Artillery Rifling systems

[Dronic69]

Good Evening All,

While pondering why some fuses have time rings which have time scales going from 0 to max in a clockwise direction (viewed from top down), others have the direct opposite, where the time scale goes in an anti-clockwise direction. What there a reason for this apart from the obvious "well it is just manufacturing differences".................perhaps linking in to the type of rifling used in the artillery guns themselves?

Which raise an old query of mine - did the Germans and British artillery guns in say WW1 had the same or used opposite rifling systems (ie groves) to spin the projectile clockwise or anti-clockwise? Rifling of course is used to "spin" the projectile, but does it mater whether the projectile is actually spun clockwise or anti-clockwise? I don't think so, as long as the goal is to rotate the projectile through the barrel.

Further, Krupp made and exported a lot of guns to different countries, so if countries say Britain had a different rifling system, then I gather the exported gun was built to the exported country's requirements?

Any ideas?

Thanks

Cheers

Drew

 

[raymeketa]

Twist direction and rate are very important. Many nose fuzes are armed by centrifugal force. Base fuzes are often threaded in the direction opposite the rifling. Fire Control computers have to accommodate spin drift which can be considerable at the extreme ranges that much artillery is fired.

Just a few examples. Twist in hand held firearms may be designed for other reasons.

Ray

 

[Alpini]

it think Drew is talking about pyrotechnical time fuzes? I think for these there is no connection between powder burning direction and projectile rotation. It's like the question if it is better to drive left or right

 

[raymeketa]

I was answering that part of his post where he asks:

"Rifling of course is used to "spin" the projectile, but does it mater whether the projectile is actually spun clockwise or anti-clockwise? I don't think so, as long as the goal is to rotate the projectile through the barrel."

Ray

 

[Dronic69]

Yes there were a few "imbedded" queries within the post.................

The main query is still did the German and British artillery have the same groove twist in WW1?
My initial thoughts are that they were the same as most WW1 British and German nose fuses have RH threads - so I would imagine as Ray mentioned re base fuses, would be threaded in the opposite direction to the rifling.

The other query relates to the early pyrotechnical fuses (basic power ring(s) types) if there was a connection to the time ring burning direction wrt to the rotation of the projectile - would the centrifugal force assist with the burn direction? An examination of an initial small sample of both WW1 German and British nose fuses highlights that the British time scale is anti-clockwise, while the German examples are clockwise.............which of course then ties back to my main query re the rifling systems used by both. However since then I have pulled out more WW1 fuses and it appears the German fuzes have time rings on different models where some are anti-clockwise and others clockwise, which leads me to assume it just basic manufacturing differences. Even found examples of British fuses (ie No 65A) which has a clockwise time ring direction - but then it seems the early British Boer war period fuses I have (No 56, No 60, 62) followed this pattern.

Thanks for the comments.

Cheers
Drew

 

[Alpini]

Germany used 99.9 % right rotating rifling. I think Great Britain too. I also don't know of any german left hand fuze thread it should be 100% RH.

The powder train inside the ring of a pyrotechnical fuze is generally burning in both directions. One of the directions ends "blind" the other direction ignites the next ring and is again burning in both directions. On fuzes with more than one ring the "useable" of both burning directions is normally changing from one ring to the next ring. So there can't be a connection between the burning direction and projectile twist direction.

About the direction of the fuze thread and the projectile rotation there is a connection but no perfect solution. If the projectile rotation has the same direction as the fuze thread, the fuze screws into the procetile when firing through inertia. That's fine when the projectile is getting fired. But if the projectile impacts in a small angle the rotation of the projectile can stop or slow down immediately. That way again through inertia the fuzes can screw out of the projectile producing duds. This effect happened very often on artillery ranges when fuzes or plugs had no set screws. A small set srew can reliable prevent this effect.

The Italian land artillery used left rotating shells, but fuze threads can be left hand or right hand, but set screws were used.