Fin Stabilised

[Lang]

Ed

I would surmise that a spin of say 10/20 turns per second for a finned projectile would not have much of an effect on an explosion initiating at many thousandths of a second. On the other hand a rifled barrel producing a spin between 2,000 and 3,000 rpm could well have some effect as you say.

It appears that the high tensile penetrating "bolt" is the go now to get the charge igniting after the armour has been penetrated rather than just a surface explosion from squash-head, shaped or conventional HE.

They are getting so sophisticated with Infantry man-carried anti-tank weapons that the tank-on-tank weapons we are talking about are almost superfluous as more than ever before in a conventional war with well equipped armies a tank is little more than a steel coffin and this is not taking into account aircraft like A10's, Mi-28 and Apaches. I think they are brave men surviving psychologically on a hope-over-experience mind-set.

This is pretty depressing if you are a tank man.
https://www.youtube.com/watch?v=CDctxC-7P9k

and this one
https://www.youtube.com/watch?v=y5xKCzdhAC8

And this would make you want to give the game away.
https://www.youtube.com/watch?v=myv7CAJ5Zpk

Lang

[motto]

I seem to remember hearing/reading somewhere that shaped charge projectiles have limitations on them as regards maximum velocity. They depend on the blast being focused due to the distance from the armour when detonated and if travelling too fast may even be knocked out of shape at the time of detonation. Maybe how squash heads were invented.
As I understand it, delivery systems for shaped charge projectiles tend to be relatively low velocity.

David

[Mike Cecil]

Dave,

MV of rounds fired from an L7A3 105mm tank main armament (eg Leopard AS1):

L52A2 APDS/T = 1,478 m/s
L35A2 HESH/T = 732 m/s
M456A1 HEAT/T = 1,174 m/s

I'm certainly no expert on the physics of shaped charges, but it seems to me the 'stand off' distance of the PIBD (Point Intitiating Base Detonating) initiator ie the distance from the initiator to the shaped charge, would be the critical factor. The higher the velocity at impact, the greater that distance would need to be to allow development of the slug by the shaped charge?

The M456A1 was fitted with a rotating Nylon band - the band rotated in the rifling, but did not impart appreciable spin to the projectile (which I think answers your query, Ed). The projectile included a set of tail fins for flight stability.

Mike

[Tony Smith]

I was always surprised that the M456 didn't have some sort of ballistic cover; it was counter-intuitive that that shape should fly right. But it seems that is exactly what the shape does:

http://sturgeonshouse.ipbhost.com/to...jectiles-work/

[Mike Cecil]

Hi Tony,

I agree - the spigot sticking out the front of a cylindrical, flat-faced projectile just seems all wrong, but it works, as the linked you provided shows.

In contrast to the M456A1's protruding spigot ,the 106mm HEAT rounds for the M40A1/M40A2 Recoillesss Rifle have a conical, hollow nose cap (as do the various Soviet Bloc RPG rounds). In the case of the 106mm HEAT round, the spin imparted by the rifling is only about 12 clock-wise revolutions per 100 metres, with flight stability provided by six fins protruding from the base of the projectile. These are housed within the cart case, and spring out after the round leaves the barrel. In this case, the MV of both the HEAT and High Explosive Plastic (HEP) rounds are about the same: about 503 m/sec for the HEAT and 498 m/sec for HEP. (HEP is the US equivalent to the Brit HESH).

Mike