With the need to adopt a combat vehicle similar in form and function to the American M109 155mm-armed Self-Propelled Gun vehicle, the Iranian defense industry developed the "Raad-2" ("Thunder 2") series. The Raad-2 followed the 1996 introduction of the Raad-1 which was a 122mm-based vehicle built from the mating of the Soviet 2S1 turret and gun with the hull of the BMP-1. Similarly, the Raad-2 features the engine and road wheels of the Soviet T-72 Main Battle Tank (MBT) with the gearbox of the T-55 MBT. The 155mm gun in play is a locally-developed and manufactured weapon.
As in the M109, the Raad-2 features a rear-set turret emplacement mounting the primary armament. The gun is a long-barrel unit with double-baffle muzzle brake and midway fume extractor and designated as "HM44". A heavy-duty hinged clamp support assembly is fitted to the front hull to lock the gun in place during transport. The turret is of a boxy shape, allowing for the needed workspace for the gunnery crew. The complete crew numbers three - driver, commander, and gunner. The driver is seated at front-left with the engine at front-right in the hull. The track-over-wheel arrangement sports six roadwheels to a hull side with armor skirts providing some basic protection to the upper track regions. Recoil supports are lowered at the rear of each track section prior to firing. As a howitzer weapon system, the Raad-2 does not required line-of-sight of the target area, lobbing its lethal ordnance at enemy positions and fortifications. Local defense is by way of a single 12.7mm Anti-Aircraft (AA) machine gun fitting on a pintle mounting on the hull roof.
The Raad-2 features an operating weight in the 36-ton range. Its overall length measures 9 meters with a width of 3.4 meters and height of 2.6 meters. Power is through a V-84MS air-cooled, diesel-fueled engine outputting at 840 horsepower. Road speeds reach 65lmh with road ranges out to 450 kilometers.
The turret design includes a standard power-assisted traversing feature with manual backup support. It can rotate 360-degrees and features an elevation range of +75 to -3 degrees. The gunnery crew is wholly enclosed in the armored turret superstructure and largely separate from the driver position in the hull.
The main gun can fire various projectile types beyond the standard High-Explosive (HE) ordnance options. These include smoke, illumination, anti-personnel, chemical, and rocket-assisted munitions.
One noted variant in the Raad-2 family is the Raad-2M. It is finished with the Ukrainian 5TDF diesel-fueled engine of 700 horsepower. The vehicle is differentiated further by its enlarged exhaust port on the front-right side of the hull superstructure.
It is believed that the Raad-2 maintains an active status in the Iranian Army. Testing was ongoing as early as 1997.