The Charlemagne will be a Premium British heavy tank released during 2021, it’s unknown how and when exactly players will be able to get it and play it. The vehicle will be competing directly with the Caernarvon Action X, but I’m sure it won’t have the same gameplay at all.
A few things you should take into consideration: the real proposed design had a 120 mm low-velocity gun that fired HESH rounds, for this reason, the expected ammo velocity was low. Why has Wargaming changed to AP and kept the low velocity it’s unclear and unknown?
Another British tank that suffers from this is the Chimera, and it makes the vehicle quite unpleasant to play, but it looks like Wargaming hasn’t learned its lessons and decided to repeat the same mistake. The other thing is the engine, the Meteorite M120 was never even considered to be mounted in the Charlemagne, Wargaming again had the full list of the proposed engines but decided to just implement something completely different. The proposed engine was the Rover Meteorite Pl Mk 202B with 585bhp and the most powerful one was the Maybach MA330 with 750bhp. Last but not final is the armour values, they are lower than the designed proposed and that changes substantially how this vehicle could play against higher Tier vehicles.
The following characteristics are from Supertest with a 100% Crew but expect them to possibly change in the near future.