# Why did Germany build Panzer I and Panzer II light tanks?



## davebender (Oct 8, 2011)

*Historical timeline.*
1933 to 1935. Sd.Kfz.11 3/4 track prototypes. Size was 6 to 7 tons.
1933. Heer orders development of Panzer I. Target size was 4 to 7 tons.
July 1934. Heer orders development of Panzer II.
Jul 34 to Jun 36. 818 Panzer I ausf A produced. ~38,000 RM each.
1935. First Sd.Kfz.11 3/4 track production model. ~20,000 RM each.
1935. Heer are so pleased with the Sd.Kfz.11 that they order an APC variant. This becomes the Sd.Kfz.251.
1937 to 1940. 1,113 Panzer II ausf C produced. ~50,000 RM each.
1938. Development of Sd.Kfz.11 and Sd.Kfz.251 3/4 tracks taken over by Hanomag.
.....From this point the program advances more rapidly.
1939. First Sd.Kfz.251 3/4 track production model. 22,560 RM.
1940. 337 Sd.Kfz.251 3/4 tracks produced.
1941. 424 Sd.Kfz.251 3/4 tracks produced.
1942. 1,200 Sd.Kfz.251 3/4 tracks produced.

*Sd.Kfz.251 3/4 Track.*
Crew of 2. Plus an infantry squad or other payload.
~7 tons empty. ~8.5 tons loaded. Depends on variant.
Frontal armor 8mm to 15mm. Armor was increased based on combat experience.
8mm armor on sides and rear.
.....All armor is nicely sloped. 
Tracks have torsion bar suspension and run most of the vehicle length. Hence the term "3/4 Track" rather then half track.
.....Relatively low ground pressure and good suspension makes for exceptional cross country mobility.
.....Tracks can steer vehicle even if front tires are shot out. This increases survivability in combat.

- The Sd.Kfz.251 3/4 track can easily carry weapons more powerful then Panzer I and Panzer II main guns. 
- With 15mm frontal amor the Sd.Kfz.251 is arguably better protected then early war Panzer I and Panzer II.
- Sd.Kfz.251 suspension is superior to Panzer I and Panzer II suspension. Better ride and superior off road mobility.
- The Sd.Kfz.251 is less expensive then a Panzer I and less then half the price of a Panzer II.
- Overhead protection can be added if desired just as Czechoslovakia did with the OT-810 variant.

So why did Germany build Panzer I and Panzer II light tanks? Give the Sd.Kfz.251 program additional resources and I think they will be rolling off assembly lines in large numbers from 1936 onward. The Sd.Kfz.251/9 should be the initial production version. This carries a 7.5cm/24 main gun with 52 rounds of ammunition. It cannot fight medium tanks but should work fine vs light tanks and for infantry support. 

Meanwhile Panzer III and/or Panzer IV programs proceed as they did historically. When larger tanks are available in numbers the Sd.Kfz.251 reverts to being an APC, weapons carrier and tractor for towing the 10.5cm howitzer.


----------



## Readie (Oct 9, 2011)

davebender said:


> *Historical timeline.*
> 1933 to 1935. Sd.Kfz.11 3/4 track prototypes. Size was 6 to 7 tons.
> 1933. Heer orders development of Panzer I. Target size was 4 to 7 tons.
> July 1934. Heer orders development of Panzer II.
> ...



Maybe the Nazi's wanted machines to cover all eventualities and possible campaigns?


----------



## davebender (Oct 9, 2011)

What eventualities can the Panzer I and Panzer II cover that the Sd.Kfz.251/9 cannot for half the production cost?


http://www.sdkfz251.com/images/armour_II_015.jpg






If mid 1930s Germany wants a full track light tank why not just add another pair of road wheels to the Sd.Kfz.251 track system? That's about all it would take to extend the tracks over the entire vehicle length. The system for steering with the vehicle tracks was already in place.


----------



## razor1uk (Oct 9, 2011)

Panzer I II were to my knowledge, mainly for learning, teaching and developing tank... tactics, industrial skills/knowledge, crews, maintainance operational army details/orders/specs etc. 
The Brits had done much work on tankettes like Vickers for instance - one of the universal/internationally exported tanks, used by most other nations post mid 30's as a jumping off point for their own more modern (non WW1 styled) tankettes/tanks.

Before the end of WW1, Germans only had a few captured tanks Mothers and Fathers, Whippets and an odd Renault FT17's and their own abysmal A7, and to develope the Panzer 3's and onwards, they had to start from somewhere... considering they came practically from scratch with tech knowhow pooled in from UK, Sweden, Switzerland, USSR etc, hence the Panzer 1's 2's.


----------



## davebender (Oct 9, 2011)

Learning what? What will armored vehicle crew and mechanics learn from the Panzer II that cannot be learned from the Sd.Kfz.251?

- Sd.Kfz.251 had a superior track system.
- Sd.Kfz.251 had a superior armor arrangement that was nicely sloped all around.
- Sd.Kfz.251 was probably more reliable.
- Sd.Kfz.251 was ready for mass production as soon as the Panzer II but at less then half the cost. With a higher program priority it could probably have been in mass production even earlier.

Want a light tank with a 2cm autocannon in a revolving turret? Nothing prevents a turret from being mounted on the chassis ILO the troop compartment. Historically there were about two dozen Sd.Kfz.11 / Sd.Kfz.251 variants. This would be just one more built on a common chassis.

Hanomag had plenty of experience building tracked vehicles.
http://www.farmphoto.com/thread.aspx?mid=299280




The Hanomag WD Z 25 was the first Hanomag crawler tractor which went in production. After a prototype WD Z 20 in 1919 went the WD Z 25 in 1920 in production. A few years later they also introduced the 50 HP WD Z 50 crawler.


----------



## tyrodtom (Oct 9, 2011)

OK, no matter what reason anybody gives, you're going to shoot it down.

We're all dieing to know what do you think the reason is ???


----------



## razor1uk (Oct 9, 2011)

I give up dave, you understand so much more, are always so friendly and approachable, and always willing to listen with measured responses..

The Hanomag has a few whippet features - the mud trough and roughly equal for aft track angles (for climbing over obstacles), front mounted engine (itself; the engine, was the only more modern part of the design) within the Hanomag..

ok heres an anology you might understand.
You begin to train a American Football team, teaching them how to move around in their equipment, what tactics they could use which ones not to, they train endlessly for months, getting all the things they've come up with together well learned, as 2nd nature to them - confident and beleiving in their abilities. 
But come the play time of the season, they have to play Ozzy Rules and ditch all the Amefto equip... they ain't gonna do so well, even if they can use some of the same stratergies.

So the Panzer arm of the army is going to develope, learn teach; manouvers, tactics, maintainance, combat theory develope them/those towards blitzkrieg, with only just the half tracks rather than full tracked vehicles and their particular mobility pro's con's, while creating Panzer arm ethos, confidence and esprit d'corps...


----------



## psteel (Oct 9, 2011)

Germany tried to purchase/build 287 tanks at the start of the 1930s, but the funding for the Panzerschiffe gobbled up the funding. The German Defense programme of the day, allowed violation of the Treaty of Versailles’s, provided they it could be concealed or disguised . This tank contract would have been for the Grosstraktor and Leichtertraktor which began their development in 1927 as "Armeewagen 20". The Neubaufahrzeug 12 followed this in 1932. The second rearmament drive had authorized the development of Panzer Kompanies within 5 years [1933] and during this time 150 training tanks were ordered since these would be difficult for the allied commission to detect. This in turn became the Kleintraktor, which became the Panzer I. This whole process took something like 7 years to reach fruition, while the initial discussions for a APC began in 1935 , the funding and agreement didn't materialize until much later. The SPW prototype development didn't begin until 1937 and production didn't begin until 1939.


Pretty sure the prices previously quoted are war time costs not prewar costs. From what I remember, the prewar tanks cost about 150,000 Rm each.

Something else. Most tanks had rear-mounted engines with forward drive and transmissions. This is supposed to give good balance when a centrally mounted turret is installed. The SPW has front mounted engined drive and transmission, which could create heavy ware problems on the front suspension and ware. Does any one know the ground pressure of the SPW vs Pz-I? That indicates growth potential.

From what I can determine SPW ground pressure was 0.8kg/cm², while the Pz I was 0.4 kg/cm². Even if you can stretch the SPW 251 from 3/4 to full, this would likely just drop the ground pressure to 0.6kg/cm². So the Pz I has greater growth potential. Another point would be steering. Tanks steer by tracks rotating in opposite direction, while Half-tracks steer by the front wheel steering.


----------



## Readie (Oct 12, 2011)

Well dave, what is your considered opinion?


----------



## Shortround6 (Oct 12, 2011)

A few "minor" considerations here.

1. a rather confused time line. Pz I was ordered into production when they were still futzing about with the half track prototypes. which means MK I prototypes and tests were already completed. Waiting for hal tracks would dealy the training program by several years.

2. The same only not so bad for the MK II. 

3. the MK II tank had 15mm armor (or close to it) all the way around not just on the front. Changing 8mm armor to 15mm armor costs about 11lbs per sq ft of armor and there are a lot of square feet on one of those half tracks. The Half track is a much larger target. 

4. Part of the reason people use tanks is cross country ability and obstacle crossing, What height vertical wall can the MK II handle vs the half track? IS there a difference in hill climbing even at walking speeds? which can turn in a smaller area? There is a lot more to "cross country" than just ground pressure and ride speed across a field.

5. Rotating turrets and turret rings are expensive. Wasn't a Stug supposed to be 30% cheaper than a tank? 

6. The Sd.Kfz.251/9 was a self propelled gun. It's gun had limited traverse, great fire support, not so good for being in the thick of an attack. Many Sd.Kfz.251/9 were armed with guns taken from MK IVs as they were up gunned, earlier production of the Sd.Kfz.251/9 involves the prodcution of more 75mm/24 guns sooner at what cost? they are no longer "free". 

7. speaking of cost, does the cost of the MK II tank include the cost of the 2cm gun or not? How about radios?


----------



## Readie (Oct 12, 2011)

Shortround6 said:


> A few "minor" considerations here.
> 
> 
> SR6,how with the esteemed Mr B answer your points when he cannot answer the basics?
> ...


----------



## davebender (Oct 12, 2011)

Panzer I production ended during 1937. Panzer I neuer Art prototypes produced during 1938 to 1943 were new designs for all practical purposes and none were mass produced. That doesn't strike me as growth potential. 

The Sd.Kfz.11 / Sd.Kfz.251 was produced in over two dozen variants with new versions introduced right up to the last year of the war. That's serious growth potential from the mid 1930s onward.

Rear engine tanks are more common but not necessarily superior. The front engine Merkava tank is arguably as good as the U.S. made M1A2 and German made Leopard II.


----------



## CharlesBronson (Oct 12, 2011)

The reason is simple, training, the Panzer I was never planned to be a frontline tank.


----------



## psteel (Oct 12, 2011)

Dave the point I was trying to make about the drive system is that to make a SPW into a fully tracked AFV system you'd increase weight with roof and enlarging the suspension from ¾ to full track. This is likely to push mass up to 9-10 tons and ground pressure up to ~ 0.7kg/cm². Add a small 20mm gun turret and the mass is over 10 tons with the ground pressure up to ~ 0.8kg/m². Also I know you understand that unit costs are tied to production numbers. Had the Panzer I been produced in the numbers of the Zg 3 ton and SPW 251; it would have been cheaper, similar to a fully tracked SPW AFV.

BTW the Pz I was in production into 1938 through the Instansetzungswagen model. According to the Osprey SPW 251 booklet the APC competition was between a all terrain truck a fully tracked AFV and the semi tracked vehicle based on the Zg tractors. However this book does indicate the SPW track system was similar to tank suspension systems and allowed the SPW pivot steering similar to a tank.

Mind you a better comparison should be done between the Pz II and the SPW-251 [3 ton Zg tractor] . According to Jentz the Pz IIb model with 20mm gun turret [180 rounds plus MG] was 7.9 tons and had 14.5mm frontal armor, while the ground pressure was around 0.65 kg/cm². This design was upgraded to C model with 20mm added to the frontal armor increasing the mass to ~8.9 tons and ground pressure to 0.73 kg/cm². The down side was it reduced top speed, but only by 0.5 kph.

Given the importance of tanks to the German doctrine I would have thought that industry devoted to the lighter Zg tractors should have been turned over to producing 9-10 ton tanks. These could include license production of the Pz 35/38t followed by wartime-massed conversion to Marder type SP ATguns, through out the war. Its clear from resent research papers that it was prolonged production of the same weapons systems, based on ‘fixed price contracting’, that was the essential element in Germany mass production boom of the later war years.


----------



## vanir (Oct 19, 2011)

If they were indeed following Guderian's doctrine then the Army had a requirement for a scout tank (PzII), an MBT (PzIII) and an assault/infantry tank (PzIV). In addition PzGr mobile-armoured infantry needed assault SPG and APC.

The PzI was a training vehicle, it fitted Treaty restrictions so that military upscaling could be started before the Treaty was formally violated. The PzII/III/IV were illegal at that stage and produced in factories disguised as tractor and truck factories. When Swiss officials were paid to warn of treaty inspections and the tanks were covered up, the trucks moved into their places, took a few days to hide a tank factory.
The PzI though, they could train with openly. Before it they used cardboard mockups on bicycles. I realise there were already treaty violations but it wasn't formally scrapped until the Czech debarcle.

You saying they should've kepts the bicycles? PzGr formations needed APCs and SPG.


----------



## psteel (Oct 20, 2011)

I think the point Dave was getting at is how much more could have been achieved had Germany channeled Pz I and II production into expanded SPW production and built that into a light tank instead.

Most historians seem to gloss over the fact that, Hitler convinced his Generals [and Admirals] that German would not have to fight a major European war until they would be ready in the mid 1940s, so they still had plenty of time. Basic German risk theory always recognized that Germanys neighbors would not sit idly by and just let her rearm. So any rearmament programme had to be as secret as possible and built around an expectation of imminent war along the lines of WW-I. 

But Hitler ignored all this and gambled Germanys future away based on his misguided racial view that the war going to be a 'do or die' struggle between German/Europe and a Jewish led America/allied threat. He believed he could crush Russia and bully the UK into joining a grand alliance against America. After Munich he believed nothing could be gained by waiting and the major European powers were too weak to prevail against Germanys racial superiority.


----------



## davebender (Oct 20, 2011)

Were half tracks illegal under the treaty restrictions?


----------



## mikewint (Oct 20, 2011)

One point that I have not seen brought up is National Pride: i.e. We have REAL tanks just like everyone else, not just converted farm tractors/half-tracks. This was a German driving force throughout the war, the quest for the Super Weapon that would demonstrate German superiority to the entire world.
Look at the latter war period. Why make the Tiger series? The Panthers were very serviceable tanks which could have done much better and perhaps been a deciding factor except the Germans turned more and more to the super heavies like the I and II and the Maus which drew money and resources into a futile effort while the US just kept churning out the inferior Shermans and refused to "play fair" and go 1 on 1 with the Tigers


----------



## tomo pauk (Oct 20, 2011)

Tiger I preceded Panther, and it was not until 1944 that Panthers were reliable. 
I do agree that Germans were giving their 45+ ton tanks too much attention resources, while neglecting the simpler lighter AFVs.


----------



## davebender (Oct 20, 2011)

The Pz I does not meet my definition of a real tank anymore then a SPW 251. Similiar weight, similiar armor and both armed with a 7.92mm MG.

The Pz II is a different story.


----------



## mikewint (Oct 20, 2011)

Tomo, thanks, i did indeed oversimplify my timeline. the Tiger I was a typical German response, i.e. if they're punching holes in 25mm increase to 50mm, if 50mm doesn't work increase to 100mm but modify nothing else so the slab-sided I resist by sheer brute force growing heavier and heavier. Come the Russians and the lightbulb goes on: let's slant the armour. the Panthers certainly had their teething problems but how much more quickly could those have been solved except for the drain caused by the Supertank approach.
Dave, what is a tank? were the jagd panzers, sturmgeschutz, Marders tanks? The Pkz I was at least a dedicated tracked vehicle, an engineering stepping stone to the next development as the Wright flyer was to the WWI planes was to the WWII planes


----------



## Denniss (Oct 20, 2011)

Don't forget the different army branches, the Panzer I/II were, without questions, tanks and belonged to the Panzertrupper, supervised by General der Panzertruppen. The 250/251 always belonged to the infantry. Also the tanks wer designed with large flat armor plates for easier applying additional armor, the 250/251 was merely a truck covered with some stronger metal plates for minor armor protections. These surfaces were not really flat thus increasing armor was not easily done.
Do you know the StuG III/IV? They belonged to the artillery branch but once they were equipped with the long gun the Panzertruppen sought to get them under their control but this failed/was denied. The Jagdpanzer IV was originally designed/named "Sturmgeschütz neue Art" and would have gotten under artillery control as well but this was worked-around via redefining them as Jagdpanzer thus it came under control of the Panzertruppen.


----------



## mikewint (Oct 21, 2011)

The only thing I can think off to delineate a TANK from all the rest is a turret


----------



## tomo pauk (Oct 21, 2011)

mikewint said:


> Tomo, thanks, i did indeed oversimplify my timeline. the Tiger I was a typical German response, i.e. if they're punching holes in 25mm increase to 50mm, if 50mm doesn't work increase to 100mm but modify nothing else so the slab-sided I resist by sheer brute force growing heavier and heavier. Come the Russians and the lightbulb goes on: let's slant the armour. the Panthers certainly had their teething problems but how much more quickly could those have been solved except for the drain caused by the Supertank approach.
> Dave, what is a tank? were the jagd panzers, sturmgeschutz, Marders tanks? The Pkz I was at least a dedicated tracked vehicle, an engineering stepping stone to the next development as the Wright flyer was to the WWI planes was to the WWII planes



Well put about Pz-I (and it's close relative, Pz-II) being a stepping stone in German tank development. No Pz-I - no Pz-III/IV etc?
As for Panther's issues being ironed out, the Soviets have their issues with anything heavier than 20 tons, too, and it took them years to sort those out.


----------



## davebender (Oct 21, 2011)

Why can't the Spw251 chassis be the light tank stepping stone? It can easily accomodate a 7.92mm MG or 2cm autocannon in a revolving turret.


----------



## psteel (Oct 21, 2011)

Time lines are not compatible. Discussions development of the heavy Zg traktors began in 1932, while development of the lighter 1 ton and 3 ton traktors followed a couple of years later. Which means any SPW could not begin development until after [1935-37] which production after that time. Pz I was developed from the Krupp experimental LSK chassis, which was developed in 1928-30 and was further developed into the LAS prototype from 1932-33, which became the Pz-I that entered production in 1934. That’s production in 1934 vs 1938.

Guderian’s Panzer concepts were still new at this time and would not pick up steam for a few years, so there was no need for a SPW prior to that time line. On the other hand there was a need for 'mechanized gun' concepts that were articulated and experimented through the mid to late 1920s. Infact proof of concept models were quickly adopted during the first rearmament drive from 1928-1932 in the form of hundreds of WD Schlepper [77mm gun 37mm gun]. The Army followed this up with a proposal to adapt the LSK prototype into a "Schlepper" for the 77mm gun, which was tested through 1932, just in time for the second rearmament drive [1932-38].

What’s important to understand here is that the Ministry of Defense authorized the expansion of the Reichmarine to 150,000 personnel in 1928 and added 11 reserve infantry divisions under the 1st rearmament drive[1928-1932]. Under the second rearmament drive, these 21 divisions would become the active divisions with a reserve field army of 63 divisions plus the creation of a number of panzer Kompanies [12-18?]. When Hitler took over in 1933 the Wehrmacht demands ballooned ,so that only a couple of years later, they were demanding 36 active divisions plus a field army of 83 divisions. Against this back drop, the need for AFV increased geometrically. Even as late as Guderian’s "_Achtung Panzer_", he is accepting that his 'Panzer battle groups' may have to make do with motorcycle recon/motorized infantry Guns etc in the short term.

The first proposed TOE for panzer divisions in 1934/35, included tanks and SP howitzers plus armored cars as the only AFVs.

Sources 
Spielberger. "Sturmgeschutz its Variants"
Spielberger. "Halftracked Vehicles of the German Army 1909-1945"
Jentz "Panzer Truppen"
Chamberlain Doyle. "Encyclopedia of German Tanks of World War Two"


----------



## vanir (Oct 21, 2011)

psteel said:


> I think the point Dave was getting at is how much more could have been achieved had Germany channeled Pz I and II production into expanded SPW production and built that into a light tank instead.
> 
> Most historians seem to gloss over the fact that, Hitler convinced his Generals [and Admirals] that German would not have to fight a major European war until they would be ready in the mid 1940s, so they still had plenty of time. Basic German risk theory always recognized that Germanys neighbors would not sit idly by and just let her rearm. So any rearmament programme had to be as secret as possible and built around an expectation of imminent war along the lines of WW-I.
> 
> But Hitler ignored all this and gambled Germanys future away based on his misguided racial view that the war going to be a 'do or die' struggle between German/Europe and a Jewish led America/allied threat. He believed he could crush Russia and bully the UK into joining a grand alliance against America. After Munich he believed nothing could be gained by waiting and the major European powers were too weak to prevail against Germanys racial superiority.



Yeah good point, but the demag was already used for this as opposed to the hanomag, right alongside the scout tanks as a radio vehicle or SPG. They wanted tanks, ideally the Pz38 czech jobs with the good suspension and 37mm sköda gun (best prewar light/field antitank gun, some German antitank squads still used heavy rifles in 42).

To some degree the industrial logistics must tailor supply for their military's specifications on the basis of request. They won't always agree, but the military works better that way.

As we all know the PzI only entered line service due to production shortages, the way I heard it in the low countries half the scout tanks were PzI whilst Pz35 mosty were used to supplement PzIII. There was a shortfall in both PzIII and IV large tanks but it was muted by the tactics used, the full commitment of German forces at finite locations and a bit of luck.

Demag production could've been geared up but Hanomag production was already maxing out because it couldn't fill the orders it had. Everybody wanted them as an APC, a military tractor and an armoured utilitary vehicle, not to mention the subvariants. The old 6 and 8 wheeler armoured cars needed replacement, artillery needed the other half tracks for tractors, Germany had a superpower military with small nation industry, half the entire infantry force according to logistical records and personal photos in 1941 were still equipped no differently to the Kaiser's troops thirty years earlier, complete with wood wheeled carriages pulled by horses and oversize rifles you go hunting bears with, not urban warfare. That was the amazing technicolour dreamcoat that was the true German war machine.

The mistaken belief the Wehrmacht was on the whole technology superior to anyone is ridiculous, all history has ever talked about on that score is local superiority gained by concentrating your best forces and any reinforcements you can muster, most of it related to industry.
Germany couldn't equip all its formations with current basic materiél, how could it possibly choose logistical supply besides "just send us whatever you've got"?


----------



## vanir (Oct 21, 2011)

It should also be mentioned that during 1942 Germany completely reorganised its Panzer warfare doctrine, and the Soviets reorganised their entire air force structure and doctrine.

By this time the PzII was reinforced to at least 50mm front armour and alongside Pz38 made pretty good scout tanks, the PzII is so much like a tankette even with skinny tracks it has very good mobility, like a T-70. The Pz38 is much better equipped to fight T-70 though, but scout tanks usually fight armoured cars or infantry.

The Panther armoured car was on the way, that was a huge bonus because it was more mobile in the Russian mud season than a PzIII and armed better than armoured cars. There were more demags and hanomags, there were those little halftrack bikes (often used as aircraft tractors), Pz35/38 got handed over to scout tank formations, production of Pz38 continued in German hands, PzIV now supplemented PzIII which were upgunned and given wider tracks.

But this was all prelimenary to receiving Tigers to replace the PzIV, which was under development. But around Oct41 another spanner got thrown in the works because they met the T-34. The Panther tank was drawn up to replace the PzIII which proved inadequate in tank vs tank against T-34 or KV-1. And only a high velocity 75mm at close range takes down a KV-1.

In other words the whole Panzergruppen update program got shoved back another couple of years before becoming a superior tank force. And the war got in the way.


----------



## davebender (Oct 23, 2011)

> Hanomag production was already maxing out because it couldn't fill the orders it had. Everybody wanted them as an APC, a military tractor and an armoured utilitary vehicle, not to mention the subvariants.


That says a lot about how good the hanomag design was. Germany produced something like 25,000 Hanomag vehicles (including all variants) and probably could have used four times that many.


----------



## vanir (Oct 24, 2011)

That and the fact in remained in production through the sixties, and front line service through to the 80s in some Euro countries. It was an epic design, that and the Hetzer.


----------

