Panther tank keeps original weight

wiking85 said:

Entirely new mechanics and IIRC a new more powerful engine, while also having to upgrade the front suspension due to the weight increase and imbalance at the front caused by twice as much armor to the front as the rear. There might have been something to balance the weight toward the back. It wasn't just a simple armor adjustment.

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What you say may very well be true but the excuse of the extra armor doesn't hold up and the people who propose "what if" the Panther had kept a 60mm front plate are whistling in the dark.

What engine was proposed or planned for the 60mm armor version? The First 250 Tiger tanks got an aluminium block HL 210 engine instead of the iron block HL 230 but the HL 230 is basically a bored out HL 210, weight difference is?

SOme people want to blame Hitler (or somebody) for the 10 ton weight increase instead of accepting the fact the Panther was never going to be a 35/36 ton tank given it's size unless a lot of the armor was reduced in thickness.
No other production tank engine came close to giving the needed power.
New "mechanics" means??? New transmission and steering gear? Was going to be needed anyway and not due to a 1 ton increase in armor weight.
Armor was already 50% thicker on the front than on the back and due to slope the front armor was well over 50% heavier to begin with.

It would seem the frontal area was larger than the rear due to the layout, which increased the weight to the front more.
Plus the under/over of the hull was thicker than advertised with 85mm for the over and 65mm for the under part, both more than the original spec. The front half of the bottom armor was doubled to 30mm from 16mm The original engine was supposed to be the HL210, but the increase from aluminum to steel would up the weight. Don't know that the weight difference was though:
https://en.wikipedia.org/wiki/Maybach_HL210

Shortround6 said:

That is the common excuse but it doesn't stand up very well.

Steel weighs 40lbs per square ft for a 1 in thickness. As a rough measure 20mm is 80% of 1in (25.4mm) or 32lbs per square ft. A chunk of armor 6.435 ft wide (distance between the tracks) and 10 ft high (roughly figuring 5 feet from hull floor to hull roof, I can't read the numbers in drawing and doubling the height for a 60 degree angle (not 55) gives a weight of armor of 2059lbs. Doesn't count the wings/triangles over the tracks counts the lower front plate.

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They didn't use just steel, but rather a heavier alloy with nickel, tungsten, molybdenum, and manganese.
https://en.wikipedia.org/wiki/Panther_tank#Armor

As the war progressed, Germany was forced to reduce or no longer use certain critical alloy materials in the production of armor plate, such as nickel, tungsten, molybdenum, and manganese; this resulted in lower impact resistance levels compared to earlier armor.[53] Manganese from mines in the Ukraine became unavailable when the German Army lost control of this territory in February 1944. Allied bombers struck the Knabe mine in Norway and stopped a key source of molybdenum; other supplies from Finland and Japan were also cut off. The loss of molybdenum, and its replacement with other substitutes to maintain hardness, as well as a general loss of quality control resulted in an increased brittleness in German armor plate, which developed a tendency to fracture when struck with a shell. Testing by U.S. Army officers in August 1944 in Isigny, France showed catastrophic cracking of the armor plate on two out of three Panthers examined.[54][55]

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And the difference in weight per cubic foot or per cubic in is what???

US Navy specified some armor thicknesses in by weight. As in 20lb bulkheads (1/2in) or decks or gun tubbs, etc. 15lb plate was 3/8 in. Adding a few percent of nickel or other alloying agents is only going to change the weight a few percent.

I have worked on the frontal area a bit more and the hull was 1850mm wide between the tracks and 1330mm high from hull floor to roof top. Doubling that for a 60 degree angle ( I can't be bothered to figure how much less it is for 55 degrees) gives 2660mm or 8.73ft. Times 6.07 ft for the width gives about 53 square ft. the "wings" over the track when added together ( and assuming a 45 degree side angle to make things easy) make a plane 1060mm wide and 430mm high (doubled to 860mm due to 60 degree angle) for another 9.8 sq ft. 62.8 square ft times 32lbs is 2009lbs. Please note that this counts the lower plate as 80mm thick and not it's actual 60-65mm and plates at 55 degrees will be a bit shorter than plates angled at 60 degrees. So this is sort of worst case. but changing the lower front plate from 60mm to 65mm gains what? 8lbs per square foot?

Maybe the turret gained a bit of weight too but obviously even changing things by 300-500lbs doesn't come close to the 10 ton gain in weight (just how much heavier do you need to make torsion bars to handle the extra load? or how much heavier are the road wheels?

While the iron HL 230 weighs more than the Aluminium HL210 the Aluminium one had some problems and in any case the heavier engine in the back should help balance the extra armor in the front.

but changing the lower front plate from 60mm to 65mm gains what? 8lbs per square foot?

Informative and stirring thread so far, without it going in circles yet either , wasn't the most of the early panther running gear - steering transmission and reduction drive gearboxes from the PzkfwIV? which mere mostly 'subservient country' slave made - hence some early reliability problems with them trying to drive a tank that was near enough double their original design weight limit from the IV - and those IV reduction drive gearbox units were based upon the III's?!?

I think if the Germans had made the track treads a bit wider between links (not as much russian wide in length per link), they would still have had a smooth ride without so many pins, bushes, links and locking grubs screws, saving much weight, and stresses from the running gear loadings and unsprung weight while increasing power to weight ratios, possible improving the ground area to weight figures even if the links were a bit longer giving slightly less ground area per track, or been used to make the links wider for improved lower ground pressure mobilty at similar weigtages?

Looking at the tanks of that era, the Germans had the most links per track than any other country, which when coupled with adequately matched torsion bar susp'n gave a smoother ride and additional track to surface obstacle grip/mobility, at the cost of extremely heavy tracks - which depending on running speeds. could aid or hinder the susp'n and the track ability to stay 'in place' on/in its wheels.

Akin to the early 2000's shared body shaped Jag Aston Martins DB7/9's that when at roughly 62mph (or 72mph) the front wheels would briefly 'resonate' and bounce upwards with their susp'n arms due to wheels not being light enough - making them heavier worsened the steering's feel and made the grip more ponderous and switchable from over to under steer let alone the increased rate of wearing out of the front tyres that'd ensue - the problem was solved if you bourght their/some carbonfibre wheels - so I remember my automech head uni lecturer saying ...all alllegedly of course.
I allegedly don't know if this is still a problem with the DB7/9 nowerdays, likely still is at specific constant speeds unless you go for improved racing susp'n units or Electronic Active Susp'n ones and or with lighter wheels. ... ahem, sorry I digress, and now, back to tanks.
[cue the sound of hatches closing, engines starting and a round being loaded.]

An interesting weight comparison between models:
https://de.wikipedia.org/wiki/Panzerkampfwagen_V_Panther#Technische_Daten
The original production version, the D-series weighed 43 tons, the A-series (which came after D for some reason) was 45 tons, and the final G-series weighed 44.8 tons.
So whatever changes were made were not initially as heavy; I think the turret was heavier than advertised, so when combined with the armor upgrade and resulting changes to the design it jumped it from 35/6 tons to 43. Without the armor upgrade in the front I think it probably would have entered production around 40 tons. Perhaps then with the Schmalturm in the F-series it would have been reduced to 38 or so tons as a result.

As above the armor upgrade in the front is about 1ton (2000lbs) give or take a few %.

Planned engine or transmission/steering gear may not have worked as intended but that cannot be blamed on the armor upgrade. If an under 3% increase in weigh causes engine or transmission failure then something was wrong to begin with.

The Panther is a large tank physically and expecting it to weigh only a few tons more than a Comet or late model Sherman or T-34/85 with their smaller hulls is just not reasonable. One foot of length on a tank that is 4.44 feet from hull floor to roof and using vertical side armor of 40mm is over 550lbs. The 15mm floor and sponson bottoms are about another 260lbs and the hull top deck (15mm?) is another 200lbs. The thicker upper hull and slope adds to the weight.

Or think of a hypothetical tank 20ft long and 10 feet wide with 40mm armor all around. If you can cut 6in (152mm) from the height you can cut 1920lbs.

Look at the size of a Panther (not just book dimensions but actual bulk) compared to the other three tanks and try to figure out how to make it that big and weigh only 35-36 tons.

If they mad it from the future teleported aluminium armour of the M113 Gavin/Galvin? then it might weigh 35ish tons...

Mmm. thinking upon the reducing ferrous and non-ferrous metal ores/material shortages, then the ability for production vehicles to be made of consistent quality and metalurigical pieces similar to those of the prototype(s) c/w-ould add weight.

Milder steel parts could be used on the internal bulkheads or non armoured structures, which as indicated by the increased proneness to impact fracturing, could suggest that the industry went from homogeneous armour to what sounds like face (outside surfaces) hardened armour.
Hence the fractures, that and having to substitute some rare to un-available elements that were replaced by different lesser elemnts or left out and replaced with additional carbon - producing more brittle and likely heavier for the same average armour resistance to projectile impact energies.

1950s/60s aluminium armor required about the same pounds per square ft as steel armor for the same protection. Weight savings came from the "skin" being between 2-3 times thicker than steel could become the "frame" and allowed the internal frame parts to be left out.

Engine mounts, frame rails and bulkheads( firewalls) probably weren't armor steel anyway. Armor is expensive (many prototype tanks were made of "mild" steel) both to buy (make) and work.

Difference in weight between different alloy steel armor is a bit overblown. Think about it. Very few steels used for armor contain any one alloying agent in quantities exceeding single digit percentages. In some cases you can use 5 different alloying agents and still not replace 5% of the iron/steel. Replacing 5% of your steel with an allying agent that is 10% heavier than steel changes the weight of you steel plate by 0.5%. Can you control the thickness of the plate (and weight) to 0.5% standards?

http://en.wikipedia.org/wiki/SAE_steel_grades

Stainless is somewhat different but then few people have tried to build a stainless steel tank

Out of curiosity would a rear drive Panther have been shorter and therefore lighter?

Probably would not be any shorter, unless the engine is turned 90 deg, like it was done with T-44 vs. T-34. It might shave some height, though, sice there would not be the drive shaft between the engine and gearbox; that can also ammount to either less weight, or staying on the same weight, but featuring a bit thicker armor.

Panther would probably only be available in mid 44 or later because you have to develop everything engine/gearbox related stuff anew.

Denniss said:

Panther would probably only be available in mid 44 or later because you have to develop everything engine/gearbox related stuff anew.

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Even if the 1941 VK3002 spec included rear drive?

Due to it's layout they had a lot of space for engine/gearbox in the rear, that wouldn't be possible in a standard tank layout.
Plus the transmission system used by DB was said to be very unreliable. No idea about the engine/gearbox layout used in it though.

Denniss said:

Due to it's layout they had a lot of space for engine/gearbox in the rear, that wouldn't be possible in a standard tank layout.
Plus the transmission system used by DB was said to be very unreliable. No idea about the engine/gearbox layout used in it though.

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Perhaps these will help, the first the Panther, the second the Jagdpanther

There was nothing excessive in the length of Panther's hull - it was in the ballpark with Comet, just a bit longer than Cromwell and T-34. KV-1's hull was a bit longer than Panther's.

tomo pauk said:

There was nothing excessive in the length of Panther's hull - it was in the ballpark with Comet, just a bit longer than Cromwell and T-34. KV-1's hull was a bit longer than Panther's.

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I meant shorter in the sense of how high the tank was, not how long.

Doh
Like above (post #51 here) - with 'all rear' powerpack, the drive shaft is no longer there, and the tank can be lower. That means lighter. However, there would be some length added, that means weight is added too, so the total weight loss would not be not so pronounced IMO.

edit: Hmm - looking at how the armor was thick on the hulls of the M 26 Pershing, KV and IS tanks, for negligible weight penalty, the 'all rear-drive Pather should've been an either better protected tank, or a much lighter one.

Again, you would need an all-new very compact transmission. this would have been very much impossible within the timeframe the Panther was rushed into production. It would have been different if such a transmission was already used in a somewhat comparable vehicle or a decision for a rear drive had been made in 1940/41.

Think you're right.
Historically, the Panther have had some reliability issues, despite using the layout the German FV industry was well familiar. Those issues were more or less cured in a reasonable time. Going for an all-new system would not make it easier.