Concept A

A drawing of the Concept IIA self-propelled howitzer.

In July 1981, a report was submitted in close collaboration with the artillery system engineering working group (ASEWG) to develop a generation of concept self-propelled howitzers with anti-armor capabilities, along with all their various support systems. The M109A2, dubbed Class I, was used as a baseline from which these various concepts were drawn up and compared to. The main commonality between all concepts was that they used 155 mm howitzers.

Class II concepts were designed with the express purpose of defeating moving armored targets, surviving counterbattery threats, and providing fire on a timely basis. Concept IIA consisted of a casemate SPH. Concept IIB consisted of an all-new turreted SPH. And lastly, Concept IIC was a heavily modified M109 SPH using systems designed for the Class II concepts.

A detailed drawing of the Concept IIA vehicle.

A drawing of the Concept IIA and its loading mechanism in action.
The rear doors could be opened to replenish the vehicle's ammunition.

The objectives for Class III were identical for for Class II, and the same shoot-and-scoot philosophy was being heavily emphasized. Similarly, Concepts IIIA and IIIB were casemate and turreted SPHs, respectively. The major difference between the two classes was the ammunition being used.

Class IV's objectives and overall characteristics were widely similar as before. However, in order to react to the counterbattery threat, it was decided that this class of concepts should be optimized to operate at incredibly long distances, to the point where 90% of enemy artillery simply had too short of a firing range. Both concepts IVA and IVB were casemate SPHs, again experimenting with different types of ammunition. IVA's was rocket-boosted whereas IVB's simply used a larger cannon.

Class V concepts were identical to Class IV, however they sought to use larger 8-Inch howitzers. And lastly, the Class VI vehicles were various foreign designs already in development, such as the SP70 and GCT, which were used for comparison purposes like with Class I.

A detailed drawing of the Concept IIIA vehicle and its loading mechanism.

A drawing of the Concept IIIA and its loading mechanism in action.
The rear doors could be opened to replenish the vehicle's ammunition.

All of the Class II, III, IV, and V casemate concepts were also considered to use different loading mechanisms than those originally outlined. One of these loaded four-shell clips using an overhead trolly into a ready rack. Similarly, a clip of propellant charges would be transferred into a gravity-fed hopper. These two pieces would be automatically selected and rammed into the cannon.

The second mechanism used a floor-mounted ammunition handling system. All of the ammunition and propellant charges were stored vertically on opposite sides of the floor. These were selected automatically and loaded manually into a vertical loading arm, which was then hoisted up to meet the breach. Regardless of the loading method, this reduced the crews of these vehicles to three: the driver, commander, and the gunner (who also acted as the loader).

An example drawing of the four-clip assembly concept.

An example drawing of the floor-mounted system in action.

The point of these loading mechanisms was to sustain a high rate of fire, sometimes as high as 18 rounds a minute. However, for a video game, this is clearly too much and will need to be cut back. In fact, for World Of Tanks, I think it would be unique if we can give this line of concepts the autoreloading mechanic. It would take a long time to initially load the shells into the clip, to the point where it could have a firing rate equivalent to its contemporaries. However, if more shells are fired like a conventional autoloader, then the firing rate drops dramatically; just like with the high-tier Italian medium tanks.

I also think four shells for Tier IX is too much, and would like to see that dropped to three.

The Concept A, as I present it, is a combination of both the Concept IIA and Concept IIIA vehicles. These SPGs are fairly mobile, but they also have rather large profiles. The guns should have average or below average characteristics in my opinion, but a relatively high shell velocity, as these vehicles were purposed to take on enemy armor. While their special ammunition likely won't be added to the game, they could also fire conventional HE shells.



Guns: 155 mm Cannon IIA (autoreloader); 155 mm Cannon IIIA (autoreloader)

Engines: Cummins VTA-903-T400 (400 hp); Cummins VTA-903-T500 (500 hp); Cummins VTA-903-T660 (660 hp)

Suspensions/Alternate Hulls, Total Weight (metric tons): Concept IIA (30.39); Concept IIIA (31.29)

Hull Armor (mm): 32/32/32

Top Speed: 61 km/h

Crew: 3 (Driver/Loader; Gunner/Loader; Commander/Radio)




Parent: XM138
Children: Concept IVB
See Also: Concept IIB

Sources:

Harvey Garver & Harold Liberman, Special Publications ARLCD-SP-81003 (AD-A102819), 1981