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Fuze pd f7

P

pedro

Well-Known Member
Ordnance approved
Found this gem a few years back; had even trained on it back in the 70's. Developed in Melbourne it is a PD fuze for 81mm mortar and has no moving parts. Operates on the principle of adiabatic compression where trapped air, superheated by the compression of impact causes enough heat and shock to initiate a detonation in a small column of PETN, obviating the need for sensitive detonator. Safe in transport handling and firing. This one is a full aluminium prototype ( I have a brass one as well). Note the similarity in external shape to the No117/119 family. The designers, in Melbourne had in mind, ease of production using the common parts (albeit different material) . Rarely seen nowadays however in 2011 I recovered one at an Army range (doing my Reserve time). Fitted to a US 81mm HE M362 model Fuze XF7.jpg
 
Pedro amazing coincidence. I actually have photos of one of these just taken yesterday to post on BOCN for my mate Ron here in Ballarat to see if we could find out any more info on it! I will post the the photos tonight after work. Ron could not work out how it worked. He had been told it was air operated. Ron has the prototype one with the anodised gaine(?) pot on the bottom. He thought it was experimental and didn't know if they went into production or not.

Tim, yes, that is the same fuze. Must be a few about at least, and unusual that one found its way to the US.

Cheers, Graeme
 
Tim, yes same one. Graeme, when I get back to OZ I'll dig out the tech spec. I trained in the detailed operation of this fuze and was very fortunate to obtain this (and 2 other versions) from the source of design/manufacture. They were in production at MF/ME (hardware and filling). Production was during the VN era and OZ was trying to flog off inventions to the US. (the only success, I believe, was the Frg Dev Comb BTrap F1A1 which is still available to ABCANZ users). In the end although the idea is sound, in practice they didn't perform well, needing just the right soil conditions to function correctly. Many UXO resulted.
 
Pedro, we would be very interested in any tech specifications or documentation you may have on the fuze.

Ron's fuze is stamped F7, 25, ME, 9/67. We assumed it was made at MF nearby. I note yours is stencilled with the filler details and year, whereas Ron's is stamped. (Yours also has a nice juicy "X" on it!)

Here are the photos. Note the column is turned around the wrong way in the fully disassembled photo.

Cheers, Graeme

P1050571.jpgP1050563.JPGP1050561.JPGP1050565.jpg
 
This one has been painted. They were supplied in the natural polished/anodised aluminium finish. The booster is laquered. Anecdotally the fuze model F7 is derived from the Fuze F3 and Booster F4. The protective cap and knurled ring are direct copies from No117/119.
F7 Lot 25 ME (Maribrynong Explosives- Cordite Ave, Maribrynong Vic) Sep 1967.. This one is missing the rubber piston seal which goes in the forward end. Mine is Marked XF7 (experimental).
I am at present at work in the ME (not Maribrynong :) ), so when i get home in Nov I'll dig out what I can find.
Below are a couple of pix I taken in 2011 showing the F7 fitted to 81mm M362.

P1010284.JPGP1010285.JPG.
 
Last edited:
Long delay but found something (file uploaded to BOCN Today, Category:Fuzes):
THE AUSTRALIAN COMPRESSION IGNITION (CI) FUZE: A HISTORY
OF RESEARCH AND DEVELOPMENT AND SUGGESTIONS FOR
USE IN FUZES FOR PRACTICE AMMUNITION

ABSTRACT


The development of the CI fuze from conception in the mid 1940's
through to the final F7 (MRL) and XF8 (EDE) models of the late 1960's is
described. Experimental data from this period relevant to recommencing an
experimental programme directed towards use of a CI fuze in practice
ammunition is detailed. Technical problems of the F7/F2 Fuze have been
identified, and research programmes to overcome these have been specified.
Some options which would lead to a more cost effective fuze have been
presented as concepts.
 
Graeme,
same as delivered on another website :)
REPORT
MRL-R-9 55
THE AUSTRALIAN COMPRESSION IGNITION (CI) FUZE: A HISTORY
OF RESEARCH AND DEVELOPMENT AND SUGGESTIONS FOR
USE IN FUZES FOR PRACTICE AMMUNITION
Robert J. Spear
Approved for Public Release

Being added under Fuzes in the Downloads names as "Develpment of Fuze PD F7"


Darkman said:
Pedro, we would be very interested in any tech specifications or documentation you may have on the fuze.

Ron's fuze is stamped F7, 25, ME, 9/67. We assumed it was made at MF nearby. I note yours is stencilled with the filler details and year, whereas Ron's is stamped. (Yours also has a nice juicy "X" on it!)

Here are the photos. Note the column is turned around the wrong way in the fully disassembled photo.

Cheers, Graeme

View attachment 82925View attachment 82926View attachment 82927View attachment 82928
Click to expand...
 
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