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    • By BarnOwlLover
      This is one modern rifle that I'm insanely interested in, especially since there was a TFB article that hinted that there was a .308 Winchester/7.62mm NATO version being worked on that might use the same upper as the 5.56mm NATO version that HK has shown in several different versions since 2017. 
       
      This is the latest (known) iteration of the 433, and if you've seen some of the POTD posts at TFB since May of last year, you've probably seen it a time or two.  In short, the 433 is HK's answer to the FN SCAR and to try and one up it.  IMO, the most interesting thing about the 433 is that it seems capable of taking way more caliber rounds than items such as the FN SCAR or the Bren 2, which needed new uppers in order to go rounds like .308. 
       
      Out of curiosity one day, since I've seen numerous (though not often very new) photos of the 433 and I've also seen patent documents (I'll provide a link to patent documents and an article on Spartanat with some photos of the Gen 5 433), I decided to see if my own thoughts on the 433 being caliber convertible beyond .300 Blackout or 7.62x39mm held water.  Using a simple image scaling and measuring program, I've determined that the 433 upper, as is, is capable of taking rounds or at least magazines of 71-72mm OAL.  Mind you, this isn't exact, and I was conservative with my measurements. 
       
      Of course, this does further peak my curiosity on what the 433 is capable of firing and how caliber convertible it may be.  On top of of course how it comes apart and various details about it.
       
      Now the documentation.  Spartanat is an Austrian site, and hence is in German, and being new here I'm not sure how Google translate works when linked, so I'll just leave the link (which has good, albeit sadly not ultra HQ/high res images, which IMO is a damn shame) to be copypasta'd into Google's translator or your favorite translator.  On the plus side, there's a PDF in the article that you can save or convert to a pretty high res JPG or PNG image, and Google does a decent job of translating the PDF, too:
       
      https://www.spartanat.com/2019/05/photo-file-hk433-mit-concamo-im-feld/
       
      Now here's the patent documents and images.  This series mostly pertains to the charging handle system, but it shows a good idea of how the guts of the 433 are laid out:
       
      https://patents.google.com/patent/DE102018001984A1/en?inventor=Wilhelm+Fischbach
    • By Curly_
      This came up in a recent discussion I had with a friend over Discord, concerning a hypothetical near-peer conflict (particularly in an urban environment). My friend is of the belief that in such a conflict there isn't no reason to field any small arms (not just service rifles or light machine guns) in anything larger than something like 5.56 NATO, the rationale being that a.) you can carry more of it compared something like 6.5 Creedmoor or 7.62 NATO, b.) you're mostly going to be using it suppressing the enemy so that you can drop high explosives on their heads, and c.) since most combat takes place under 300 meters the extra range would be unnecessary. Is there any merit to this line of thinking? What cases can be made for using more powerful, longer ranged cartridges in SDMRs and (tripod or vehicle mounted) machine guns?
    • By LoooSeR
      I want to show you several late Soviet MBT designs, which were created in 1980s in order to gain superiority over NATO focres. I do think that some of them are interesting, some of them look like a vehicle for Red Alert/Endwar games. 
           
           Today, Russia is still use Soviet MBTs, like T-80 and T-72s, but in late 1970s and 1980s Soviet military and engineers were trying to look for other tank concepts and designs. T-64 and other MBTs, based on concept behind T-64, were starting to reaching their limits, mostly because of their small size and internal layout. 
       
      PART 1
       
       
      Object 292
       
         We open our Box of Communism Spreading Godless Beasts with not so much crazy attempt to mate T-80 hull with 152 mm LP-83 gun (LP-83 does not mean Lenin Pride-83). It was called Object 292.
       
       
       
          First (and only, sadly) prototype was build in 1990, tested at Rzhevskiy proving ground (i live near it) in 1991, which it passed pretty well. Vehicle (well, turret) was developed by Leningrad Kirov factory design bureau (currently JSC "Spetstrans") Because of collapse of Soviet Union this project was abandoned. One of reasons was that main gun was "Burevestnik" design bureau creation, which collapsed shortly after USSR case to exist. It means that Gorbachyov killed this vehicle. Thanks, Gorbach!
       
          Currently this tank is localted in Kubinka, in running condition BTW. Main designer was Nikolay Popov.
       
          Object 292, as you see at photos, had a new turret. This turret could have been mounted on existing T-80 hulls without modifications to hull (Object 292 is just usual serial production T-80U with new turret, literally). New Mechanical autoloading mechanism was to be build for it. Turret had special Abrams-like bustle for ammunition, similar feature you can see on Ukrainian T-84-120 Yatagan MBT and, AFAIK, Oplot-BM.
          Engine was 1250 HP GTD-1250 T-80U engine. 152 mm main smoothbore gun was only a little bit bigger than 2A46 125 mm smoothbore gun, but it had much better overall perfomance.
          This prototype was clearly a transitory solution between so called "3" and "4th" generation tanks.
       
          Some nerd made a model of it:
      _________________________________________________________________________________________________________
       
       
      ........Continue in Part 2
    • By OnlySlightlyCrazy
      The full title of this work is "Weaponeering - Conventional Weapon System Effectiveness" by Morris Driels, who teaches at the USN Postgraduate School, and the cover of the edition I have in hand can be seen below.


       
      The book aims to "describe and quantify the methods commonly used to predict the probably of successfully attacking ground targets using air-launched or ground-launched weapons", including "the various methodologies utilized in operational products used widely in the [US military]." Essentially, this boils down to a series of statistical methods to calculate Pk and Ph for various weapons and engagements. 

      The author gave the book to my mother, who was a coworker of his at the time, and is of the opinion that Driels is not as smart as he perceives himself to be. But, hey, it's worth a review for friends.

      I will unfortunately be quite busy in the next few days, but I have enough spare time tonight to begin a small review of a chapter. I aim to eventually get a full review of the piece done.

      Our dear friends @Collimatrix and @N-L-M requested specifically chapter 15 covering mines, and chapter 16 covering target acquisition.

      Chapter 15
      Mines

      The mine section covers both land mines and sea mines, and is split roughly in twain along these lines.

      The land mine section begins with roughly a page of technical description of AT vs AP, M-Kill vs K-Kill, and lists common US FAmily of SCatterably Mines (FASCAM) systems. The section includes decent representative diagrams. The chapter then proceeds to discuss the specification and planning of minefields, beginning with the mean effective diameter of a mine. Driels discusses a simplified minefield method based on mine density, and then a detailed method.

      The simplified method expresses the effectiveness of the minefield as a density value. Diels derives for the release of unitary mines from aircraft

      NMines = Fractional coverage in range * fractional coverage in deflection * number of mines released per pass * reliability * number of passes

      and for cluster type

      NMines = FRange * FDefl * NDispensers * Reliability dispenser * NMines per Dispenser * Reliability Submunition * number of passes

      and then exploits the evident geometry to express the Area and Frontal densities. Most useful is the table of suggested minefield densities for Area Denial Artillery Munition and Remote Anti-Armor Mine System, giving the Area and Linear densities required to Disrupt, Turn, Fix, and Block an opponent. 


      Whereas the simplistic method expresses effectiveness as a density, the detailed model views the targets and mines individually, assuming the targets are driving directly through the minefield perpendicular to the width and that there is only one casualty and no sympathetic detonations per detonation. The model computes the expected number of targets destroyed by the minefield, beginning with the Mean Effective Diameter and the PEncounter based on distance from the mine. 

      Driels derives the number of mines encountered which will be encountered, not avoided, and will engage the target. I can't be arsed to type the equations in full, so here you go.



      The section concludes with an example calculation using the detailed mine method. Overall, this shows the strengths and weaknesses of the book fairly well - it is a reasonable derivation of open-source statistical methods for predicting Pk and Ph and the number of sorties required, but US-specific and limited in scope and depth. 

      The treatment of Sea Mines  begins by describing the various types and uses of said mines, importantly noting that they have both defensive and offensive uses, and that the presence of the threat of mines is equally important as the actual sinking which occurs. There are three classifications of sea mines, contact, influence, and controlled.

      Shallow water mines are treated trivially, considering them equivalent to land mines with Blast Diameter in the place of MED, and assuming that the mines cannot be avoided.

      Deep water mines are approached in a similar manner, with the desire to determine the number of mines needed to achieve the required probability of damage, and planning missions from there. Two features of sea mines must be considered, however - mine actuation by passing of the target, and mine damage to the target. The probability of activation is, unfortunately, dependent on the depth of the mine and distance, forming a series of stacked bowls as below.


      The mean value of PActivation is the statistical expectation of the curve. Because I don't feel like screencapping another equation, the Width of Seaway where an actuation can occur is qualitatively merely the area under the actuation curve calculated for a specific mine and target combo.

      The damage function is also of interest - because we require the mine to both actuate and damage the target, this limits our earlier area under the curve to that area integrated to the limits of the damage function. The selection of mine sensitivity plays a very large role in the effectiveness of our mines. A high setting will lead to many more actuations than damages, which can be indicated by the ratio of the actuation area and the damage area from earlier. Setting the actuation distance equal to the damage distance means that every actuation causes damage, but the probability of actuation is only around 42%. The compromise which selects some Areadamage / Areaactuation of around .8 to .93 is generally preferred. This gives us several useful terms -
      PA+D = Reliability * Areadamage / Widthminefield . The probability that the first ship to transit a minefield is referred to as the threat, or
      Threat T = 1 - (1 - PA+D)^NMines = 1 - (1 - Reliability * Areadamage / Widthminefield ) which can obviously be solved for NMines to get the desired number of mines for a desired threat level.

      Anti-submarine mines are an interesting subset of deep sea mines, as they turn the problem from two-dimensions to three. Driels accounts for this by replacing the mine damage width with the mine damage area, to no one's surprise. Driels claims that the probability of actuation and damage is 

      PA/D =  Damage Area / (Width * Depth of minefield). Despite my initial confusion, the reliability term safely reappears in the threat definition below.

      T = 1 - (1 - (Reliability * Area damage)/(Width * Depth of minefield))^NMines, with a solution for number of mines for given threat level fairly easily taken out as before.

      Lastly, there is a summary of topics for each chapter, though unfortunately they are qualitative descriptions. Including the final derived equations in this part would be a major benefit, but is overlooked. Ah well. They are quite good for review or refreshing the material.

      As before, this is a relatively interesting if shallow engagement with the statistical methods to calculate Pk and Ph and the number of sorties required. Going more into detail regarding selecting Threat values or common (unclass) parameters would be interesting, but is lacking. Assuming I don't slack off tomorrow, I should have most or all of the Target Acquisition chapter covered.
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