Armored vehicle preference

[PJOsborne]

My original source on armour piercing ammunition's website was shut down. it had some very simple but understandable diagrams and a detailed description of each. Wikpedia gives some answers on HESH ammunition:

http://en.wikipedia.org/wiki/High_explosive_squash_head

As to Challenger armament, i refer to the Encyclopedia of Armoured Fighting Vehicles, 2002 edition, page 113:

"Challenger 2 is armed with a Royal Ordnance L30A1 120mm rifled gun with a chrome lined barrel to reduce wear. Ammunition types are as follows: APDS-T (L15A4), DS-T (L20A1), HESH (L31), HESH Practice (L32A5), Smoke WP (L34), and APFSDS-T (L23A1)."

as to the effectiveness of ERA panels:

http://armor.kiev.ua/fofanov/Tanks/EQP/era.html

 

[McG]

. . . and what about the HEAT being unable to spin?

 

[PJOsborne]

My original source was a former Swedish Army tanker whose website has since been shut down. i did find another webpage that details the problems with spin and HEAT:

http://www.geocities.com/Augusta/8172/panzerfaust1.htm

 

[Infanteer]

Sources are all gone.

Isn't that convienent....

 

[TangoTwoBravo]

The ability to fire HESH is, in my opinion, an advantage.  HESH (High Explosive Squash Head) has better effects against non-armoured targets than HEAT (High Explosive Anti-Tank).  If you are trying to suppress infantry in positions or buildings then HESH is the round of choice between the two.  In urban operations HESH is an ideal round as it makes an entry point and can destroy bunkers/strongpoints.

ERA (Explosive Reactive Armour) is designed to counter the explosive jet from a HEAT round.  It may well degrade a HESH round but spaced armour is the real counter to HESH.  Your hypothetical MICV with ERA that is hit by a 120mm HESH round is in for a very bad day.

Going to "sabot", an APC hit by one will have to be very lucky to survive.  If the vehicle is hit from the front the dart will probably go the length of the vehicle, doing quite nasty things along the way.  This might drive the gunnery gods mad, but I would use sabot against a BMP, particularily if the target or I was moving.

I have read that HEAT rounds work best when not "spinning", but the US fired HEAT rounds of their rifled 105mm guns for years.  Bear in mind thatI'm like Oddball and I don't know how the things work, I just ride them.  The HEAT vs HESH argument for tanks is a minor one, since tanks also carry sabot rounds of various descriptions.  Again, the advantage of HESH is that it is more versatile. 

I would glady take an M1A2, Challenger II or Leopard II.  Both the M1 and Challenger II are battle-proven.  I've trained in the M1A1 so my preference is there.  The Challenger II is an excellent tank, but I'd rather not have multiple piece ammunition.  This is all a moot point.

Cheers,

2B

 

[PJOsborne]

2Bravo, when you said "spaced" armour, were you referring to the Chobham-style armour plate found on the Challenger series (and others)? if you were, you're quite right, the varying compositions of such armour do indeed provide excellent protection to HESH. i've had a debate with a friend on the name of it though. apparently "spaced" armour means having armour layers separaded by air in between (like the 'bazooka plates' on the sides of a Leo). a good example of this that i use a lot is the Panzer IV G from the second world war, which had a band of thin steel wrapped like a horseshoe around the turret to defend against shaped-charge warheads.

apparently the correct term for chobham-style armour is "split" armour

 

[TangoTwoBravo]

Osborne,

Actually, spaced armour and composite armour (Chobham) are somewhat different concepts.  Composite armour is designed primarily to defeat the jet from a HEAT warhead and can also affect sabot penetrators.  ATGMs are pretty much universally equipped with HEAT warheads and it was the Israeli experience in the '73 war spurred development of armour that could defeat HEAT projectiles.  The UK approach was composite armour while reactive armour was pursued elsewhere.  Composite armour may well be able to dissipate the HESH shockwave. 

Spaced armour is indeed just that.  It involves spaces in the armour where the spalling induced by the HESH shockwave bounces around instead of inside the crew compartment.  A tank can have both spaced and composite armour (by having spaces in the composite armour, and all composite armour may well be this way), but some older tanks have only spaced armour.  Spaced armour on its own might have some ability to dissipate the HEAT jet but I wouldn't count on it. 

Armour protection is rarely "open source" and even the crews are usually in the dark about what is in the armour (since the crew don't need to "operate" the armour).  There are some board members here who now much more about the inner workings (I'm a tanker, not an engineer).

Cheers,

2B

 

[PJOsborne]

I can see where spaced armour can protect a tank against HESH rounds, but spaced armour like i mentioned regarding the Panzer IV was developed to protect against HEAT warheads. how it does this is beautifully simple: a HEAT charge needs to be detonated a certain distance away from the armour plate in order for the explosion to form a focused jet of molten gas (known as the Monroe effect). the gasesous jet imparts burning and melting stress on the metal as well as about 20 tons of pressure per square inch. the jet is only able to sustain its shape for a short length. the spacing plates don't necessarily have to be thick; in previous conflicts the spacing element could be anything from sheet aluminium to chain link fence or chicken wire (like in Vietnam). the extra space between the detonation point and the armour itself was what killed the jet stream. just another part of the gun / armour race... (see Tank vs. Tank, Macksey, 1991)

 

[TangoTwoBravo]

Osborne,

Side skirts and "bazooka plates" were indeed put WW II and subsequent tanks in an attempt to deal with shaped charges (HEAT).  I've seen pictures of metal mattress frames welded onto T-34s at the close of WW II which are perhaps the ancestors of the cage armour being used in Iraq. 

As for the effectiveness of "spaced" armour (ie, built into the design of the armour and not an add-on screen) against HEAT rounds I guess the proof is in the pudding, so to speak.  I've seen this one argued around a table in the mess, but again, I'm a tanker and not an engineer.  My gut feel is that I would rather have true composite armour as found on M1s, Leo IIs and Chally IIs to protect against HEAT rounds than rely on spaced armour alone.  Before Chobham, several tanks were being designed on the premise that you couldn't really stop HEAT rounds and therefore focused on firepower and speed (Leopard 1 and AMX-30 for example).  As an aside, reactive armour and active armour look a little too prone to failure or subject to counter-measures.

Going back to your prior point about HESH as a disadvantage, large calibre HESH can mess up a target even if it does not penetrate or cause spalling.  For a tank ammo load, I would prefer having sabot and HESH over sabot and HEAT.  This makes the tank much more versatile in terms of target selection and fire support tasks.  Tanks with only sabot and HEAT can give limited fire support with their main guns against anything other than vehicles.  HESH is an excellent round for firebases and urban operations and I hope that it is included in the MGS.

2B

 

[PJOsborne]

i see your point, 2Bravo. I'm sure they'll think about giving the MGS HESH rounds, since its main function (according to CASR) is to provide DF support for the infantry.. but with such a small magazine, i don't think they'll last too long