Panzer IV

[Sauragnmon]

I'm not quite thinking Brumbar, so much as a more armored Wespe with the 15cm gun mounting, on the Pz IV chassis.  Use the bigger Panzer IV, with the 15cm, enclose the system, it's a hell of a knockout punch against the breakthrough tanks of the Soviets or the Allied Heavies.  Hits like a sledgehammer, has by and large a better profile than the Jagdtiger.  I'm not saying I'd turn down Panther G's, they're good tanks - pain in the right arse to maintain with that suspension, but when they're running they're a nice, smooth, stable ride.  I wouldn't say I'd turn down the good tanks, but for a support unit, the StuH IV would be quite an effective unit I would think.

[Logan Hartke]

So something more like, say, the SU-101 and SU-102 on a Pz IV chassis with either a 8.8cm KwK 43 or 15cm StuH 43/1, is that what you're looking for?



That's definitely the configuration to go for, I'll give you that.  I think I'd have to go for the 8.8cm KwK 43-armed vehicle over the 15cm StuH if I was faced with heavy armor.  In a Stalingrad or Warsaw Uprising scenario, sure, give me the 15cm StuH, but otherwise, no thanks.

Logan

[Sauragnmon]

Yeah, the Su-100/102 designs are the concept I was looking for, though perhaps with a lighter slope on the sides to the upper structure, and with a mounting designed for higher angle, at least maximum elevation 45 degrees, for optimal ranged fire.  The 15cm gun would be optimal as a multirole design, but yes, the 88 would be optimized as a tank smasher for longer shots.

[dy031101]

Off topic, but what is in your opinion the best tank gun in WWII?

Watching Valkyria Chronicle anime made me think about the idea of something along the line of the M26 Pershing but (kinda like the Geschützwagen III/IV) would recycle components of both the Panzer III and Panzer IV tanks......

I've also heard of a Panzerkampfwagen auf Einheitsfahrgestell III/IV, which allegedly was also to recycle quite a number of parts from the existing medium tanks.

Hum...... that's another potential 3DS Max project...... Geschützwagen or Einheitsfahrgestell III/IV could probably serve as a good reference.

[Logan Hartke]

My opinion?  If I had to pick my optimal tank design, it would have a Centurion hull and turret, US-designed torsion-bar suspension (including tracks) and FM radios, .50 cal for AA and coaxial MGs, Soviet D-10 tank gun (although built to higher standards, including ammunition), German intercoms and gun sights, MG42 for loader hatch, and powered by a Continental AV-1790 engine.

So, what do I think the best tank gun of WWII was?  Depends on what size category you're talking about.

In order of size, my top guns would be:

Soviet 45mm
British 6pdr/57mm
German 7.5cm KwK40
American M3 90mm
Soviet D-10 100mm
US T5E1 105mm
German 12.8cm KwK 44

Why don't you see some of the biggest names in there?  The British 17pdr, the German 7.5cm KwK 42, or the 8.8cm German KwK 43?  For me, they're not great all-around tank guns.  They're very good at putting holes in tanks, sometimes good at causing serious or catastrophic damage, too, but they have serious drawbacks.  One is the low lifetime of the gun.  They fire rounds at such high velocities that they destroy the barrels in no time.  Unless you plan on dying soon (the most popular choice), you had better strap a couple extra barrels to the side of your tank; you'll need them in a month or two.  The bigger problem for me, however, is their puny HE rounds.  None of those three "GREAT" tank guns had a better HE round than the US 75mm armed Sherman had.  A Chaffee could do more damage to a soft target than a King Tiger.  Pathetic.  I read a story about a couple of Panthers in the Battle of the Bulge that pounded some American infantrymen in an old stone Belgian house.  The US soldiers reported that the Panthers fired many, many rounds of 7.5cm HE at the wall of the house facing them to no effect.  He said it just chipped the paint off the stone wall.

If you arm most of your tanks with one of those weapons, then you will absolutely need some specialized infantry support tanks mounting short-barreled 105mm guns for throwing HE around.  Otherwise, you may stop enemy tank attacks, but your infantry will be stopped by the first serious dug-in infantry line you go up against.  The British learned that the hard way in North Africa in 1942.  AP alone may win defensive battles, but you'll never take and hold ground without proper HE.

Cheers,

Logan

[tahsin]

The ultimate in such anectodes is the G.I. who had his throat grazed by an 88 in the Battle of Bulge

[rickshaw]

Depends what role you envision for your tanks.  The Americans and Russians saw their tanks as infantry support weapons.  The Germans and British as anti-tank weapons.  That saw their choice in weapons.  For the Americans and Russians, a high-capacity HE round was the primary weapon of the tank.  For the Germans and British, the ability to perforate the enemy's tanks was more important, hence their reliance on AP rounds. Basically you simply cannot divorce the vehicle from the doctrine which it was intended to serve.

I find the choice of torsion bar suspension interesting as well.   Torsion bar suspension is difficult and expensive to produce.  It also has problems if mines are encountered - they tend to cause worse damage to the suspension if its of a torsion bar design than if it is of an externally mounted system, such as VVS, HVSS, Horstman, leaf-spring or Belville-washer style (with those, all that happens is the suspension unit is blown off the hull whereas a torsion bar system has to have those bars replaced as well which is a difficult job).  Indeed, that was one of the major reasons why the Israelis chose Horstman over torsion bar for the Merkava.  While the Germans were, by war's end attempting to change over to the Belville-washer style from torsion bar because of their metallurgical problems by that stage of the war (one of their worst decisions had been the adoption of torsion bar suspension for the Panther over the much cheaper and easier to produce leaf-spring system which had been proposed for the Henschel proposed version of the Panther).

[Logan Hartke]

Depends what role you envision for your tanks.  The Americans and Russians saw their tanks as infantry support weapons.  The Germans and British as anti-tank weapons.  That saw their choice in weapons.  For the Americans and Russians, a high-capacity HE round was the primary weapon of the tank.  For the Germans and British, the ability to perforate the enemy's tanks was more important, hence their reliance on AP rounds. Basically you simply cannot divorce the vehicle from the doctrine which it was intended to serve.

Countries THOUGHT they wanted something different.  In the end, however, they all came around to the same basic ideas.  Not AP (British & Germans) or HE (US), but BOTH.  The Russians were actually in the BOTH camp before the war, not the HE.  That's why you saw the Russian 45mm as the only light tank gun with a useful HE round.  Nobody else had that at the time.  They just had a more practical approach in developing an AP weapon.  In fact, the Soviet 122mm gun was chosen for the IS tanks over the 100mm gun for two main reasons.  One was that it was more readily available.  You could build more IS-2/3 tanks faster if they were armed with the 122mm gun than if it were armed with the 100mm gun.  The second reason?  It was better at killing German tanks.  While the 100mm gun was in some cases just as good or better at penetrating thick armor than the 122mm, German armor quality had gone down in the second half of the war and the greater mass of the 122mm gun was causing very, very nasty things to happen to German tanks.  The armor was spalling far worse, welds were breaking and whole armor plates were falling off, plates were cracking like the glass in a window.  It was bad.  The Soviets knew this because they made their decision based on testing against a captured German Panther, not test armor plate.

The 122mm gun was not picked because it had a better HE round (although it did) and the IS-2 was envisioned for "infantry support".  That's a myth.  The SU- and ISU-152 were intended moreso for that role (and heavy tank busting, too).  It was picked because it was the more lethal tank killer and was more readily available.  The Soviets were smart enough to see that a future war would not be fought against countries with brittle armor and they knew the 122mm gun was inefficient for its weight, so they planned for their next tank to have a 100mm gun, not a 122mm gun.  That tank would be the T-54 and it shows the Soviets were on top of their game at the end of WWII when it came to tank design.

I find the choice of torsion bar suspension interesting as well.   Torsion bar suspension is difficult and expensive to produce.  It also has problems if mines are encountered - they tend to cause worse damage to the suspension if its of a torsion bar design than if it is of an externally mounted system, such as VVS, HVSS, Horstman, leaf-spring or Belville-washer style (with those, all that happens is the suspension unit is blown off the hull whereas a torsion bar system has to have those bars replaced as well which is a difficult job).  Indeed, that was one of the major reasons why the Israelis chose Horstman over torsion bar for the Merkava.

Yeah, I agree and I often go back and forth on which suspension is the best.  I will agree that torsion bar suspension has major limitations.  Practically, for a Sherman-size vehicle, HVSS was probably the best.  It allowed for higher top speeds than Horstmann, but was likewise externally mounted and very, very easy to replace.  HVSS isn't optimal when you get into the heavier weights, though.  Horstmann suspension is very durable and externally mounted, but not perfect.  It doesn't give as nice of a ride as torsion bar (important when engaging targets on the move) and doesn't allow for as high speeds.  That's the reason why the Merkava no longer uses Horstmann-style or Horstman-inspired suspension on the Merkava starting with the Merkava 3.  The greatest development of the Centurion, the Olifant 1B and Olifant 2 ditched the Horstmann for torsion-bar.  It's the better suspension.  All things have their good and bad points, however.

Indeed, that was one of the major reasons why the Israelis chose Horstman over torsion bar for the Merkava.  While the Germans were, by war's end attempting to change over to the Belville-washer style from torsion bar because of their metallurgical problems by that stage of the war (one of their worst decisions had been the adoption of torsion bar suspension for the Panther over the much cheaper and easier to produce leaf-spring system which had been proposed for the Henschel proposed version of the Panther).

I agree here.  After the PzKpfw III, torsion bar was the wrong choice for the Germans.  Really this was as much due to new metallurgical concerns as anything, but the excessive weight of new German tanks had as much to do with it as anything.  Whatever the reason, you play the hand you're dealt and the Germans played it poorly when it came to tank suspension.  I've read the stories of Panther breaking torsion bars (especially up front) when just sitting around because it wasn't designed to take the Panther's weight (Hitler had it uparmored before it went into production).  Basically, it had no room for growth.  German torsion bars couldn't be as strong as they had to be because they didn't have the quality of metal they had earlier in the war.  For that reason, they just doubled the number of roadwheels and torsion bars, which allowed everything to be weaker, or that was the idea at least.  That's why you saw that overlapping roadwheel style of suspension.  Ridiculous.  That isn't a choice at all.  Americans could build much higher quality torsion bars, as could the Soviets.  The Soviets also had weight control in tank design.  Germans didn't think about that, apparently.  For that reason, you saw Americans and Soviets building high-quality torsion bar suspension for their medium and heavy tanks at the end of the war and sticking with it to this day.  It works and works well.  More maintenance-free than most externally-mounted suspension types, too.

Cheers,

Logan

[Sauragnmon]

I dunno - Primary Soviet Suspension is Torsion Bar if I recall.  Back to the topic of DIY Monster Tank:

I'd probably consider Christie Suspension, a good solid Soviet engine, design all armor at a nice 60 degree slope to incorporate the light weight and good protection.  Decent width tracks, to keep ground pressure nice and light.  If I were going for Tank killing, I'd probably aim the turret design to house one of the heavy hitters, like the 88 KwK 42, a gun that can smash tanks with the best of them.  If I were to go somewhat more Infantry Support with the tank, I would likely actually keep the 88, but adapt 88mm Timed Fuse rounds to the breech design and install a fuse timer so as to allow airbursting of rounds over the infantry, or else give them a small selection of pre-timed rounds for speed of fire.  I'd also at the same time consider designs for Infantry Support and Heavy Tank Destroyer models derived from this design, featuring 15cm or 12.8cm guns for true destructive firepower.

But then, we know I'm a madman.

[Logan Hartke]

Yeah, the primary Soviet suspension was torsion bar.  Christie suspension was awful.  It was maintenance intensive but not maintenance friendly and took up a TON of internal volume.  Nobody used it after they had an adequate replacement.  The Soviets replaced it with torsion bar and the British with Horstmann because they found that really high speeds were not essential on their battlefields.

There is no 8.8cm KwK 42.  You have the 8.8cm KwK 36 & 43 and the 7.5cm KwK 42.  The long-barreled 88s suffered from short barrel life, as I mentioned earlier, and really puny HE content.  Timed fuses are great, but this is before the era where you have adequate rangefinders, so you'd be wasting a lot of ammo just to figure out what to set the timer for.  Not only that, but those fuses take up even more room in the round, so by the time you're done designing that round, it will have the HE content of a fragmentation grenade.  If your fuses are preset, they're not going to hit anything, because you'd either need 40 rounds each set for different times or you'd have to take 45 sec to set each fuse even if you knew the precise range!

Airburst munitions like that have to be SUPER-precise when you're using them in a high-velocity, straight line weapon.  Why?  Well, with a 105mm howitzer, a tenth of a second may not mean the difference between hitting the target or not.  With the KwK 43, however, you've got a weapon with twice the velocity and half the HE content, meaning you need to be AT LEAST four times as precise to hit your target.  A tenth of a second is more than half a football pitch's distance.  Considering you average MG nest isn't going to be any bigger than the goal, you don't have a chance of getting a proper airburst and you don't have enough HE anything if you hit it directly.

It's complications like these that make me choose an all-around decent weapon.  A great penetrator doesn't do anything for the infantry and a great HE thrower is up a creek when another tank shows up on the battlefield.  Having two tanks with different guns only works if they're in the exact right place at the exact right time.  It's wasteful or resources and risky.  It's best to just have a gun that's generally good against both types of targets.

Cheers,

Logan

[dy031101]

It is said that, from mid 1937 to late 1940, attempts were made by Krupp and Daimler-Benz to standardize the production of Panzerkampfwagen III and Panzerkampfwagen IV.

Does anyone know what parts-commonality the two vehicle types enjoyed at the completion of these attempts?

For the DIY tank, can I simply lengthen as well as widen the Geschützwagen III/IV chassis and then add another pair of leaf spring arms (four more roadwheels) to cope with the enlargement (remember that I want a counterpart to the M26- so the armament has gotta be at least 88mm- but also aim to recycle as many Panzer III and Panzer IV components as possible)?

An Alkett/Rhinemetall-Borsig design described on this page is said to utilize Geschützwagen III/IV chassis as well...... is it just me, or does its armament placement really seem to suggest that the engine is relocated to the rear?

The below picture is the Edelweiss, the hero's tank of Valkyria Chronicle with a Königstiger-inspired turret, relatively-narrow tracks based on those of the Panzer III/IV, and torsion bar suspension......

It's the inspiration behind me asking the afore-mentioned questions...... but I guess I should stick with the leaf spring suspension......

[Logan Hartke]

It is said that, from mid 1937 to late 1940, attempts were made by Krupp and Daimler-Benz to standardize the production of Panzerkampfwagen III and Panzerkampfwagen IV.

Does anyone know what parts-commonality the two vehicle types enjoyed at the completion of these attempts?

Yeah, they actually attempted that at least four times between 1937 and 1944.  In the end, they had very little to show for it.  They were not too interchangeable at all, to be honest.  A few parts here and there.  A number of chassis used combinations of PzKpfw III and IV parts.  The Hummel and Nashorn are often described as being on a PzKpfw IV chassis when they're really a combo of the PzKpfw III and IV (as you mentioned, the Geschützwagen III/IV).

For the DIY tank, can I simply lengthen as well as widen the Geschützwagen III/IV chassis and then add another pair of leaf spring arms (four more roadwheels) to cope with the enlargement (remember that I want a counterpart to the M26- so the armament has gotta be at least 88mm- but also aim to recycle as many Panzer III and Panzer IV components as possible)?

An Alkett/Rhinemetall-Borsig design described on this page is said to utilize Geschützwagen III/IV chassis as well...... is it just me, or does its armament placement really seem to suggest that the engine is relocated to the rear?

The below picture is the Edelweiss, the hero's tank of Valkyria Chronicle with a Königstiger-inspired turret, relatively-narrow tracks based on those of the Panzer III/IV, and torsion bar suspension......

It's the inspiration behind me asking the afore-mentioned questions...... but I guess I should stick with the leaf spring suspension......

Rickshaw would probably say PzKpfw IV leaf-spring, but I'd say PzKpfw III torsion bar.  From what I've read, the torsion bar was the more durable of the two.  I know Russian tests showed as much.  I just went railing on German torsion bar a couple of posts ago, but let me clarify.  That's the overlapping roadwheel torsion bar of the Tiger and Panther.  The PzKpfw III's was just fine.  The StuG III was probably the most successful AFV the Germans produced in WWII (I'm not saying it was the best design, I'm just saying I think it was their best investment).  The PzKpfw III's suspension was great.  It could use a wider track, but that's about it.

That vehicle was based on the Geschützwagen III/IV chassis.  Moving the engine back and forth doesn't mean it wasn't based on that chassis.  Look at the Wespe and PzKpfw II, Marder III/Grille and PzKpfw 38(t), or M12 GMC and the M3 Lee.

My DIY "ideal" medium tank of WWII would actually probably look just about like the German Panzerkampfwagen III/IV Einheitsfahrgestell.



I'd probably just replace the powertrain for that of an M4A3 (450hp Ford GAA engine, transmission, differential, etc), give it a gyrostabilizer, FM radios, an optional MG mount on the roof, and optional rubber tracks.  That would be about the ideal medium tank of WWII.

Cheers,

Logan

[dy031101]

That's the overlapping roadwheel torsion bar of the Tiger and Panther.  The PzKpfw III's was just fine.

What if I'm limiting the industrial and metallurgical considerations regarding this DIY tank to that of the real-life Germany after 1942?

[Logan Hartke]

That's no trouble.  They made the StuG III up until 1945.  Its chassis wasn't heavy enough to need the super-strong alloys that non-overlapping roadwheels would have required under the crushing weight of the Panther, Tiger, or King Tiger.  At least, that's my limited understanding of the situation.  Regardless, as long as you're not planning on a 50 ton beast, you should be fine.

Cheers,

Logan

[Sauragnmon]

Were the double-layer roadwheels for suspension sake, or were they for the cross country stabilization of the tank on the move?  I know the Panther over terrain without Serious problems was a rather smooth ride.