Proximity fuze

FU-RALEC DE F3 is a French high-explosive (HE) radio fuze (Prox) used with standard NATO 155 mm HE munitions. It has impact (PD) and delayed action modes. FU RALEC DE stands for “Fusée Radioélectrique Double Effet” (Double Effect Radio-Electric Fuse).

The operating principle is based on receiving a signal reflected from the target: the fuze sensor functions like a radar, with a combined radio transmitter and receiver in a single unit.

• Length: 151 mm
• Diameter: 61 mm
• Weight: 626 g
• Country of origin: France

By turning the cap, set the fuze to either impact action or airburst. The fuze body shows a schematic representation of ground and air activation.

OF Zonar 75B is a radio fuze (Prox) produced by a Swedish manufacturer, specifically designed for the Archer system, using projectiles such as SGR77, ÖVNGR54-77 Z, and M77. It provides multiple ranges of fragmentation (HE), high-explosive, point-detonating (PD) action, and delayed action. It also allows for airburst settings. It can be used with other NATO munitions as well.

The airburst is achieved by receiving a signal reflected from the target: the fuze sensor functions like a radar, with a combined radio transmitter and receiver in a single unit.

The fuze is protected from impacts from a height of 1.5 m and is moisture-resistant.

• Length: 164 mm
• Diameter: 61 mm
• Weight: 770 g
• Country of origin: Sweden
• Packaging: Hermetically sealed box, 12 units

It has eight setting positions:

• S – Transport position
• 1F – High-explosive action with delay (Delay)
• 2F – Standard high-explosive action
• 3Ö – Ultra-sensitive fragmentation action; detonation occurs on any contact. Useful for achieving an airburst in wooded areas
• 4Ö – Standard fragmentation action
• 5Z – Airburst, 3-6 m above the target, for personnel engagement
• 6Z – High airburst, 6-12 m above the target, for personnel engagement
• 7Z – Point detonation, for armored vehicle engagement

PPD-440 is a Norwegian high-explosive (HE) multi-purpose fuze that can function as a proximity fuze with detonation upon approach or be used purely for impact action with 155 mm and 203 mm caliber projectiles.

Key Features of PPD-440:

Multi-purpose Design:

• PPD-440 can function as a proximity fuze or as a traditional impact fuze.
• It is used with various munitions, primarily medium and large caliber shells (155 mm and 203 mm).

Proximity Functionality:

• In proximity mode, the PPD-440 uses a radar sensor that activates at a specific height above the target (typically around 10 meters).
• The fuze’s electronic system analyzes signals to accurately determine the moment the projectile passes over the target.

Backup Impact Mode:

• If proximity activation fails for any reason, the backup impact mode is triggered. This is crucial for ensuring the fuze’s reliability in combat conditions.
• In impact mode, the fuze activates directly upon contact with the target.

Power Supply:

• PPD-440 does not use batteries to power its electronic systems. Instead, it is equipped with a built-in generator that obtains power during projectile flight.
• The generator works via a propeller located in an air intake at the tip of the fuze. The propeller rotates due to the airstream during the projectile’s flight, allowing it to generate the necessary electrical energy

• Length: 151.6 mm
• Weight: 485 g

Fuze Installation:

To set the fuze to proximity mode (airburst action), remove the black protective cap from the fuze. In this mode, the projectile will detonate at a height of 10 meters above the target.

Fuze Adjustment: Before firing, you can select one of the two operating modes of the fuze — proximity or impact. To switch to impact mode, place a special cap on the tip of the fuze.

Application: The PPD-440 fuze is used both on the battlefield and for suppressing targets behind cover. Its versatility allows it to effectively engage both enemy personnel and equipment.

The M728 is an American-made high-explosive (HE) radio fuze (Prox) used with standard NATO 155 mm HE munitions. It also features an impact action mode (PD).

The fuze contains a continuous wave radio transmitter/detector with antennas and a power source, which performs the target detection function. The timing mechanism is synchronized with the radio transmitter to enhance the reliability of the fuze’s activation.

The fuze scale is set to a predetermined impact time. When approaching the target, 5 seconds before the set time, the radio wave transmission begins. When the reflected signal reaches the set amplitude, an electronic switch activates the explosive train at an optimal distance from the target. If this mode fails, the fuze will detonate on impact (PD).

The fuze is designed for airburst, making it most effective against enemy personnel and lightly armored targets.

• Visible length: 95 mm
• Overall length: 218.44 mm
• Weight: 993 g

Fuze Installation:

The fuze is screwed into the nose of the projectile using a wrench. The setting scale, with divisions ranging from 5 to 100 seconds, is adjusted to the desired time before impact with the target.

If only impact action is required, the scale on the fuze should be set to a time greater than the impact time.

When approaching the target, 5 seconds before the set time, radio wave transmission begins. When the reflected signal reaches the specified amplitude, an electronic switch activates the explosive train at the optimal distance from the target. If this mode fails, the fuze will detonate upon impact (PD).

Specifics of Use:

• The M728 fuze is designed for both airburst and impact actions, making it versatile for various combat scenarios.
• Airburst Mode: The fuze is most effective when used for airburst to target enemy personnel or lightly armored vehicles. Setting the fuze scale to the calculated time ensures detonation at an optimal height, increasing the area of effect.
• Impact Mode: If airburst is not possible, the fuze will function in impact mode, ensuring that detonation occurs when the projectile hits the target, suitable for more direct engagement.
• Time Setting: The time scale can be set between 5 and 100 seconds. To achieve the desired effect, careful calculation of projectile flight time is essential.
• Reliability Mechanism: The proximity activation begins 5 seconds before the set detonation time. This feature provides a dual mechanism to ensure target engagement—either by airburst or by impact if the initial mode fails.
• Safety Note: The fuze should be handled carefully to avoid accidental activation, especially during installation and setting adjustments.