German 8,8cm Kw.K 43 hollow-charge shell (8,8cm Gr39 HI)


#1

Happy collecting, Peter


#2

Does that AZ 38 fuze have to set off the gaine at the base of the main charge, it is a long hop?

gravelbelly


#3

Correct, the “initiator” in the fuze is full scale detonator. Hence the “Flanged steel frustum” to protect the liner from too much shrapnel and deformation.


#4

gravelbelly, The fuze type is called a, Point Initiating, Base Detonating, Spit Back, or PIBDSB. The booster on the base of the fuze will be a shaped (hollow) charge and when initiated, sends the shape charge (spit back) into the base detonator (gaine). Cheers, Y’all, Bruce.


#5

Bruce, the German PIBD detonators for HEAT warheads had no “cavities” (like tiny shaped charges).
Only the Russians (and later on their allies) used this system.


#6

EOD, Thank you for your knowledge of WWII German fuzing. I was not aware that they did not “Spit Back”. Cheers, Y’all, Bruce.


#7

Bruce, now I wonder if the shaped charge “spit back” (thank you for introducing me to this term) is only for a safer transmission of the “flash” to the base element or if it also reduced the tiny shrapnel which might have effected the liner. At least the Russians used the “frustum” in their later designs too (some being very heavy and solid for some reason).


#8

Could it be that particular shape of the cone deflector upset the formation of the liner plug the least? The liner also look a bit funny, but that could be because it is made of steel(?)
Always been fascinated by the shaped charge principle…
Soren


#9

EOD, I learned the term "spit back at the old Indian Head EOD School in '83. We still use PIBDSB a lot in such items as the 40mm HEDP Grenade (both for the M203 and the MK 19). From what I remember of later items that used a frustum, like the PG-7 and I think the PG-9, we termed it a “wave shaper” and it supposedly affected and concentrated the plasma jet. They always seemed to use a much steeper angle of cone in some of their items than we in the West did. Supposedly, our engineers developed what we thought was the “perfect” angle of cone in the M72 LAW and pretty much stuck with it. Seems nobody told the Soviets and theirs seemed to work equally well.

mausernut, A lot of countries in WWII used a hemispherical cone. Besides the Axis, the Brits used it in the No. 68 and we used it in the 57mm Recoilless. I think there was some other use, but I can’t remember right off hand.


#10

Mausernut, hope I got you right (my English is not native), I doubt that since this will hardly influence the jet. The shape of the frustum is reaching high to keep ricocheting shrapnel from the side walls of the upper part of nose section. (my assumption)

The liner here is of the early pattern when lots of experimentation was still going on. The German HEAT designs for projectiles were the HL/A, HL/B and HL/C which referred to the shape of the liner. What we see here might be one of the HL/A. Tha last type the HL/C looked much more like what we are used to today.


#11

[quote=“bacarnal”]EOD, I learned the term "spit back at the old Indian Head EOD School in '83. We still use PIBDSB a lot in such items as the 40mm HEDP Grenade (both for the M203 and the MK 19). From what I remember of later items that used a frustum, like the PG-7 and I think the PG-9, we termed it a “wave shaper” and it supposedly affected and concentrated the plasma jet. They always seemed to use a much steeper angle of cone in some of their items than we in the West did. Supposedly, our engineers developed what we thought was the “perfect” angle of cone in the M72 LAW and pretty much stuck with it. Seems nobody told the Soviets and theirs seemed to work equally well.

mausernut, A lot of countries in WWII used a hemispherical cone. Besides the Axis, the Brits used it in the No. 68 and we used it in the 57mm Recoilless. I think there was some other use, but I can’t remember right off hand.[/quote]

Bruce, as said my English is not native, all I know I had to learn by myslef (as I did with ammunition, my EOD licences are for the sake of having them as regulations require). So the “spit back” is now nice to know. Thanks again!
The Russian PG-7 and PG-9 as well as some others of this design are not really part of the above. Keep in mind that their nose elements are only piezo generators containing no explosives at all. The “double wall” on these warheads is simply a contact of the electric circuit for the + and - poles for the electrically ignited BD (armed pyrotechnically). Today for example there are such war heads which omitted the “inner nose cone” and replaced it by a simple wire which leads form the piezo nose element down to the BD section. (this will cause a head ache in future for all those using grid armor)


#12

I know that at the time research was still very much going on and the shape as well as the material of the liner had both influence on the formation of the jet. But I am of course looking on this subject from the vantage point of 50 years of R & D. The fact that copper was a “Sparstoff” at the time i Germany could have dictated the use of steel which iirc needs a slightly different shape than copper to function optimally.
Not having todays piezo technology available it is still a smart idea to get bottom detonation from a comparatively simple point fuze. If the only problem was to avoid hitting the liner with the flame from the fuze, that frustrum is a small price to pay.
Soren


#13

Right you are. Once I was surprised myself when I had seen a liner made of zinc in a Panzerfaust war head.


#14

Does anyone know the history of the shaped charge? Who first realised the possibility of focusing the effect of an explosion and when? When was the first practical application of the idea? Are there patents existing or were the developments kept secret because of the military application?

Many thanks in advance.

Happy collecting, Peter


#15

I believe that the shaped charge concept was based on the “Munroe effect” discovered by Charles Munroe working on U.S. Navy Torpedoes in 1888.

Check the wiki article on “Munroe effect” for more.