A lot of planning, time and effort goes into creating new tanks -- yet some never enter service, probably because they serve as examples of what not to do. Here's a list of tanks that weren't all that successful in the real world, but are pretty awesome in World of Tanks.
Originally designed as a light tank, its size blossomed into a medium, comparable to the Sherman. Unlike the other vehicles here which merely squandered steel and time, an entire factory was built in Bettendorf, Iowa specifically for its production. Seven came out of the Quad Cities Tank Arsenal before the tank was cancelled.
There were 1,700 tanks built with its signature radiator on the front of the tank, but not one was sent to fight. Only one remains because it was buried -- presumably the crew really wanted to be rid of it. Recent research indicates that its mechanical issues were eventually fixed, though that didn’t help the woeful armament and light armor.
The Army built 250 of these before anyone knew if they worked. The mobility and low silhouette showed promise, but just like the Tiger (P) (below), the electrical transmission was more trouble than it was worth. The one redeeming feature: the turret was put onto the M4 Medium. Read more about this in Chieftain's Equipping the Force Part IV.
A lot of effort went into making this tank, and it demonstrated positive features and capability. After building just over 60, they recognized the inefficiency of building this instead of buying M3s and Matilda IIs, so production came to a halt and none saw combat. Watch Inside the relevant Chieftain's Hatch videos (Part I, Part II) for more.
This pet project of Ordnance was well oversized for the job, and was never entirely reliable -- and the Army didn't want it. The big problem was transporting this nearly 60-ton tank across the Atlantic and then through Europe. Of the 40 built, they were only for propaganda in the US. Read more in Equipping the Force Part II.
Designed by "The Old Gang", who created the original WWI tanks, and expected WWII to be the same sort of trench warfare. This 80-ton monstrosity has almost nothing about it to recommend, but still exists in Bovington for fans of the Royal Navy wanting to see it.
The only tank where production was knocked out by Allied bombing. It hasn't explained quite how the Germans planned to fuel and protect this 180-ton beastie.
This tank is so overpowered that it's not even on the NA World of Tanks servers. In reality, the US Army’s testing facility called it “thoroughly unreliable, mechanically and structurally unsound, underpowered and equipped with unsatisfactory armament.” Fortunately for the Dutch, the Japanese capture of the Dutch East Indies meant that their soldiers never had to drive them.
The impetus for this tank was the losses on the Russian Front to 14.5mm rifles. After creating the prototype hull, designers found that simply hanging sheet metal off the sides would provide the desired level of protection to existing designs. Since this was simpler than building a whole new tank type, the Germans canned the project.
The US never wanted it to begin with; it was designed at the behest of the British. And so one was sent to the Brits to compete against Excelsior, and the other remained home for testing. Suspension and running gear proved to be the most troublesome component. The tank wan't selected for British service, and that was that.
The Japanese paid over a half-million Reichsmarks for a 55-ton Tiger. Just one teensy problem -- there was no way of getting it from Germany to Japan. Shipped to France in the hope a submarine with sufficient cargo capacity (an I-400 or two) might show up, but unsurprisingly this never happened. When the Allies invaded, the tank saw service with the German army anyway.
They spent much effort in making a small number of Panthers look like M10s in late 1944. All were detected and destroyed, for no apparent gain compared to what could have been accomplished without wasting precious Panthers. Read more on the Chieftain's Hatch.
The M22's basic premise was questionable to begin with -- put the turret into the fuselage of a C-54 transport, and hang the hull underneath it. Then, land a large, valuable aircraft on an airfield behind enemy lines, reassemble the tank, and then fight things smaller than it. Over 800 were built and eight were sent into combat in British gliders; two didn’t make it to the landing zone; two didn’t make it out of the landing zone, and the other four were simply useless.
The problem with the Chi-Ha isn’t necessarily a bad design, it was just entirely underwhelming in combat. After getting its posterior kicked by BT-series light tanks, the Japanese decided they might want a better gun on it. The resulting 47mm was utterly inadequate against the M3s, M4s and Matildas it encountered. Combine this with a failure by the Japanese to follow their own modern doctrine, the tank didn't do what it could have.
Accepted for service as the 3” Gun Motor Carriage M9 -- production was going to be limited as a stopgap to cover the development of the M5, which also failed. Once the design was approved, someone then counted the number of guns available to build M9s -- about two dozen. They ended up cancelling the project.
The ARL is a pre-WWII design updated to be viable in the post-war era, and looks it. Considering the development of tanks between 1940 and 1945, one can see how optimistic this was.
Touted as the best tank in the world at the beginning of WWII, it utterly failed to achieve its potential. The one-man turret completely negated the advantages of speed and armor. It didn't help that the mechanical bugs weren't worked out by the time the shooting started.
More an honorable mention than a total fail, given the chassis' redemption as the Ferdinand; nevertheless, Porsche’s breakthrough tank candidate was a mess of mechanical issues. Its greatest contribution was for creating the turrets for the Henschel Tiger. One turreted tank saw combat. Read more in Chieftain's "Hello Kitty".
The Soviet Union was the only country to run with the multi-turreted idea, with this and big brother, T-35. While giving them credit for trying something new and the T-28 for having some novel features becoming standard in later tanks, there’s no denying the impracticality of the design. They did not fare particularly well against either the Finns or the Germans.
Hah, just kidding!