Competition: Californium 2250

[Xoon]

I think I am done with my suspension, for now:

 

It comes out at roughly 350 kilograms. I would say probably closer to 400kg though. 

 

 

 

On the hull:

[Whatismoo]

Thoughts on the Proper Use of Mechanized Forces in Defense Against the Probably Enemy to the West,  Military-Scientific Thought, Summer 2250

 

Inspired by the current procurement of a new armored vehicle, the author has briefly made a closer study of the terrain on our axes of probable deployment, based in their experience of war in the former Nevada.

 

The elevations in the Northern Theater of Military Affairs, excepting the Columbia Plateau on the former Oregon-Washington border and the Snake River Basin, tend towards above FL040 and in fact are often above FL050.

 

In the Eastern Theater of Military Affairs, the terrain is likewise often above FL040 or FL050 throughout northern Former-Arizona, Former-New Mexico, and Former-Utah. Much of the terrain is above FL040, even the valleys between ridgelines in Former-Nevada, where the remnants of pre-war road networks, arid unforested scrub, and relatively flat ground allow the dushman toyota cavalry to utilize their greater tactical mobility. Worse still would be an engagement in one of the open dry lakes which dot these valleys, where their greater on road/salt flat/lakebed speed enables them to decisively outmaneuver nearly any conceivable tracked vehicle, and attack the sides/rear with their powerful anti-tank means.

 

The peaks which separate these valleys are dominating terrain features, often rising above FL100, however the limited engagement ranges of current fire control systems mean that the ability to observe often the entire >10 mile width of the valley (weather permitting) is hampered by an inability to engage the targets observed, at the least with tank gun fire. An interesting conundrum, no doubt. It is conceivable that the very high caliber guns being pursued by the various parties of this competition may be able to engage such targets, using fire by direct aiming to deliver HE-FRAG, VT, or DPICM against the lightly armored opponents.

 

On the other hand, this job could be better accomplished by heliborne light infantry with long-ranged ATGM and a light, airmobile SPH of c.4.75" caliber able to fire shells to 10 miles (15 with RAP), and effective aviation support (fixed or rotary wing). The low "footprint" of the light infantry soldier, in comparison to the heavy mechanized unit, would reduce sustainment needs relative to armored forces, and reduce the effectiveness of enemy ISTAR means. A mission-tailored task grouping based off of an airborne infantry regiment could take any point in the whole of the Newark and Diamond valleys to the East and West under fire, and direct air and artillery fires against throughout Eureka, White Pine, and Elko counties. A lower profile force could be used, consisting of a network of observation posts with long-range radio systems to plot enemy movements, and use rotary or fixed wing aviation to "herd" or channelize the zealots into coordinated fire-strikes using high power artillery or the weapons of our illustrious rocket-missile troops.

 

Indeed, we need a unique kind of vehicle to support this style of warfare. Tentatively termed "4th Dimensional" (three dementions+3D cross domain personeuver) warfare. While past authors have spoken of similar needs for high speed tracked vehicles for this purpose, due to their higher cross country ability and greater protection than wheeled death traps, their suggestions, derived from the pre-war M113 Gavin APC, would be hopelessly outclassed by the toyota cavalry of the mormonhideen. Thus, inspiration should be taken from the pre-war Combat Vehicle (Recconaissance) Tracked series of vehicles. Of particular note are:

 

FV101 "Scorpion" light tank, so named for the 'sting' of its 76mm gun

 

FV-107 Scimitar Reconnaissance vehicle, armed with a 30mm cannon and named for the famous sword of the Medieval Arab cavalryman who's descendants perfected the toyota cavalry concept.

 

FV105 Sultan Command track, allowing the 4th Dimensional personevuer commander to keep pace with their subordinates even in the highest tempo actions

 

FV102 Striker ATGM carrier, able to sling lethal highly maneuverable missiles from outside enemy gun ranges

 

FV103 Spartan Armored Personnel Carrier, as light and maneuverable as the light infantry inside, with low ground pressure and good power to weight allowing it to be far more of a 'go anywhere do anything' vehicle than the "jeep" of WWII

 

However, the modern requirements of today require a new approach, and some new vehicles. The Light Tank would need increased lethality compared to the pre-war 76mm, for example, and a 4.75" howitzer motor carriage would be required. Further additions may include an engineering vehicle, Anti-Aircraft gun motor carriage, and a mortar carrier.

 

Armed with these new vehicles, light infantry forces would be able to move faster, across, through, and over worse terrain, with heavier weapons, than the mormonhideen. The efforts of the Armored Branch to continue investment in over-complicated expensive vehicles is indicative of the decadence, sedentaryism, and intellectual lethargy which has arisen within the Armored Branch. One might reasonably expect such simple-minded solutions from the robotic money-grubbing degenerates in Cascadia or insane religious fanatics of the tribes who inhabit the Eastern wastes. To see such behavior within the PAF Armored Branch is beyond the pale. Instead of thinking of new ways to skin cats, our fellow officers might best be thinking about how to herd them.

 

-Colonel Miguel Chispas, 1st Tactical Studies Group (Airborne)

[Sturgeon]

I was going to mention that JBM is not so good for fin rounds. It's OK for full caliber AP and APCR.

[Datengineerwill]

Quick Random question... Is shaving cream available for use as a material?

[Lord_James]

First 2 armor arrays completed. I changed around some thicknesses, and had to completely remake the first array: 

 

Lower Front Hull Array: 

Spoiler

 

4.73 Mg total. Sloped @ 45^o: 

 

45mm RHA 

80mm Air gap 

25mm HHA 

202mm NERA-light (192mm with 10mm gap from brackets; sloped at 71^o from vertical) 

28.5mm RHA (first NERA brackets are attached to this plate) 

45.5mm Glass Textolite (with additional 2mm steel back plate) 

202mm NERA-light (same configuration as first NERA) 

63mm JPA (second NERA brackets attached to this plate) 

 

top plate is 40mm RHA, sloped at 75^o. 

 

 

Front Right Hull Array: 

Spoiler

 

2.23 Mg total. Sloped @ 60^o:

 

45mm RHA 

63.5mm Air gap 

20mm HHA 

115mm NERA-light (105mm of NERA with a 10mm gap for brackets; sloped at 71^o from vertical) 

28.5mm RHA (first NERA brackets attach here) 

36mm Glass Textolite (additional 2mm steel back plate) 

115mm NERA-light (same configuration as first array) 

63mm JPA (second NERA brackets attach here) 

 

top plate is 28.5mm RHA, sloped at 83^o from vertical. 

 

 

New LoS thicknesses are : 

 

Lower Front: 980mm 

Front Right: 976mm 

 

Will work on KE and CE thicknesses. 

[N-L-M]

4 hours ago, Datengineerwill said:

shaving cream

Shaving cream is Haram, as it is a reminder of the days of Patriarchy and toxic masculinity.

[Lord_James]

ok, I have a question about the reactive elements in the array: 

 

in the calculation doc, it says P_r = P_i / k1 - k2 * LoS_t … but using this verbatim gives me negative numbers, which isn't a good thing when calculating residual penetration. 

 

Is it suppose to be calculated P_r = (P_i / k1) - (k2 * LoS_t) or maybe P_r = P_i / ([k1 - k2] * LoS_t)? I just cant seem to get my NERA arrays to work with the initial formula. 

 

 

Anyway, I have my KE values for the 2 completed arrays: 

 

Lower Front: 590mm (593) 

Front Right: 730mm (734) 

[N-L-M]

25 minutes ago, Lord_James said:

P_r = (P_i / k1) - (k2 * LoS_t)

Yes.

If you end up with negative numbers when doing this it means the sandwich defeated the threat.

[Toxn]

So I think I've pushed the RAP-FS concept about as far as I can in this gun configuration:

 

The core is now two 30x350mm rods threaded together. The forward rod has a 13x51mm tungsten carbide bit in the front (underneath a fibreglass cap), while the rear rod screws into the nozzle for the rocket motor. The entire assembly is now somewhat undersized in the bore, with a set of forward fins to stabilize the front and a combination of the rear fins and a rear buffer to stabilize the rear. The fins are now fixed. The whole assembly weighs 8.8kg, with the pad weighing around 500g.

 

The RAP-FS round leaves the barrel at around 1900m/s, with the rocket motor being ignited in the bore via a flash hole in the pad. The rocket burns for around 1.5 seconds after ignition, and is capable of boosting the assembly to around 160m/s from a standing start. In practice, it serves simply to offset the drag of the shell assembly, keeping the round moving at more-or-less its initial speed for around 3km before falling off rapidly. As a result the round has a very strange trajectory.

 

Penetration is around 420mm RHA at the muzzle, with the more slender tungsten bit providing a fair proportion of the overall total (around 78mm).

 

A side effect of the way the shell is constructed is that the steel walls of the outer shell itself make a fairly potent anti-armour weapon. This might result in secondary penetration of as much as 130mm of RHA in a ring around the core assembly, with suitably impressive levels of spalling and shrapnel generation. If the round impacts the target before motor burnout, any remaining unburned fuel also turns into a rather impressive incendiary as it gets pulled into the penetration pathway of the core and/or outer shell. As a result the RAP-FS round is very effective at dealing with light vehicles and bunkers at shorter ranges.

Edit: optimising and calculating the penetration turned out to be a bear, as the way I set up my spreadsheet every change in rod parameters sets off a cascading series of mass and velocity changes that have to be accounted for. Right now, the way I'm doing it is to take the length of the rod, minus the length of the tungsten tip, adjust the parameters until the velocity matches the original velocity, take that penetration, divide by 1.15 and then add in the penetration of the bit at the correct velocity.

 

[LostCosmonaut]

Just to prove I'm actually working on this thing, some calcs for my basic 130mm round;

 

 

Also, the A R M O R   S P R E A D S H E E T (work in progress)

 

[Whatismoo]

10 minutes ago, Toxn said:

As a result the round has a very strange trajectory.

How are you ensuring it reliably follows the same trajectory, and that that trajectory can be calculated with the mechanical/electro-mechanical computers available?

 

How does the rocket firing inside the bore effect barrel life? Wouldn't that rapidly raise the chamber pressure? If I'm reading right aren't APCP's exhaust is not good to breathe and has a prominent signature, do you have any plans to address this?

[Toxn]

6 minutes ago, Whatismoo said:

How are you ensuring it reliably follows the same trajectory, and that that trajectory can be calculated with the mechanical/electro-mechanical computers available?

Visually it just needs a wonky sight with strangely-spaced range markings, same as an RPG-7. Calculation is no more or less complicated than normal, at least as far as I know.

 

In terms of accuracy, that will mainly depend on the reliability of the motor. There's only one, though, so there should be less issues than in, say, a cluster arrangement.

 

6 minutes ago, Whatismoo said:

How does the rocket firing inside the bore effect barrel life? Wouldn't that rapidly raise the chamber pressure? If I'm reading right aren't APCP's exhaust is not good to breathe and has a prominent signature, do you have any plans to address this?

The rocket is ignited in the bore but the shell should be outside before anything noteworthy actually happens since it takes a certain amount of time for the motor to develop thrust once ignited.

 

The exhaust is probably not good to breathe in, but then if you're close enough to suck in concentrated exhaust fumes you're almost certainly near the muzzle or the path of the projectile and thus dead.

 

The rocket should indeed leave a hilarious smoke trail pointing all the way back to the muzzle of the main gun, and frankly the mental image is too funny for me to bother looking for an alternative low-smoke propellant.

[Lord_James]

… ok... now, I am either extremely wrong, or my armor array is ridiculously good... 

 

I calculated at least 4782mm CE for the lower front array, which I find completely bananas. But I cant seem to find my error when solving for max thickness: 

 

4782 - 63.6 = 4718.4        RHA

4718.4 / 1.3 = 3629.5       AIR (1.3 is from multiplying 1.19 [how many decimeters LoS in this section] to 1.1) 

3629.5 - 70.7 = 3558.8     HHA 

3558.8 / 2 = 1779.4          (2 is the k1 for NERA at 19^o)

1779.4 - 55.3 = 1724.1     (12 / cos71 = 36.85 ; * 1.5 = 55.3) 

1724.1 / 2 = 862.1 

862.1 - 55.3 = 806.8        (it passes through 2 NERA layer) 

806.8 - 40.3 = 766.5        RHA 

766.5 - 33.5 = 733           Textolite 

733 / 2 = 366.5                 (3rd NERA layer) 

366.5 - 55.3 = 311.2 

311.2 / 2 = 155.6              (4th NERA layer)

155.6 - 55.3 = 100.3 

100.3 - 104.7 = defeated 

 

I have a very strong feeling I did something monumentally wrong, but I cant find where I made the mistake!

[Whatismoo]

Just now, Toxn said:

but then if you're close enough to suck in concentrated exhaust fumes

Wouldn't the crew be close enough when they open the breech?

[Kal]

7 hours ago, Lord_James said:

… ok... now, I am either extremely wrong, or my armor array is ridiculously good... 

 

I calculated at least 4782mm CE for the lower front array, which I find completely bananas. But I cant seem to find my error when solving for max thickness: 

 

4782 - 63.6 = 4718.4        RHA

4718.4 / 1.3 = 3629.5       AIR (1.3 is from multiplying 1.19 [how many decimeters LoS in this section] to 1.1) 

3629.5 - 70.7 = 3558.8     HHA 

3558.8 / 2 = 1779.4          (2 is the k1 for NERA at 19^o)

1779.4 - 55.3 = 1724.1     (12 / cos71 = 36.85 ; * 1.5 = 55.3) 

1724.1 / 2 = 862.1 

862.1 - 55.3 = 806.8        (it passes through 2 NERA layer) 

806.8 - 40.3 = 766.5        RHA 

766.5 - 33.5 = 733           Textolite 

733 / 2 = 366.5                 (3rd NERA layer) 

366.5 - 55.3 = 311.2 

311.2 / 2 = 155.6              (4th NERA layer)

155.6 - 55.3 = 100.3 

100.3 - 104.7 = defeated 

 

I have a very strong feeling I did something monumentally wrong, but I cant find where I made the mistake!

Problem is not the calcs, problem is that k1 value drastically reduces on parallel follow on NERA.  So yes, your CE is fantasy.

 

2nd and 4th nera layer can be ignored.    And rotate the 3rd nera layer if you don't want to ignore it either.

 

I also think your first air gap is off.  

 

 

[Toxn]

7 hours ago, Whatismoo said:

Wouldn't the crew be close enough when they open the breech?

What, and sit for a few minutes puffing on it like the world's biggest bong? The crew has many more worryingly toxic things nearer to hand to deal with in any case. A few wisps of rocket exhaust getting into an open breech after the fume extractor has done it's work is something like 100th place on the list of things that will give ex-tankers cancer.

[A. T. Mahan]

2 minutes ago, Toxn said:

What, and sit for a few minutes puffing on it like the world's biggest bong? The crew has many more worryingly toxic things nearer to hand to deal with in any case. A few wisps of rocket exhaust getting into an open breech after the fume extractor has done it's work is something like 100th place on the list of things that will give ex-tankers cancer.

 

That reminds me, we should all make sure to put Prop 65 warnings on everything

[T___A]

On 4/11/2019 at 6:40 AM, Toxn said:

The propellant for the rocket is some version ammonium perchlorate composite, for which a wealth of surviving literature exists.

 

 

After mentioning this idea to the Chief Auditor of Rocketry, I and the folks up at Lumpoco would appreciate water/alcohol as the propellant since we have a large stockpile of it and manufacturing expertise from our A series derived rockets. 

[Toxn]

37 minutes ago, T___A said:

 

 

After mentioning this idea to the Chief Auditor of Rocketry, I and the folks up at Lumpoco would appreciate water/alcohol as the propellant since we have a large stockpile it and manufacturing expertise from our A series derived rocket. 

Your most serene radiance, rest assured that we have already considered this very issue and requested our sister Auditors in the Department of Rocketry to develop and manufacture a suitable engine and associated fuel tanks, pumps etc. Unfortunately, our most learned sisters have since informed us telephonically that it may take a significant amount of time for their engineers to miniaturise the A-series tanks and motors to fit a sub-133mm form factor. We would accordingly humbly ask your assistance in motivating the various Auditors involved to apply their full effort to the project given their shared enthusiasm with the advantages it could provide, and eagerly await news from them of any further progress. We will of course happily provide whatever humble technical assistance may be necessary (including providing blueprints of our existing gun and shell designs, and detailed requirements for the motor's thust and specific impulse) to assist our sisters in these endeavours going forwards.

 

Here we should note that we have also taken the liberty of approaching the Department of Aero Engines for assistance in designing and producing a suitable ramjet engine for use as a motor to drive an armour-piercing shell from our existing 133mm gun. This project would, we feel, provide a secure backstop should our most respected sister Rocketry Department Auditors encounter unforseen technical difficulties in achieving their promised goals.

 

Until then, in the interests of beating back the phallocentric Cascadian dogs who even now threaten our Northern border, we have elected to press forward with production of the present shell and motor configuration purely as a stop-gap measure. By the grace of Hubbard, our sisters Auditors will soon deliver a technological marvel to assist us in our fight, but until then we are committed to pressing on as quickly as possible for the sake of the security of our glorious Dianetic People's Republic.

[Toxn]

1 hour ago, A. T. Mahan said:

 

That reminds me, we should all make sure to put Prop 65 warnings on everything

The ancient ways must be respected.

[Kal]

What acceleration is permissible to consider a heat warhead as 6 diameters effective? Vs the acceleration to consider a heat warhead as 5 diameters effective.

 

I want to use rpg 29 warhead at less than double its acceleration (currently 40% more acceleration). its still low pressure.  Can i assume i can retain its penetration?  This is in a BMP 3 style turret.

[N-L-M]

2 hours ago, T___A said:

water/alcohol as the propellant

Troop surveys suggest they too are in favor of this fuel arrangement.

 

[N-L-M]

1 hour ago, Kal said:

What acceleration is permissible to consider a heat warhead as 6 diameters effective?

Cockerill 90mm LP and lower.

[Kal]

2 hours ago, N-L-M said:

Cockerill 90mm LP and lower.

Sweet

[Lord_James]

8 hours ago, Kal said:

Problem is not the calcs, problem is that k1 value drastically reduces on parallel follow on NERA.  So yes, your CE is fantasy.

 

2nd and 4th nera layer can be ignored.    And rotate the 3rd nera layer if you don't want to ignore it either.

 

No offense, but I don’t trust you as much as some of the other people on this forum; they have proven their knowledge. So, I’m gonna have to ask for a second opinion. 

 

@N-L-M, @Toxn, any confirmation on what I did wrong? 

 

BUT!, your response does make sense, and I probably should have considered that. 

 

8 hours ago, Kal said:

 

I also think your first air gap is off.  

 

Yeah, I just checked and I think I mis-clicked a button on my calculator, but it’s 113mm LoS (80mm / cos45 = 113.1), which is 1.13 decimeters. Multiplied to 1.1 gives me 1.24. I’ll make some corrections when I have time.