For understandable reasons, armoured vehicles evolved more quickly during WWII than at any time before or since. One of the side effects of this rapid evolution was that it resulted in a vast number of armoured vehicle types, which produced considerable confusion over where some types ended and others began. The confusion still exists today because there’s no hard-and-fast way of defining precisely where the dividing lines are – but for whatever it’s worth, here’s how I interpret and categorize these vehicles.
First, there are the vehicles that fall on what proved to be the main evolutionary line of tanks, which began in WWI with the Renault FT and which continues in the present day in such forms as the M1 Abrams. These are the vehicles with a standard tank configuration consisting of an armoured hull with the driver at the front, the engine at the back and a caterpillar track on each side, on top of which sits a rotating armoured turret containing the tank’s main gun, the tank’s commander, and usually other crew members such as a loader and a gunner. In WWII, this general configuration was expressed in such variations as light tanks, medium tanks, heavy tanks and super-heavy tanks such as the Maus, plus the British categories of cruiser tanks and infantry tanks. All basically contained the same elements, with their differences being mainly in the areas of scale and of ratios.
The lightest tanks weren’t much use against armour, and the heaviest tanks were mainly intended for use against armour, but all conventional tanks had in common one important feature: they carried a direct-fire main gun. This means that their gun was meant to shoot in a straight line at targets that the gunner could see with his own eyes and which were located at short to medium ranges. This type of gun is fundamentally different from howitzer-type artillery, which operates on the principle of indirect fire: howitzers fire shells on a high-arc trajectory against targets which the gunner typically can’t see with his own eyes (the fire needs to be targeted by other means) and which is often intended to deliver plunging fire against targets (such as trenches) which are difficult to attack with direct-fire weapons.
The direct-fire guns of WWII tanks also tended to be – but were not always – high-velocity guns (especially compared with howitzers, which tend to be low-velocity weapons). High-velocity guns are well suited to penetrating armour at short to medium ranges because the force delivered by a projectile is equal to its mass times the square of its velocity – meaning that an increase in shell speed gives better results than an increase in shell size and weight. Generally speaking, high-velocity guns were the best choice for a WWII tank because they were very effective against armour when they fired armour-piercing rounds, and because in a pinch they could also be reasonably effective as infantry-support weapons when firing high-explosive rounds. This made them more versatile than low-velocity tanks guns, which were fine as as infantry-support weapons but ineffective as armour-piercing anti-tank weapons.
So much for conventional tanks. Now we get into the messy territory of tankettes, tank destroyers, assault guns and self-propelled artillery.
Tankettes don’t need much analysis: they were mostly small, open-topped tracked vehicles that served as troop carriers or light weapon carriers, they were popular in the 1920s because they were cheap, and combat experience in WWII quickly showed them to be useless.
Tank destroyers in WWII more or less fell into two types: German-type and American-type, for want of a better designation. The classic German-type tank destroyers were the Jagdpanther and Jagdtiger, which were basically Panther and Tiger chassis caring an armoured box rather than a rotating turret. Their advantage was that they were cheaper than turreted tanks, they could carry a bigger gun, and their front superstructure could be more heavily armoured. Their disadvantage was that their turretless design required the whole vehicle to be turned in order to aim at a target, and that they tended to be slow. I’m less familiar with American tank destroyers, but my understanding is that they tended to be fast, fairly light (meaning not well armoured) vehicles, some designs having turrets and some being opened-topped. Tank destroyers had high-velocity guns, since their primary job was to kill armoured vehicles. Turretless tank destroyers pretty much disappeared after WWII, but the Swedish Stridsvagn 103, or S-tank, which operated in the 1960s and 1970s, was based on their configuration.
The basic thing to remember about assault guns and self-propelled artillery is that these armoured vehicles weren’t intended to fight other armoured vehicles (unlike tank destroyers, the whole point of which was their anti-armour function). Self-propelled artillery, which survives to this day, is fairly easy to define: it has more or less the same functions as towed artillery, but it can move around the battlefield under its own power, on the same terrain as tanks (because it too has tracks), and it offers its crew a certain degree of armour protection. SPA typically functions in an indirect-fire role, firing low-velocity, high-explosive shells, often over medium or long distances. Assault guns, unlike SPA, didn’t outline WWII. They tended to carry large-caliber, low-velocity, direct-fire guns mean to attack targets at short ranges, in direct support of infantry. They were useful against certain types of fortifications, an application for which a powerful explosive charge delivered at low velocity was more useful than a mostly solid armour-piercing shell delivered at high velocity.
These multiple vehicle types are interesting to study, but the distinctions between them are far too complicated to all be depicted in a game like A&A. The list I gave above (light tanks, medium tanks, heavy tanks, super-heavy tanks, cruiser tanks, infantry tanks, tankettes, German-type tank destroyers, American-type tank destroyers, assault guns and self-propelled artillery) adds up to twelve different categories, which is almost the same number of unit types found in A&A 1940. A little more variety – say, a couple of extra tank types – would be fun and practical, but going further than that would probably be too much.
