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QF3.7" AA shell
- Thread starter B.D.R.E.
- Start date
martijncornet
Active Member
This one with original markings
Darkman
Well-Known Member
Yes, I have got a number of photos of original shells, as I am currently restoring one myself. Will post later when I get home from work in about 6 hours time. A chap in Malta also recently posted photos or original shells he had too. Try a search on this forum.
Cheers,
Graeme
Cheers,
Graeme
Darkman
Well-Known Member
Attached photos show paint and stencilling on original Mark 1C HE projectiles. The first one has additional words "Conv 1-45" signifying that the projectile was converted in Jan 1945 by the addition of a Smoke Box - also denoted by the green circles. The page is from the May 1940 handbook.
Typical markings on the shell are: 1" green ring when the shell is filled with HE (usually TNT which is stencilled on the ring); red crosses to denote suitable for use in hot climates; 1.5" green circles to denote smoke box fitted; "G.11.1.3" - Gaine No. 11, mark 1, batch 3; "8029" the drawing number of the filling method; "EXPR.C.E." Exploder type C.E. (Composition Exploding); [on reverse] month and date of filling MM/YY; filling station monogram e.g. RL; lot number in a segmented circle.
All of the above is explained in a handbook, so it would be helpfull if you could get hold of, or get a look at one.
I have also noted that different factories place the information in different places on the shell, so there are no hard and fast rules.
Hope this helps,
Cheers,
Graeme
Typical markings on the shell are: 1" green ring when the shell is filled with HE (usually TNT which is stencilled on the ring); red crosses to denote suitable for use in hot climates; 1.5" green circles to denote smoke box fitted; "G.11.1.3" - Gaine No. 11, mark 1, batch 3; "8029" the drawing number of the filling method; "EXPR.C.E." Exploder type C.E. (Composition Exploding); [on reverse] month and date of filling MM/YY; filling station monogram e.g. RL; lot number in a segmented circle.
All of the above is explained in a handbook, so it would be helpfull if you could get hold of, or get a look at one.
I have also noted that different factories place the information in different places on the shell, so there are no hard and fast rules.
Hope this helps,
Cheers,
Graeme
Attachments
shrapnell
The current usage particularly by the media is that anything thrown by an explosion is scrapnel. True Artillery speak then shrapnell is balls in a shell that dispersed forward of the shell when the fuze triggers and internal explosive. There has been much discussion on this very topic here on BOCN.
The current usage particularly by the media is that anything thrown by an explosion is scrapnel. True Artillery speak then shrapnell is balls in a shell that dispersed forward of the shell when the fuze triggers and internal explosive. There has been much discussion on this very topic here on BOCN.
Darkman
Well-Known Member
As 2pounder says, shrapnel shells contain balls and are an anti-personnel weapon, timed to detonate above troops. They use a Time and Percussion fuse so that if the time element fails it will still explode on impact. HE shells are also used against troops with a Percussion fuse only. The 3.7" HE shell with a No. 199 fuse was used in an anti-aircraft role only.
The No. 199 fuse is a Powder Train Time Fuse (PTTF) - time only. It has no percussion element so as not to explode on impact with the ground (in a friendly area) if the time element failed to detonate the shell. Operation: On firing the rapid acceleration of the shell and inertia caused the needle to pierce the detonator thus igniting the powder. The powder burns around the circular time ring grooves for a duration as determined by the ring setting (up to 30 sec) and then ignites the magazine at the bottom.
The "setter No. 11" would be for manually setting the time duration on the fuse by turning the movable time ring. However I thought most 3.7" guns (maybe later marks?) had automatic fuse setting.
The overall length of the shell (projectile and 199 fuse) is 438mm or 17 & 1/4 (17.25) inches.
Cheers, Graeme
The No. 199 fuse is a Powder Train Time Fuse (PTTF) - time only. It has no percussion element so as not to explode on impact with the ground (in a friendly area) if the time element failed to detonate the shell. Operation: On firing the rapid acceleration of the shell and inertia caused the needle to pierce the detonator thus igniting the powder. The powder burns around the circular time ring grooves for a duration as determined by the ring setting (up to 30 sec) and then ignites the magazine at the bottom.
The "setter No. 11" would be for manually setting the time duration on the fuse by turning the movable time ring. However I thought most 3.7" guns (maybe later marks?) had automatic fuse setting.
The overall length of the shell (projectile and 199 fuse) is 438mm or 17 & 1/4 (17.25) inches.
Cheers, Graeme
The 3.7AA was used in the ground attack role particularly in Italy but I think the intention of Shrapnell rounds for AA guns, and there were othersusing it, was for close range anti aircraft to get more of a shot gun effect. By WWII shrapnel was out of favour as anti personel although there was some left from earlier manufacture.
Gunnerwho?
Active Member
No 199 was igniferous, ie powder burning. MT fuzes were being developed between the wars, albeit without notable alacrity. They were based on the German Thiel mechanism (as were all UK developed MT fuzes unless I've got it the wrong around) captured in WW1. IIRC MT fzes for 3.7 didn't become available until well into 1940. Of course powder burning fuzes were well suited to shrapnel but with HE they needed a gaine and 199 wasn't designed for this (some field arty powder burning fuzes did for HE use).
Shrapnel shells project bullets forwards from the nose. 3.7 HE seems to have been designed to produce bigger fragments that field arty HE shells, makes sense since the target was airframes and bigger fragments go further.
IIRC No 11 fze setter was a automated and linked to the predictor. Manual fuze setting was well short of ideal for AA because the fuze setting is different for each shell fired, because each is aimed to burst in a different place (aircraft are moving targets, bit of a surpriase that). Effective AA fire needed accurately predictable rate of fire so that each round was fired with the most accurate data to burst it in the right place, machine fuze setting was an important part of this.
Shrapnel shells project bullets forwards from the nose. 3.7 HE seems to have been designed to produce bigger fragments that field arty HE shells, makes sense since the target was airframes and bigger fragments go further.
IIRC No 11 fze setter was a automated and linked to the predictor. Manual fuze setting was well short of ideal for AA because the fuze setting is different for each shell fired, because each is aimed to burst in a different place (aircraft are moving targets, bit of a surpriase that). Effective AA fire needed accurately predictable rate of fire so that each round was fired with the most accurate data to burst it in the right place, machine fuze setting was an important part of this.
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The first fuze, time, mechanical to enter service in the British Army was the No. 200. Its hard to work out the date as the first were captured German fuzes using an adaptor ring to fit the 2" fuze thread. The 'Thiel' mechanism was reversed engineered and manufactured in th UK. It was used in a number of other 200 series fuzes.
From the attached documents one can see that the shortcomings of the No. 199 were known in 1936, maybe earlier. The file doesn't give an explanation as to why the Tavaro fuze was not adopted - it was costed at 15/- plus an 1/- royalty, whereas the 206 was costed at 21/-.
TimG
From the attached documents one can see that the shortcomings of the No. 199 were known in 1936, maybe earlier. The file doesn't give an explanation as to why the Tavaro fuze was not adopted - it was costed at 15/- plus an 1/- royalty, whereas the 206 was costed at 21/-.
TimG
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Gunnerwho?
Active Member
IIRC the Thiel mech was used in all UK designed MT fuzes, just as Junghans was used in US ones. The last UK MT fzes were those designed for 105mm FD HE and smk.