What's new
British Ordnance Collectors Network

This is a sample guest message. Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Grenade, hand , IR-RP, Nr520, with fuze Nr.521

pzgr40

Well-Known Member
Premium Member
Cutaway model of a “Grenade, hand , IR-RP, Nr520, with fuze Nr.521”
This grenade emits smoke that masks activity of friendly troops. As the smoke consists of -hot- burning particles of red phosporous material this prevents enemy infra red sighting equipment to visually penetrate the smoke.
The grenade consists of two main parts; the grenade body , and the fuze No.521
The grenade body consists of a rubber can filled with three stacked rings of pressed red phosporous material. Each ring is cut over the lower half of the height of each ring, forming four 90 degrees segments. In the centre of the rings a plastic tube with black powder is placed which explodes if it is ignited by the pyrotchnic delay. The space between the tube and the rings is filled with graphite powder.
The fuze No.521 is of the mouse trap type, however is designed in such a way that the lever does not fly off. This is done for safety to prevent the lever from flying through the cockpit of a plane or helikopter when thrown from the cockpit.
The safety pin has to be rotated 90 degrees before it can be retracted.
The flame of the firing cap ignites the 1-1,5 seconds pyrotechnic delay pellet which ignites central exploder tube.

When thrown, the lever flips over, allowing the firing pin to rotate and hit the firing cap. The flame of the firing cap ignites the 1 to 1,5 seconds pyrotechnic delay which ignites the tube with black powder. This ignites the rings of red phospor, breaks the rings in 90 degrees segments and raises the pressure in the rubber grenade body up till the moment it rips open and spreads the pieces of burning phospor, blocking the vision of enemy IR sighting equipment.

Data:
Height of complete grenade: 138mm
Diameter of the complete grenade: 70,5mm (body diameter 65mm)
Mass (complete): 395 grams
Smoke composition (red phosporous): 228 grams
Delay : 1 to 1,5 seconds
Smoke screen during 50 seconds
Effective IR smoke screen during 40 seconds
Dimension smoke screen; where scattered red phosporous particles are clearly burning, a 1mtr wide and 1 mtr high effective IR smoke screen.

Regards, DJH
 

Attachments

  • 01 - grenade smoke IR Nr.520 cutaway model.jpg
    01 - grenade smoke IR Nr.520 cutaway model.jpg
    226.5 KB · Views: 53
  • 02 - grenade smoke IR Nr.520 backside.jpg
    02 - grenade smoke IR Nr.520 backside.jpg
    123.5 KB · Views: 42
Top