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New (to me) historical gun

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Brockpaine

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21

Wednesday, October 1st 2008, 3:48pm

Impressive.

Commodore Green

The Irish Legend

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22

Wednesday, October 1st 2008, 9:16pm

Mother!!!!!

26 miles, 340 yards!!!!!!!!

The marathon is only 26 miles, 385 yards!!!!!


emm, could I maybe talk you into putting them 27 miles from Danish borders????

Desertfox

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23

Wednesday, October 1st 2008, 9:24pm

Too small... :P

Don't you have the plans for the Dora liying around?

Earl822

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24

Wednesday, October 1st 2008, 10:11pm

Quoted

emm, could I maybe talk you into putting them 27 miles from Danish borders????


Immediately places an order for 10 to be placed around Malmo

Hrolf Hakonson

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25

Wednesday, October 1st 2008, 10:40pm

Quoted

Originally posted by Desertfox
Too small... :P

Don't you have the plans for the Dora liying around?


The rate of fire's too low (even if you assume it will be doubled in a fixed position mount) for shooting at moving targets.

Hrolf Hakonson

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26

Wednesday, October 1st 2008, 10:41pm

Quoted

Originally posted by Earl822

Quoted

emm, could I maybe talk you into putting them 27 miles from Danish borders????


Immediately places an order for 10 to be placed around Malmo



Not to mention the consideration of extended range projectiles (like a saboted 38cm projectile, for instance).

Krupp is happy to take orders from Nordmark.

This post has been edited 1 times, last edit by "Hrolf Hakonson" (Oct 1st 2008, 10:42pm)

HoOmAn

Keeper of the Sacred Block Coefficient

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27

Wednesday, October 1st 2008, 11:55pm

Don´t understand the fuzz about the guns range....

The OTL 28,3cm guns of the Scharnhorst class (28cm/54,5 SK C/34) had a range of about 42+km according to Gröner. NavWeaps lists them at least at 40,93km at 40° elevation. Now knowing that the max range will be reached at 45° it´s not surprising the guns could hit the 42km mark....

Also according to NavWeaps the historical 21" gun had a range of at least 47,5km.

Hrolf Hakonson

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28

Thursday, October 2nd 2008, 12:41am

I'm not sure why the excitement about the range either, unless it's the penetration at that range....

howard

Unregistered

29

Thursday, October 2nd 2008, 6:37am

Quoted

Originally posted by Hrolf Hakonson
Shouldn't be a problem, considering the 80cm gun Heavy Gustav had no problems and the prototype for that weapon was on the test range in 1939.


That, Gustav, was on a double rail truck, on a double recoil trunnion with lots of rail travel to disperse the shock over tau (time) wasn't it? This gun, you suggested, is supposedly on a naval rifle coast defense mount with limited recoil travel and would rotate on a turntable. You also suggested a possible pair mount for this rifle as an emplacement?

The shock-load is much worse I might suggest under those technical conditions, especially in the flat trajectory when the gun is fired . I seriously worry about the slue and elevate loads of these large caliber bore guns when you get into those 1-2 megajoule recoil force loadings when you have to damp recoil in less than a barrel's length of travel and the shock is more or less vectored horizontal to the plane of the mounting.

That is just cautious me, though.

H.

Hrolf Hakonson

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30

Thursday, October 2nd 2008, 11:42am

Gustav was deployed on a double track railroad carriage, yes, but did not move when firing. So there shouldn't be a problem (unless you possible overstress the mounting by firing both weapons at the same time, but that's a training issue or a safety could be installed to prevent it).

HoOmAn

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31

Thursday, October 2nd 2008, 12:07pm

Wouldn´t firing one such gun off center of the mount cause a problem with stress and shock? Wouldn´t you have quite some rotating force?

Hrolf Hakonson

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32

Thursday, October 2nd 2008, 1:44pm

Only if your recoil system wasn't working correctly. If the guns recoil system is working correctly, the shock loads transmitted to the cradle and to the turret structure shouldn't cause a problem, any more than any other turret-mounted weapon in a multi-gun turret would. A 21" gun is just a slightly larger problem than a 20" gun (as "planned" for H-44) or an 18" gun.

HoOmAn

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33

Thursday, October 2nd 2008, 1:54pm

*cough cough*

A 21" is as much larger than a 18" as is a 15" over a 12" rifle - and we all know the picture from NavWeaps that compares sizes, right?

Hrolf Hakonson

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34

Thursday, October 2nd 2008, 2:19pm

Sure, from a pure size perspective. From an engineering problem perspective, it's the same thing, just scaled up a bit.

Red Admiral

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35

Thursday, October 2nd 2008, 2:25pm

Springsharp isn't a good way to model the weights of turrets. By my calculations and scaling off the twin 406mm turret the weight should be around 3300tons. The weight Springsharp gives is ludicrously low as its barely heavier than the 406mm twin. A triple turret for the US 18"/48 was estimated to weigh around 3000tons, similar to the IJN 460/45 triple and 510/45 twin.

Personally I'd stick with the 406mm in single mountings.

Quoted

Now knowing that the max range will be reached at 45°


It'll actually be around 48-49° for large weapons as density reduces considerably with the looping trajectories to high altitude.

Scaling is not a simple thing in engineering. It just doesn't work for most things.

Hrolf Hakonson

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36

Thursday, October 2nd 2008, 2:40pm

Turret weight is probably perceived as low because on a mounting without a hull like this, SS doesn't calculate a barbette weight.

Recoil and turrets are a well known, well understood problem by this period, after proofing gives a rough recoil value then creating a mounting that will handle it should not be a problem (as evidenced by the lack of problems encountered with the various increases in main gun sizes in ships historically). In this case, because it's a shore battery weapon, excess strength (hence weight) can easily be accommodated for safety reasons, it won't cause problems for the ship.

The 16" doesn't give enough of an advantage over the 15" to bother with, and doesn't completely overmatch most defenses.

howard

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37

Thursday, October 2nd 2008, 6:25pm

Quoted

Originally posted by Hrolf Hakonson
Gustav was deployed on a double track railroad carriage, yes, but did not move when firing. So there shouldn't be a problem (unless you possible overstress the mounting by firing both weapons at the same time, but that's a training issue or a safety could be installed to prevent it).


http://www.youtube.com/watch?v=ISwyMoautxw&NR=1

http://www.youtube.com/watch?v=rUf7LFrL7LQ&feature=related

I believe that the videos show truck movement on the tracks as part of the gun recoil. I could be mistaken, but I don't think this is the case.

H.

thesmilingassassin

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38

Thursday, October 2nd 2008, 9:24pm

Looks that way to me.

Commodore Green

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39

Thursday, October 2nd 2008, 10:16pm

Quoted

Originally posted by Hrolf Hakonson
but did not move when firing


Correct!

Quoted

Originally posted by Howard
I believe that the videos show truck movement on the tracks as part of the gun recoil.


Also Correct!

How can it be so, I hear you ask.

I would imagine that Hrolf meant that they didn't fire while "on the move" (a la modern tanks), and Howard refers to the movement brought about by the recoil.

Am I right?

Hrolf Hakonson

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40

Friday, October 3rd 2008, 3:58am

Actually, no, the gun we see recoiling so dramatically in the second clip isn't Gustav at all, that's one of the smaller 21cm or 28cm railway guns, it's much lower and smaller than Gustav and the shape of it's mounting is quite different. There is one clip of Gustav firing on YouTube that I saw that appeared to show the gun barrel moving, but it wasn't clear that the mount was moving. Might have been the camera, or the mounting above the railway trucks.