N-L-M

ADDENDUM 1

Armor details:

1. Fixes.

A. ERA spacing: results from the labs show that ERA need only have 2 sandwich thicknesses away from other elements and not 3 as previously required.

B. Spaced armor: Spaced armor rules apply to the main warhead in a tandem immediately, as the precursor slug counts as a sufficient "face". Base penetration is not however affected.

Light threats (155mm HE frag, SLAP) experience spaced armor effects from 10mm face.

2. Clarifications.

A. In reactives, the K2 factor applies only to the steel LOS in the sandwich. The rubber or explodium do not affect penetration other than by giving the dynamic effect.

B. The spacing between reactive elements is measured normal to the face.

C. To get the ERA/NERA effect, the penetration LOS must enter the front face and exit the back face of the sandwich. Edge and corner hits count only as the steel LOS value.

D. Penetration of light threats:

SLAP-

30mm at 750m

35mm at 500m

40mm at 250m

45mm at 50m

155mm HE-

40mm at 15m

45mm at 10m

50mm at 5m

E. Light threats do not experience dynamic effects of RA (K1 but do experience LOS feeding (K2).

F. The light threats experience spaced armor effects from 10mm LOS steel.

G. The weight of brackets for reactive armor is selectable, where 10% is light and flimsy and 30% is solid.

This affects multi-hit ability in a non-quantified way.

H. The density of rubber and explodium fills of RA is 1.5g/cm^3.

I. Any RA element hit by a precursor takes no part in the action of the main warhead; in passive elements, only the depth not involved in the penetration of the precursor takes part in the action of the primary.

J. DPICM- 40mm HEAT with 4 CD =160mm CE.

3. Additions.

A. Face hardened armor.

Hardened to a depth of 20% or 10mm, whichever is less. Hard face acts like HHA, including making it difficult to attach things to.

B. Equations for K1 curves:

Will be posted soon, check back in 12 hours from the time of posting.

 

Other spec changes.

A. Norman killing ranges reduced to 1.5/2.25/3km with a 50% Phit, where rounds that have a lesser Phit are grouped until they do. (For example, 0.3 Phit has a combined probability of at least one hitting of (1-0.7^2)=0.51, so rounds are counted as half a stowed kill).

B. DPRC APFSDS may be of Maraging steel of up to 400 BHN hardness.

 

Changes may take up to 12 hours to be updated in the OP spec.

6 hours ago, A. T. Mahan said:

Edit: RIP my math skills, I was wrong.

Low energy, SAD!

 

5 hours ago, A. T. Mahan said:

What is CA’s production capacity for Al2O3, SiC, and aramids?

Not available in the quantities required for AFV protection. Aramid is available in sufficient quantities for select spall lining applications.

 

4 hours ago, A. T. Mahan said:

I just want to give the tank crews fire-protective clothing and body armor.

DPRC armor crews are already outfitted with hypo-allergenic free-range non-GMO organic ergonomic fire retardant clothing and flak vests, which do not count against their weight-lifting ability.

You are however invited to design spall and frag resistant seats and crew stations.

 

I would however remind you that crew survivability is a strictly lower priority than vehicle survivability and continued fightability.

 

1 hour ago, DIADES said:

My experience with AFV interiors is that they are too tight for ease of movement even if one was stark naked and fully greased up..........

Some are better than others but this is pretty accurate.

Though I find that youre actually more maneuverable inside in full protective gear (including helmet), as youre less worried about bashing your head in on sharp corners and the like.

 

Properly designed crew stations and gear have all the annoying sharp corners away from the egress route.

11 hours ago, Collimatrix said:

Are you implying that the Cascadian government would supply Deseret with ATGMs?

The Cascadian Propaganda Service claims any Cascadian weapons in the hands of the Mormonhideen fell of the back of a truck during one of their long range recon patrols into Deseret territory.

 

9 hours ago, Collimatrix said:

light ERA

I should clarify- the k2 rule applies only to the steel LOS in the sandwich. Also I'm not sure how you get to 36mm just from the k2 rule when the sandwich is 3/3/3.

 

There will be a post within the next 24h with a few detail changes to the armor specs and the k1 equations.

9 hours ago, Xoon said:

If a AFV lacks a turret, can it ignore the turret requirements? 

Yes.

9 hours ago, Xoon said:

Does the same apply for a AFV lacking a hull? 

How do you propose to have a vehicle without a hull?

8 hours ago, Lord_James said:

is laminated armor available in DPRC? 

No.

1 hour ago, A. T. Mahan said:

I meant is it 100g of elemental tungsten, or 100g of a given tungsten alloy?

100g of elemental tungsten, to be used as seen fit (WC, WHA, or friends).

 

Assorted rare earth elements are not available for use other than in trace quantities as alloying materials or in limited electronics applications.

1 hour ago, A. T. Mahan said:

molybdenum deposits?

 

Additionally, how is the tungsten being assayed for use in armor piercing projectiles?

1. Moly is available in sufficient quantities for steel alloys but not for other uses.

2. Tungsten supplies are limited and no more than 100g may be used per shot.

30 minutes ago, Xoon said:

What is the minimum amount of crew required? 

0.

General rule of thumb- if it isn't deliberately written down in the introductory post or appendices, it is not limited and you may use your design sense as you see fit. Your choices will be judged in the context of the alternatives proposed by the other competitors.

The DPRC is accepting of diversity in the design of tanks as it is in many other fields.

6 minutes ago, Toxn said:

@N-L-M Can you give the equations used for the graphs in appendix 1?

 

I have some optimisation I want to try out...

Sure, I'll post them later.

Somewhat optimisitcally modified from the numbers in the TRADOC bulletin for the T-62.

Yes, for rounds with a Phit above 50%.

For rounds with less than that, they count as less, by the number required to get a Phit of 0.5.

So if we have HEAT rounds with a Phit of 0.3, the chance that of 2 rounds at least one will hit is 1-(0.7*0.7)=0.51.

So every 2 HEAT rounds carried count as 1 stowed kill.

9 minutes ago, DIADES said:

Stowed kills

The stowed kills requirement is for the given number of rounds, with a Phit over 50%. 

So if we assume for example a M60A1 carrying 20 APFSDS, which have 50% Phit rates against Norman-sized targets at 2km, it counts as 20 stowed kills.

2 hours ago, Collimatrix said:

But then we're only allowed four pieces of side skirt armor

4 pieces requiring a crane.

Components under 25 kg (like Kontakt 1 bricks, for example) are not limited in number.

2 hours ago, Collimatrix said:

2)  How exactly do the .50 cal SLAP, DPICM and 155mm HE threats work?

DPICM- 40mm HEAT, 4 CD= 160mm pen.

.50 cal SLAP

30mm at 750m

35mm at 500m

40mm at 250m

45mm at 50m

155mm HE fragments:

40mm at 15m

45mm at 10m

50mm at 5m

HE may be assumed to be airburst, both fragments and SLAP ignore dynamic effects of armor (k1) but not LOS feeding (k2).

Will be added to the spec soon.

2 hours ago, Collimatrix said:

If the precursor warhead penetrates into a NERA element, is that element considered "expended?"

Yes.

That's the plain old Norman: 60mm HHA- 20 cm gap- 200mm RHA LOS. The dedication to defeating speculative future Cascadian perfidy ahead of time is, however, lauded.

10 minutes ago, Lord_James said:

I don’t understand the difference between K1 and K2 in those calculations. 

K1 is the dynamic portion that breaks up the penetrator, reducing its overall penetration by a certain factor, and is modelled as being angle-dependent.

K2 is the erosion of the penetrator by feeding material into its path, and is modelled as being constant.

Quote

Light and heavy NERA use the same k1 curves as their ERA equivalents.K2 is 2 for ERA and 1.5 for NERA.

Note that the NERA sandwiches are thicker but require less open spacing between them to function.

Pinning a single number is difficult due to the dynamic interaction of the armors with the penetrators; the effectiveness in terms of penetration "eaten up" by the armor is therefore also dependent on the threat impacting. See Appendix 1 for details on armor protection estimation.

34 minutes ago, Lord_James said:

...

1. Neither Uranium nor Tantalum reserves are available for tactical ground forces use.

2. HHA is sufficiently well-constructed that it will not shatter under standard ballistic impacts.

RHA is alloyed per the pre-cataclysm MIL-A-12560H. 

3. FH armor is available; the outer 20% or 10mm (whichever is less) functions as HHA and the rest as RHA. May be used for structural purposes, but fitting equipment to the hardened face becomes... interesting.

5 hours ago, Xoon said:

So no Strv 103?

 

True, but its neat to have the option. 

 

Aluminum is really hard to weld in my experience, compared to steel, so I was just worried about the weld quality. But I assume they are equal. 

 

1. Strv 103-alike is allowed if you can show an ability to engage targets in the extended frontal arc without a notable disadvantage compared to turreted alternatives.

2. The option is there if you can make it work.

3. Aluminum is more difficult to weld which makes it more expensive, but in terms of actual weld quality the DPRC can weld aluminum just as well as it can weld steel.

The People's Auditory Forces armored branch has not yet set a definite date for handing in the finished designs, but it is likely to be more than 2 months from the present.

25 minutes ago, Xoon said:

I have a few questions:
1.  Is a 360 degree turret required?
2.  Are tracks required?
3. What type of terrain is the vehicle expected to operate in? 
Marsh, swamp, snowy, rocky, hilly, forested, mountainous, many rivers? , many lakes?, frequent river crossings?  Urban fighting? Frequent use of tunnels? etc. 

4. What is the quality and capability of the welding industry? Does aluminum welds reach the same quality as steel welds? 

5. When requiring it to fit the average soldier at 1,7m, does that mean the 95th percentile of a population with a average height of 1,7m?

6. If manufacturing capability is present, can technology be "invented"? FCS, RCWS, autoloaders, ballistic computers, engine components etc, made from technology in other industries?
Example, manufacturing industries use pneumatic PID regulators,  a similar technology could be used for FCS?

1. A 360 degree turret is not required, but the ability to engage targets within the extended frontal arc is.

2. Tracks are not required, but the ground pressure requirements are MMP and not NGP; good luck getting anywhere near them with wheels.

3. Any and all of the above, within reason. Hence the ground pressure requirement.

4. Aluminum 5083 is as weldable as RHA.

5. No; it means the average one. 95th percentile soldiers belong in infantry, not armor.

6. The idea is 1960s tech and current day knowledge. If you can get it to work convincingly, go ahead.

High and Low intensity conflict. 

AKA "All out war with the Cascadian Entity" and "Enforcing peace on the Mormonhideen"

The whole spec is in metric, to avoid confusion, yes.

Military Load Class, all up weight may not exceed 120 tons.

Restricted: for Operating Thetan Eyes Only

By order of Her Gracious and Serene Majesty Queen Diane Feinstein the VIII

The Dianetic People’s Republic of California

Anno Domini 2250

SUBJ: RFP for new battle tank

 

1.      Background.
As part of the War of 2248 against the Perfidious Cascadians, great deficiencies were discovered in the Heavy tank DF-1. As detailed in report [REDACTED], the DF-1 was quite simply no match for the advanced weaponry developed in secret by the Cascadian entity. Likewise, the DF-1 has fared poorly in the fighting against the heretical Mormonhideen, who have developed many improvised weapons capable of defeating the armor on this vehicle, as detailed in report [REDACTED]. The Extended War on the Eastern Front has stalled for want of sufficient survivable firepower to push back the Mormon menace beyond the Colorado River south of the Vegas Crater.
The design team responsible for the abject failure that was the DF-1 have been liquidated, which however has not solved the deficiencies of the existing vehicle in service. Therefore, a new vehicle is required, to meet the requirements of the People’s Auditory Forces to keep the dream of our lord and prophet alive.

 

 

Over the past decade, the following threats have presented themselves:

A.      The Cascadian M-2239 “Norman” MBT and M-8 light tank

Despite being approximately the same size, these 2 vehicles seem to share no common components, not even the primary armament! Curiously, it appears that the lone 120mm SPG specimen recovered shares design features with the M-8, despite being made out of steel and not aluminum like the light tank. (based on captured specimens from the battle of Crater Lake, detailed in report [REDACTED]).
Both tanks are armed with high velocity guns.

B.      The Cascadian BGM-1A/1B/1C/1D ATGM

Fitted on a limited number of tank destroyers, several attack helicopters, and (to an extent) man-portable, this missile system is the primary Cascadian anti-armor weapon other than their armored forces. Intelligence suggests that a SACLOS version (BGM-1C) is in LRIP, with rumors of a beam-riding version (BGM-1D) being developed.

Both warheads penetrate approximately 6 cone diameters.

C.      Deseret tandem ATR-4 series
Inspired by the Soviet 60/105mm tandem warhead system from the late 80s, the Mormon nation has manufactured a family of 2”/4” tandem HEAT warheads, launched from expendable short-range tube launchers, dedicated AT RRs, and even used as the payload of the JS-1 MCLOS vehicle/man-portable ATGM.
Both warheads penetrate approximately 5 cone diameters.

D.      Cascadian HEDP 90mm rocket
While not a particularly impressive AT weapon, being of only middling diameter and a single shaped charge, the sheer proliferation of this device has rendered it a major threat to tanks, as well as lighter vehicles. This weapon is available in large numbers in Cascadian infantry squads as “pocket artillery”, and there are reports of captured stocks being used by the Mormonhideen.
Warhead penetrates approximately 4 cone diameters.

E.      Deseret 40mm AC/ Cascadian 35mm AC
These autocannon share broadly similar AP performance, and are considered a likely threat for the foreseeable future, on Deseret armored cars, Cascadian tank destroyers, and likely also future IFVs.

F.      IEDs

In light of the known resistance of tanks to standard 10kg anti-tank mines, both the Perfidious Cascadians and the Mormonhideen have taken to burying larger anti-tank A2AD weaponry. The Cascadians have doubled up some mines, and the Mormons have regularly buried AT mines 3, 4, and even 5 deep.

2.      General guidelines:

A.      Solicitation outline:
In light of the differing requirements for the 2 theaters of war in which the new vehicle is expected to operate, proposals in the form of a field-replaceable A-kit/B-kit solution will be accepted.

B.      Requirements definitions:
The requirements in each field are given in 3 levels- Threshold, Objective, and Ideal.
Threshold is the minimum requirement to be met; failure to reach this standard may greatly disadvantage any proposal.

Objective is the threshold to be aspired to; it reflects the desires of the People’s Auditory Forces Armored Branch, which would prefer to see all of them met. At least 70% must be met, with bonus points for any more beyond that.

Ideal specifications are the maximum of which the armored forces dare not even dream. Bonus points will be given to any design meeting or exceeding these specifications.

C.      All proposals must accommodate the average 1.7m high Californian recruit.

D.      The order of priorities for the DPRC is as follows:

a.      Vehicle recoverability.

b.      Continued fightability.

c.       Crew survival.

E.      Permissible weights:

a.      No individual field-level removable or installable component may exceed 5 tons.

b.      Despite the best efforts of the Agriculture Command, Californian recruits cannot be expected to lift weights in excess of 25 kg at any time.

c.       Total vehicle weight must remain within MLC 120 all-up for transport.

F.      Overall dimensions:

a.      Length- essentially unrestricted.

b.      Width- 4m transport width.

                                                              i.     No more than 4 components requiring a crane may be removed to meet this requirement.

                                                             ii.     Any removed components must be stowable on top of the vehicle.

c.       Height- The vehicle must not exceed 3.5m in height overall.

G.     Technology available:

a.      Armor:
The following armor materials are in full production and available for use. Use of a non-standard armor material requires permission from a SEA ORG judge.
Structural materials:

                                                              i.     RHA/CHA

Basic steel armor, 250 BHN. The reference for all weapon penetration figures, good impact properties, fully weldable. Available in thicknesses up to 150mm (RHA) or 300mm (CHA).
Density- 7.8 g/cm^3.

                                                             ii.     Aluminum 5083

More expensive to work with than RHA per weight, middling impact properties, low thermal limits. Excellent stiffness.

 Fully weldable. Available in thicknesses up to 100mm.
Mass efficiency vs RHA of 1 vs CE, 0.9 vs KE.
Thickness efficiency vs RHA of 0.33 vs CE, 0.3 vs KE.
Density- 2.7 g/cm^3 (approx. 1/3 of steel).

For structural integrity, the following guidelines are recommended:

For light vehicles (less than 40 tons), not less than 25mm RHA/45mm Aluminum base structure

For heavy vehicles (70 tons and above), not less than 45mm RHA/80mm Aluminum base structure.
Intermediate values for intermediate vehicles may be chosen as seen fit.
Non-structural passive materials:

                                                            iii.     HHA

Steel, approximately 500 BHN through-hardened. Approximately twice as effective as RHA against KE and HEAT on a per-weight basis. Not weldable, middling shock properties. Available in thicknesses up to 25mm.
Density- 7.8g/cm^3.

                                                            iv.     Glass textolite

Mass efficiency vs RHA of 2.2 vs CE, 1.64 vs KE.

Thickness efficiency vs RHA of 0.52 vs CE, 0.39 vs KE.
Density- 1.85 g/cm^3 (approximately ¼ of steel).
Non-structural.

                                                             v.     Fused silica

Mass efficiency vs RHA of 3.5 vs CE, 1 vs KE.

Thickness efficiency vs RHA of 1 vs CE, 0.28 vs KE.
Density-2.2g/cm^3 (approximately 1/3.5 of steel).
Non-structural, requires confinement (being in a metal box) to work.

                                                            vi.     Fuel

Mass efficiency vs RHA of 1.3 vs CE, 1 vs KE.

Thickness efficiency vs RHA of 0.14 vs CE, 0.1 vs KE.

Density-0.82g/cm^3.

                                                          vii.     Assorted stowage/systems

Mass efficiency vs RHA- 1 vs CE, 0.8 vs KE.

                                                         viii.     Spaced armor

Requires a face of at least 25mm LOS vs CE, and at least 50mm LOS vs KE.

Reduces penetration by a factor of 1.1 vs CE or 1.05 vs KE for every 10 cm air gap.
Spaced armor rules only apply after any standoff surplus to the requirements of a reactive cassette.

Reactive armor materials:

                                                            ix.     ERA-light

A sandwich of 3mm/3mm/3mm steel-explodium-steel.
Requires mounting brackets of approximately 10-30% cassette weight.

Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects).

                                                             x.     ERA-heavy

A sandwich of 15mm steel/3mm explodium/9mm steel.
Requires mounting brackets of approximately 10-30% cassette weight.
Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects).

                                                            xi.     NERA-light

A sandwich of 6mm steel/6mm rubber/ 6mm steel.
Requires mounting brackets of approximately 10-30% cassette weight.
Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage.

                                                           xii.     NERA-heavy

A sandwich of 30mm steel/6m rubber/18mm steel.
Requires mounting brackets of approximately 10-30% cassette weight.
Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage.

The details of how to calculate armor effectiveness will be detailed in Appendix 1.

b.      Firepower

                                                              i.     2A46 equivalent tech- pressure limits, semi-combustible cases, recoil mechanisms and so on are at an equivalent level to that of the USSR in the year 1960.

                                                             ii.     Limited APFSDS (L:D 15:1)- Spindle sabots or bourelleted sabots, see for example the Soviet BM-20 100mm APFSDS.

                                                            iii.     Limited tungsten (no more than 100g per shot)

                                                            iv.     Californian shaped charge technology- 5 CD penetration for high-pressure resistant HEAT, 6 CD for low pressure/ precision formed HEAT.

                                                             v.     The general issue GPMG for the People’s Auditory Forces is the PKM. The standard HMG is the DShK.

c.       Mobility

                                                              i.     Engines tech level:

1.      MB 838 (830 HP)

2.      AVDS-1790-5A (908 HP)

3.      Kharkov 5TD (600 HP)

                                                             ii.     Power density should be based on the above engines. Dimensions are available online, pay attention to cooling of 1 and 3 (water cooled).

                                                            iii.     Power output broadly scales with volume, as does weight. Trying to extract more power from the same size may come at the cost of reliability (and in the case of the 5TD, it isn’t all that reliable in the first place).

                                                            iv.     There is nothing inherently wrong with opposed piston or 2-stroke engines if done right.

d.      Electronics

                                                              i.     LRFs- unavailable

                                                             ii.     Thermals-unavailable

                                                            iii.     I^2- limited

3.      Operational Requirements.

The requirements are detailed in the appended spreadsheet.

4.      Submission protocols.

Submission protocols and methods will be established in a follow-on post, nearer to the relevant time.

 

Appendix 1- armor calculation

Appendix 2- operational requirements

Addendum 1 - more armor details

Good luck, and may Hubbard guide your way to enlightenment!

Aight

We're 90% of the way there

SOON

The Panther didnt go nearly far enough for Colli.