Nammo’s (Booth 1001) 25mmx137 APEX (armour-piercing with explosive) ammunition has been qualified for the F-35 Lightening II advanced stealth fighter following flight trials at the US Navy’s Naval Air Weapons Station in China Lake, California, earlier this year.
Designed specifically for the F-35, the APEX is intended to defeat a spectrum of target types – ranging from air targets to both so and armoured ground targets. e ammunition features an explosive filled warhead with a delayed initiation – meaning that the blast, fragments and incendiary are delivered inside the target and a tungsten carbide penetrator to defeat heavier armoured targets.
The hit mechanism of the projectile body is divided into separate phases depending on the type of target engaged. The mechanical fuze will support the transition between the phases of target defeat. For targets with light to medium protection, the projectile body can make full penetration with a time-delayed fuze to ensure maximal blast and fragmentation well inside the target.
The tungsten carbide penetrator is able to penetrate armoured targets because of the full utilisation of focused energy and high-density tungsten materials.
The penetrator is a sub-calibre design with high L/D ratio for performance and it is securely fastened inside the projectile body. The tungsten carbide penetrator is placed in the front end of the projectile for maximum performance during penetration, and will generate lethal fragments inside the target by splitting into multiple heavy fragments.
2016 saw a major milestone for the 25mm APEX ammunition: the round obtained full operational capability approval from the US Navy Safety Board, as well as approval for test flights from the US Air Force.
The maiden F-35 flight firing trials in 2017 were the last of a number of APEX ammunition flight certification activities for Navy’s Live Fire Testing and Evaluation (LFT&E) programme.
LFT&E was designed to evaluate the lethality of the ammunition when delivered against a variety of representative targets in realistic operational scenarios. When the LFT&E programme is finalised, the data will be incorporated into the Joint Munitions Effectiveness Manual (JMEM) to support mission planning for the F-35.