Although originally intended as a lightly armoured, self-propelled anti-aircraft weapon system, the NM135 was utilised as a mechanised infantry fighting vehicle to transport Stormer troops and in the armed reconnaissance role. First entering service in the early-mid 1980s, it remained in operation until the introduction of the Hägglund CV9030N in the late 1990s and was progressively withdrawn from service in the 2000s.
Design
Layout
The NM135's primary modification from a standard M113 is the replacement of the commander's cupola with a one-man rotating and powered turret originally made by Hägglund and Söner for the Swedish Pansarbandvagn 302 APC. The 20mm Hispano-Suiza cannon on the Pbv 302 was replaced with a 20mm Rheinmetall cannon. A vertical bank of three smoke grenade launchers are fitted to each side of the turret. Conversion and fitting of the turret was undertaken in Norway. The NM135 featured a 3-man crew – driver, gunner and commander. The driver was located in the front left in the same position as a standard M113 and featured the usual arrangement of four vision blocks but with the central optical block replaced with an passive IR block. The driver's hatch was hinged and opened to the right so as not to impede the commander's cupola. Behind the driver's hatch was located the commander's non-rotatable cupola, which featured vision blocks but no armament. The commander's hatch was hinged and opened to the rear. To the right of the commander's cupola was located the Hägglund turret manned by the vehicle's gunner. Due to size constraints imposed by fitting of the turret, the available space in the troop compartment of a standard M113 was reduced in the NM135, and a maximum of eight troops could be carried.
Armament
The NM135 has as its primary armament a non-stabilised Rheinmetall mk20 RH-20220mm autocannon mounted off-centre to the right of the Hägglund and Söner turret. This weapon fires 20 x 139 mm ammunition with a rate of fire of around 900 rounds per minute and features a ballistic computer to assist the gunner in aiming using the weapon's optical and passive IR sights. The turret was also fitted with a Rheinmetall MG3 7.62mm general purpose machine gun mounted coaxially above the 20mm cannon, Firing NATO 7.62×51mm ammunition with a rate of fire of 1,000-1,300 rounds per minute to provide infantry support fire and for use against lightly-armoured vehicles and other 'soft-skinned' targets. A 71 mm LYRAN mortar is also fitted at the rear of the turret which along with illumination rounds could also fire high-explosive / anti-personnel and smoke rounds.
Armour
The NM135 has the same level of protection as a standard M113 with the hull being made of rolled 5083/5086 H32 aluminium armour of the following thicknesses:
Upper front: 38mm at 45 degrees
Lower front: 38mm at 30 degrees
Upper sides: 44mm
Lower sides 32mm
Rear: 44mm at 9 degrees
Ramp: 44mm at 8 degrees
Top: 38mm at 8 degrees
Floor: 32mm at 90 degrees
In 1996 additional appliqué armour was added to the vehicle front and sides for some vehicles deployed on active duty to Bosnia with IFOR. This increased the nominal vehicle weight from 11.7 tons to 12.2 tons, and load capacity was reduced from 1,200kg to 950kg
Drivetrain
The NM135 is equipped with a Detroit Diesel 6V53 non-turbocharged two-cycle diesel engine rated at 212 hp from the M113A1, driving through an Allison TX-100-1 automatic transmission with three forward and one reverse gears. In 1997 the suspension, cooling system, and final drives were updated to M113A2 standards.
Mobility
The NM135 used the T130E1 rubber-padded steel tracks as fitted to a standard M113A1, with 128 track links per vehicle. However, late in its service life some vehicles were equipped with Soucy rubber band-tracks for improved cross-country performance in snow and ice.
Production history
Conversion of fifty-three M113A1 APC to NM135 IFV commenced in 1981–1982. Although the turrets were of Swedish manufacture conversion of and fitting to the M113 hull took place in Norway, at a unit cost of $183,088–$184,389. All vehicles were issued to the Norwegian army - none were exported to foreign operators.
Operational history
Following the restructuring of its army in 1989, Norway's fifty-three NM135s were deployed across the country to NATO units under Norwegian command as follows:
The 1st Armoured Battalion featured a mechanised company of Stormer squadrons with NM135s in the role of infantry fighting vehicles to support the Leopard I MBTs, as well as a reconnaissance squadron of four NM135s assigned at the battalion level to the support company. Total 29 vehicles.
A reconnaissance squadron each of three vehicles was assigned to 1, 3, 7, 8, 12 and 13 Brigades. Total eighteen vehicles. A reconnaissance squadron each of three vehicles was assigned to Brigade Sør-Norge and Brigade Vestlandet. Total six vehicles.
Withdrawal from service
Commencing from the introduction of the CV90 in 1999 the NM135 was progressively withdrawn from service as units upgraded to the new vehicle. By 2009 no NM135s remained in active service.
