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Posted

I suspect that shortly after Normandy where there was enough dead Shermans to strip for parts, that the workshops would take a good transmission and final drive and send it to a field repair unit to keep it ready. Then they swap it with the damaged one, where it go back to a rear workshop to be torn down and rebuilt from parts shipped over from UK/US. It's then pushed forward to the field unit. Repeat as required.

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Posted
1 hour ago, Colin said:

I suspect that shortly after Normandy where there was enough dead Shermans to strip for parts, that the workshops would take a good transmission and final drive and send it to a field repair unit to keep it ready. Then they swap it with the damaged one, where it go back to a rear workshop to be torn down and rebuilt from parts shipped over from UK/US. It's then pushed forward to the field unit. Repeat as required.

Probably.  Plus we also know that the US sent an ungodly amount of components along with the M4's so there were generally tons of spares ready to go in.

Posted (edited)
10 hours ago, nitflegal said:

You raise an interesting point as anything that we're doing today has the benefit of the best practices developed through the 1950's.  I have not been able to find data on the Panther in any significant wartime references as to time/difficulty.  With modern restoration teams there is some anecdotal data; Saumur staff told me that a transmission change took over a week for their team, not counting the time rebuilding it after removal.  At the time they had four people on site but whether they had four people every day for the 7+ days I do not know.  From the Collins folks IIRC they cited several days to put the transmission in and reinstall everything (also no idea of how many people were working on it beyond their core four).  From experience, three of us spent about 10 hours just putting the interior back together but that was without radios and some other equipment.  I swear I spent over an hour just putting the driver's seat back in with help.  I would expect a trained Heer maintenance company would do much better but then I expect a US Army company to be likewise much more efficient and practiced than modern day restorers.  All of that said, you can also clearly see with the M24 that they put a lot of thought into how this could be even more efficient.  That thing is a damned Cadillac of tanks!

At the risk of channeling Hillary Doyle, I have to mention that the Germans tended to have specialized tools for the job, which made it less hard to do these procedures. I wouldn't choose the word "easier", but certainly less hard. Doyle in particular has pushed back whenever Nick pointed out things like the difficulty of transmission changes, and changing the gun on the Jagdpanther, which is probably not without reason.

Also, IMHO it's hard to argue that a U.S Army repair section would hypothetically be faster than museum staff, because we already know from a report fragment that it took 80 man-hours to remove and replace the transmission unit, with gearbox repair alone taking up ~16 man-hours. 

10 hours ago, nitflegal said:

I would say without having seen it the possibility to underestimate just how much time is spent removing and installing the damned thing in a Panther is high.  That fit is so tight I'm surprised the hull opening wasn't coated in Astroglide first.  Keeping in mind that you have to drop it in most of the way and then pull it to the left and then drop it some more and then sweep it back, all without crunching it on anything you can have a 4-5 person team spend 2-3 hours just fitting it back into place BEFORE attaching the damned thing. 

2-3 hours just to put it in sounds quite reasonable, if the total operation would have taken a full day of work, including realignment, bolting everything back in place, splining the steering unit axles to the final drives, reconnecting everything, etc. The time scales from the museum people speak for themselves, but at the same time, it doesn't seem like there is much of a correlation between museum repair/replacement times and actual field repair/replacement times.

10 hours ago, nitflegal said:

Put it this way, there are reports from the French post-war 503 that if the transmission or final drives blew on one of their Panther they preferred to replace it from one of the other 41 they'd refurbished immediately post-war than replace it with harvested parts.  To be fair, there are other reasons they may have gone that route including the wear and tear on the Panthers they were fielding but it is at least suggestive.

 

If the final drive blew, you didn't have to replace the gearbox + steering unit, just the final drive. Final drive replacement is the same as on any other tank, and that's really the main issue. Most people know about Panthers for final drive failures, gearbox and steering units were much rarer. But when people talk about a Panther breaking down because of its final drives, they immediately think about replacing the whole transmission. It seems as if the online pushback against Wehrabooism in the past 10 years just tipped the balance in favour of an opposite but equally biased narrative instead of being more moderate and more truthful.

ddsesKj.jpg

I feel that Nick's choice on what to emphasize whenever he brings up the old Sherman vs Panther topic has strongly influenced this incorrect perception. For example, you can see something like this in the first Google search result when you type in "Panther transmission replacement": https://www.reddit.com/r/TankPorn/comments/7l5okn/repair_of_the_transmission_on_a_panther/

 

Edited by Interlinked
Posted

It's a valid statement, Interlinked, and I also acknowledge that a lot of times folks will confuse final drive changeouts with transmission change-outs, but I wonder if folks are missing the woods for the trees in this discussion.

I use the transmission replacement idea as a demonstration because it is an easy-to-grasp visualization of the concepts of 'ease of repair' and 'modularity'. (And if I really wanted to push the issue, I'd use Tiger or Panzer III as the comparison, as that required removing more than just the driver/funker positions. Yes, the Germans issued a tool... an entire overhead gantry crane!). It doesn't really matter if the specifics are 60 man-hours to pull the housing (I don't know if that particular transmission repair also required separating the transmission from the housing, which might also increase time, I wonder if SSnake's assuming that the only difference is just in unbolting the front housing) vs 80 for Panther or 20 vs 40 or whatever. It doesn't even matter very much if the biggest difference in maintainability is in fact the turret traverse pump which is easily swapped out in front of the gunner in an M4 vs so far under the turret in Panther that after the Littlefield Panther's turret traverse motor sprang a leak, they considered it too much bother to attempt to repair it. That's hard to 'show' in an easy-to-grasp comparative photo.

I cannot say if other nations did the same thing or not, but whilst at the beginning of the war the US would place maintenance concerns in part of the overall test report, eventually the US ran test projects -only- on maintenance work. Usually entitled something like "Ease of Maintenance Report on Tank, XXX", but they did at least one project purely on maintenance of T26 turret components. That was it. The project didn't test if the components did the job, it was an entire test cycle done simply on maintaining and replacing them.

The bottom line point I'm trying to get across is that US vehicles are designed with maintainability in mind, even if there is a possible cost of combat capability. In the case of the turret traverse motor, a thinner turret requiring applique armor, for example.

Posted

I think a point made in Germany and the 2nd World War regarding the battles in Ukraine in 1943 after Kursk is pertinent here. Reading the histories of the Panzer divisions, it seems like they went from victory to victory as they were shuffled from one hot spot to the next but the frontline ended the year at the border of Ukraine while the march of the Panzers was marked by broken down tanks that couldn't be recovered in time.

Posted
On 3/22/2023 at 11:40 AM, RETAC21 said:

I think a point made in Germany and the 2nd World War regarding the battles in Ukraine in 1943 after Kursk is pertinent here. Reading the histories of the Panzer divisions, it seems like they went from victory to victory as they were shuffled from one hot spot to the next but the frontline ended the year at the border of Ukraine while the march of the Panzers was marked by broken down tanks that couldn't be recovered in time.

All my reading (Limited compared to many here) is that the Germans excelled at tank recovery and field repair, mainly because they had to. Not holding the battlefield imposed a heavy tax on their tank supply as potentially repairable vehicles were lost.

Posted
25 minutes ago, Colin said:

All my reading (Limited compared to many here) is that the Germans excelled at tank recovery and field repair, mainly because they had to. Not holding the battlefield imposed a heavy tax on their tank supply as potentially repairable vehicles were lost.

But this only worked when front were more or less fixed, in mobile situations, such as Ukraine, they were unable to recover their tanks and the panzer divisions may prevail tactically, but were becoming progressively weaker to the point of impotence.

Posted
2 hours ago, Colin said:

All my reading (Limited compared to many here) is that the Germans excelled at tank recovery and field repair, mainly because they had to. Not holding the battlefield imposed a heavy tax on their tank supply as potentially repairable vehicles were lost.

They excelled at battlefield recovery. Repair was a different matter and was severely limited by the lack of spares that is well illustrated in the examples given by Junior FO. A good indicator is the difference in the classification system they used. Tanks (and other AFV) were either ready for action or not ready for action, repairable in less than two weeks, repairable in more than two weeks, and destroyed. Prewar at least in theory it was expected those not repairable in less than two weeks would be returned to Germany for repair and then returned to the unit or another replacement would be sent. For the Eastern Campaign that was modified with a centralized but ad hoc parts depot and repair system added basically to the army group. Both systems quickly was overwhelmed and collapsed. Units soon realized that sending away a tank for repair meant they would never get it back and that even simple repairs required spare parts that were difficult to come by, so tended to horde "hanger queens", which were used for spares. That resulted in disasters like the aftermath of Kursk, when 40-odd Panthers in the HG-S depot were lost when they could not be evacuated in the face of the Soviet counteroffensive and the same occurred in Normandy when Operation COBRA and its aftermath overran the 7. Armee depot.

In contrast, the American and British Army classification counted AFV as either operational or operational in less than six hours, non-operational but repairable in less than 24 hours, and non-operational, repairable in more than 24 hours. Any vehicle in the last category was evacuated to a 4th or 5th Echelon maintenance facilitating for repair and was replaced from reserves in theater. Nearly everything else was repaired by unit maintenance at division-level or below.

Of course, the Allied system was not perfect either, especially the American, where reserve tank levels were too low to ensure prompt replacements and strong unit strengths. Other issues were the confusion attended by the sheer number of Ordnance depots established on the Continent and a less than robust parts inventory system that led to Ordnance officers from the front going on foraging expeditions to find critical spares far in the rear.

Posted (edited)
On 3/22/2023 at 4:14 AM, Interlinked said:

If the final drive blew, you didn't have to replace the gearbox + steering unit, just the final drive. Final drive replacement is the same as on any other tank, and that's really the main issue. Most people know about Panthers for final drive failures, gearbox and steering units were much rarer. But when people talk about a Panther breaking down because of its final drives, they immediately think about replacing the whole transmission. It seems as if the online pushback against Wehrabooism in the past 10 years just tipped the balance in favour of an opposite but equally biased narrative instead of being more moderate and more truthful.

If the Panther's final drive is repaired from the outside in a way similar to the Sherman's, I've been confused by Nick implying here that the amount of time that it would take to replace the Panther's entire transmission is how long it would take to replace its final drive.

 

Edited by Erik2
Posted
1 hour ago, Erik2 said:

If the Panther's final drive is repaired from the outside in a way similar to the Sherman's, I've been confused by Nick implying here that the amount of time that it would take to replace the Panther's entire transmission is how long it would take to replace its final drive.

 

Yep. That was an error on my part.

Sometimes I just screw up on camera.

  • 2 months later...
Posted
3 hours ago, Tim Sielbeck said:

 

Yep.  Track pitch makes sense, and I sort of understand metal roads.

Posted

The dreaded HEAT plasma again... No, the copper stays solid, well below its melting point (1358K). Plasma would require the copper to be heated beyond its boiling point (2868K), and then be ionized (usually through even more heating to seven-digit Kelvin figures, or, nebulae-Astronomers' favorite, through exposure to intense ionizing radiation).

The term is "superplasticity", where the metals' behavior under extreme pressure can be described as if they were liquids (even though they aren't).

Posted

But 'plasma jet burning through armor' rolls off the tongue so eloquently...

Posted
1 hour ago, shep854 said:

But 'plasma jet burning through melting the armor' rolls off the tongue so eloquently...

FIFY!

Posted
42 minutes ago, Stuart Galbraith said:

Does it mention HESH anywhere?

No, because the focus is on 120mm ammo used by the M1 series.  But the Tank Museum released a good video on tank ammunition last Friday and that one did feature HESH:

 

 

Posted
2 hours ago, Stuart Galbraith said:

Does it mention HESH anywhere?

No, he's talking about 120mm rounds from a US perspective.

Posted
2 hours ago, Stuart Galbraith said:

Does it mention HESH anywhere?

Please!  Those poor benighted foreigners don't even have a proper boiling vessel for tea, let alone something as glorious as HESH.

 

Posted
On 6/15/2023 at 2:25 AM, Ssnake said:

The dreaded HEAT plasma again... No, the copper stays solid, well below its melting point (1358K). Plasma would require the copper to be heated beyond its boiling point (2868K), and then be ionized (usually through even more heating to seven-digit Kelvin figures, or, nebulae-Astronomers' favorite, through exposure to intense ionizing radiation).

The term is "superplasticity", where the metals' behavior under extreme pressure can be described as if they were liquids (even though they aren't).

In fairness, I did kindof correct myself by posting the text from the Ballistics Research Laboratory document on the screen.

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