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pac 75mm long?
TopSmith
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Posted: Sunday, October 15, 2017 - 03:47 PM GMT+7
Did the Germans ever use the 75mm from the Panther as a pac gun? If so which pac gun was it?
I was thinking of making a paper panzer. Combining a Marder 3 M with the long 75MM gun. Should be a reasonable combination.
Bonaparte84
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Posted: Sunday, October 15, 2017 - 06:46 PM GMT+7
Hi there.
You are referring to Kwk 42 L70. It was never used in a confuguration as towable Pak, unlike e.g. the Pak 40. The Kwk 42 was used only in the Panther and - with very minor modifications, incl. being renamed pak - in the jagdpanzer IV/70. You could have a look at the pak 43 to determine what the gun shield could have looked like. When doing your conversion, keep in mind that the rounds used for the Kwk42 had different dimensions from that of the pak 40. Arguably, someone expert in the technical side of things would tell you that the chassis of the Marder 3 would be too weak to deal with the increased recoil... Maybe those things dont bother you (and they don't have to).
Cheers!
RobinNilsson
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Posted: Sunday, October 15, 2017 - 09:40 PM GMT+7
Improvised solution for a different gun:

Dragon 6522. Maybe it can provide some inspiration.

Another severely underweight carrier packing a heavy piece:
http://www.ebay.com/itm/CustomScale-1-35-Self-propelled-Gun-7-5-KWK-42-L-70-Sd-Kfz-251-Resin-Kit-35033-/122474838864
CustomScale 35033:


Either a "simple" screen similar to other Marder variants, just enough to cover from the top of the Marders own armour up to over the heads of the crew when working the gun
OR
Reuse the mantlet from the tank mounting on the principle: gun and mantlet lifted from original vehicle and plunked down on a pillar/pivot from a regular 75 mm PaK.
OR
Replace the gun in the regular 75 mm PaK and reuse the shield and mounting.

/ Robin
TopSmith
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Posted: Monday, October 16, 2017 - 03:31 AM GMT+7
Knowing how things were not intended to live a long healthy life, if it could fire 100 rounds in the anti tank roll It would probably would have been successful. It sounds like I need Mengs Panther to get the breach and gun sence there is not a pac gun available.
barkingdigger
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ARMORAMA
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Posted: Monday, October 16, 2017 - 05:38 AM GMT+7
IIRC some DML Panthers also come with a breach. If you get the Black Knights Panther A kit you can harvest the breach and one of the barrel options, and still have a gun left over to build a buttoned-up whole tank!

Don't worry about the recoil - the test-bed for the Sherman Firefly had a 17pdr in a rigid (ie. NO recoil mechanism!) mount that transferred all the force through the turret and apparently made the tank quite lively to fire... Needs must in wartime.
TopSmith
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Posted: Monday, October 16, 2017 - 06:26 AM GMT+7
Thanks. Is it just the breach or most of the gun?. If not who makes a turret interior for the Panther and I can get the entire assembly.
barkingdigger
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ARMORAMA
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Posted: Monday, October 16, 2017 - 07:07 AM GMT+7
It's a bit simplistic, as a two-part assembly that incorporates the mount, recoil cylinders, and breach, so you will need to do some detailing. I reviewed it here if you want to see the parts.
TopSmith
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Posted: Monday, October 16, 2017 - 10:30 AM GMT+7
I noticed Takoms cad drawings of the Panther turret interior looked fantastic. The interior breach area and the parts behind the mantlet would make this an easy project. I could still build the Takom kit in a closed hatch setup. I wonder when their release date is?
TopSmith
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Posted: Monday, October 16, 2017 - 10:44 AM GMT+7
To handle the recoil on the light chassis the rear of the Marder could have two spades that are dropped and backed up to set. Just drive forward to unseat the spades and keep going until it is safe to stop and lift them manually. There is not enough armor on the Marder to worry about keeping the front to the enemy.

I wonder what the weight difference between the L40 and the L70 version is?
salt6
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Posted: Tuesday, October 17, 2017 - 11:20 AM GMT+7
If you have room, a longer recoil for the gun would mitigate some of the recoil problems.
TopSmith
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Posted: Tuesday, October 17, 2017 - 11:28 AM GMT+7
If you rotate the gun so the right side is up, the breach block handle will be on top and the recoil cylinder will also be on top and be easier to adapt the existing mount.
RobinNilsson
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Posted: Tuesday, October 17, 2017 - 07:16 PM GMT+7

Quoted Text

To handle the recoil on the light chassis the rear of the Marder could have two spades that are dropped and backed up to set. Just drive forward to unseat the spades and keep going until it is safe to stop and lift them manually. There is not enough armor on the Marder to worry about keeping the front to the enemy.

I wonder what the weight difference between the L40 and the L70 version is?



or a single spade:


With two spades you could have a risk of sideways motion if one of the spades has got a better grip in the ground. The one with the "loose" grip could get pushed backward.
With a single wide spade this risk is reduced but not completely eliminated. There could also be a working platform on the legs of the single spade to free up some space in the vehicle and possibly also allow a longer recoil. If the gun is mounted on a reinforced frame connected to the spade attachment points it would send most of the recoil forces into the spade and remove stress from the chassis (a PaK is firing more or less horizontally, a howitzer would be a very different case).

Weight difference:
Some Googling
KwK 42
https://en.wikipedia.org/wiki/7.5_cm_KwK_42
Weight with muzzle brake and breech: 1,000 kg (2,200 lb)
Recoil length: 400 mm (normal), 430 mm (maximum)

PaK 40 https://en.wikipedia.org/wiki/7.5_cm_Pak_40
The whole thing, gun, shield, carrige and wheels weighed 1425 kg so there is quite a difference.

KwK 40 L/48 (and L/43)
On this page (a forum)
https://forum.axishistory.com/viewtopic.php?t=182979
there is a post claiming that the KwK 40 L/48 weighed 750 kg, a little more than half of the complete PaK 40, which makes sense.

/ Robin
barkingdigger
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ARMORAMA
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Posted: Wednesday, October 18, 2017 - 05:25 AM GMT+7
Another option for the gun is a detail set from Tamiya:

Tamiya 1/35 Metal Gun Barrel Set - German Panther Ausf.D # 12664

(I saw some on ebay.) Looks like you get the whole deal - barrel, breach, recoil mechanism, etc.
TopSmith
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Posted: Wednesday, October 18, 2017 - 07:46 AM GMT+7
Looks like this is firming up well! This makes more since than most of the paper Panzers with the exception of the Panther F.
The next issue is how to lift the spade when not in use. The twin spade is light enough that 2 people could manually lift each one. the single looks hefty..
Invincible
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Posted: Wednesday, October 18, 2017 - 07:58 AM GMT+7
Perhaps you could use a cable and pulley system? Bit like the shell loading crane on the sturmtiger?
RobinNilsson
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Posted: Wednesday, October 18, 2017 - 08:43 AM GMT+7

Quoted Text

Perhaps you could use a cable and pulley system? Bit like the shell loading crane on the sturmtiger?


Check the rear end of the BergeHetzer I linked to, it has some sort of pulley system.
In an open vehicle I could imagine two ropes/chains, one each side, going to some kind of hand operated winch attached approximately waist high (say 4 feet) on the inside of the side armour, possibly with a pulley at the top corner of the side armour.

I don't know what they might have looked like at that time but this is the general type I was thinking of



This one looks a little more "engineered" and could possibly look more credible in the military role, and the cog wheels and gears are hidden -> easier to build from scratch



/ Robin
TopSmith
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Posted: Wednesday, October 18, 2017 - 02:22 PM GMT+7
I see the KwK 40 and the KwK 42 had close to the same recoil length.
ALBOWIE
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Posted: Thursday, October 19, 2017 - 10:05 AM GMT+7

Quoted Text

I see the KwK 40 and the KwK 42 had close to the same recoil length.




Whilst the Recoil length may be approx equal the FORCE of the recoil would be significantly higher in the case of the Kwk 42, BTW it is PAK (Panzer Abwehr Kanone)


Al
TopSmith
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Posted: Thursday, October 19, 2017 - 11:46 AM GMT+7
Thanks. I agree about the recoil. If the Meng Panther cad drawings are accurate to the kit, I can rotate the gun so the rightside is up and the recoil cylinder would be on top. Now I would have to plan where the forward part of the recoil cylinder would attach and how to do it as there won't be a Panther mantlet. I can still use the recoil guide rail from the existing Kwk 40 because of similar recoil distances.

Any ideas?
RobinNilsson
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Posted: Thursday, October 19, 2017 - 04:49 PM GMT+7

Quoted Text


Quoted Text

I see the KwK 40 and the KwK 42 had close to the same recoil length.




Whilst the Recoil length may be approx equal the FORCE of the recoil would be significantly higher in the case of the Kwk 42, BTW it is PAK (Panzer Abwehr Kanone)


Al


or rather PaK, P for Panzer (a noun), a for abwehr (defend/defence, not a noun) & K for Kanone (another noun).
Nouns get written with a capital first letter, always ...

/ Robin
Bonaparte84
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Posted: Thursday, October 19, 2017 - 08:30 PM GMT+7

Quoted Text


or rather PaK, P for Panzer (a noun), a for abwehr (defend/defence, not a noun) & K for Kanone (another noun).
Nouns get written with a capital first letter, always ...

/ Robin



Of course Abwehr is a noun. The typical German abbreviation is Pak anyway, just as Flak. In certain contexts, a capital letter might be used to emphasise the "Kanone" aspect.
Cheers!
RobinNilsson
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Posted: Thursday, October 19, 2017 - 08:51 PM GMT+7

Quoted Text


Quoted Text


or rather PaK, P for Panzer (a noun), a for abwehr (defend/defence, not a noun) & K for Kanone (another noun).
Nouns get written with a capital first letter, always ...

/ Robin



Of course Abwehr is a noun. The typical German abbreviation is Pak anyway, just as Flak. In certain contexts, a capital letter might be used to emphasise the "Kanone" aspect.
Cheers!



Of course.
You're right
After some
It is a noun and gets written with a capital 'A' when it is on its own. In this context it is part of the compound noun (die) Panzerabwehrkanone, and that is why it gets a lower case 'a', the same goes for the 'k'.
https://www.duden.de/suchen/dudenonline/Panzerabwehrkanone

/ Robin
TopSmith
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Posted: Friday, October 20, 2017 - 12:41 AM GMT+7
This is why I love this site. I always learn something new. Robin, It would be smart to just use the Berghetzer spade with a winch since it is the same chassis.
RobinNilsson
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Posted: Friday, October 20, 2017 - 01:06 AM GMT+7

Quoted Text

This is why I love this site. I always learn something new. Robin, It would be smart to just use the Berghetzer spade with a winch since it is the same chassis.



I wasn't sure about the chassis (which Marder you were thinking about) but the difference in chassis width would be manageable in any case. The Bergehetzer uses the (internal) recovery winch for the spade and that might not work for you so I suggested the "figure eight" shaped winch.
Handcranked winch and a heavy spade -> use two winches and two soldiers to get more muscle power and be able to use a faster gear ratio to get that spade up when in a hurry to get out of a firing position.

Keep us posted with the progress on this project
/ Robin
ericadeane
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Posted: Friday, October 20, 2017 - 01:19 AM GMT+7
Not meaning to be overly pedantic but since we're here to learn and be correct in our details, I noticed an terminology error repeated in this thread.

The cannon has a "BREECH" not a "BREACH"

Breach is the verb as in "the squad breached the outer defenses" whereas "the cannoneers loaded the shell in the still-smoking breech"

Hope this helps!