Short barreled Pak 40

Discussions on the fortifications, artillery, & rockets used by the Axis forces.
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peeved
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Pak 50 no short barreled Pak 40

#31

Post by peeved » 03 Jun 2009, 19:06

peeved wrote:Hohlladungsgranate 38 C of the 7,5-cm-KwK 37/L/24 pierced 75 mm of armour at all distances which the 5-cm-PzGr 39 from a Pak 38 only matched at point blank ranges (as usual German penetration figures being given at an 60 deg. angle of impact).
My source Waffen und Geheimwaffen des deutschen Heeres 1933-1945 by Fritz Hahn, apparently has too low figures for the 7,5-cm-KwK 37 L/24 HEAT performance: According to Datenblätter für Heeres-Waffen, -Fahrzeuge und -Gerät the penetration of 7,5 cm Gr.38 Hl/C was 90 mm at all ranges so the L/24 was distinctly superior to the PzGr 40-less Pak 38 at all ranges in armour penetration also.
The Pak 40 chop shop theory is based on little sense although it would have been a blast... Muzzle blast; merely wasting ballistical potential in a barrel about half the length of the one intended by the Pak 40 designers.
In fact the rifling length of an imaginary Pak 50 with Pak 40 chamber would be only ca. 40% of the Pak 40 rifling length 1719mm - 716 mm (Pak 40 chamber length) = 1003 mm vs. 2461 mm. One can approximate the effect of this amputation from the formula way below from Rheinmetall's Waffentechnisches Taschenbuch. xe being rifling length, mp projectile weight, mc propellant charge weight, ve muzzle velocity, A cross-sectional area of the bore, ηp pressure relation and pm maximum gas pressure in bore. Using known values for the Pak 40: xe 2,461 m, mp 6,8 kg, mc 2,77 kg, ve 792 m/s, A ca. 0,805 x 0,075^2 m^2 and pm 2800 x 10^5 N/m^2 (2800 bar) the ηp would yield 0,822718 which with a rifling length of 1,003 m would yield ca. 505 m/s of muzzle velocity. The actual muzzle velocity as given by the formula for the imaginary Pak 40/50 would be somewhat higher since ηp is calculated from: mean pressure / max pressure and mean pressure would be higher in a shortened tube. It is still hard to believe that the Germans would have gone through all the trouble to lose that much muzzle velocity, i.e. making the Pak 40 punier than a Pak 97/38, and to produce a lot more telltale sound and fury with the increased muzzle blast. Sort of contradicts such previous statements as:
Alanmccoubrey wrote:The Pak 50 as described by this WR 102 is a compleytely illogical waste of effort while the Pak 50 as described in Hogg's Artillery book and Lexikon der Wehrmacht is at least based on a bit of sense.
and
The idea of the Pak 50 was supposedly to provide a lighter gun with a similar a/t performance tro the Pak 40
Spontoon: I'm pretty sure the Pak 50s were bored out Pak 38s. The German documents consistently use the verb ausbohren, bore out in the context of Pak 50; the reboring was just my slightly inaccurate translation. Reboring just seemed to me the more usual term although technically it could also include relining.

Markus
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HGKanonier
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Re: Short barreled Pak 40

#32

Post by HGKanonier » 10 Jul 2009, 19:25

Here's an IG37 at Ft Polk Louisiana that I restored with a fellow reenactor, and used at Camp Swift and Camp Mabry, Austin, TX:
Image
Vertical breach block:
Image

My own interests are 2,0 cm Flak 30, 38 and Flak-Vierling, 3,7cm Flak 39


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Re: Short barreled Pak 40

#33

Post by Bob_Mackenzie » 01 Sep 2009, 15:30

Anyhoo based on available information the Pak 50 remained experimental at a small scale so any effort expended was relatively minor.
I was under the impression tat the PaK-50 saw (limited?) active front line service?

If it did it would be nice to know which units its served with

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Re: Short barreled Pak 40

#34

Post by jopaerya » 08 Dec 2009, 21:18

Hello

Here 2 blurry picture's of the 7.5 cm PaK 37 or later renamed I.G. 37 from Ebay.usa .

Regards Jos
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Re: Short barreled Pak 40

#35

Post by jopaerya » 31 Dec 2009, 16:28

Hello

Here a color picture of the muzzle-brake of the Pak 50 during the same visit as the second photo on this Topic .

Photo = Ullstein Bild

Regards Jos
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Re: Short barreled Pak 40

#36

Post by peeved » 08 Jan 2010, 23:39

7,5 cm Pak 37 towed by VW Kübel at http://forum.axishistory.com/viewtopic. ... 93#p399393 , 3rd photo from top.

Markus

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Re: Short barreled Pak 40

#37

Post by peeved » 28 Mar 2010, 19:44

7,5-cm I.G. 37 with the Pz.Div. GD. According to the seller there's Hasso von Manteuffel in the crowd (Source eBay.de).

Markus
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jopaerya
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Re: Short barreled Pak 40

#38

Post by jopaerya » 28 Mar 2010, 22:08

Hello Markus

Very nice picture , the small guy above the first -i - of gipi63 is Hasso von Manteuffel .

Regards Jos

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peeved
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Re: Short barreled Pak 40

#39

Post by peeved » 28 Mar 2010, 22:21

Hi Jos,

And thanks for the General ID.

Regards,
Markus

jopaerya
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Re: Short barreled Pak 40

#40

Post by jopaerya » 20 Jun 2012, 16:57

Looks to me 7.5 cm Infanteriegeschütz 42 ??
http://pics.zuport.dk/imageuploads/1238 ... 021-22.jpg

Othere information very interesting to read , thanks Jens
http://www.museumscenterhanstholm.dk/vi ... &PAGE=6647
http://pics.zuport.dk/imageuploads/file ... ipment.pdf

Regards Jos

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Re: Short barreled Pak 40

#41

Post by jopaerya » 11 Mar 2013, 21:08

Here a museum with the I.G. 37 from Ebay .

Regards Jos
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Re: Short barreled Pak 40

#42

Post by Spontoon » 13 Mar 2013, 02:18

So, it's safe to say this gun didn't see much combat?

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Stan P
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Re: Short barreled Pak 40

#43

Post by Stan P » 21 May 2013, 20:07

Hello All

One more photo of 7,5cm PaK50 from page 40 of Maksim Kolomnec's russian book AT Artillery of Wehrmacht in WW2 (Противотанковая артиллерия Вермахта во Второй Мировой войне - Protivtankovaya Artyleria Wermachta Vo Vtaroi Mirovoy Voyne)

Regards
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7,5cm PaK50 in France, September 1944.JPG
7,5cm PaK50 in France, September 1944

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Re: Short barreled Pak 40

#44

Post by jopaerya » 21 May 2013, 21:07

Thanks Stan

Great picture 8O 8O 8O

Regards Jos

Laurence Strong
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Re: Short barreled Pak 40

#45

Post by Laurence Strong » 22 May 2013, 03:00

Yes sweet piccie.



Larry

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