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Fact file: Denel 35mm Dual Purpose Gun

The Denel 35mm Dual Purpose gun is a standard close-in weapon system aboard the Valour-class frigates.

Designation:

Denel 35mm Dual Purpose Gun

Type:

Breech-loading twin 35mm automatic cannon.

Country of origin:

South Africa

First deployed:

2005.

Delivered to the SAN:

2005.

Manufacturer:

Denel Land Systems Lyttleton

Numbers:

Four.

Cost:

-

System components:

Two Denel GA35 cannons, turret, support equipment.

General:

 

The 35DPG fires the full range of the effective standard NATO 35 x 228 mm rounds at 1 100 rounds per minute, with a muzzle velocity of 1 175 meters per second.

 

That gives it the firepower to effectively engage aerial targets out to 4 000 meters, and surface targets out to 6 000 meters.

 

With electric gun drives, the gun can slew through 180 degrees in four seconds, delivering projectiles at an accuracy and dispersion of less than 1mrad and 2mrad, respectively.

 

Carrying 500 ready rounds the 35DPG cater for more than 12 engagements of 2 second each before reloading, which can be carried out by two persons within 10 minutes from the ready use lockers installed behind the gun.

 

The 35DPG's anti-missile capability can be enhanced by using AHEAD programmable fuzed ammunition from Rheinmetall Defence (previously Oerlikon-Contraves). Evaluation results with AHEAD exceeded expectations, and proved that the required kill probability can be achieved against surface-to-surface missiles.

 

A further enhancement of the 35DPG's anti-missile capability is possible by adding the unique Closed Loop Fire Correction system developed by Denel.

 

This upgrade allows the 35 mm projectiles to be tracked all the way to the target, enabling the fire-control system to implement real-time corrections for bias errors caused by the combat system, and also to compensate for the effects of meteorological conditions.

 

The 35DPG has also been designed from the outset to be simple to integrate with an existing ship and its systems:

• It is a non-deck-penetrating mount that only needs sufficient free deck space to be installed, making no demands on below deck volume other than for a console in the operations room. For this reason, it could be installed above the rotorcraft hangar.

• Its own on-board computers handle ballistic calculations and the fire-control function, which means that it depends on the ship only for real time three-dimensional target information provided by the combat management and tracking systems. That greatly simplifies integration with a wide range of combat management and tracking s y s t e m s.

• Weighing only 5 500Kg (unloaded) and with a barrel sweep of 3.8m facilitate installation on ships as small as 200 tons.

• The 35DPG uses fully modular subsystems and subsystem elements to simplify maintenance and give maximum adaptability. It also uses commercial-off-the-shelf (COTS) components where those are suitable, which further simplifies maintenance.

• The 35DPG's combination of non-deck-penetrating design, relative ease of integration with combat management and tracking systems, modular design and the use of COTS components, result in a very cost - effective system: The initial cost is kept down by the ease with which it can be installed and integrated; the through-life costs are kept down by a maintenance friendly design and the use of COTS components

 

The GA35 multipurpose cannon is exceptionally rugged and simple to maintain. Optimised for simplicity and reliability, the system has only 200 components and can be dismantled without the use of any special tools. Mounted on naval platforms, the GA35 can operate single or double mounted, integrated cannon system or with missiles in a hybrid role.

 

The GA35 is gas operated, firing belted ammunition from an open breech position. T h e positively locked breech, mechanical firing pin and four installation positions enhance safety and versatility.

 

The cannon allows for single gas driven feeders with ammunition feed from three directions without additional parts or double gas driven feeders with first shot selection between different ammunition types.

 

State-of-the-art electrical drive technology is used for the gun drives. The gun drive sub-system comprises of elevation motor-gearbox assembly, azimuth motor-gearbox assembly, elevation sensor gearbox, azimuth sensor gearbox assembly, power transformer and gun drive electronics unit.

Integrates into:

Combat Management System.

Acquisition modes:

Designated by ship’s combat management system.

Guidance:

Electro-optic tracker.

Weight:

6.5mt loaded, 5.5mt unloaded.

Gun:

  • Calibre:

  • Range:

 

 

  • Trajectory:

  • Dimensions:

    • Length:

    • Width:

    • Height:

  • Swept radius:

  • Muzzle velocity:

 

  • Rate of fire:

  • Elevation:

  • Traverse:

  • Accuracy:

  • Dispersion:

  • Magazine:

 

  • 35x228mm

  • 4km anti-aircraft, 6km surface target. AHEAD: 2.5km for cruise missiles, 1.5km for high-speed missiles.

  • Ballistic.

 

  • 5.4m.

  • 2.9m.

  • 2.3m.

  • 3.8m at 1.310m.

  • 1175m/s (HEI, HEI-T, SAPHEI, TP, TP-T), 1050m/s (AHEAD).

  • 550rpm.

  • -10deg to +85deg, elevates at 40deg/s.

  • Up to 360deg, traverses at 70deg/s.

  • Less than 1mrad.

  • Less than 2mrad.

  • 240 rounds per gun.

Ammunition:

  • Length:

  • Type:

 

 

  • Weight:

 

 

 

  • AHEAD:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  • Fuze:

 

  • 0.387m

  • AHEAD, High Explosive Incendiary (HEI), HEI-Tracer, Semi-Armour Piercing HEI, APCI, Target Practice (TP), TP-Tracer.

  • 1.552kg (SAPHEI round), 1.58kg (HEI, TP, TP-T), 1.565kg (HEI-T), 1.78kg (AHEAD); 0.210kg (link), 0.550kg (HEI, SAPHEI, TP, TP-T projectile), 0.75kg (AHEAD projectile).

  • AHEAD gives the 35DPG its anti-missile capability. The crux of the AHEAD system is timing the flight of a round fired towards the point of impact in such a way that at a distance of somewhere between 10 and 40 meters ahead of the target, 152 heavy tungsten metal sub-projectiles are released from the round.1 This cloud of sub-projectiles then flies towards the approaching target and on impact tiny spin-stabilized tungsten cylinders, each weighing 3.3 grams, penetrate into the target body - even at low angles of impact. Due to their high kinetic energy (the relative velocity is about 1,200 m/s), they can be expected to cause massive damage to the target's functional system components. The precisely timed ejection of the sub-projectiles is only ensured if all critical functions are perfectly coordinated. “To achieve this, absolutely accurate target tracking is required in order to calculate the projectile flight time from the gun muzzle to the optimal point of sub-projectile ejection. The time fuze of each AHEAD projectile is programmed at the muzzle velocity measuring base, depending on its individual muzzle velocity,” Rheinmetall argues.

  • -

Penetration:

Does not penetrate deck

Power needs:

440V, 3-phase 60Hz and 115V, single-phase 400Hz.

Comment:

 

 

The guns were acquired to provide the Valour-class frigates a close-in or “inner layer” ballistic anti-missile and anti-aircraft system. As such its primary role is to destroy attacking helicopters, fixed-wing aircraft and surface-to-surface missiles. Its secondary role is against surface vessels and shore targets, both in symmetrical and asymmetrical combat as well as in law enforcement situations in which fire may be opened but where accuracy is critical and no collateral damage is generally acceptable.

 

 

 

 

 

 

 

1 Rheinmetall Defence, Air Defence Systems, Upgrades, http://www.rheinmetall-detec.com, accessed on January 21, 2006.


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