[sci.military] Merkava-chains etc

military@att.att.com (Bill Thacker) (06/20/89)

From: military@att.att.com (Bill Thacker)

[ mod.note: The following posting was received anonymously.  - Bill ]

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This is a comment on two matters:
1. the merkava(sp?) chains, you wrote:
>[mod.note: While skimming (i.e., reading without paying for 8-)  ) a
>"Defense International" magazine last night, I noticed a picture of an
>Israeli Defense Force Merkaval.  The rear turret overhang (quite prominent
>on this tank) had been fitted with a "fringe" of metal balls dangling on 
>chains, which reached almost to the deck; while I've never seen this
>before, and no explanation was offered in the article, I think this must
>be to prevent thrown grenades, etc, from entering the area beneath
>the turret overhang.  Clever...  - Bill ]
According to armor experts the purpose of the chains is to disturb the
forming of the penetrator jet from a shapecharge warhead by forcing the
warhead to explode at a less-than-optimum standoff distance from the
armor. Ive seen photos of WP tanks with chains hung in frames across the
front of the tank, so apparently they too uses the same idea. It could also
be assumed that with the proliferation of reactive armour (eg "blazer"),
intermediate measures, like the WP chains, would become obsolete, or at least
, be moved to second rank units. However, i think that the merkava chains
fill a gap where it would be hard or impossible to apply reactive armor.
The turret/deck border is well known to be one of the weakest points in a tank
The function of keeping throw objects off this area IS a possibility, however.
Especially since molotovs are a so populaar weapon for unconventional forces.
Indeed, they are even used on the westbank & gaza today!

2. Tankturrets&engineplacement:
An other MBT that got its engine in gront of the crew,gun&ammo assembly
is the swedish Strv-103 collocially known as "The S Tank". 
(Im on REALLY thin ice with tis one, ive only driven one once, and that was
some years ago. But i THINK it got its engine in front, The chance that
i am correct is as high as 90%).
The S tank is a turretless design with a fixed gun that dates from the late
60's. The traning ofthe gun is accompliced with hyudraulics that moves the
whole track assembly. The glacis is EXTREMLY sloped and the hull defillade
signature is very small, viritually all you can see is the gun and the commanders
cupola and the antennas. The hyudraulic design has one great disadvantage,
it is impossible to fire on the move with great accuracy, so the main
purpose of the S tank is as an defensive tank killer.
This design is an obvious forerunner of the now popular concept with a MBT
mounting its gun in a small, unmanned barbette over the hull. The technology
to make the ammo-transfer work in this configuration was unfortunately
not available in the late 60's.

There is an other interesting example of a swedish design so before iths
time that it couldnt be realized: In a book on the history of the Bofors40mm
FLAK gun, there is a picture of a swedish concept vehicle from the 50's or 60's.
The vehicle is a airdefence tank, It's got a normal hull & a BIG square turret.
The turrets got two 40mmL70 in a dual mounting in the center-front of the 
turret, and to big radars on the back of the turret! Get the image?

Unfortunately this early attemt was as illfated as the late Sgt York (DIVAD)
and apparently for the same reason: The radar tecnology then was not suffici-
ent to make it work as planned.

3. Exploding bullets & Banned bullets:
Some authors have claimed that the geneva and other conventions regarding
banned weapons will be recognized, just because iv one side begin using
them the other soon will follow and so the advantage is lost. I dont belive
that this is a correct prediction of what will happen, The reasons are twofold:
ONE: One side might not be prepared. If you havent manufactured bullets
that are extremely unstable or have some other means to impact excessive
damage on the target BEFORE the war the enemy is free to use them against you,
knowing that you can't retaliate before it is to late!
TWO: The winner always decides who is a warcriminal and who isn't. 
That this is especially evident when fighting against some ideology or 
religion that belives that is is destinied to win in the end, like nazism
or communism belived (belives(?)). The atrocities thats been committed 
by these kind of people are numerous & well known, but as an example:
In the Korean war, during the first assault by the North Koreans, both
captured US soldiers and South Korean citizens was massacred on several
occations. This seems now to have been a knowingly preformed deed, planned
in advance of the attack and with the purpose to speed up the attack by
not having to detatch troops for the keeping of prisoners.
And, in hindsight, it is obvious that, had they won, No-one would ever have
known about this. (ie The winner writes the history)
SUMMARY: When put against forces with ideologies or religions that decree that
they are destinied to win; Expect _anything_ from the part of the enemy.

yla@IDA.LiU.SE (Yngve Larsson) (06/21/89)

From: Yngve Larsson <yla@IDA.LiU.SE>
In article <7594@cbnews.ATT.COM> someone anonymous write:
>>before, and no explanation was offered in the article, I think this must
>>be to prevent thrown grenades, etc, from entering the area beneath
>>the turret overhang.  Clever...  - Bill ]
>According to armor experts the purpose of the chains is to disturb the
>forming of the penetrator jet from a shapecharge warhead by forcing the
>warhead to explode at a less-than-optimum standoff distance from the
>armor.

I wonder if this is such a great idea, since I have heard that the real
problem with HEAT rounds is to get them to detonate at a great enough 
distance from the armor plate, in order for the jet (or more properly:
metal slug) to attain maximum velocity. The chains would not prevent this,
rather they would facilitate this. Comments?

[mod.note:  Shaped charges have an optimum standoff; an increase or
decrease is detrimental to performance.  As the shells themselves are
designed to detonate at the optimum distance, any premature detonation is
bad.  This principle was used in WWII by the Germans (who applied side
-skirts or "schurzen" to some tanks) and the Americans (who did the
same with wood planks and sandbags). - Bill ]

>2. Tankturrets&engineplacement:
>An other MBT that got its engine in gront of the crew,gun&ammo assembly
>is the swedish Strv-103 collocially known as "The S Tank". 
>(Im on REALLY thin ice with tis one, ive only driven one once, and that was
>some years ago. But i THINK it got its engine in front, The chance that
>i am correct is as high as 90%).

Actually, I belive the S tank has TWO engines, one diesel for transport
and one gas turbine for combat move. Both are located on front of the crew
compartment. The crew number only 3, a driver, gunner and commander, since
the tank have an efficient auto-loader (comparatively easy with a fixed gun).
The gun is a rifled 105 mm (British L5?) firing (in the latest upgrade) HE,
HEAT, AP and APFSDS. 

The suspension is capable of depressing the gun some 20-25 degrees, making
it really fun watching one sneak up a hillside with the chassis horizontal.
In a good firing position it will only expose some 30 cm of extremely 
sloped glacis.

The tank is however plagued with tactical disadvantages (not a very good
vehicle for a mobile assault) and technical problems with the complex 
suspension. This makes it likely to be retired in favour of the re-re-upgraded
Centurions of the Swedish Army. Also, a new domestic tank design is now 
discussed, probably with a >=120mm gun and possibly in a remote turret.


>There is an other interesting example of a swedish design so before iths
>time that it couldnt be realized: In a book on the history of the Bofors40mm
>FLAK gun, there is a picture of a swedish concept vehicle from the 50's or 60's.
>The vehicle is a airdefence tank, It's got a normal hull & a BIG square turret.
>The turrets got two 40mmL70 in a dual mounting in the center-front of the 
>turret, and to big radars on the back of the turret! Get the image?

But this design have been sort of intuitive for Air defence vehicles since
the German "Whirlwind" Flakpanzer of WWII, hasn't it?


>Unfortunately this early attemt was as illfated as the late Sgt York (DIVAD)
>and apparently for the same reason: The radar tecnology then was not suffici-
>ent to make it work as planned.

One other reason for the demise of Sgt York that I have heard was that the
range of the 40mm Bofors gun was too short (4 km, I believe). In Sweden, on
the other hand, I think this range is sufficient enough, since you will be
hard pressed to find a Line-of-sight exceeding 2 km anywhere!

		Yngve Larsson


-- 
Yngve Larsson                               UUCP: ...mcvax!enea!liuida!yla
Dept of CIS                                       Internet: yla@ida.liu.se
Linkoping University, Sweden                          Phone: +46-13-281949

cmr%cvedc.prime.com@RELAY.CS.NET (Chesley Reyburn) (06/27/89)

From: Chesley Reyburn <cmr%cvedc.prime.com@RELAY.CS.NET>
In article <7594@cbnews.ATT.COM> you write:
>In the Korean war, during the first assault by the North Koreans, both
>captured US soldiers and South Korean citizens was massacred on several
>occations. This seems now to have been a knowingly preformed deed, planned

I.F. Stone alleged that Dugout Doug was responsible for these deaths.

[mod.note:  I'll probably regret posting this... anyway, let's keep
the flames in email. 8-) - Bill ]

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