Alternative German tanks & AFVs

[don4331]

I don't think the torsion bars would require a full foot. Just eyeballing your picture, maybe 10-15cm?

As for alternative suspensions, what about hydropneumatic? I'm not aware of any applications to tanks in the WWII time-frame, but AFAIU oleo struts were used in aircraft so at least the principle was well understood.

Spielberger quotes it as 14cm in his book on Panther and Variants for the height addition due to torsion bars.

Torsion bars had the advantage of being protected from mud and other debris by being inside the hull. They also allowed the Panther to travel cross country at almost 45 km/h, while leaf suspension limited the Pz. IV to barely 20km/h.

For reference: The T34 made about 25km/h and Sherman just under 40km/h​

Test were done at Betonwellenband test track in Germany​

 

[tomo pauk]

Back to the German light tanks.
Looking at the schematics of the the Pz-IB, the 'consumption' of the protected volume by the propulsion group seems excessive. The Vickers Mk.V light tank , while having the similar motorization, was a lot shorter affair, also lighter, with space for 3 men crew (vs. just 2 on the Pz-I). Perhaps relocating the engine aside the gearbox (and opposite to the driver) would've freed a lot of space.
The Pz-II is a tougher cookie, the bigger gearbox was occupying the best part of the front volume aside to the driver. Here a shorter engine would've helped, especially if relocated amidships. The I6 engine really took a lot of space, as it can be seen by the Wespe cutaway, that saw the engine relocated from the rear position - perhaps this is a right place for a small radial, or for a V6?
Rotating the engine by 90 deg on the Pz-II/Wesepe might've freed more of internal space.

In cases of both Pz-I and -II, all of these nip & tuck jobs also cancel the volume needed for the prop shafts and their protection.

 

[Admiral Beez]

I don't think the torsion bars would require a full foot. Just eyeballing your picture, maybe 10-15cm?

You may be right. What we really need to do is get that driveshaft out of the way by putting the transmission and sprockets in the back, like on the T-34. Or scrap the transmission entirely, like on….

Panzer IV with Hydrostatic Drive

 

[Shortround6]

Looking at the schematics of the the Pz-IB, the 'consumption' of the protected volume by the propulsion group seems excessive. The Vickers Mk.V light tank , while having the similar motorization, was a lot shorter affair, also lighter, with space for 3 men crew (vs. just 2 on the Pz-I). Perhaps relocating the engine aside the gearbox (and opposite to the driver) would've freed a lot of space.

The Pz-Ib was a bodge job. They had screwed up sticking an underpowered flat 4 engine of 3.5 liters (air cooled) into a 5 ton tank and it was not working. The Ib was an attempt to solve the problem with minimal retooling. Stretch the hull, put in inline 6 in place of the flat 4 opposed engine and mount an extra road wheel to carry the extra weight (which wasn't all that much) and size. They made fewer Ib's than they did Ia's. They used the same engine that was in the 1 ton half-track.
They could have done better but why? Production ended in 1937 for all practical purposes.
There were two later "versions" that were total wastes of time, resources. A side from general size they had nothing in common with the Pz Ib.
They were ordered in late 1939 but due to other things having "priority" they were not built (or completed) until the middle of 1942. They were bad ideas in the Fall of 1939, proved to be bad ideas in the BoF in 1940 and may only have been built to keep cash flow going to the companies. They were useless in 1942.

8 tons 30mm armor on the front, 20mm sides and rear, still a 2 man crew. A high revving 4.7liter engine and 8 forward gears and 2 in reverse (or a 4 speed with a 2 speed?)
The gun was a odd ball firing the same 7.9mm ammo as the German AT rifles. Whatever use it had in 1939/40 was long gone in 1942 and there was no HE ammo (I am sure this time)
40 built. It was fast and it was fast and it was.............................fast.
The other was worse.

Somebody saw a British photo of a Maltida I and said "we got to have something even stupider!!!"
So they labored mightily for over 2 years and produced something that was even dumber than the Maltida I.
At least the Matilda I was cheap.
This thing was twice as heavy (24 short tons, 80mm armor on the front), used an engine of nearly twice the power and went twice as fast (A blistering 25kph, on a road)
Twin MG34s may have been better than the MG 13s in the Pz I but wither they were much better than a Vickers gun is subject to question.
30 built or at least partially. Turrets may have been used in some fortifications?
What is truly astonishing is that each of these had a further development prototype built or building.

The Pz II was an improved Pz I
British were testing this in 1938.

But it didn't really enter production until the summer of 1940.
You need a heck of an improvement to get a Pz II up this level in 1940-41 or even up to the level of a Soviet T-26 mod 39.

Engineering time should have been going into better/improved Pz III & IV tanks (or new 24-28 ton tank)

 

[tomo pauk]

They could have done better but why? Production ended in 1937 for all practical purposes.
There were two later "versions" that were total wastes of time, resources. A side from general size they had nothing in common with the Pz Ib.
They were ordered in late 1939 but due to other things having "priority" they were not built (or completed) until the middle of 1942. They were bad ideas in the Fall of 1939, proved to be bad ideas in the BoF in 1940 and may only have been built to keep cash flow going to the companies. They were useless in 1942.

Idea is not to go overboard with the MG-armed tanks, but to make something less cluttered and more useful in the years before ww2. Thus a not-Pz-Ib (ie. a tank made instead the Pz-Ib) with the engine being next to the transmission and the combat compartment in the rear, armed with 20mm gun in a revolving turret, 3 crew members. It also makes outfitting of the chassis with some more substantial weapon easier, even if going with the 150mm howitzer on it is not recommended. Perhaps install the turret from the PSW 222 (85 deg elevation for the 20mm), or some short 75mm in the 'casemate'. Or a 37mm ATG in an open-topped turret, or the 47mm in the less compromised mount than it was on the PzJgd-I.
Heck, Germans installed a 105mm M16 howitzer on the captured Vickers light tanks.

While the Pz-I was not a stellar tank, German army was still 'hungry' not just for tanks, but also for all kinds of self-propelled mounts.

These heavy MG-armed tanks were really a waste.

The Pz II was an improved Pz I

Pz-II was also pretty ... lavish in how the volume under armor was spent. The inline 6 engine is a great volume-eater unless it is installed parallel to the gearbox and/or next to it, while the prop shaft also adding to the negative math. IMO, the Pz-II should've been also with the engine next to the gearbox from the day one, thus offering much more of volume for crew/ammo/main weapon.
If the 'distributed' powerpack layout is still insisted upon, engine needs to be a V6, or a small radial. Once the engine is moved to the center, like in the case of the Wespe, it also makes the combat compartment bigger, but without the increase in outward volume.

With 20mm moved down to the Pz-I, the Pz-II needs to start out with 37mm.

 

[z42]

It seems that German tank design, similar also to aircraft, suffered from an expectation of a short victorious war, and thus there was not enough resources to put into the pipeline of future tanks under development, which came to bit them later on.

I agree with tomo pauk 's suggestion that the Pz III and IV were 'too similar' to each other; it would have made more sense to make a support version of the Pz III with the short 7.5cm gun (like the later Pz III Ausf N actually did), and instead develop the Pz IV as a true next generation tank in the 30-35 ton size class. Developed from the outset with a high velocity 7.5cm gun (the L43/48) in mind, with upgrade potential to eventually mount the 7.5cmL70 from the OTL Panther?

Engine-wise, KISS. Make a family of engines all sharing the same bore, pistons, valves, etc., and make I4, I6, V8, V12 configurations depending on the requirements for each application. V8 for a medium tank, V12 for a heavy.

 

[tomo pauk]

and instead develop the Pz IV as a true next generation tank in the 30-35 ton size class. Developed from the outset with a high velocity 7.5cm gun (the L43/48) in mind, with upgrade potential to eventually mount the 7.5cmL70 from the OTL Panther?

Good knows that Germans were making a whole host of 75mm guns that were begging to be installed in the tanks. Barrel lengths (to make the best use of the ammo 'power') from 26, 34, 36, 40.8, and 60 calibers were made before ww2, while the ww2 saw the L43 and L48 sharing the same ammo, and the 46 cal (pak 40) used the ammo of similar dimensions to the L60 Flak weapon. Even the L54 weapon was made in a few dozens. Then we have the ~75mm guns from Czechoslovakia and from Poland, and, indeed, the L70 weapon for the Panther.

Still, it took Germans an eternity to move up from the short 75mm gun. Even the M36 mountain gun and the FK 18 were more powerful than the Kwk 37, with muzzle energies being some 25-30% greater.
Making a real effort to up-gun the Pz-III with a good 75mm gun would've netted the Germans with a tank comparable (if slower) to the early Cromwell, but years earlier. And a much better tank than the 75mm gunned Valentine.
(turret ring diameter was 1530 mm on the Pz-III, 1450mm on the Cromwell)

 

[Admiral Beez]

Good knows that Germans were making a whole host of 75mm guns that were begging to be installed in the tanks.

Makes me wonder just how far the 75 mm could be developed postwar.

 

[ssnider]

Makes me wonder just how far the 75 mm could be developed postwar.

The post war French 75s were a direct development of the Panther L70 gun

 

[tomo pauk]

Wrt. the Pz-II engine layout, the transversal engine installation was used on the stretched spin-off armed with the 15cm howitzer (a V8 engine was used there):
To make room for the long lower carriage [of the howitzer], a water-cooled Büssing NAG engine, the L 8 V, was installed transversely at the rear. The cardan shaft ran forward on the right side to the drive and control elements, which came from the Panzer II.
(from here)

There is really no reason for such the layout not to be used on the Pz-II very early and with it's long and slender I6 engine, as well as on the Wespe, thus freeing a lot of internal volume.

 

[Shortround6]

it would have made more sense to make a support version of the Pz III with the short 7.5cm gun (like the later Pz III Ausf N actually did)

Tanks were often space (volume) limited. Granted a lot of high command requirements (especially before the war) where based on theory and not practice.
A MK IV carried about 30-33% more main gun ammo than the MK III (after they were converted). MK IV also had power traverse. MK IV J had the power traverse deleted, picked up enough fuel storage to increase driving range by around 50%.
You would need a lot more 'support' MK IIIs to give you the same support fire power than the MK IVs. Even more ammo carriers don't quite work the same. You need to get the the tanks back to a safe/safer ammo to replenish ammo and you need to do it rotation (by platoon) if things get drawn out.
German tank doctrine may have been screwed up, but until you change that (pre-war) adding a 2nd support company (even if both are reduced a bit) to the battalion is not saving much in the way of costs of all kinds.

instead develop the Pz IV as a true next generation tank in the 30-35 ton size class.

The Pz III was too small to take the big 75mm guns. So it seems that idea is to 'blend' the Pz III and IV, which means a bigger, heavier, costly tank than the Pz III even if not as costly as the Pz IV. Not sure if total cost is actually much different. The Germans went overboard on the Panther, but they needed a 30-35ton tank in 1942, not 1940.
They got overconfident (or believed their own speeches) on superweapons.

 

[Shortround6]

Converting field artillery to tank guns just gives you a starting point, ammo, tube (sort of) and breech block. You need to come up with mounts, recoil systems, and sights.
A lot of engineering time. Pick wisely. And the bigger guns need bigger turret rings to absorb the recoil without cracking ,or being damaged. Some turrets used a small number of rollers. Much of of the recoil may be directed to just a few rollers.
SP guns are a lot easier, leave the back of the fighting compartment open and use the space to recoil into, mounts can be simple ( use all the "stuff" of the field guns, or a little conversion). Stugs used the same recoil system/s as the MK IV tanks.

 

[tomo pauk]

The Pz III was too small to take the big 75mm guns. So it seems that idea is to 'blend' the Pz III and IV, which means a bigger, heavier, costly tank than the Pz III even if not as costly as the Pz IV. Not sure if total cost is actually much different.

How about this crazy idea: ditch the Pz-III all together?
You pay a tad more (steel is cheap and air is free, but V12 engines, transmissions, cannons, radios, sights, intercoms and accommodation for 5 are not), and get a less constricted platform. While the production of Pz-IIIs picked up handsomely from mid-1940 and on, it was actually Pz-IV that was a more numerous tank during the winter of 1939/40, and was conceived a tad earlier (despite the nomenclature suggesting otherwise).

The Germans went overboard on the Panther, but they needed a 30-35ton tank in 1942, not 1940.

A 30-35 ton tank would've been nice to have in 1940, while for 1941 it would've been essential.

Converting field artillery to tank guns just gives you a starting point, ammo, tube (sort of) and breech block. You need to come up with mounts, recoil systems, and sights.
A lot of engineering time. Pick wisely. And the bigger guns need bigger turret rings to absorb the recoil without cracking ,or being damaged. Some turrets used a small number of rollers. Much of of the recoil may be directed to just a few rollers.

A muzzle brake was a standard feature on the German tanks & StuGs from early 1942 on, and it was understood piece of engineering well before ww2 started (Germans have had a muzzle brake on the M36 mountain cannon). Slap the darned thing on a good 75mm gun and Bob's your uncle.
Another benefit is that German logistics becomes a tad easier, with one ammo type to work with.

 

[Admiral Beez]

The post war French 75s were a direct development of the Panther L70 gun

You reminded me of the AMX Sherman.

 

[z42]

Tanks were often space (volume) limited. Granted a lot of high command requirements (especially before the war) where based on theory and not practice.
A MK IV carried about 30-33% more main gun ammo than the MK III (after they were converted). MK IV also had power traverse. MK IV J had the power traverse deleted, picked up enough fuel storage to increase driving range by around 50%.
You would need a lot more 'support' MK IIIs to give you the same support fire power than the MK IVs. Even more ammo carriers don't quite work the same. You need to get the the tanks back to a safe/safer ammo to replenish ammo and you need to do it rotation (by platoon) if things get drawn out.
German tank doctrine may have been screwed up, but until you change that (pre-war) adding a 2nd support company (even if both are reduced a bit) to the battalion is not saving much in the way of costs of all kinds.

I'd be fine with tomo pauk 's suggestion to skip the Pz III then and just use the Pz IV for everything initially, in case the smaller volume of the Pz III is a serious enough issue. The Pz IV was not significantly more expensive than the III anyway, add in economies of scale from manufacturing and supporting one model rather than two and it might have ended up cheaper anyway.

As for the late war Pz IV variants lacking power traverse, AFAIU that was more a desperation cost cutting maneuver when everything started going pear shaped. ~1min30s for a full 360deg traverse is better than no tank at all, I suppose, but sheesh.

And for doctrine, yes I agree. But that is kind of expected, since tanks were a pretty new weapon at the time. Early in the war the German tank doctrine was arguably less screwed up than that of their adversaries. Everybody had learnt quite a lot by 1944 about what works and what doesn't.

The Pz III was too small to take the big 75mm guns. So it seems that idea is to 'blend' the Pz III and IV, which means a bigger, heavier, costly tank than the Pz III even if not as costly as the Pz IV. Not sure if total cost is actually much different. The Germans went overboard on the Panther, but they needed a 30-35ton tank in 1942, not 1940.
They got overconfident (or believed their own speeches) on superweapons.

Seems the Pz IV was pretty marginal for taking the long barreled 75mm gun, as well. The later war Pz IV variants had issues with the front suspension bottoming out. Obviously also due to the heavier frontal armor, not only the gun, but still. So yes, they would have needed a new bigger tank for the 75L43/48 rather than retrofitting it to the Pz IV.

As for the Panther going overboard, maybe, maybe not. When it was eventually introduced, I don't think a 45 ton general purpose tank was necessarily a bad choice. But probably they'd had been better off with a 30-35 ton tank mounting the 75L48 a couple years earlier rather than the OTL Panther.

And for the later war supertanks, yes obviously more or less a complete waste of time (but hey, maybe they kept a bunch of engineers from being sent to the front..). Except for the Landkreuzer Ratte, that would surely have won the war all by itself.

 

[tomo pauk]

The Germans went overboard on the Panther, but they needed a 30-35ton tank in 1942, not 1940.

As for the Panther going overboard, maybe, maybe not. When it was eventually introduced, I don't think a 45 ton general purpose tank was necessarily a bad choice.

If Panther offered an all-around armor protection like the KV-85 or IS tanks did, then it would've been really a great tank. (Un)fortunately, sides were every bit as vulnerable as it was the case with the Sherman or T-34 of the time, while the Panther represented a rewarding target to shoot at, and it was not as fast and easy to manufacture as these two tanks (= shortcomings of a heavy tank). Greater weight also meant that any corner-cutting measure will backfire in service, even before the chance to fire at enemy. Vehicles to tow it - again, one cannot use the stuff that is not well-dimensioned to do it, and these don't come in cheap.
Roof armor was very thin, 16mm.

The gun chosen was light and compact for the AP performance it offered, but it meant that a whole new gun and ammo needs to be designed and manufacture; ammo was not compact anymore, as it was the case with the gun Pz-IV used, the barrel life was bad, a consequence of the big propellant weight (30-50% more than on the Tiger's gun for AP shots) and the high MV. At the end of the day, the known 88mm did that job as good, it was with the better HE abilities, and with triple the barrel life. Redesigning the Tiger's gun to be a bit more compact would've probably been a good thing to do, so it is as compact as the Soviet 85mm gun?

 

[z42]

If Panther offered an all-around armor protection like the KV-85 or IS tanks did, then it would've been really a great tank. (Un)fortunately, sides were every bit as vulnerable as it was the case with the Sherman or T-34 of the time, while the Panther represented a rewarding target to shoot at, and it was not as fast and easy to manufacture as these two tanks (= shortcomings of a heavy tank).
Greater weight also meant that any corner-cutting measure will backfire in service, even before the chance to fire at enemy. Vehicles to tow it - again, one cannot use the stuff that is not well-dimensioned to do it, and these don't come in cheap.
Roof armor was very thin, 16mm.

Didn't mean to imply that I think the Panther was perfect. Just that for a general purpose tank entering service in 1943, a target weight in the 40-45 tons might not be a bad idea. As for towing, bridge equipment etc., as their previous generation tanks (Pz III and IV) were in the 20-25 tons range, a new 30-35 ton tank would require new such supporting equipment just like a 45 ton one would. As the upwards trend in tank sizes showed no signs of slowing down at that point, might as well leapfrog the 30-35 ton generation and go for 40-45 tons. As they were going to be outnumbered no matter what, a qualitative advantage for their new 'standard' tank vs. the hordes of T-34s and Shermans coming their way would have been useful.

As for why the Panther had, for it's weight, relatively poor armor except on the frontal arc, surely the humongous hull needs to take some of the blame? A lower profile hull with a rear mounted transmissions, and ditching the bow gunner, could have saved quite a lot of weight. But switching to a transverse gearbox design and mounting it in the rear might not have been feasible in short order at the time.

The gun chosen was light and compact for the AP performance it offered, but it meant that a whole new gun and ammo needs to be designed and manufacture; ammo was not compact anymore, as it was the case with the gun Pz-IV used, the barrel life was bad, a consequence of the big propellant weight (30-50% more than on the Tiger's gun for AP shots) and the high MV. At the end of the day, the known 88mm did that job as good, it was with the better HE abilities, and with triple the barrel life. Redesigning the Tiger's gun to be a bit more compact would've probably been a good thing to do, so it is as compact as the Soviet 85mm gun?

I'd be fine with a compact variant of the Tiger gun shooting the same ammo as the Tiger's 88L56. Probably still more expensive than the 75L70 gun and ammo, but OTOH reducing the number of calibers in service brings benefits as well. And indeed as you say, significantly better HE capability as well as better barrel life.

 

[cherry blossom]

I am not sure if the panther was as expensive and hard to build as some posters seem to imply. Figures at other fora suggest 117,000 RM for a Panther against 103,000 RM for a Panzer IV and also only slightly more man hours than a Sherman, 55,000 against 48,000 https://ww2f.com/threads/tank-costs-£.30374/, Man hours and tank production – SU compared to Germany - Axis History Forum. The problem with these figures is the well known question of what is included.

 

[Shortround6]

A few points.

While the production of Pz-IIIs picked up handsomely from mid-1940 and on, it was actually Pz-IV that was a more numerous tank during the winter of 1939/40, and was conceived a tad earlier (despite the nomenclature suggesting otherwise).

That may have been doctrine and not related to actual production capacity, or related as much. They seem to have done fairly well with the MK IV design from the start. In part because it was 18-19 ton tank from the start. But even at 20 tons (D model) it only had 30mm armor at the front and 20mm armor on the sides, earlier MK IVs were even thinner. The Early MK IIIs (A-D) were 16 ton tanks with 15mm armor. They also were built in small numbers, perhaps because they were not happy with the suspension (changed 3 times) the transmission (or performance (also changed 3 times) and there was the argument between the tank guys (we want a 50mmgun) and the regular army supply guys (37mm gun/ammo is cheaper and is common with the infantry for easier logistics). Perhaps due to shorter hull the MK III had 30mm side armor on the E model (Dec 1938?) MK IV didn't get 30mm side armor until the F model of April 1941 (maybe my old source book is wrong?) Building lots of early versions they didn't like or were experimenting with might not have been smart.
One book claims the 37mm gun weighed 195kg. This may be for the complete gun and not just barrel and breechblock. The short 50mm was 223kg, the log 50mm was 305kg and the short 75mm was 285kg. It is not just a question of the weight of the gun, If you are using a nearly 300kg gun instead of a 200kg gun you need better (larger/heavier) elevating and traverse mechanisms or perhaps go to power traverse (but see later) the larger turret ring and other knock-on effects.

Another benefit is that German logistics becomes a tad easier, with one ammo type to work with.

True but in 1939/early 1940 there was not quite the logistics nightmare there would be later.

As for the late war Pz IV variants lacking power traverse, AFAIU that was more a desperation cost cutting maneuver when everything started going pear shaped. ~1min30s for a full 360deg traverse is better than no tank at all, I suppose, but sheesh.

You are quite right, it was cost cutting maneuver, or supply problem (copper for the electric motor). But it does illustrate the volume problem. The fuel tank that replaced the traverse system was 200 liters. Most earlier MK IVs held 470 liters. There was never enough room for everything inside the tank. Until an army had seen a fair amount of combat judging was truly important vs just nice to have had room for error.
On the Panther, trying to hold just about the same ammo (80 rounds vs 87?) of the much larger ammo means you need a larger hull.

Increasing the mg ammo storage by about around 60-66% didn't help (around 3000 rounds to around 5000 rounds) In US terms that is 10 of familiar 200 round ammo cans. Not that bad in itself but with everything else that needs to fit in?

 

[tomo pauk]

On the Panther, trying to hold just about the same ammo (80 rounds vs 87?) of the much larger ammo means you need a larger hull.

Panther's ammo was wider at the rim, 122 mm vs. 111 for the Tiger. Or, the area of the case bottom was ~20% greater. So stacking 80-90 of either might've result in the Panther's ammo needing greater volume than the Tiger's ammo.

You are quite right, it was cost cutting maneuver, or supply problem (copper for the electric motor). But it does illustrate the volume problem. The fuel tank that replaced the traverse system was 200 liters. Most earlier MK IVs held 470 liters. There was never enough room for everything inside the tank. Until an army had seen a fair amount of combat judging was truly important vs just nice to have had room for error.

Perhaps not using diesel fueled engines on their tanks was one of bigger mistakes that Germans made? Not only that one gets the better mileage, but the external fuel tanks are an actual thing to do, and not some disaster waiting to happen.
FWIW, here is what the Japanese did back in ww2 for their tanks (can be easily translated): link. The Soviet experience about the diesel engines is well known.