Pakistan Army Orders 200 More SH-15 Self-Propelled Howitzer Units !

[Haji Thanos]

Will continue to serve SP role for some time. Not going anywhere. Excellent thing for Counter bombardment and harassing fire. Packs quiet a punch.

chinese were bulding a 203 but they shelved it.
two types if i recall correctly
1 was something like the 203 we use and other was truck mounted L52ish gun
i personally feel like 203 is more of psycological-impact thing and if coupled with a guided RA shell it can act as an effective command post destroyer

 

[Signalian]

Another rarely talked about issue with wheeled SPH is accuracy.

Lighter wheeled SPH systems typically have less inertia and less dampening structure to absorb and delay the recoiling motion, which means the entire structure could start to deviate before the projectile have left the gun barrel and this resulting in decreased accuracy. For reference, typical truck howitzer like Caesar have dispersion diameter around 1/200th or 1/300th of the firing range, for example at 20km 50% of the shells would land within 100 meters of the target. In comparison, tracked howitzers can typically achieve around 1/1000th in terms of accuracy, which really can make a difference since in most cases guided shells would not come into play.

And this is another reason why PA may have chosen the SH-15/PCL-181 system, which is one of the first truck guns that features high degrees of chassis-gun carriage integration, both designed as a part of a system instead of an existing gun modified to be mounted on an existing truck. Norinco figures suggest that SH-15 can managed accuracy beyond 1/1000th and is on par with their tracked systems, which is quite outstanding compared to even larger and far more complicated competitors, such as the archer.

And this is also why ultra-light self propelled artillery designs may not always be the most ideal.

How would that impact the accuracy of a GPS guided projectile ?
and
why won't the calculations of trajectory of a SP gun involve the error rate metrics for accuracy ?

 

[Signalian]

the SH15 has hydraulics which enable it to basically kiss the ground with the entire chassis, that combined with the stablizer under neath and behind the truck make it extremely stable.

Relax.

The error rate is calculated for accuracy for every gun which results in accuracy of firing. Also when the first round is fired, it sets a parameter for the next rounds from other guns, i dont remember now what is this procedure called.

Calculations are put in practice along with firing protocols of different artillery guns.

 

[Harbyharb]

How would that impact the accuracy of a GPS guided projectile ?
why won't the calculations of trajectory of a SP gun involve the error rate metrics for accuracy ?

It does not impact the accuracy of GPS/Laser-guided projectiles. But again, in most fire suppression/firepower preparation missions, howitzer units are expected to achieve area coverage, combined with the still relatively exorbitant cost for guidance kits and their potential vulnerabilities to electronic warfare, accuracy with unguided shells is still a very very important metric

Some wheeled SPH systems do attempt to account for recoil-induced errors such as Caesar mk2, and it does somewhat increase its accuracy (allegedly). The issue however is that the recoil conditions for howitzers are inherently somewhat chaotic, varying depending on temperature, humidity, elevation and orientation of the system, minor deviation in centre of gravity in each shell and the burn rate specific to each propellant charge, etc. Specific mechanical design focused on structural robustness offers more broadly applicable tolerances with far less complexity.

 

[Signalian]

It does not impact the accuracy of GPS/Laser-guided projectiles. But again, in most fire suppression/firepower preparation missions, howitzer units are expected to achieve area coverage, combined with the still relatively exorbitant cost for guidance kits and their potential vulnerabilities to electronic warfare, accuracy with unguided shells is still a very very important metric

Some wheeled SPH systems do attempt to account for recoil-induced errors such as Caesar mk2, and it does somewhat increase its accuracy (allegedly). The issue however is that the recoil conditions for howitzers are inherently somewhat chaotic, varying depending on temperature, humidity, elevation and orientation of the system, minor deviation in centre of gravity in each shell and the burn rate specific to each propellant charge, etc. Specific mechanical design focused on structural robustness offers more broadly applicable tolerances with far less complexity.

If the SP guns couldn't calculate errors and reduce error probability to achieve accuracy, then the SP guns would have been sold to scrap by now.

 

[Harbyharb]

If the SP guns couldn't calculate errors and reduce error probability to achieve accuracy, then the SP guns would have been sold to scrap by now.

That is a very curious argument. All gun systems, from the earliest cement mount howitzers of the 18th century, to towed guns, to SPHs, all have some measures and attempts to pursue greater precision (there's a very distinct difference between precision and accuracy, do be mindful of that wording)

It does not mean that imprecisions, in this case shell dispersion, can be completely eliminated, that's just the physical fact we have to contend with. There are so many variables that contribute to deviations, from propellant burn rate, shells' centre of gravity, barrel warpage, barrel rifling wear, muzzle blast, etc etc that calling a howitzer a chaotic system would not be outrageous.

The question is, can these SPHs fulfil their requirement and accomplish their mission despite their innate imprecision? Yes, most wheeled SPH systems are less precise than their tracked counterparts, but not to a point where it diminishes their value in strategic mobility, including much longer MTBM and operational range. Higher precision is a more desirable attribute, but it alone does not make or break a wheeled SPH system.

 

[Haji Thanos]

chinese were bulding a 203 but they shelved it.
two types if i recall correctly
1 was something like the 203 we use and other was truck mounted L52ish gun
i personally feel like 203 is more of psycological-impact thing and if coupled with a guided RA shell it can act as an effective command post destroyer

Chinese W90 203mm SPG

 

[Haji Thanos]

chinese were bulding a 203 but they shelved it.
two types if i recall correctly
1 was something like the 203 we use and other was truck mounted L52ish gun
i personally feel like 203 is more of psycological-impact thing and if coupled with a guided RA shell it can act as an effective command post destroyer

chinese were bulding a 203 but they shelved it.
two types if i recall correctly
1 was something like the 203 we use and other was truck mounted L52ish gun
i personally feel like 203 is more of psycological-impact thing and if coupled with a guided RA shell it can act as an effective command post destroyer

correction: it was an L45

 

[Signalian]

Chinese W90 203mm SPG
View attachment 44863
View attachment 44868
View attachment 44869

Looks like a copy of M-110 given to PA by USA.

 

[Signalian]

The question is, can these SPHs fulfil their requirement and accomplish their mission despite their innate imprecision?

I doubt the imprecision part to start with.

 

[Vi-va]

Another rarely talked about issue with wheeled SPH is accuracy.

Lighter wheeled SPH systems typically have less inertia and less dampening structure to absorb and delay the recoiling motion, which means the entire structure could start to deviate before the projectile have left the gun barrel and this resulting in decreased accuracy. For reference, typical truck howitzer like Caesar have dispersion diameter around 1/200th or 1/300th of the firing range, for example at 20km 50% of the shells would land within 100 meters of the target. In comparison, tracked howitzers can typically achieve around 1/1000th in terms of accuracy, which really can make a difference since in most cases guided shells would not come into play.

And this is another reason why PA may have chosen the SH-15/PCL-181 system, which is one of the first truck guns that features high degrees of chassis-gun carriage integration, both designed as a part of a system instead of an existing gun modified to be mounted on an existing truck. Norinco figures suggest that SH-15 can managed accuracy beyond 1/1000th and is on par with their tracked systems, which is quite outstanding compared to even larger and far more complicated competitors, such as the archer.

And this is also why ultra-light self propelled artillery designs may not always be the most ideal.

For reference, typical truck howitzer like Caesar have dispersion diameter around 1/200th or 1/300th of the firing range, for example at 20km 50% of the shells would land within 100 meters of the target. In comparison, tracked howitzers can typically achieve around 1/1000th in terms of accuracy, which really can make a difference since in most cases guided shells would not come into play.

Russian 2S19М1 Msta-S circular error probable [CEP] of 0.5% of the range
M109’s CEP of 0.7% of the range
M777 is specified to have a CEP of 50 metres at 25 km range.

I heard SH-15 CEP is better than 1/300th, it's damn good for SPH.(Please correct me if I am wrong)

1/1000th is only possible with the guided projectile.

 

[Harbyharb]

I doubt the imprecision part to start with.

Are you aware of the concept of dispersion?

When you shoot a rifle, even if you account for range and wind perfectly, the bullet may deviate from where you are aiming.

When battleships of old duel each other, even when one vessel got the other perfectly ranged, the salvo could straddle around the target and not score a single direct hit.

Errors and imprecision are something you cannot eliminate because they are innately random and chaotic, what you can do is to try to minimize their impact.

Russian 2S19М1 Msta-S circular error probable [CEP] of 0.5% of the range
M109’s CEP of 0.7% of the range
M777 is specified to have a CEP of 50 metres at 25 km range.

I heard SH-15 CEP is better than 1/300th, it's damn good for SPH.(Please correct me if I am wrong)

1/1000th is only possible with the guided projectile.

You are right, I must've misremembered the data for something else. 1/300th sounds more reasonable now that I'm reminded of it.

 

[Luciferdd]

True. I didn't ask for the Archer to be inducted, but something similar, that lets the crew operate without dismounting, and provides NBC protection at the same time.

Given Chinese R&D, a similar or better system could have been possible.

It's the SH-16 SPH,with a Unmanned turret.

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[Luciferdd]

 

[Signalian]

Are you aware of the concept of dispersion?

Occurs in towed systems too.