Mechanization

[davebender]

Developing special guns "just" for the mechanized troops that took different ammo was a luxury nobody could afford.

The mechanized chassis costs a lot more then a 105mm howtizer. If Britain cannot afford to purchase light howitzers then how are they supposed to purchase SP artillery of any type?

Price examples.
16,400 RM. 10.5cm leFH18 howitzer.
22,000 RM. Sd.Kfz.11 towing tractor. Normal tow vehicle for a 10.5cm howitzer.
about 50,000 RM. Panzer II. The smallest possible chassis that can carry a 10.5cm howitzer.

 

[Shortround6]

British had been working on the 25pdr for a number of years. They weren't going to adopt a 105 howitzer in 1938-1940 no matter what.

 

[Shortround6]

I have a vehicle like you're describing on the pipeline, it would not take much for the British to come out with one
IIRC the cause for artillery not firing on max rate was the barrel's imminent overheating, after a minute or two of firing at max rate?

For the 25pdr the firing rates were

Rates of fire---------Gunfire------Intense------Rapid------Normal--------Slow--------Very slow

Rounds/Minute------6 to 8---------5------------4----------3------------2--------------1

I haven't found the firing rate/s for the 18pdr yet but I would be very surprised if it was under 12 rounds a minute for it's max rate of fire and may have been as high as 15-20rpm with prepared (fused) ammunition. Shell was crimped to cartridge case so one piece loading with no charge adjustment.

A US 105 howitzer was supposed to do 8rpm for the first 1/2 minute, 4 rpm for 4 minutes, 3 rpm for 10 minutes and 100 rounds an hour. If the crew has time to prepare ammo and lay it out (zone charges adjusted and shells fused) then having a single loader ammo handler might not be too bad, depending on far from the gun breech the rounds are after the first 10 or so. That is assuming they want 25-30 fused shells laying about. If fuses have to be fitted and zone charges adjusted while firing one man is going to be overwhelmed.

While too heavy a chassis is a waste too light a one reduces accuracy or rate of fire. Recoil spades help but too much gun for the chassis means a lot of bounce between firing and the gunner has to re-aim the gun more often, or at least check the aim. Some towed guns suffered from this.

 

[davebender]

Rate of fire is nice but having enough HE filler in the shell to defeat field fortifications such as concertina wire is more important for indirect fire artillery. That lesson should have been learned during WWI. I'd rather be supported by 120mm mortars then 25 pounder field guns. Not as accurate and range is shorter but at least they have enough punch to get the job done.

 

[Shortround6]

Problem being that if your opponent has 25pdr field guns and a competent spotting group you won't have your 120mm mortars very long.

If you are depending on 120mm mortars to defeat field fortifications then your divisional and corp artillery are not doing their job.

How much effort did the Germans put into lengthening the range of their 105 howitzer from 10,675meters to 12,325 meters?

 

[tomo pauk]

The mechanized chassis costs a lot more then a 105mm howtizer. If Britain cannot afford to purchase light howitzers then how are they supposed to purchase SP artillery of any type?

Price examples.
16,400 RM. 10.5cm leFH18 howitzer.
22,000 RM. Sd.Kfz.11 towing tractor. Normal tow vehicle for a 10.5cm howitzer.
about 50,000 RM. Panzer II. The smallest possible chassis that can carry a 10.5cm howitzer.

In British case, they will initially use the guns that are already produced, or are being produced; the artillery branch will use a chassis priced between the Bren carrier and Pz-II (while it would be produced less 'real' light tanks), while the tank branch will not buy historical CS tanks, but the SP assault guns (main task providing HE support for 2pdr armed tanks accompanying infantry).

For the 25pdr the firing rates were

Rates of fire---------Gunfire------Intense------Rapid------Normal--------Slow--------Very slow

Rounds/Minute------6 to 8---------5------------4----------3------------2--------------1

I haven't found the firing rate/s for the 18pdr yet but I would be very surprised if it was under 12 rounds a minute for it's max rate of fire and may have been as high as 15-20rpm with prepared (fused) ammunition. Shell was crimped to cartridge case so one piece loading with no charge adjustment.

A US 105 howitzer was supposed to do 8rpm for the first 1/2 minute, 4 rpm for 4 minutes, 3 rpm for 10 minutes and 100 rounds an hour. If the crew has time to prepare ammo and lay it out (zone charges adjusted and shells fused) then having a single loader ammo handler might not be too bad, depending on far from the gun breech the rounds are after the first 10 or so. That is assuming they want 25-30 fused shells laying about. If fuses have to be fitted and zone charges adjusted while firing one man is going to be overwhelmed.

Many thanks for the fire rates.
The LT-based SP vehicle should have 2 loaders, commander, aimer and driver (as it was the case for the German conversion). Once in the firing spot, the driver can assist the loaders.
The A9 based vehicle will fire as fast/as slow as the StuG-III with long 7,5cm.

While too heavy a chassis is a waste too light a one reduces accuracy or rate of fire. Recoil spades help but too much gun for the chassis means a lot of bounce between firing and the gunner has to re-aim the gun more often, or at least check the aim. Some towed guns suffered from this.

Comparing the British conversion with German, the shell weight is some 45-50% less in the British example, MV being about the same, so the recoil is about a half of what was the case for German conversion.

Once more, I agree that too light/small a vehicle can hamper the performance, but once more I repeat that British*, in this thread, are still learning about the finesses of the SP artillery. Some 3 years earlier than historically

*didn't even started with others yet

 

[Shortround6]

Tomo, the German conversions of the MK VI tank used a WW I left over howitzer, not the standard howitzer. Barrel was about 300mm shorter, top velocity with the zone 5 charge was 395m/s. max range 9225 meters. 4 degrees of traverse (?) 2 to each side of centerline.

 

[tomo pauk]

Thanks for the correction; I knew that the 10,5cm lefh 16 was in question, but assumed that MV values are similar.
So, if I'm calculating it correctly, the 10,5cm shell has the momentum equal to 5846 kgm/s vs 4132 for the 18pdr, or, the 18pdr has a recoil of some 72% of the lefh 16?

 

[davebender]

How much effort did the Germans put into lengthening the range of their 105 howitzer from 10,675meters to 12,325 meters?

None.

The 10.5 cm leFH 18/40 change was intended to lower production cost. A bit more range and higher rate of fire was just a bonus.

 

[Shortround6]

Thanks for the correction; I knew that the 10,5cm lefh 16 was in question, but assumed that MV values are similar.
So, if I'm calculating it correctly, the 10,5cm shell has the momentum equal to 5846 kgm/s vs 4132 for the 18pdr, or, the 18pdr has a recoil of some 72% of the lefh 16?

Could be, 70-80% should be in the area ( weight of propellant times escape velocity of the gasses). The German conversion was done by/for a second line unit that probably couldn't even get enough draft horses.

 

[Shortround6]

None.

The 10.5 cm leFH 18/40 change was intended to lower production cost. A bit more range and higher rate of fire was just a bonus.

Try looking at the changes from the 10.5 cm leFH 18 to the 10.5 cm leFH 18M. New shell, new propelling charge, muzzle brake and changed valving in the recoil system. The 10.5 cm leFH 18/40 had nothing to do with it.

Of course those changes were totally unnecessary as the Germans should have been using 120mm mortars with1/2 the range, right?

 

[davebender]

There's more then one way to solve a military problem. The 10cm Kanone was the Heer solution to counter battery and other such long range artillery missions.

Welcome to Landships! - A site for WW1 Military Hardware WW1 Military Modelling
10cm Kanone M14. 724 produced 1914 - 1917.
10cm Kanone M17. 192 produced 1917 - 1918.
10cm Kanone M18. about 1,500 produced 1934 to end of WWII.
.....19km max range.
During 1941 to 1945 the 10cm Kanone was supplemented by about 350 of the more powerful 17cm Kanone.

This has nothing to do with general infantry support missions which were accomplished using howitzers with shorter maximum ranges.

Before designing a SP artillery piece we first need to determine it's mission. I am thinking in terms of general infantry support which means being able to defeat field fortifications such as concertina wire. Apparently you are thinking of a long range counter battery weapon to suppress enemy artillery fire.

 

[tomo pauk]

I would suggest that the mortar vs. howitzer debate should be located to some other thread. Thank you.

 

[Shortround6]

ALL artillery and mortars can be call upon to fire in counter battery mission. The Infantry battalion will attempt to silence the enemy mortars with their own mortars. If they cannot reach the target then a request will be passed up to regiment or brigade or Division. Where ever the next longer ranged ordnance is held.

The same goes for Regimental guns, howitzers and heavy mortars held at the regimental brigade levels. The unit involved tries to see it the job can be handled by it's own assets and if it can't requests help from a higher echelon.

Equipping units with substandard weapons because they are CHEAP and expecting to get needed support from Corp or Army echelon weapons whenever needed is a surefire way to to suffer high causalities and failed missions.

This applies to self propelled weapons or mechanization as well.

As far as Mechanization and infantry support goes I would suggest taking a very good look at the German Stug batteries in France. The Stug used an artillery style periscope sight, used though and opening in the roof. They were issued in batteries of 6 vehicles and had specialized ammo carriers (Sd Kfz 252 and Sd Kfz 250/6) attached to the batteries along with one VERY special addition, The Sd Kfz 253 light armoured observation post, later replaced by the Sd Kfz 250/4. Strange that what many people view as a direct fire weapon system had at least one armoured forward observation post vehicle issued for every 6 gun vehicles?

I would agree with Mr. Bender on this "Before designing a SP artillery piece we first need to determine it's mission"

Are we looking for a SP anti-tank gun? A support weapon for a tank company or battalion (in the British army to replace the support <smoke> tanks)? A SP divisional support weapon ( placing the normal divisional artillery on tracks)?

A major advantage of tracked artillery ( that NEVER shows up in civilian war games) is it's ability to keep up with a fast moving advance ( or retreat), not so much in the sense of being able to drive along side tanks through mud, snow or sand but in the fact that the tracked battery can get out of a firing position, drive to a new firing position, set up and commence firing much faster than a towed battery can. This means the advance (or rear guard) is without artillery support for much less of the time than if the artillery was all towed.

Now if you are trying to mechanize an army in 1937-40 where are you going to get the most "bang for your buck"? Mechanizing some special purpose guns/mortars/whatevers or mechanizing some/all of the mechanized brigade/division's regular artillery component?

 

[davebender]

The weapon costs the same whether it's towed or SP. So it comes down to the cost of a tow vehicle vs the cost of tracked vehicle sturdy enough to handle howitzer recoil.

In the German Army a Sd.Kfz.11 towing tractor costs about half as much as the lightest possible armored vehicle chassis (i.e. 10 ton Panzer II). In addition the towing tractor can be used for supply missions when the howitzer is stationary. So if you want "bang for the buck" a towed howitzer wins every time.

If money is no object then SP howitzers are preferable for reasons already stated. Faster to set up and faster to bug out for the purpose of evading counter battery fire.

Armored divisions are the exception to the rule. All division elements including artillery must keep pace with the tanks. Artillery support is crucial for suppressing enemy AT guns and your tanks need it immediately if they are to survive.

 

[tomo pauk]

@ SR6

Equipping units with substandard weapons because they are CHEAP and expecting to get needed support from Corp or Army echelon weapons whenever needed is a surefire way to to suffer high causalities and failed missions.

This applies to self propelled weapons or mechanization as well.

For the 3rd time: in this thread, the British are aware of the incoming war. They are experimenting with an novelty, an SP gun for their artillery arm, with intent to use it in indirect fire role (the A9 'stug' is to be used in tank units, instead of historical CS tanks). As an experiment, it uses an affordable chassis and an already produced artillery piece. If the experiment fails, it was not costing them too much. If it works, they would produce more examples, either same type, or improved, or substantially better designs. The 18pdr is an useful piece, and implying it's 'substandard' is way out of mark.

As far as Mechanization and infantry support goes I would suggest taking a very good look at the German Stug batteries in France. The Stug used an artillery style periscope sight, used though and opening in the roof. They were issued in batteries of 6 vehicles and had specialized ammo carriers (Sd Kfz 252 and Sd Kfz 250/6) attached to the batteries along with one VERY special addition, The Sd Kfz 253 light armoured observation post, later replaced by the Sd Kfz 250/4. Strange that what many people view as a direct fire weapon system had at least one armoured forward observation post vehicle issued for every 6 gun vehicles?

Thanks for the information. BTW, any info about the max elevation of the early StuG-III gun?
It's obvious that LT-based SP gun would need observation posts/units, they can use the 'Bren' carrier, or maybe another LT based vehicle.

I would agree with Mr. Bender on this "Before designing a SP artillery piece we first need to determine it's mission"
*Are we looking for a SP anti-tank gun? **A support weapon for a tank company or battalion (in the British army to replace the support <smoke> tanks)? ***A SP divisional support weapon ( placing the normal divisional artillery on tracks)?

Think I've covered this before, but anyway:
*Not yet (prior Sept 1939).
** Yep, the A9 based vehicle, firing both HE smoke shells.
***That's one of the aims, LT-based SP piece being sorta proof of concept.

A major advantage of tracked artillery ( that NEVER shows up in civilian war games) is it's ability to keep up with a fast moving advance ( or retreat), not so much in the sense of being able to drive along side tanks through mud, snow or sand but in the fact that the tracked battery can get out of a firing position, drive to a new firing position, set up and commence firing much faster than a towed battery can. This means the advance (or rear guard) is without artillery support for much less of the time than if the artillery was all towed.

Agreed.

Now if you are trying to mechanize an army in 1937-40 where are you going to get the most "bang for your buck"? Mechanizing some special purpose guns/mortars/whatevers or mechanizing some/all of the mechanized brigade/division's regular artillery component?

The 1937-40 is out of question for an completely mechanized army, even if that's the British (small size, but heavily on the path of motorization (and it will remain there when army starts a steady grow), so the mechanization would require just an 'extra mile' effort, contrasted with, say, German army (big army, but even the motorization is out of question). So just a smaller part of the army would be initially mechanized, growing more as the war progresses (providing the beligerent don't collapse prior, of course).
A 'free' gun plus a cheap/free/mass produced chassis would make the best 'bang for buck'. So having, say, 1/3rd, or 1/4th of the army being mechanized would be an asset. Implementing the combined arms approach, that should involve the mechanization of AAA, AT infantry units, too.

 

[davebender]

Then you need a weapon with enough punch to do the job.

105mm howitzers are tried and true. Favorite size for general infantry support for the past 100 years (Soviet Union excepted). That's good enough for me.

 

[Shortround6]

The weapon costs the same whether it's towed or SP. So it comes down to the cost of a tow vehicle vs the cost of tracked vehicle sturdy enough to handle howitzer recoil.

You continue to misunderstand. If you have limited funds and have to chose between mechanized divisional artillery of your "mechanized" division/s or mechanized "special purpose" artillery vehicles and towed divisional artillery which is the better buy?

 

[Shortround6]

Then you need a weapon with enough punch to do the job.

105mm howitzers are tried and true. Favorite size for general infantry support for the past 100 years (Soviet Union excepted). That's good enough for me.

British did not switch to the 105 until the late 1950s. But then they don't count do they??
British gun makers were selling 105s to other nations since the early 1920s.

105s WERE NOT the favorite size for general infantry support for the last 100years. They only became the favorite size from the middle of WW II on, about 70 years. While the US adopted the 105 howitzer in the early 30s they didn't make more than a couple dozen until 1941. Which is why the forces in the Philippines used 75mm guns. Many other nations used a mixture of 75-76mm guns and 100-105 howitzers as divisional artillery. Often in a ratio of 2 or 3 batteries of 75-76mm guns for every battery of 100-105 howitzers. The 75-76mm gun and the 100-105mm howitzer were the heaviest weapons that could be moved as "field artillery", that is keep up with marching infantry when horse drawn. Anything bigger, 90-105mm guns or longer ranged 120 howitzers (or short ranged 150mm howitzers) were part of the heavy artillery and while mobile could NOT move the same distance per day as an infantry unit in the march.
Granted things got much easier with motor transport but only the British army and the Americans were motorized (not mechanized) in 1939.

By the way, from about 1910-1940 there were around a 1/2 dozen 12cm howitzers in use by a number of smaller (and larger, Russia) nations that were about the same weight as a 105 Howitzer. They used shells of about 20-23kg but had ranges of about 6-7 km. These were made by Krupp, Rheinmetall, Schneider and others.

 

[Shortround6]

For the 3rd time: in this thread, the British are aware of the incoming war. They are experimenting with an novelty, an SP gun for their artillery arm, with intent to use it in indirect fire role (the A9 'stug' is to be used in tank units, instead of historical CS tanks). As an experiment, it uses an affordable chassis and an already produced artillery piece. If the experiment fails, it was not costing them too much. If it works, they would produce more examples, either same type, or improved, or substantially better designs. The 18pdr is an useful piece, and implying it's 'substandard' is way out of mark.

Sorry but the substandard was in relation to 12cm mortars, however it applies to some extent to the 18pdr depending on model and year. There are 2 different 18pdr barrel and recoil mechanisms and 3 rather different carriages. there is also a modernized HE shell. AS to the carriages I am not referring to the the type of wheels or brakes but wither it had the pole trail carriage, the box carriage or the split rail carriage. The carriage affects the elevation and traverse limits for a simple conversion ( cut the wheels off, cut trail/s down and mount on/in vehicle) Building new elevation/traverse mechanisms tends to run up the cost. The problem here is that the most desirable carriages for conversion to SP guns (the MK IV box trail and MK V split trail) are also the most desirable for the British to convert to 25pdrs as towed artillery. as an example 704 of the converted 18/25pdr guns were lost in France along with 216 18pdrs. The least desirable guns for conversion were the pole carriage guns. These had an elevation limit of 16 degrees with rather limits the range. They also had a total of 8 degrees of traverse. the box trail offered 30 degrees of elevation and the Split trail offered 37.5 degrees. The box trail equipment was sometimes given a turntable like the 25pdr for easier large arc traverse movement.

There were 90 of the 25pdr MK II (the "standard 25pdr")in England in May of 1940 and none are supposed to have gone to France.

For your experiment the 25pdr MK I (18/25pdr) is as good as it gets (from 1937 on), the guns/mounts to be turned into the 25pdr MK I are second best and perhaps spoken for but available in small numbers. The older guns with pole carriage, recoil cylinders on top of the barrel and so on are the "cheapest" they are also slated for scraping or training commands, have limited range about 6000 meters (the change from 16 degrees to 30 degrees was worth 2600yds) have a different breech mechanism ( a slower two motion breech instead of a single motion breech).
The Experimental Birch guns used the later 18pdr barrels, breeches and recoil systems and that was in 1925. there were experimental gun carriers in the First World War based on the Big British tanks. The British played with the Birch guns fot 6 years.

the French had built 8 different prototype SP guns by 1919 and the US had built 12 different models by 1922. The Idea was not novel but exact doctrine and technique needed a lot of work.

Thanks for the information. BTW, any info about the max elevation of the early StuG-III gun?
It's obvious that LT-based SP gun would need observation posts/units, they can use the 'Bren' carrier, or maybe another LT based vehicle.

Stug elevated to 20 degrees.
The OP unit needs to mount the standard OP optics (not much of a problem) a small map area, (not much of a problem) and a decent radio set ( a bit more of a problem). The First German OP unit mentioned Sd Fkz 253 actually had thicker armor on the front than the standard half track. It might be better to use the LT chassis rather than go cheap with the "Bren" carrier.

Think I've covered this before, but anyway:
*Not yet (prior Sept 1939).
** Yep, the A9 based vehicle, firing both HE smoke shells.
***That's one of the aims, LT-based SP piece being sorta proof of concept.

an A9 "Stug" doesn't really have the armor to take part in the direct fire battle, the A9 itself didn't have the armor. A10 maybe.
If you have this kind of influence ( ) get the British to make and issue an HE round for that 3.7in smoke mortar and an HE round for the 2pdr.

The concept is already somewhat proven, what is needed is a "practical" vehicle to carry it to the next step. Small vehicles with limited ammo storage, limited firing arcs (if used with 8-9 degree traverse mounts) limited working room and some what limited cross country performance (step and trench) are NOT needed in any numbers. The MK VI light tank also had a primitive steering system. It used the clutch and brake system which was OK on the level and climbing hills, it would reverse steer descending a hill unless the engine was under load (accelerating). To steer the 'inside' track was de-clutched and if needed was braked as the outside track continued to be powered causing the tank to slew (turn). going down hill on a trailing throttle as soon as the 'inside' track was de-clutched it ' free wheeled' (free tracked ? ) and the normally driven track held back causing the vehicle to turn in the opposite direction intended. Not great in any vehicle, in a top heavy SP gun??

Part of the British resistance to SP guns in the late 30s was not so much cost but mistaken tactical beliefs. Like the tank was invulnerable (even with 30mm or less armor) and so didn't need artillery support to suppress enemy defenses.