |first1=Philip |url=https://books.google.com/books?id=iaSjCwAAQBAJ&dq=Finns+army+replaced+bt-42&pg=PA42 |title=Finland at War 1939–45 |last2=Snodgrass |first2=Brent |date=2012-07-20 |publisher=Bloomsbury Publishing |isbn=978-1-78200-156-0 |language=en}}</ref>

<gallery>
Image:Bt42 parola 1.jpg|Front view
Image:Bt42 parola 3.jpg|Left-rear quarter view
</gallery>

==In popular culture==
The [[Parola Tank Museum]] in [[Parola (Hattula)|Parola, Finland]], houses the world's last surviving BT-42.<ref>{{Cite web |title=Etusivu |url=https://www.panssarimuseo.fi/museokalustoa/ |access-date=2025-01-07 |website=www.panssarimuseo.fi |language=fi}}</ref> The tank was featured as the primary vehicle of [[List of Girls und Panzer characters#Jatkosota (Keizoku) High school|Jatkosota High School]], a minor school in the Japanese anime ''[[Girls und Panzer]]''. The museum was seeking funds for an outdoor shelter for several of their tanks, including the BT-42. A large group of Japanese ''Girls und Panzer'' fans raised over €10,000 in order to help the museum preserve its BT-42.<ref>{{Cite AV media |url=https://www.youtube.com/watch?v=de1_0-DynRY |title=How Girls Und Panzer Saved Oarai, and Tanks, In Real Life |date=2023-08-03 |last=Ascendant Fiction |access-date=2025-01-07 |via=YouTube}}</ref>

==See also==
*[[BT-43]] - another Finnish conversion of the BT-7 tank
*[[Beutepanzer]]

==Footnotes==
<references/>

==External links==
*[http://www.jaegerplatoon.net/ASSAULT_GUNS.htm Specifications and operational use] at www.jaegerplatoon.net
*[[YouTube]]: [https://www.youtube.com/watch?v=HQhThoaQdnU BT-42 (English subtitles)]

[[Category:World War II military equipment of Finland]]
[[Category:World War II assault guns]]
[[Category:Tanks of Finland]]
[[Category:Military vehicles introduced from 1940 to 1944]]