Shipbucket

This is a very interesting aircraft.

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Hi all,

Hopefully-final version of the Modell 1937 Ausf.39 (incidentally, if you check the image, you'll see that I need to start coming up with shorter names!)



Also, hoping to check a couple of things with regards to engines.

So far, my thinking has been that as a small (albeit rich) nation, New Saxe-Weimar-Eisenach doesn't have a hope of competing with the UK, let alone the US, in terms of production capacity. This is somewhat mitigated by the fact that neither the US nor the UK are devoting their full energies to squashing New Saxe-Weimar-Eisenach like a bug, but it's still not an ideal situation.

So, in an attempt to accomplish the most with the least, NSWE has, since the start of their recovery in the early 1930s, been trying to just eliminate redundancies from their military. The New Saxe-Weimar-Eisenach military, for instance, simply doesn't support the various different types of ammunition that other militaries do - tank guns, for instance, are only provided in 37, 55, 75 and 88mm calibres, and these are the same calibres used in naval guns (though the naval guns do go up to higher calibres).

For engines, NSWE has almost entirely switched to producing air-cooled radials from their two major suppliers, New Hannover Motor Works and the Zeppelin Motor Works - in a blatantly protectionist move, NSWE law requires that any company registered in NSWE be owned by a NSWE citizen, a move that resulted in the cadet branches of a few German families decamping to the island group, Heinrich Quandt in BMW's case, Helene von Zeppelin and Alexander Graf von Brandenstein-Zeppelin in the case of the Zeppelin works - but both are producing engines to a common design (after much grumbling and discreet protest) - the Modula series engines.

Available in nine different basic versions - a 5-cylinder sleeve-valve radial in one or two rows of 800mm diameter and power levels ranging from 300kW to approximately 900kW, mainly intended for tank use (hence the small diameter); a 7-cylinder in one, two or three rows of 1100mm diameter and power levels ranging from 420kW to approximately 2000kW, mainly intended for use in multi-engine craft (allowing the engines, not mounted in the fuselage, to have a smaller engine nacelle) and a 9-cylinder in one to four rows of 1400mm diameter and power levels from 500kW to 3,500kW, intended to fit in the bigger fuselage of single-engine craft, the engine is indeed modular, it being possible to take a row of cylinders out of a Modula-9-1 engine and use it to replace a row in a Modula-9-4 engine - or indeed a cylinder from a Modula engine and use it in another, provided the cylinders come from the same performance grade, though this does require some fairly substantial dis-assembly of both engines - the "row" is actually a (strong) mounting that the individual cylinders are secured into, then connection rods run to the crankshaft, etc, etc.

Does that sound feasible?

Regards,
Adam

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Well, it is at least tdchnically possible since that's how modern two-stroke marine engines are constructed, but I doubt it scales down particularly well. I'm pretty sure they're going to be longer and heavier than engines of comparable power. Also, depending on the number of cylinders you choose to optimise around you're going to have reliability problems on engines with more and those with fewer will be even more overweight.
And one more thing. Usually when talking about engines diameter refers to cylinder bore.

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Hi Thiel,

Yeah, I thought the cylinders thing was pushing it a little. I can see it maybe being useful (sleeve on a cylinder has seized? No problem, just take that cylinder off and put a new one on!) but I had doubts about how to make the structure strong and light - you're fundamentally talking about a hoop with cylinder-sized holes knocked in it, doesn't sound that strong...

Will amend that, then. Is the picture OK for the FD AU thread, do we think?

Regards,
Ad

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Does this really work ?

1) Historically sizes where normally added 1 at a time (so say 37mm in maybe 1935 and then 55mm in 1939, 75mm 1940-41, 88mm 42-44)
So you are not really building them at the same time and once you have older tools (to small to make big guns/ammo) to make the old guns/ammo you may as well keep using them for secondary usage.

2) Tanks/AA/Artillery/Ship/etc guns are not really the same they are have different design compromises (Velocity/weight/etc and they use deferent shells anyway) so I'm not sure that you save much anyway.

JSB

Hi JSB,

Fair points. Perhaps I should have stated that, as the new calibres are developed (e.g., 55mm becoming available first as a tank gun before it in it's turn is inadequate) the New Saxe-Weimar-Eisenach military-industrial complex places a premium on re-using existing tooling rather than developing entirely new calibres. When you're as short of production capacity as NSWE is (comparatively) you wouldn't waste time developing a 57mm calibre if you already had a 55mm that was "good enough". The 88mm, they'd have lifted wholesale from the Germans once it displayed it's usefulness in the Spanish Civil War (who wouldn't, given the option?). I don't think it'd be particularly realistic for New Saxe-Weimar-Eisenach to start the war knowing quite how far the tank armour \ tank gun arms race is going to progress - can't see any reason for them to start the war fitting the 75 or 88 to tanks, what on earth would they be shooting at with that sort of gun in '39?

With regards to ammunition - again, a fair point, I can't see much use equipping a Panzer IV with AA rounds (though presumably they'd make a mess of infantry) - but there would be some cross-overs, surely? The AP round that the 37mm tank gun fires is going to be substantially similar to that fired by the airborne 37mm ground-attack aircraft, no ? (Yes, I do plan to have one of those. If the actual real-life Luftwaffe can fit an actual 75mm on an Hs129 I see no reason to be restrained by the bounds of sanity myself! EDIT: That is, the 37mm ammunition fired by the ground attack aircraft. The aircraft itself is not 37mm ) - the naval stuff will probably be slower and heavier - although, that said, if you look at the 37mm as an example, the shell weights and muzzle velocities are quite close - that one calibre you could perhaps make an argument for it being essentially the same ammunition, though doubtless the guns would have significant differences.

Regards,
Adam

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Airborne tsnkbuster cannons tended to use much lower powered rounds than similar sized ground based guns. Honestly, I'm not sure there's much to grain logistically from forcing the calibres to be the same. The 37mm anti tank gun is going to be air cooled and manually loaded. The aerial gun will use a substantially smaller load so the barrel can be a lot lighter and since you want to keep overall weight down as much as possible to compensate for the overly heavy engine you're going to need to make it. The naval AA gun on the other hand can afford to be a lot heavier and it's likely to be watercooled to boot. Not to mention that 37mm might not be the optimum calibre for the job.
And honestly, even if you do use that system I doubt you're going to save much production capacity. You'll still need x amount of barrels per month and in a war situation that's likely to exceed the capacity of any one production line. From a tooling perspective it doesn't matter what the line is producing as long as it only makes that one thing. It's retooling that's the problem.

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Oh and if your production capacity is as low as you suggest how do you keep your 150mm gatling guns fed? Or even invent them in the first place?

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Hi Thiel,

In general I agree with you (apart from anything else, the airframe itself is unlikely to be a sturdy as the tank a dedicated tank gun would be mounted in) - I mentioned the 37mm specifically because the weights and muzzle velocities seemed to be fairly compatible at first glance - the BK37 airborne weapon (0.380-0.685kg@780-1170m/s) was a development of the Flak 18 (0.623-0.659kg@770-820m/s) and it seemed comparable to the Pak 36 (0.368-0.685kg@745-1020m/s) - so at a first glance, I thought that even with the different guns (agree there, no sense making a shipboard weapon that size and not having it water-cooled, likewise the airborne weapon would want to be lighter than the tank gun because, well, lighter, but could possibly afford to be as barrel heating issues would be mitigated by the airflow?) there might be scope for having similarly-produced ammunition. I figure that while there's scope for differences - hotter powder, longer barrel, etc, etc - it was close.

With regards to the guns, while there are going to be substantial differences I'd thought that by standardising on a calibre you'd be able to keep your production line that's already set up with the right gun drills, rifling stuff, etc (yes, that "etc" was me exhausting my knowledge of the gunsmithing process) humming along, hadn't considered that there would be so much it'd be in several different plants. Will have to re-consider. The production capacity's not supposed to be particularly low but it's certainly not comparable to the US, hence the ruthless efficiency drive to get as much as possible from the available resource. Although as I type the sentence I have images of a 1940s Robert McNamara, am I going to have to introduce a Luftwaffe equivalent of the F111 to stay in character?

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I mist admit McNamarra did come to mind, though the M14 debacle springs to mind as well.
It's also worth noting that those three guns are going into entirely seperate supply chains.

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“Close” only counts with horseshoes, hand grenades, and tactical nuclear weapons.
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Source Materiel is always welcome.