Jump to content
Sturgeon's House

Recommended Posts

  • Replies 542
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

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

Comrades! The time of your waiting is over! I introduce to you the Sierra Nevada VagonZavod AFV-50 Gun Tank   Frontal Dimensions Frontal Armor Turret Cheek Armor Array (n

Report from Lt. Col. [REDACTED] People's Auditory Forces Directorate of Political-Moral Reliability, Auditory and Political Officer for SNVZ and Military-Industry Liaison Officer for RFP "New Battle T

4 hours ago, DIADES said:

The rule of thumb 1.5 is just that, a rule of thumb.  It dates to the 50s and there was work in the 80s that continued to advocate it in public domain material.  It is the outcome of a calculation that has several simple parameters.  The most critical of these relate to the structural limits of the soil/sand whatever that the vehicle is maneuvering on.  The magic number can go a high as 3 depending on the soil data used.  Does not correlate well with experiment and the experiments are limited to very hard flat ground.  I reckon the professionals have their own metrics.  I calculate LEO 1 to be 1.85 - comfortably over the 1.5 limit.  I don't recall the users complaining about LEO1 maneuverability!  Recent publications also show that number of road wheels has an effect.  More road wheels = better theoretical maneuverability.  Track tension also important, lower is better.

 

 

I'm not sure how you get 1.85 for the Leo 1.

 

lxp2rfA.png

 

This picture shows that the Leo 2 clearly has a longer total aspect ratio than the Leo 1.

 

But this picture:

Na7ukev.png

 

shows that the ratio of contact length to track center length is only 1.62 for the Leo 2.

 

 

I do buy that more road wheels would affect maneuverability.  More road wheels reduces MMP, and the lower the MMP, the lower the penetration of the tracks into the soil.  The less the tracks sink into the soil, the less soil they have to shift sideways when the tank turns.

Link to post
Share on other sites

OK, some initial goofing with the armor system:

 

 

Because Scientologists can't weld worth a damn, they are really short on options for armor with good thickness efficiency.  Now, granted, Sea Org-spec HHA is pretty great fucking stuff, and it's noticeably better than actual 1960s HHA.  It's comparable to top of the line 2019 HHA, actually.  But they can't weld it, they can't make it thicker than 1.7 inches, and they can't laminate or explosively bond it to make double or triple hardness steel.

 

This means that their armor arrays are going to be þikcqqqq.

 

3Yi3iQg.png

 

 

Link to post
Share on other sites
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.

Link to post
Share on other sites
9 hours ago, Collimatrix said:

 

 

I'm not sure how you get 1.85 for the Leo 1.

 

shows that the ratio of contact length to track center length is only 1.62 for the Leo 2.

 

It turns out I thought I was looking at at what I had searched for rather than what was delivered.  The data I used was for LEO 2 and found in Armour, Nov, Dec 1976.  Actually for a LEO2 proto and it differs slightly from your better looking data.  It gives track on ground length as 5,030mm rather than the 4,733mm in your data.  Track width was 630 rather than your 635.  Track centres at 2,710mm rather than your 2,785mm (hard to read that one?).  Other primary dimensions agree.   Interesting - the track on ground length in your image is actually centre to centre of first and last road wheel.  True track on ground will be longer but not by a lot.

 

Anyway!  My point was and is that 1.5 is not a limit as such so if designs are presented that exceed this metric, knowingly, then they may well be valid.

 

 

 

 

Link to post
Share on other sites

What are our holdings in Colorado and Nevada?

 

Particularly, do we have access to the Henderson and Climax Molybdenum mines in Colorado, or the Mount Hope, Nevada; Lucky Jack, Colorado; or Rico Deposit, Colorado molybdenum deposits?

 

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

 

 

Link to post
Share on other sites
8 hours ago, Xoon said:

What is the minimum amount of crew required? 

At least two LGBTQQIP2SAA and/or racial minorities

1 hour ago, A. T. Mahan said:

What are our holdings in Colorado and Nevada?

 

Particularly, do we have access to the Henderson and Climax Molybdenum mines in Colorado, or the Mount Hope, Nevada; Lucky Jack, Colorado; or Rico Deposit, Colorado molybdenum deposits?

 

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

 

 

 

I am interested in your participation Citizen Mahan, I have read your file and you are under suspicion of the heresy of believing that that Xenu brought humans to Earth on Boeing 707s rather than the one true DC-8. 

Link to post
Share on other sites
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.

Link to post
Share on other sites
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.

Link to post
Share on other sites
17 hours ago, Collimatrix said:

 But they can't weld it, they can't make it thicker than 1.7 inches, and they can't laminate or explosively bond it to make double or triple hardness steel.

 

 

Just stack several HHA plates and encase them in RHA. You get whatever thickness you want.

Link to post
Share on other sites
7 hours ago, holoween said:

 

Just stack several HHA plates and encase them in RHA. You get whatever thickness you want.

 

 

That would work!  The total array efficiency would be somewhat less efficient than pure HHA due to the RHA holding it together, but it would be admirably efficient overall, and certainly quite thin.

 

I was thinking of arrangements where steel armor of different hardnesses is laminated together (note: this is tricky to do).  An arrangement with a harder, more brittle steel as the strike face backed by a softer, tougher steel is more protective than the sum of those two plates on their own.  An arrangement with soft/hard/soft is better still.

 

Metallurgically trickier still are laminates with aluminum bonded to high hardness steel.  I haven't read much about them, except that they're supposed to be quite good, and also a bitch to make.

Link to post
Share on other sites

I would just like to say that I am deeply offended by the fact that the ATGM arcs are wider in the LIC spec than the HIC spec.  Are you implying that the Cascadian government would supply Deseret with ATGMs?  Are you saying that the government of a developed, democratic republic would consider supplying advanced guided missile systems to a bunch of religious zealot insurgents just so screw over an opposing state?

 

That strategy would obviously backfire.  Who would be that stupid?

Link to post
Share on other sites

OK, so I've had enough time to think about the armor system to have _somewhat_ cogent thoughts:

 

 

The 90mm HEAT rocket has 360mm of armor penetration.  I know a lot of you played World of Tanks, which had tanks with all-steel armor and penetration was calculated (more or less) as a function of LOS thickness of all steel armor.

 

360mm is a whole hell of a lot of penetration vs. all steel armor.

 

d3GrX8b.jpg

 

That will centerpunch a Chieftain through the thickest part of the glacis with about 85mm of penetration left over.  And that's on the best part of the Chieftain's armor, from head-on, and with one of the weaker threats in the specification inventory.  And that's on a fairly heavy tank.

 

The next temptation is to thin down the steel armor to the structural minimum, and use the remaining weight on the armor with the best mass efficiency.

 

That doesn't work either.  The best passive material on the armor list against HEAT is the fused silica with a thickness efficiency of 1 and a mass efficiency of 3.5.  But that damn tandem-warhead ATGM has a combined penetration of 1320mm.

 

Once you add the underlying chassis and the confinement, you're looking at an armor package that's the better part of a meter and a half thick.  And if you look at the best estimates for actual MBT armor array thickness, they're not anywhere near that huge:

ZEnt4Wf.png

 

And the protection spec against the HEAT demands protection against a fairly wide arc.

 

The saving grace is that the reactive armor rules and the spaced armor rules are essentially multiplicative with the armor arrays underneath them.  The passive armor is all basically additive.

 

So, as an example, say we hang a 12.5mm thick HHA plate off of some sort of bracket, and then hang a light ERA panel 18mm away (N-L-M said he was going to change the ERA spacing rules to require 2x sandwich thickness spacing instead of 3x, and that he would add that as soon as he updates the secondary threat rules), and then slant it all at 60 degrees from the vertical, and then park it about four inches away from the main armor, then against the 90mm basic bitch rocket we have:

 

1)  RPG hits the high-hardness armor burster plate and explodes
2)  RPG penetrates the high hardness armor burster plate.  The LOS thickness is 25mm, and HHA has a TE of 2 against CE threats, so the jet loses 50mm of penetration, bringing it down to 310mm.

3)  RPG penetrates the ERA casette.  The K1 coefficient looks to be about 1.5 for 60 degrees off the vertical, and K2 works out to 36mm.  So the 310 pen is reduced down to 170mm.
4)  The jet from the RPG is traversing the 100mm offset between the ERA and the main armor.  The HHA burster plate is thick enough to invoke the spaced armor rules, and the 100mm gap reduces the penetration of the jet down to 155mm.

 

And just to keep things simple, let's say we have a 155mm LOS steel chassis plate to soak up this hit.

 

That array comes to 370mm LOS thickness (25mm HHA, 90mm for ERA plus spacing, 100mm air gap, 155mm steel structure underneath it all), but it's protecting the same as 360mm of steel and only weighing 53% as much.  So that's a TE of .97 and an ME of 1.86.  For an extremely simple and clearly un-optimized armor array.  The ME would go down a bit once we add proper mounts for the HHA and ERA, but the bottom line is that this is much lighter than steel, and much smaller than the equivalent textolite protection.  On top of that, it is an imminently practical array.  The ERA is protected by the HHA, so it can't get popped by machine gun fire or scraped off by the tank running into things.

 

Now, this array only provides 255mm against KE.  But you get the idea.  Reactive armor FTW.

Link to post
Share on other sites
1 minute ago, Toxn said:

So my first pass at optimisation revealed something fascinating.

 

Basically solver decided that light ERA and light NERA are the way to go. Intriguingly, however, it decided that the ERA layer works best when completely flat...

 

Did you double check whether you were measuring angle from the vertical or angle from the horizontal?

Link to post
Share on other sites
7 minutes ago, Collimatrix said:

 

Did you double check whether you were measuring angle from the vertical or angle from the horizontal?

Yup.

 

Solver decided that it wanted two-ish layers of light ERA (I forgot to force it to use whole numbers) on the flat, and 10-ish layers of light NERA at 64' from the vertical (ie: alpha is 26).

 

The result, when draped over a flat RHA base with the bare minimum thickness (45mm) is a 1-metre deep array that will stop both the highest KE and CE threats and has a total areal density of ~5 tonnes per square metre. Which is amazing given that an equivalent RHA armour plate would be ~10 tonnes per square metre.

 

I don't think I've reached a perfect solution here, but I suspect that when I do it will involve the same components in differing configurations.

Link to post
Share on other sites

Oh, yeah, @N-L-M mentioned that he wanted to clarify that the explosive filler of ERA has a density of 1.5 gm/cm^3.

 

Which means that light ERA has a density of 5.7 gm/cm^3, or 7.41 gm/cm^3 after you account for brackets.  Which means that flat light ERA has a mass efficiency of 2.1 thanks to the K2 rules!

Dang, you're on to something there.

 

Now, watch all the submissions resemble those Azov Brigade creations covered in several tons of layered explosives.

Link to post
Share on other sites
10 minutes ago, Collimatrix said:

Oh, yeah, @N-L-M mentioned that he wanted to clarify that the explosive filler of ERA has a density of 1.5 gm/cm^3.

 

Which means that light ERA has a density of 5.7 gm/cm^3, or 7.41 gm/cm^3 after you account for brackets.  Which means that flat light ERA has a mass efficiency of 2.1 thanks to the K2 rules!

Dang, you're on to something there.

 

Now, watch all the submissions resemble those Azov Brigade creations covered in several tons of layered explosives.

The perfect Californian tank is impenetrable to all attacks, but occasionally detonates when left in the sun for too long...

Link to post
Share on other sites
7 minutes ago, Collimatrix said:

Each flat light ERA casette provides 36mm RHAE of protection, but they need to be spaced 36mm apart from each other.  So, the TE isn't all that great.

Yeah, on that note I'm not sure why solver decided on the particular ratios of light ERA and light NERA that it did.

 

Trying to force it to go for thinner arrays just results in failures to solve, and minimising thickness instead of mass results in nearly the same array but with a 10cm air gap shoved in.

Link to post
Share on other sites
3 hours ago, Collimatrix said:

 

 

That would work!  The total array efficiency would be somewhat less efficient than pure HHA due to the RHA holding it together, but it would be admirably efficient overall, and certainly quite thin.

 

I was thinking of arrangements where steel armor of different hardnesses is laminated together (note: this is tricky to do).  An arrangement with a harder, more brittle steel as the strike face backed by a softer, tougher steel is more protective than the sum of those two plates on their own.  An arrangement with soft/hard/soft is better still.

 

Metallurgically trickier still are laminates with aluminum bonded to high hardness steel.  I haven't read much about them, except that they're supposed to be quite good, and also a bitch to make.

 

@N-L-M, is laminated armor available in DPRC? 

 

I dont think I’ve seen anything on the process for laminating armor plates, though I do know Hot Isostatic Pressing can laminate different metals together, albeit it takes a while. 

Link to post
Share on other sites
  • N-L-M unfeatured this topic

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Content

    • By Toxn
      This is the competition entry thread.
       
      Please submit your complete entries here (all entries will be judged complete when judging begins in the first week of November) and keep the other competition thread for discussion and chatter.
       
      Once judging is complete I will make a post here to discuss the entries and announce a winner.
       
      Best of luck!
       
      Update: final submissions should be in hand by the 22nd of November 2020.
    • By SH_MM
      Found a few higher resolution photographs from the recent North Korean military parade. We didn't have a topic for BEST KOREAN armored fighting vehicles, so here it is.
       
      New main battle tank, Abrams-Armata clone based on Ch'ŏnma turret design (welded, box-shaped turret) and Sŏn'gun hull design (i.e. centerline driver's position). The bolts of the armor on the hull front is finally visible given the increased resolution. It might not be ERA given the lack of lines inbetween. Maybe is a NERA module akin to the MEXAS hull add-on armor for the Leopard 2A5?
       
      Other details include an APS with four radar panels (the side-mounted radar panels look a lot different - and a lot more real - than the ones mounted at the turret corners) and twelve countermeasures in four banks (two banks à three launchers each at the turret front, two banks à three launchers on the left and right side of the turret). Thermal imagers for gunner and commander, meteorological mast, two laser warning receivers, 115 mm smoothbore gun without thermal sleeve but with muzze reference system, 30 mm grenade launcher on the turret, six smoke grenade dischargers (three at each turret rear corner)
       


       
      IMO the layout of the roof-mounted ERA is really odd. Either the armor array covering the left turret cheek is significantly thinner than the armor on the right turret cheek or the roof-mounted ERA overlaps with the armor.
       


      The first ERA/armor element of the skirt is connected by hinges and can probably swivel to allow better access to the track. There is a cut-out in the slat armor for the engine exhaust. Also note the actual turret ring - very small diameter compared to the outer dimensions of the turret.
       
      Stryker MGS copy with D-30 field gun clone and mid engine:

      Note there are four crew hatches. Driver (on the left front of the vehicle), commander (on the right front of the vehicle, seat is placed a bit further back), gunner (left side of the gun's overhead mount, next to the gunner's sight) and unknown crew member (right side of gun's overhead mount with 30 mm automatic grenade launcher mounted at the hatch). The vehicle also has a thermal imager and laser rangefinder (gunner's sight is identical to the new tank), but no independent optic for the commander. It also has the same meteorological mast and laser warner receivers as the new MBT.
       
      What is the purpose of the fourth crew member? He cannot realistically load the gun...
       
      The vehicle has a small trim vane for swimming, the side armor is made of very thin spaced steel that is bend on multiple spots, so it clearly is not ceramic armor as fitted to the actual Stryker.

       
      The tank destroyer variant of the same Stryker MGS copy fitted with a Bulsae-3 ATGM launcher.
       

      Note that there is again a third hatch with 30 mm automatic grenade launcher behind the commander's position. Laser warning receivers and trime vane are again stand-out features. The sighting complex for the Bulsae-3 ATGMs is different with a large circular optic (fitted with cover) probably being a thermal imager and two smaller lenses visible on the very right (as seen from the vehicle's point of view) probably containing a day sight and parts of the guidance system.
       

      Non line-of-sight ATGM carrier based on the 6x6 local variant of the BTR, again fitted with laser warning receivers and a trim vane. There are only two hatches and two windows, but there is a three men crew inside.
       
       
      There are a lot more photos here, but most of them are infantry of missile system (MLRS' and ICBMs).
    • By Toxn
      You are an engineer at an Italian locomotive and tractor-making company in early 1943. The writing is on the wall for the Italian army in North Africa, with a lot of equipment having been lost and the enemy on the brink of kicking the axis out of Tunisia and then heading across the Mediterranean. In short, things are looking more than a little desperate. 
       
      However, all is not lost. Il Duce himself has stepped in and, with the assistance of the Germans, procured both some of their finest captured vehicles for use in the upcoming defense of the homeland. Since many of these vehicles have been... gently used, and the existing firms like Ansaldo are flooded with orders, your firm has been asked to work on them in order to bring them up to the standards demanded by modern warfare. 
       
      In addition to these vehicles, the Germans have also graciously agreed to sell weapons from their existing stock of captured equipment, as well as providing production licenses for some of their more modern equipment. You have also been given permission to work with local weapons manufacturers in order to modify existing artillery to suit your needs. Italian automotive and engine manufacturers are similarly available to help. Finally; your firm's experience in locomotives and tractors means that you can modify hulls and put together turrets and turret rings. You can also produce castings (although not very large ones) and weld armour plates.
       
      Your job, which you have no choice but to accept, is to choose a vehicle from among the captured stock being offered for sale, and propose a series of plausible fixes in order to give it a fighting chance against the American and British equipment currently in the field (specifically light tanks and light anti-tank weapons).
       
      It is not foreseen that any of these vehicles will be able to plausibly take on modern medium or heavy designs head-on. Instead, what is wanted are general, implementable improvements to the characteristics of the chosen vehicle. These improvements should be aimed at making these vehicles more useful in the initial battles which are foreseen taking place against airborne and landing forces, in general cooperation with infantry, and as scouts.
       
      The submission should include one or more drawings or blueprints (at least a side view of the vehicle, but preferably a 3-point view and isometric view), a description of the modified vehicle, a description of how the modifications would be accomplished and a description of how the modifications would improve the design overall. The text of the submission should short and descriptive rather than long and exhaustive, and should not exceed 1000 words in total. Images may be photoshopped using existing pictures.
       
      Judging will be done on the basis of plausibility and effectiveness, with innovative solutions being encouraged in order to get the most bang for buck out of the base vehicle. Beyond implementation, the fixes should prioritise combat effectiveness while also improving reliability, crew ergonomics, communication, mobility and protection as much as possible.
       
      The foreign vehicles available for modification are:
      Renault R35 (already in service) Hotchkiss H35/39 Somua S35 (already in use for training purposes) T-26 BT-5 T-28 (only available in very small numbers, so need to be extremely effective) Panzer II Ausf.C  
      The foreign weapons immediately available for purchase are:
      15mm ZB-60 25mm Puteaux and Hotchkiss 3.7cm KPÚV vz. 34/Pak 34 (t) 3.7cm ÚV vz. 38/KwK 38(t)
      3.7cm Pak 36 4.0 cm Pak 192 (e) 45mm M1937 (53-K) 4.7cm KPÚV vz. 38/Pak 38 (t) 47mm APX 7.5cm Pak 97/38 7.62 cm F.K.297(r) and  7.62 cm PaK 39(r) 8.8cm Raketenwerfer 43  
      Licenses are also available for the manufacture of foreign engines (Maybach HL62 TRM, Maybach HL120 TRM and Praga Typ TNHPS/II), periscopes, sights, radios, cupolas and automotive subassemblies. All foreign vehicle weapons, subassemblies and components are available for reverse engineering and manufacture.
       
      IMPORTANT NOTE: This competition hasn't been finalised, and is waiting on your input! Vote to participate by giving this topic a 'controversial' (grapefruit-induced tears being the only currency of value), and if we get enough participants we'll pull the trigger. Ask any questions you want below, and when/if the competition goes forwards I will make a new thread for entries.
       
      Edit: thanks to excellent feedback, the competition proposal has been somewhat edited. If you want an idea of what my mindset is here, read up on the battle of Gela (bearing in mind that the wikipedia entry is shite) and ask how much better the counter-attack could have gone if the Italian vehicles had been equipped with radios and had the ability to move faster than jogging speed.
       
      Edit 2: since I failed to mention this above - this is not a one-man, one-entry sort of competition (although I'm not keen on the ten-men, one entry approach either).
      If you have two good ideas then you can submit twice. The only rules are not to test my patience and to keep it within the bounds of good taste.
    • By Toxn
      So I got a request recently from {NAME REDACTED} as to whether we have a how-to guide or something for competitions. After a few moments of bitter, bitter laughter at the decade-plus of my life that I've spent cobbling together things that can maybe, sort-of, squint-your-eyes produce a facsimile of a realistic vehicle, I thought I'd share my process:
       
       
      Note: I was half-right - we definitely have supplementary info for aspiring pretend tank designers pinned to this very board.
       
      Finally, I'm inviting our forum grognards and past winners to share their process for folk that haven't been here since before the last ice age, so that all can benefit.

×
×
  • Create New...