00:20World War II
00:21These tanks were one of the fastest armored vehicles of World War II,
00:24and only the late-war M18 Hellcat had higher top speed,
00:27even though these vehicles were developed in the early 1930s.
00:32They were the most numerous tanks in the Soviet army before the T-34 type appeared,
00:37and though they featured light armor and armament, they were a unique design.
00:42These were the BT series cavalry tanks, so let's see the history of these vehicles today.
00:56Sovjet forces laid down tactics for the so-called long-range operations,
01:00very similar to the German Blitzkrieg, which required fast-moving tank forces to penetrate
01:05deeply into the enemy lines and given advantage to the following forces to destroy the disorganized
01:10defenders. For this they needed fast and nimble vehicles, the so-called cavalry tanks,
01:16and interestingly they found the type which was the best fit for their goals
01:20on the other side of the world in the United States.
01:24John Walter Christie, an American engineer, was designing armored vehicles since the First World War,
01:29and offered many of his designs to the US military.
01:32In the early 1920s, he already demonstrated an amphibious tank prototype,
01:37which though it worked as intended, didn't spark any interest in the military.
01:43He continued to work on new tank designs, and on his model 1928,
01:47he came up with a new innovative suspension, to fix the poor off-road performance of earlier tanks.
01:53This was the so-called Christie suspension, with large road wheels,
01:57and each of them using independent springs and suspension components.
02:01This innovation, combined with the so-called convertible track design,
02:05which allowed the tracks to be removed and use the tank as a wheeled vehicle,
02:08resulted in unparalleled speed, both on and off-road.
02:12The US Army ordered and tested several prototypes,
02:15and they also purchased Christie's patents for a hundred thousand dollars,
02:19allowing them to design future vehicles using his work.
02:23But Christie had very different views than the Army board,
02:26resulting in numerous arguments between them.
02:28His designs were in the end rejected by the US Army, citing the high cost of these vehicles.
02:34And a disgruntled engineer started to advertise his designs to foreign powers,
02:38though he did it without the approval of the US government.
02:41In the late 1920s, a Soviet commission traveled Europe and the US to look for suitable tanks.
02:47And they were very impressed by the Christie design,
02:50especially after they managed to get their hands on the specifications and early plans.
02:55Later, they started to discuss a deal with Christie's company, the US wheeled track layer corporation,
03:01about purchasing his design.
03:02They of course approached them through one of their shell companies, M-Torg,
03:06which was just a front for the Soviet agents.
03:09Eventually, in 1930, a deal was struck, and Christie's company agreed to sell two M-1931 tanks to the M
03:15-Torg
03:16corporation, for 60.000 dollars.
03:19These two models were built without turrets or armament,
03:22and they were shipped to the Soviet Union without government approval,
03:25labeled as agricultural attractors.
03:29After they arrived to the Soviet Union, the two Christie models were delivered to the Harkov
03:33locomotive plant for examination and testing.
03:37These vehicles were called fast tanks by the Soviets, and from this name came the abbreviation B-T.
03:43Based on the two Christie models and earlier obtained plans, the Soviets copied these vehicles,
03:48and building of their first variant, called the B-T-1, started in May 1931.
03:54This model used a Soviet version of the Liberty engine, producing 400 horsepower,
03:59and was only armed with two machine guns.
04:01But soon this setup was found to be unsatisfactory, and only one model was built.
04:06By September the same year, two further prototypes were finished,
04:10featuring a new turret, housing a 37mm gun, and they were designated B-T-2.
04:16The most notable difference between the Christie models and the early Soviet B-T tanks,
04:20is the American models used welded construction, while the early B-T tanks were built with riveted armor.
04:29These B-T-2 prototypes appeared on the October military parade, making a big impression,
04:34one of them running on tracks, the other one on wheels.
04:40These variants had a road speed of 100 km an hour, and off-road speeds of 60 to 70 km
04:46an hour.
04:48The serial production of these new tanks started in January 1932.
04:53The design was unique with the Christie suspension, making it able to run either on tracks or wheels.
04:59But eventually this feature turned out to be useless, as it was rarely utilized.
05:05Two further experimental variants were built using the same basic setup.
05:09The B-T-3 model featured a 45mm gun, instead of the earlier 37mm one,
05:15solid wheels without spokes, and a new turret design, with no mantlet guard,
05:20but featuring ammo storage at the back.
05:22These models also switched to metric measurements, but only a small batch of them were built.
05:28The following B-T-4 was an experiment, to build a B-T tank featuring a twin turret like on
05:33the T-26.
05:34But it was an unsuccessful design, and only a few prototypes were built.
05:40At the end of 1932, a more extensive upgrade of the type was planned, with more powerful armament,
05:46a coaxial machine gun, and more crew space inside.
05:49So this new variant, the B-T-5, featured a new improved turret,
05:53housing the 45mm M1932 gun, and a coaxial machine gun.
05:59Serial production of this new improved model started before the end of 1932.
06:05The next B-T-6 variant was a planned upgrade of the B-T-5 using welded armor.
06:10But it was skipped, and the B-T-7 model became the successor of the B-T-5.
06:16These models appeared in 1935, and featured several upgrades.
06:19The original engine was replaced with the M17T model, developing 450hp.
06:26They received a new transmission and steering system, and their armor protection was increased as well,
06:31from 13 to 22mm on the hull, and 15mm on the turret.
06:36And now they used fully welded construction.
06:41They featured the same turret as the B-T-5 variants, but that was soon replaced with a conical design,
06:47featuring double periscopes on the top, and more sloped armor.
06:58The B-T-7 was 5.68m long, 2.2m wide, and 2.43m tall.
07:08It featured 22mm thick armor on the hull front, and 13mm on the sides,
07:14while the turret featured 15mm thick armor plates all around.
07:20Because of the relatively thin armor, the tank only weighted 13.8 tons.
07:25The lightweight vehicle used the 450hp M17T engine, making it very mobile.
07:32It could reach a top speed between 70 to 80 kmh on roads,
07:36and around 50 kmh off-road.
07:40Its operational range was around 250 kmh on roads, or 120 kmh off-road.
07:48The tank's main armament was the 45mm M1932 gun,
07:53and its secondary armament was one 7.62mm machine gun.
08:06The main production variants of the B-T series were the B-T-2 model,
08:11which was the first production variant, featuring the 400hp Liberty engine,
08:15a 37mm gun, and riveted armor.
08:20620 units were built.
08:23It was followed by the B-T-5, which featured a new turret, a 45mm gun, and a coaxial machine
08:30gun.
08:31The early B-T-5 models used a cylindrical turret, featuring a very sharp mantlet design.
08:37It was so replaced by a new turret design, which had an overhang at the back, double hatches,
08:42and a more rounded mantlet.
08:44From the B-T-5 variant, more than 2000 units were built between 1933 and 1935,
08:50before it was replaced by the B-T-7 model, which became the definitive variant of the B-T tanks,
08:56featuring many upgrades.
08:58The old Liberty engine was replaced with the more powerful 450hp M17T model.
09:05The tank received a new transmission and steering system as well.
09:09They also used a fully welded construction and thicker armor plates than the earlier models.
09:15Initially they featured the same turret as the B-T-5 models.
09:18But in 1937 the new conical turret was introduced,
09:22with more sloped armor and double periscopes on the top.
09:26From this variant more than 5000 units were built,
09:29plus around 800 units from its B-T-7M sub-variant,
09:33which was equipped with the new V12 diesel engine.
09:39Apart from the main models, there were several experimental and specialized variants of the B-T tanks.
09:44Like the R-B-T-5, which was a modified B-T-5, carrying two 420mm so-called tank torpedoes.
09:52These rockets were very inaccurate, so this variant never gone to production.
09:57The B-T-5A featured a short-barreled 76mm howitzer, instead of the original 37mm gun.
10:05The B-T-5 also had an amphibious experimental variant, the B-T-1A, with a redesigned body.
10:12The B-T-IS variant concentrated on the mobility of the vehicle and featured all-wheel drive.
10:18So if the tank lost a track in battle, it could still move on its wheels.
10:22It was deemed too complicated and only experimental models were built.
10:26The B-T-7A variant featured a 76mm howitzer, just like the B-T-5A model,
10:32while the B-T-7A L11 used a 76mm L11 gun, the same type which was used on the early
10:39T-34 models.
10:41The B-T-SV-2 variant featured heavier sloped armor, between 25 and 45 mm thickness,
10:47but because of the significant weight increase to 24 tons, this model was abandoned.
10:53The B-T-7 model was a threatless command vehicle.
10:57And finally, the B-T-42 was a Finnish modification of the type, equipped with a 114mm howitzer.
11:12The B-T tanks first saw action in the Spanish Civil War, when about 100 B-T-2 and B
11:17-T-5 models
11:18were sent to fight on the Republican side, operated by crews trained by the Soviets.
11:23They suffered many losses, though that was mainly the fault of planning and tactics.
11:28They were used in greater numbers in 1939 during the battles of Kalkingol,
11:33where the B-T-5 and B-T-7 models were used against the Japanese forces.
11:38Here their mobility and firepower proved to be effective,
11:41but the fighting also highlighted that their petrol engines can easily catch fire when hit.
11:47They were also used during the Winter War against Finland,
11:50where the type again suffered heavy losses against the Finnish forces,
11:53who just like the Japanese before, used Molotov cocktails to set the engine compartment of the tanks on fire.
12:00By 1941, the time of the German invasion of the Soviet Union,
12:04most older B-T-2 and B-T-5 models were used up and replaced by the newer B-T
12:08-7 type,
12:09which was the most numerous tank in the Soviet Army at the time.
12:13Though in technical specifications, the B-T-7 was not worse than its most common opponents,
12:18the Panzer II and Panzer 38T, featuring similar armor protection and armament,
12:23but it fell short of the newer Panzer III variants.
12:28If you want to know more about these German types, check out my earlier videos about them on the channel.
12:34The coordination of the Soviet forces was also far worse than the German tactics,
12:39and they suffered very heavy losses.
12:41It was estimated that in the first year of the fighting, more than 2000 B-T tanks were lost.
12:47But by that time, the B-T series was slowly replaced by the new T-34,
12:51which was a much better tank in every aspect.
12:54Still the remaining B-T-7 models stayed in service, and were used until the end of the war.
13:00Though the B-T tanks were designed years before World War II,
13:03and their thin armor and weak armament made them obsolete,
13:07but they were an important stepping stone in Soviet tank design.
13:10And their evolution through the A-20 and A-32 experimental designs,
13:14in the end, led to the famous T-34 tank.
13:21Hope you guys enjoyed this video. Please leave a like, subscribe to my channel,
13:25and in the comments let me know, if there's any interesting events or vehicles you'd like to see.
