Recent Developments

sumdud said:

The crew space part make sense: The only other wheeled APC to have such space efficiency is the Piranda II. Althought I find it hard to accept such a case from China.

As for the elongated front: Is it worth it to sacrifice performance for power? I doubt it in the fields. Plus, if you do this, can't you also move forward the wheels? They will be exposed, but they are suppose to! And when hit it has a tire system for a reason. (Gee, tracks are much more efficient.)

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I'm not sure if you are sacrificing performance for power with an elongated front, because it shouldn't be a problem in ascending uphills. Also, I think the wheels are placed forward far enough, which is probably why they made it four wheels instead of three. Besides improving living space for the troops inside, the new hull is also flexible in its configurations, making it suited for a variety of tasks.

Gollevainen said:

First of all I must say that it's nice to have some real artillery discussion in SDF for change

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You asked for it, here it comes

Well, personally I think the calculation illustrates the
effectiveness of SPH's. Yes, cost of procurement is lower but
IMHO the effectiveness and ability to survive of SPH's compared to
traditional or even APU FH's justify the additional cost.

VT-fuze or multiple fuze should be considered to be standard fuze
outside Finnish and perhaps Chinese armies. Compared to shells fired
as "sensitive" VT fuze is much more effective against soft targets
as US army already found out during WW II. With enemy firing VT to dig
in is not enough, one needs top cover too. Sometimes, but only
sometimes, a shell fired as sensitive can explode when hitting
tree branches and having a top burst effect but that is no certainty.

It's possible to destroy a SPH by firing shells as insensitive but
that lessens the odds very much compared to firing VT or even
traditional HE to a firing position. That's one of the lessons
of Second World War and the reasons behind this are fairly simple.

Following comes mostly from memory without accessing necessary
Finnish or US field manuals, please feel free to correct.
This is a statistical excursion, but hopefully informative.

Consider the enemy has plotted your gun position with perfect
accuracy and fire against it with a battery of six 155mm howitzers
on distance of 12 km's with a volley of three shells. The spread
of fire is, say, perhaps 0,5 percent lateral and 1 percent
longitudal. Without going into mathematical finesse let's
represent the area as an ellipsoid of 60x120 metres, or 5600m2. Now,
there's total of 18 shells going into that ellipsoid. Naturally
more shells arrive closer to intended point of impact than
on the borders.

Let's have a SPH and a APU FH as targets. A Pzh-2000 has total
dimensions of 11,7m x 3,6m. To have effect upon it a HE fired as
insensitive has to arrive directly on top of it or very close
nearby. Let's allow a distance of five meters from outside
extremes. If one fires shells as insensitive if they
do not hit their intended target they will get buried before
they explode.

So, we have a target with dimensions of 18x9 meters,
or 162m2 within an area of 5600m2. The rest is math. Yes,
SPH can have tough or good luck.

Second target is APU FH with a gun crew. Enemy knows this and
fires VT. Again, there go the 18 rounds into that
ellipsoid of 5600 meters. The dimension of target gun position
is roughly 10x10 meters, 100m2.

Now, kill radius for a single VT 155mm round is 50 meters, or 1960m2.
The 50m kill radius is pretty optimistic counting from target's
viewpoint. In addition to having a very nasty effect on gun crew
fragments of VT have high possibility of damaging an APU FH as it
has exposed electronics and hydraulics. In this sense older FH's
are less vulnerable to indirect fire. Also, in addition to gun and
crew there is also other vulnerable, exposed stuff lying around
including ammunition etc. Again, APU FH can have tough or good
luck but to be inside German sardine can is a much surer bet.

Let's switch for M483A1 DPICM and fire the same fire mission over
again. Boom, 18 shells with a total of 1854 M42/M46 grenades arrive.
Things go iffy for our German sardine can but the conditions of APU
FH are even worse, as to even damage a SPH a submunition has to hit
it in a suitable spot. On the other hand, even if our APU FH has
gotten into boggy ground resulting in a number of ICM duds (say, 20%),
there's still some 1500 cluster munitions exploding around that
roughly 5600m2 area, each with a kill radius of some 7 meters or
38m2...

Doing a sprint naturally reduces APU FH vulnerability but considering targetting perhaps not as much as one would suppose. First, if terrain is any more
complicated than a billiard board there probably is one, maximally two
directions to go. With amount of necessary support, command, etc. vehicles and exposed personnel it's still worthwhile to fire a counter-battery fire mission into APU FH firing position area as it is very probable to damage at least support personnel or vehicles. With SPH's same vulnerabilities exist but in diminished form.

A military conflict is naturally not a statistical exercise
but overall vulnerability of a APU FH compared to SPH cannot
be explained away. If enemy has calculated your own position
less accurately or spread of fire is greater the same math still applies.
VT's or DPICM's anti-personnel radius is so much larger than HE's or DPICM's
kill radius against a SPH.

APU FH's can have semi-automatic loader yes, but no autoloader
which permits MRSI, which is really one of the killer applications
(in context of weapons a term which really fits) of modern SPH's.
As artillery demi-god V.P. Nenonen already found, against
even hard targets first rounds which are the most effective.
That's why multiple-round-simultaneous-impact is so important.
And that's why even a smaller number of MRSI capable guns
are practically just as effective as a smaller number of
non-MRSI guns.

Well I've met my master...or do I?


As for the protection and surviability, Its true that when looking the issue from that angle that solely focus on the shape of the gunsystems, yeas SP guns are far better protected and are most likely being able to withstand heavier penalties. And against enemy artillery, this is just like you have said. My point was that towed guns, expsecially APU fitted towed guns, there are compensating factors like reduced change to being detected and even hit by other enemy units (non-artillery). For example SP guns are far bigger and easily spotted targets for enemy helicopters and ground attack planes. Also when sudden enemy armoured attack comes against SP guns, there is little change for the crew to survive as they are inside the box.

The area of impact you calculated cannot be used as such to explain the effect of enemy artillery against towed battery. The distance of the guns between each others alone can be as long as 50-100 meters. The battery command post is usually over 1 km away from the guns. So the change to hit towed guns is in fact smaller than in SP battery as the distances between the units in SP battery are smaller than in towed battery.

The MRSI is undouptly one of the biggest benefit to SP guns, but with modern towed guns with modern fire control computers you can have the same effect when stepping the firing by having different guns firing different charges and with time fuzes set to have all the rounds go off simulateiniously. So as the lower cost of APU guns permits havinmg them on greater numbers than SP guns, the edge is narrowed.

I would still like to point out that I'm not suggesting SP guns to be completely useless, quite contary, modern units like PZH2000 are quite appealing. I'm only advocating that APU guns can reach strikingly close in overall performance and effectivity of the guns and thus shouldn't be ignored. The cost-effectiviness is huge factor when politicans decides what to buy and in cases like China, they really should consider the option as modernisating it's entire artillery branch just with SP units is impossiple.

Gollevainen said:

The area of impact you calculated cannot be used as such to explain the effect of enemy artillery against towed battery. The distance of the guns between each others alone can be as long as 50-100 meters. The battery command post is usually over 1 km away from the guns. So the change to hit towed guns is in fact smaller than in SP battery as the distances between the units in SP battery are smaller than in towed battery.

The cost-effectiviness is huge factor when politicans decides what to buy and in cases like China, they really should consider the option as modernisating it's entire artillery branch just with SP units is impossiple.

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Just one final comment, I think the distance of 1km between battery command post and large distance between guns is somewhat optimistic especially if the situation is fluid, eg. demanding rapid shift of firing positions. That's because if the guns and support elements are far away from each other they can't arrange their own local security. During Iraq war, for example, that made US artillery units to use tighter formations as there were instances in which artillery had to defend their firing positions.

Also the air threat may demand tighter grouping as there's a limit what area the anti-air unit covering the field artillery unit can cover.

If there's no enemy air threat, or there's enough anti-air cover, and the firing position area is considered secure there's of course nothing to stop from using a widely spread area.

The cost is larger, and of course it's question whether armed forces strive for quality or quantity. In China's case, IMHO, there's more need for forces capable of fighting outside the borders than inside the borders. And that's when logistics really start counting as prearranged depots can't be trusted. But's I think each one has made his point clear

Jon the SPH man to Gollevainen the APU man, out...