M30 tank

The M30 (official classification Tank, Medium, M30) is a Planum series of main battle tanks that was first developed in 1947 to replace the M6 medium tank, which had reached weight and complexity limits that led to reliability problems that would prove catastrophic. The M30 was built with the M24 heavy tank chassis to minimize development cost and unit price.

The first variants of the M30 had a 100 mm Leeway-Andrews AM-270 gun, tanks from the Mk III to the Mk V had a 100 mm Leeway-Andrews AM-302 autoloader gun and tanks from the Mk VI onward had a 122 mm M47/1955 autoloader gun.

The M30 was replaced in Planum service in 1972 by the M55, the last tanks being pulled in the late 1990s. In other countries, it continues to serve even today.

The Second Great War
The M6 medium tank was developed in 1939 to provide the Planum with extra firepower to counter the expected Ravenfielder offensive.

It was one of the most successful tank designs of the Second Great War. Tens of thousands were built and exported to 21 countries, mostly the Mk III and Mk VII.

As the Second Great War raged on, M6 tanks were built and refitted with more armor and powerful guns. This threatened to stress their transmission and suspension, which remained unchanged through all of the M6 revisions. By 1945, the M6 was in its eight revision, with an 88 mm gun and armor that was even better than the T-44/M. All of these modifications made the M6 eight tonnes heavier than the Mk VII, at 40 tonnes.

The added weight resulted in a severe reduction in reliability and difficulties in transporting the tank. Only 24% of the Mk VIII tanks arrived in combat-ready state for the Battle of Tonchester in 1946.

M157: A Super-Heavy Disaster
From the Planum Military Magazine, Issue #782 (July 1996)

The Crapstorm Begins
After the development of the M30 Mk I had concluded, the Planum high command demanded a heavy tank based on an extended M6/M24 chassis to serve as a breakthrough tank. The tank was to weigh 65-70 tonnes and have a 125 mm gun from either the NSR or a domestic model.

The tank proposal created by Planum designers was the T157 heavy tank, weighing 64 tonnes with the requested 125 mm gun, a 1250 hp engine, 5 crew and up to 240 mm of armor. This much weight stressed the transmission and suspension, originally designed for 35-tonne tanks to the point that breakdowns were as common as on the T-42/H. The shells often exploded from the recoil, killing at least 8 tank crew. The problems were ignored and the tank was pressed into service. In June of 1950, the first production M157 tanks were rolled off the Kansar tank factory and straight into the military parade, where their performance became apparent: only 2 of the 30 tanks produced worked until the end of the parade. This was an embarrassment to the Planum and its high command, and they demanded that production of the M157 stop immediately.

M157's Bane
Their demands were not heeded, instead the designers behind the M157 proposed that it be redesigned again!

For the Mk II, "improvements" included even more armor and a 1400 hp engine, conveniently neither the suspension nor transmission nor gun was modified or rebuilt to actually handle the weight. This brought the mass of the M157 to an insane 75 tonnes, still with the suspension built for a 35-tonne tank!

Production started in July 1955, 35 Mk II tanks were built before the production line was forcefully stopped by Supreme Leader Hayden. All working M157s (around 200) were recalled from the frontline to be refitted with new transmissions and suspensions that could handle the weight, while the ammo racks were completely redesigned to not explode cause less damage to the tank and crew when the gun exploded.

Third Time's The Charm, Right?
Hayden was too late to stop the M157 disaster, the designers behind the catastrophe were developing a THIRD variant of the M157, now with a back-mounted 75 mm gun! This only served to limit the main turret's traverse and reduce its ammo capacity, as the AM-47 gun (first developed in 1933!!!) fitted on the back turret was useless against any contemporary threats! It also added three more crew, that meant three more crew that would die in case the back or front ammo racks exploded, which was likely to happen.

The answer to this was apparently, according to the designers, to add even more armor, bringing 300 mm armor to more sides of the tank. This brought the mass to 80 tonnes (according to the designers themselves), or more likely 90-100 tonnes (according to Aaron Hary and John Hayden). The extra mass made the tank even slower and more susceptible to breakdowns, this for a tank that originally had transmissions built for 35-tonne tanks!

The Planum high command did everything to stop it, but unfortunately failed, and in March 1958 the M157 Mk III, aka Cthulhu-on-land was unleashed onto the country.

A Happy Ending
When the M157 designers attempted to bring their design to the Kansar tank factory that produced the original blunders, General Hayden was there to stop them. He seized all designs and imprisoned the designers for wasting the Planum's resources on useless vanity projects. Three prototypes were built, now sitting at the Planum National Military Museum and never to drive or spark anyone's imagination to repeat the disaster ever again.

The M157 Mk Is and IIs continued to serve the Planum until the 1990s, when most of them were scrapped and the rest sent to military museums. Some are still in running condition.