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  1. #1
    Join Date
    24.05.2003
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    Holland
    Posts
    2,853

    Default URG-86 grenade Czechaslovakia

    Cutaway model of a Czech URG-86 handgrenade. The URG -86 is an universal anti-personel grenade with characteristics of both an offensive and defensive grenade.
    The grenade consistes of a green plastic grenade body (1) with a green plastic fuze body (2) screwed on top. The fuze has two different settings; a time fuze and an all ways fuze.
    Inside the grenade body, shrappnel consiting of steel cuttings -ø1 mm dia, 3mm long- is cast into a white plastic sphere (3). Inside this sphere, the explosive charge (4) is placed.

    The fuze function can be set by switching a switch beside the lever (13) up or down, changing the function from time fuze (up) to all ways fuze (down). On the inside of the fuze an upper (5) and lower (6) plastic inertia weight is placed, both with a lead weight ring around the outside. These two inertia weights are kept apart by an axial fixation pin (7) which is fixated by a spring loaded radial pin (8 ), kept in position by the switch. Both inertia weights have a round top, placed in the chamfered side on the inside of the fuze body. The flat surfaces of the inertia weights face one another.

    Three pyrotechnic delay fuzes are placed in the upper inertia weight; a short one -1,2 sec- (9) in top of the inertia weight, a longer one (10) in the stem of the firing pin, which is screwed to the base of the upper inertia weight. And a short pyrotechnic delay (11) inside the inertia weight, just above the axial fixation pin (7) prevents the pin from moving inward and fixates the two inertia weights apart. A small hole is placed between both short pyrotechnic delays (9&11) , enshuring the short pyrotechnic delay in top of the inertia weight (9) ignites the other one (11). A seperate channel (not visable in picture) is drilled opposite to the pyrotechnic delays to allow gasses of the combustion of the pyrotechnic delays to be lead away into the fuze body. This is to prevent a build up of gas pressure in the inertia weight.

    The lower inertia weight houses a firing cap (12) in the lower part of the weight
    Both inertia weights are axial connected to one another by the tube (10) of the long pyrotechnic delay, screwed in the upper inertia weight (5), which telescopes in the lower inertia weight (6). In radial movement they are free to move towards one another.

    Functioning of time fuze :
    The switch is switched downward , thereby preventing it from falling away from the grenade when the lever (13) is released.
    Before throwing, the split pin is removed. If the lever is kept pushed against the grenade body, the grenade is safe. If the grenade is thrown, the spring loaded –mouse trap type- firing pin rotates and hits the firing cap (14) in top of the fuze body. This activates the short pyrotechnic delay (9) in top of the upper inertia weight (5), which ignites the other two pyrotechnic delays (9 & 11). As the switch is in the lower position, the spring loaded radial pin (8 ) will not fall away, fixating the Axial pin (7) in it’s position. Thus, the burning away of the pyrotecnic delay above this pin (11) is of no consequence, the all ways fuze is not functional.
    The pyrotechnic delay (9) in the tube burns down and ignites a small heat sensitive squib (14), which launches the tip of the firing pin into the firing cap (12) in the lower inertia weight. The flame of this firing cap ignites the detonator (15), which ignites the main charge. The delay of the grenade is between 3,2 and 4,6 seconds.

    Functioning of all ways fuze:
    The switch is not switched downward , thereby allowing it from falling away from the grenade when the lever (13) is released.
    Before throwing, the split pin is removed. If the lever is kept pushed against the grenade body, the grenade is safe. If the grenade is thrown, the spring loaded –mouse trap type- firing pin rotates and hits the firing cap (14) in top of the fuze body. This activates the short pyrotechnic delay (9) in top of the upper inertia weight (5), which ignites the other two pyrotechnic delays (9 & 11) . As the switch and the spring loaded radial pin (8 ) both fall away, the axial pin (7) is released, rendering the all ways fuze functional. The two inertia weigts are now kept apart by a weak spring (16), keeping the firing pin away from the firing cap (12).
    Upon impact on the base of the grenade, inertia moves the firing pin of the upper inertia weight (5) down into the firing cap (12) of the lower inertia weight (6) igniting the firing cap. If the grenade lands on it’ t top (fuze), inertia will move the firing cap (12) in the lower inertia weight (6) into the firing pin of the upper inertia weight (5).
    If the grenade lands on it’s side, both inertia weights will move downward climbing the chamfered edges of the inside of the fuze body with the rounded sides of the inertia weights , forcing both inertia weights to telescope towards one another, pushing the firing pin into the firing cap (12). This will ignite the firing cap, which ignites the detonator (15), igniting the main charge (04) of the grenade.

    Data URG-86 grenade :
    Weight grenade : 440 grams
    Length grenade: 117mm
    Diameter grenade : 60mm
    Explosive charge : 43 grams PL-U-EP14
    Lethal radius : 8 meter

    Regards, DJH
    Attached Images Attached Images
    You wanna make a piece of ammo look interesting? .......cut it!

    Looking for / Suche noch:
    -8,8cm Pzgr.40.

  2. #2
    Join Date
    12.02.2016
    Posts
    118

    Default

    very nice cut, as always!!
    Tracer works in both directions!

  3. #3
    Join Date
    08.05.2003
    Posts
    4,661

    Default

    DJ, well done! Great to see the internal fuze parts as these are usually missing in the grenades offered.
    Ich suche Wissen!

    SCIENTIA POTENTIA EST!

    Wer nichts weiß muss alles glauben!

    Und wer toleriert uns?

    Studiert den Hooton-Plan, den Kaufman-Plan und den Morgenthau-Plan!

    Ich bin verantwortlich für das was ich sage, nicht dafür was jemand anders versteht!

    https://blog.naanoo.com/musik/deutsc...xt-strophe-1-3
    https://www.youtube.com/watch?v=1UkmhtoXCPA
    https://www.youtube.com/watch?v=_aw9aRyjLcI

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