View Full Version : 50 cal, 20mm and bomb fuse

08-12-2005, 03:29 AM

Today a screenshot of a a P40 in the colours of 2OTU RAAF was posted in the screenshot forum.

These shells and the fuse were all collected from the Mildura disstrict where 2 OTU was based during WW2.

The 50 cal and 20mm stuff I have a good handle on but any info about the bomb fuse (still with remove before flight tag) would be appreciated.



08-12-2005, 04:42 AM
The bomb fuze is just that, a fuze for a bomb to be dropped from an aircraft. This is a mechanical fuze. It is screwed into the nose or tail of a bomb once the bomb is loaded onto the aircraft. A safety wire is threaded through the pin, this wire ends at the bomb rack that holds the bomb. When the bomb is released, the safety wire pulls the pin out of the fuze. The propellor on the fuze is now free to turn. After a specific number of rotations, the fuze is armed and will detonate the bomb upon impact. Fuzes can also be designed to detonate at a specific altitude or to detonate a specific time after impact, usually just a few seconds.

Read all about bombs and their fuzes.

08-12-2005, 05:29 AM
Thanks stansdds.

That sounds pretty logical to me. I suspect this fuse is to be attached to the rear of the bomb as the airflow would wind it the wrong way to allow the striker to function if it were attached to the nose. There is a very light spring in the unit to keep the striker from sliding forward. It looks like it was designed for the impact of the bomb striking the ground to bring the striker (pointed shaft) forward, like you say, it would be possible to set the minimum altitude at which the bomb would go off by altering the number of turns on the propeller.

Any idea what size of bomb it would be off?

I think a lot of 12 lb practice bombs were used at the OTU.

Cheers Nickle

08-12-2005, 05:32 AM
the designation S.G.M. 3/17 no 7.1 is stamped into the body of the unit.

08-13-2005, 03:31 AM
Bang! http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

08-13-2005, 06:24 AM
No idea about the size of the bomb this would have fit and yes, "BANG" is a possibility with old ordnance and fuzes.

08-13-2005, 06:55 PM
Point taken, a silly thing to joke about.

The empty casings (which have marks where the firing pin has struck them) were found seperatly from the rounds. The rounds themselves are steel cored brass in the case of the 50 cal and solid steel with a copper or bronze rifling ring in the case of the 20mm.

The fuse has had the forward secttion with the primer removed as the striker protrudes from the bottom of the unit when fully depressed. There is no explosives contained within the unit which I have.

I'm interested in WWII aviation, but not mad enough to keep live ordinance in my house!

If you know of any reason why these items may be unsafe, please let me know.