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  1. Tank You
    N-L-M reacted to OnlySlightlyCrazy in Partial Review of Driel's "Weaponeering"   
    I finally got around to doing a review of the Acquisition Chapter. Apologies to @N-L-M for the delay, and apologies in advance for the length.
    This topic comes at perhaps an opportune time given a previous conversation with @Sturgeon regarding the Survivability/Lethality Onion.
    In this model of lethality, a target must be
    First, Seen
    Once Seen, Acquired
    Once Acquired, Hit
    Once Hit, Penetrated
    Once Penetrated, Destroyed
    With survivability obviously working in reverse. This model has proven quite robust and is extremely popular amongst those studying weapon systems and their survivability. Its terms are generally self explanatory, though it's worth clarifying the first two. Seeing refers to the perception of any given object via some form of sensor. Acquisition, then, refers to processing the perceived object *as a target*, by some form of identification or feature recognition.
    That pretentiousness aside, Driels in this chapter will address both topics; the US Joint Munitions Effectiveness Manual (JMEM) considers them in three parts: Target Detection, Target Recognition, and Target Identification under the titular Target Acquisition model. Detection under JMEM’s model correlates most closely with “See” under the Onion, with the remaining two falling under Acquiring the target.
    Driels begins by outlining several historical physiological and psychological models for Target Detection, before describing the work by Johnson which is at the core of the US Army’s Acquire model. Terrain, run-in effects, and conversion of range to probability of launch are accounted for, and the factors are combined with the Acquire model to describe the JMEM’s Target Acquisition model.
    Unlike the prior chapter, this chapter is much more explicitly focused on Air-to-Surface weaponeering. While the physiological and sensor models will obviously hold true for a variety of detectors, they are used here exclusively to create a model for the range and probability at which an aircraft will detect some ground target. Terrain masking is equally applicable to cases beyond that of Air-to-Surface, but such things as run-in effects and the minimum time taken to bring an aircraft to a required heading are limited in their application.
    Published in 1970, the JMEM Air-to-Surface Target Acquisition Manual divides the acquisition process into the aforementioned three steps of detection, recognition, and identification. Their exact definitions have been included here to preserve the granularity.
    Blackwell’s research during WW2 began with experiments into the contrast values required to just discriminate circles projected on a screen. Importantly, target size in Blackwell's model is angular in a fashion evident to anyone familiar with MOA.  Beginning with a definition of contrast as
    C = abs val of (Luminance of Stimulus - Luminance of Background)/(Luminance of Background)
    And of relative contrast as

    Cr = actual target contrast / threshold contrast

    This definition becomes clear when one examines the situation where Cr = 1, wherein threshold conditions apply and detection probability is 50%. A table of threshold contrast values has been included here, followed by detection probability as a function of the relative contrast.

    Practically speaking, to predict detection with this model would require calculating the angular size of the target, then calculating the actual contrast of the target, looking up the threshold contrast, calculating the relative value, and finally determining the probability of detection with the graph. Evidently a complex and lengthy process, these limitations motivated the creation of further detection models.

    Overington’s model seeks to correlate the target size and target contrast to the point at which the target is just detectable. This begins with the assumption that the target generates a stimulus between two adjacent retinal receptors between which the boundary of the target and background is located, the magnitude of which will obviously depend on the  magnitude of the contrast. Through a complex series of equations that do not bear reiterating, a relationship is drawn between

    .163 * Contrast = K1 * nReceptors + δ

    Where K1 is some constant and δ is the minimum stimulus the brain can detect. From this equation, a threshold contrast value can later be obtained. A great deal of care is paid to the amount of receptors which will be stimulated - the minimum even when seeing very small objects (eg stars) is cited as nine.To account for this, a value of

    nReceptors = 9.9[(height + width)^2 + .83]^.5 is derived, where height and width of the object are in mrads.
    Overington then solves K1 and δ experimentally; they depend on the retinal luminance, which is itself dependent on the scene luminance and the pupil diameter. These equations are not directly solved, and the reader will have to content themselves with the relation of

    K1 = 15.4 Retinal Luminance-.5 + .48
    δ = .00125 Retinal Luminance -.5 + .0004

    With Retinal Luminance equal to pi*pupil diameter squared * scene luminance * 1/4

    We can obviously now simplify our earlier equation into

    Contrast Threshold = (K1 * nReceptors + δ)/.163

    Which is in good agreement with the Blackwell model from earlier. It would later be discovered, however, that these models under-predicted the threshold contrast luminescence. Testing conducted by Johnson in the 1950s wherein observers viewed the side of an M48 (a tank not know for it’s small size, as N-L-M will doubtless attest) showed that the threshold value was higher by around a factor of three compared to the Blackwell and Overington models.
    My only brief complaint with this section is that it would benefit from a lengthier comparison between the predicted values and the empirical values for threshold contrast. The history and physiology is interesting, of course, if somewhat dry if all we are given is a simple “it does not work by this factor”.
    Johnson’s Frequency-Domain Experiments grew out of these simple “detection” tests, beginning with the fact that mere detection is not sufficient for many military tasks, and that neither a threshold data nor model existed for the tasks of recognition or identification. Initial experiments showed that a nonlinear scaling existed of contrast required with range, which led Johnson to model targets in a frequency rather than spatial domain, best explained visually here.

    Each pair of black and white (practically, gray and dark gray) lines is a cycle, and the cycles per milliradian is the cycle frequency. The equivalence between a cycle frequency and a target is constructed as follows.

    1. A small image of a military target is projected onto a black screen.
    2. An observer is rolled into a position where he can just detect that there is an object on the screen.
    3. The image is replaced with a rectangle made of very high cycle frequency bars. The frequency is reduced until the observer can just determine the number of bars.
    4. The rectangle is replaced by the image, and the observer is wheeled forward until he just recognizes it. Step 3 is repeated.
    5. Step 4 then 3 are repeated with the observer having to identify the target.
    The procedure's results have been included here.
    This is a strikingly robust and useful model, and has proven sound even when applied to a number of passive sensors such as FLIRs, TVs, and image intensifiers. With it, we can predict acquisition ability of a sensor by measuring its ability to resolve contrast modulated bar patterns. In this passage, Driels discusses an extremely fascinating way of looking at sensors, in a method that’s surprisingly easy to follow given his early work in the chapter. The model seems so simple and robust that one questions why the earlier models are even included, as the Acquire Model to soon be discussed uses Johnson’s work rather than the earlier physiological models.

    The US Army’s Acquire Model makes use of Johnson’s Frequency-Domain work, while accounting for significantly more factors. The model begins by calculating the critical dimension (sqrt of the presented area) in mrads, and then selecting an intrinsic contrast value based on the illumination, background, detector, and filters. The attenuation due to atmospheric factors is also taken into account, though the JMEM model only accounts of distance and meteorological factors. Using these factors, the apparent contrast at the sensor is calculated, with

    Apparent Contrast = Intrinsic Contrast * Sky to Ground Luminance * e(-3.91 * Range Kilometers / VIS)

    VIS represents the atmospheric visibility, and is defined as the range at which contrast is diminished to 2% of Intrinsic Contrast.

    The sensor in question is then analyzed using Johnson’s method described earlier. A common measurement standard is a four-bar pattern which can be of varying frequency - ie, the bars can be very few or very many milliradians wide. For a given frequency, the illumination through the sensor is increased from zero until the bars are just able to be distinguished, and this value of contrast is paired with the frequency to construct a Minimum Resolvable Contrast curve. A particular value of frequency for a given apparent contrast on this curve is a Spatial Frequency, yielding

    N cycles resolved = SF * critical dimension / Range

    Acquire then features a probability for some task (either Detection, Recognition, or Identification) as a function of the ratio between the number of cycles resolved and the number required for a 50% chance of that task being accomplished, included here.
    This is a very powerful result, and is again presented quite cleanly and clearly. I appreciate these two passages a great deal more than the earlier parts, especially since they seem most easily applicable to things outside the A2S realm.
    Flight profile accounts for the fact that an aircraft does not always approach the target directly down the line of sight, and that several actions must occur for a successful attack even after the target is detected. The aircraft must decide to attack, must roll into and then execute a turn before exiting the turn and operating the weapon system - respectively XD, XRI, XRO, XOP, and RMIN in the diagram here. These will combine with the beginning kinematics and geometry - the turn radius of the aircraft r and nose angle ⍺ - to produce the following RRQ equation.

    RRQ = (A cos ⍺ + r sin ⍺) +- Sqrt[ (A cos ⍺ + r sin ⍺ )^2 - (A^2 - B^2)]
    This minimum range to maneuver and launch will be included further along in the model in addition to the maximum range for detection. An omission which may be deliberate is the possibility to reverse engineer a target approach to maximize the possibility of detecting the target in time to launch a weapon. 
    Searching refers to the process of moving the sensor’s field of view, the solid angle which it can actually “see”, over the entirety of the solid angle the sensor is capable of moving, referred to as the field of regard. Driels places this towards the end of the chapter, but it appears best suited to address earlier. The US Army’s Acquire model expresses the probability of detection as
    P = P1 x P2, where P1 is some time-independent probability of detecting the target, and P2 the conditional probability for some amount of time, best explained below.
    Terrain has the effect of blocking almost all sensors used by aircraft, with the particular quandary that terrain can vary quite rapidly and unpredictably. (Something anyone attempting to learn land navigation can attest to.) Driels constructs a workable model for the angle at which an aircraft’s sensors are unmasked as follows - for a given “type” of terrain, place an observer at some random point. The observer measures the angle to the highest terrain feature along a given bearing, which is the unmask angle. This repeats this for the entire circle, producing a cumulative probability distribution of the unmask angles, and the process may be repeated for a variety of terrain types to any desired level of granularity.

    The JMEM target acquisition model covers flat farmland, smooth desert, rolling farmland w/ close forests, rolling desert, flat farmland with close forests, gently rolling hills, rough desert, and sharply rolling hills with trees, though it should be evident that any particular terrain type could be easily calculated. The omission of any form of urban terrain is puzzling, however, and the question of which existing terrain to model it with is thought provoking. Perhaps sharply rolling hills with trees? That this 2004 book does not cover the acquisition of targets in urban terrain is no great discredit, as it has likely been accounted for in more recent versions of the JMEM acquisition model, but it certainly merits further discussion moving forward to a doubtless more urbanized battlefield.
    There are now models in hand for the two major limits on range of detection, terrain and visibility, and from this Driels proceeds to construct a conversion between range and the probability of detection and launch.
    This equation, and the cumulative probability that one can derive from it, accounts for not only the distance the aircraft must close to before detecting the target, but also the time taken to search the volume available to the sensor suite and the minimum time/distance required to maneuver the aircraft to launch position. The constant K accounts for the skill level of the pilot, Pmax is assumed to be 1, R is the smaller of the unmask range or the visibility detection range established earlier, RRQ is the minimum range to maneuver and drop. A series of calculations have been performed in the chart here - these seem to be far lower than occurs in reality, potentially due to the choice in parameters.  
    Driels then details the usage of the JMEM Target Acquisition Model, a screen of which is included here. (Note that PL is significantly higher than his table earlier.) Inputs to the model can be taken from the Joint Air-to-Surface Weaponeering System (JAWS), as well as additional information regarding the target, vision conditions, weapon trajectory, and launcher kinematics - the latter two obviously determining RRQ.
    In Summary, the chapter examines physiological models of detection by Blackwell and Johnson, addresses their implementation in the US Army’s Acquire model, and then details the Joint Munitions Effectiveness Manual’s use of Acquire and the additional information its model includes. This chapter is interesting and offers a great deal of unexploited potential - the models are all extremely fascinating, and I can easily imagine their direct applicability towards S2S or passive A2A detection. Crucially, however, the acquisition models all appear to completely negate *active* sensors, possibly for reasons of confidentiality. Still, the fundamentals behind the two-way radar equation aren’t that complex, and could easily be slotted into the existing maximum range of visibility parameter. Beyond that, it is an interesting chapter, and one of the most insightful in the book.

    I think I'm done with the book for now. I may do some simulation of infantry fires by plagiarizing Driels' direct fire chapter, but that is a tale for another day.
  2. Tank You
    N-L-M reacted to Andrei_bt in The Soviet Tank Thread: Transversely Mounted 1000hp Engines   
    On November 27, 1984, the MBT T-80U tank was officially accepted for service in Soviet army by order № 1184-301 of Central committee of Communist party of USSR and council of ministers.

    Also this day by the order № №П83-300сс of Central committee of Communist party of USSR and council of ministers T-72B was officially accepted for service in Soviet army.

  3. Tank You
    N-L-M reacted to Toxn in The Soviet Tank Thread: Transversely Mounted 1000hp Engines   
    I updated the model to resemble the mock-up

  4. Tank You
    N-L-M reacted to Toxn in The Soviet Tank Thread: Transversely Mounted 1000hp Engines   
    I made a model of the T-34M:

    Astute viewers will notice that the commander's cupola is wrong - it's supposed to be a T-50 cupola rather than the T-34/85 model I stuck on.
    Rivet counters will notice that the exhausts don't have the crazy bolt arrangement they should have (and are kind of the wrong shape), the front hooks are missing, the radio antenna is missing, the hull periscopes are missing, and that the turret periscopes are of the wrong type.
  5. Tank You
    N-L-M reacted to Collimatrix in US Politics Thread: Year 2 of 1000 of the TrumpenReich   
    I am saying that.  If the Democrats want to remain competitive, they need to dig out decades worth of Chicago machine apparatchiks and Clinton lackeys and send them to the salt mines.  If the Republicans wish to continue riding this populist high, they need to give in to their bases' desire for blood, and drag out hundreds of Bush-era neocons and give them life sentences for being counterrevolutionaries.  That would be a good start.
    One thing that Shattered makes very clear is that, while Hillary Clinton was an absolute dud on the campaign trail, she was extremely methodical about building up her support in order to cinch the nomination.  The lesson she learned from the 2008 primary rodeo was that the only real threat to her inevitable ascendancy were other Democrats.  Therefore, she worked hard on developing a network of operators within the party who could guarantee her nomination.  By all indications, her team put way more thought into how to win the primary than how to win the actual election.
    So, in a very real sense, if Hillary decides to run again in 2020 (which would obviously be disastrous), job number one for any enterprising, up-and-coming Democrats will absolutely be to purge the party of her malign influence.  The party is filled with Clinton agents programmed to steal votes and money, and the party will not function correctly until they are all rounded up, given show trials, and shipped off to somewhere cold and miserable.  As soon as the rest of the Democrats realize that these people are parasites, and not comrades, their days are numbered.  Right now they're too spooked to clean their own house.  But perhaps, after a few more painful humiliations, some of the young, bright ones will come to see what must be done.
    The Republicans have a similar problem, but the solution is somewhat different.  Simply put, Republican voters have despised Republican politicians for years.  They (barely) tolerated them because they saw them as the lesser of two evils (but only very slightly).  But now that they have the new Trump movement, what need do they have for the old, legacy Republicans?  The answer is that they have no need for them whatsoever.  But that salt ain't gonna mine itself!
    Summary:  Gulags.  Gulags for all.
  6. Tank You
    N-L-M reacted to Sturgeon in Designing A Rifle From Scratch(ish)   
    Clearer labeled diagram of the gas system:

  7. Tank You
    N-L-M reacted to Walter_Sobchak in Post Election Thread: Democracy Dies In Darkness And You Can Help   
    I'll have to take your word for it.  I have been avoiding this thread for the past few weeks, so I haven't read all the posts here.  
    Anyhow, here are my observations thus far.  I don't think any of these are particularly controvertial or original:
    1)  Trump continues to be a polarizing figure, driving up voter turnout both amongst his supporters and opponents.
    2) The historical trend of Party holding the presidency losing seats in congress holds true, although the Republicans were able to avoid trouble in the Senate due to a very favorable election map (repubs were defending far fewer senate seats than dems).  
    3) Holding onto the Senate allows the Republicans to continue dominating high court appointments, something that has been a priority for them, and will continue to cause Dems great consternation.
    4) Gaining control of the House allows Dems to proceed with more investigations against Trump.  Whether this tactic will ultimately hurt or help them remains to be seen.
    5) While I haven't seen detailed breakdowns of the voting demographics, it would appear that the electorate is becoming more polarized along rural/urban lines and race and gender.  Certainly the election rhetoric was some of the most highly charged that I have seen in my lifetime.
    6) Republicans should probably be concerned that they lost so many House seats despite the strength of the economy.  They did not seem to be able to capitalize on the economy issue as much as one would expect, although its been a weird sort of recovery in which real wages for working people have not been going up as much as overall economic growth would suggest.  Trump seemed more interested in promoting divisive social issues than in running on the strength of the economy, which probably plays well with his base but less well with the middle.
    7) Democrats still have yet to come up with a really compelling, unified vision.  They can't just run against Trump, they need to figure out a way to stop letting Trump take up all the oxygen in the room. They also need to make sure the Clintons go away, never to be heard from again.  
    8) There is a lot of chatter that there may be a good deal of turnover in the Whitehouse following the midterm.  Personally, I hope General's Mattis and Kelly stay onboard, they seem to provide a stabilizing influence on President's Trumps somewhat mecurial and unpredictable tendencies.  
    9) Be prepared for a couple years of congressional gridlock.  
    10) I have no idea how the situation at the Justice Dept and the Mueller probe will eventually play out.  Does Trump try to clean house?  If so, does it turn into a modern "Saturday Night Massacre"?  Does Mueller actually have the goods to get more indictments?  What legal powers does he even have to pursue indictments against a sitting president?  Will Trump play the pardon card if push comes to shove?  There are so many x factors regarding this stuff that I could see it going in all sorts of different directions.  
    It's going to be an interesting couple of years.  And by interesting, I mean my consumption of Alka-Seltzer will probably keep increasing.  What times we live in....
  8. Tank You
    N-L-M reacted to OnlySlightlyCrazy in Partial Review of Driel's "Weaponeering"   
    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

    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.
  9. Tank You
    N-L-M reacted to LoooSeR in Competition: Tank Design 2239   
    Detailed look at each submission.
       Finally, my expanded review of each submission of this competition was put together, and now it is here. During 2nd phase of judging, all 3 judges were exchaning their opinion on vehicles, some of points made here could be covered in other judges posts, but i am still leaving them here for sake of completion. 
       Each vehicle was reviewed based on models shown (general level of skills of poster with 3d modelling was taken into account), description given and my own knowledges of subject. In those reviewes i will generally not get into stats or direct comparisons with other submissions much, but look at features of each design, viewing them in relation to requirements, basics of AFV design and common sense.
       @A. T. Mahan, @Whatismoo
    57mm Gun Full Tracked Light Tank M48A4E4 “Koskiusko”
       This light tank is not fulfilling requirements as much as it could on both weight and firepower sides, with main weapon system more optimised for Tank destroyers. Vehicle have  protection level of APC but with bloated profile thanks to oversized turret. For general purpose light tank M48A4E2 have awkward weapons, low frontal protection. For recon vehicle it have unnecessary big profile and no advanced recon/observation kit. Only tactical mobility is good on this vehicle, and maybe not bad FCS. 
       Combination of negatives for me did not outweighted positives, so this is why i considered this light tank as worse than several other submissions. Although, i thank use of not totally boring loading system on this vehicle, haha 
    120MM GUN TANK T44
       As this vehicle was eliminated from competition i didn't made any serious/deep review of this vehicle. Leaving some questinable stats and features of this submission, few other things that jumped out for me:
       This vehicle is outside of capabilities of industry to produce it with reasonable price. Some of features are not bad - extensive use of ERA is not a bad way to increase protection of vehicle while keeping inside of weight limitation. There are questions to main weapon very long barrel, but it does provide serious firepower that would allow to not bother with armament upgrades for long time. 
       But i can't say more on this vehicle as it jumped out for me as more of Abrams wankery than a submission for requirements, i felt it went against spirit of this competition.
       Even if submission was not taken for "competitive judging", i looked at what we had on hand and made some notes about it.
       XM42 "Prettyboy"
       This submission would have been a solid entry in this competition if more time was given to completing basic requirements. Turret shape could be changed for expected future upgrades with layered armor/NERA. Only you bothered to model SPG based on proposed tank chassis, too.
       As both vehicle have plenty of similarities, i made a combined notes on both.
     XM8 “Elk”
       Well, Toxn's heavy was close 2nd place in 45t category and his light varaint was a winner in 25t category. Both vehicles are reasonable machines, but in few places those tanks are too "1940-50s" level of design (for example - wet ammorack instead of separated ammunition compartment). I liked first armor upgrade that could easily be used on basic proposal. Both vehicles were more mature and detailed in design and were more focused on requirements and their spirit.   
       As your heavy tank won, i will begin with light AFV that didn't managed to repeat a success of his bigger brother.
    XM-2240 RED FOX
       This wheeled death trap is focused on AT work and dealing with low-protected vehicles but leaves HE capabilities to be less than other proposed vehicles managed to show. MCLOS ATGMs also were considered to be not good enough compared to more boring classic medium caliber cannons for AT work, although they could be mentioned for future upgrades of this vehicle, when they would be SACLOS. All this combined with 10 tons of unused weight (15t vs max 25t) and generally low level of protection, bad cross country capabilities, this vehicle is too specialised on narrow type of warfare and losses in several key areas to other designs. 
       Wheeled death trap was pretty solid entry in this competition and unique compared to other proposals.
       XM-2239 NORMAN
       Norman is most detailed and mature design with a lot of attention given to a crew and their working space. Well protected with balanced mobility, firepower and means for easy upgrades being built-in, this submission won first place for a reason.
       Now we came to a part of this post that you apperently really wanted to see. Let's begin with light tank
       Sandy in both configurations are vehicles with potential, but with problems that compromise this potential. "Light" version would have been a serious contender... in other competition. We didn't had requirements to be capable to be easily transportable by air, or be airdroppable. Light Sandy was designed with self-imposed objectives. It also have number of problems because of that, like very low level of protection, question with crew comfort and so on. 
       Heavy variant with new turret was much more serious contender in 25t category, but very low level of hull protection, questinable upgradeability of chassis and turret, layout of vehicle were it's main failings in my eyes.
    M15 Roach

       Roach was in my opinion mediocre vehicle. Submission lacked level of details and autism of NLM and Toxn's works, which would played against it. Shape of hull and turret was made without ease of upgradeability in mind, turret armor weakspots and few other things were other factors playing against Roach. Weapon upgrades, firepower and adequate FCS for it, general level of armor protection outside of weakspots and armor upgrades were positives of this submission. In my mind i put it on 3rd place out of all 45t category submissions, with a noticeable gap between it and 2nd place. 
       M12 Donward
       As it was eliminated from competition i did only a short review of it.
       Donward have same problem as Roach - it is 1950s level of tech tanks without much of modern AFV design features considered for it, unlike what we see in Norman and to slightly less degree in Elk. Roach was re-mix of T-55, while Donward looks like be T110E5-inspired design. Turret and hull shape would be harder to match with advanced armor upgrades that should be expected by designers in this AH story. Turret also have problems in terms of protection outside of very narrow frontal arc, especially it will be more and more problematic to protect as time goes on and better shells appear.
       And this submission also lacks details, which mean that it feels less mature and thought out compared to NLM's and Toxn's entries. On top of not fitting into basic requirements.
  10. Tank You
    N-L-M reacted to Clan_Ghost_Bear in United States Military Vehicle General: Guns, G*vins, and Gas Turbines   
    Don't think I've seen this posted here before- An alternative proposal for the IFV component of ASM:
  11. Tank You
    N-L-M reacted to skylancer-3441 in United States Military Vehicle General: Guns, G*vins, and Gas Turbines   
    About two and a half years ago i've stumbled across some russian book about western IFVs, which apparently was a mere compilation of articles from western magazines translated into russian. There was a mention of some 58-ton heavy IFV, called SAIFV, which was described as vehicle baised on Abrams chassis, and they also claimed that a prototype was biult and tested. (which seems dubious to me now) Than, two years ago, I've stumbled across this article about SAIFV https://medium.com/war-is-boring/the-u-s-army-wanted-to-replace-the-bradley-38-years-ago-dffb6728dd11 which has 3 drawings - "artist conceptions". Than, half a year ago I was reading some US DOD bidget hearings transcripts about MICV/IFV development, and stumbled across mentions of 50-55 metric tons $800,0000 - 1,000,000 SAIFV of Crizer study, and than I've googled a Mobility analysis of IFV task force alternatives (1978-07) report (which is allmost the same as Appendix D of that report which is described below). Unfortunatelly there weren't any proper pictures, (and also i've thought that those 3 drawings from medium.com article are modern "artist conceptions", not one from 1978). 
    Than several things happend in the right time and place, which invlolved twitter, AUSA-2018, NGCV-OMFV, and author of that arcticle at medium.com, and when I asked him about that article - it turned out that there is a report about SAIFV, which is readily available on the internet there http://cdm16635.contentdm.oclc.org/cdm/singleitem/collection/p16635coll14/id/56079/rec/1

    884 pages, with 7 normal chapters and chapter 8 which consists of 6 appendices.

    cost figures from Appendices F and B:

    things like those cost figures, coupled with deceiving percents like this (Ch. IV p.17):
    (there were also other versions mentioned in Senate hearings of FY1978-1980s - 91.6%, 92%, 95%, and also they've mentioned soviet motorized rifle division instead of tank regiment)

    apparently saved Bradley. Although in 1979 those $370,000 turned out to be $472,000 (in same FY1978 dollars), - and later according to FY1983 bidget hearings - $1,350,000 (which is about $880,000 in 1978 dollars). 
    btw, GAO's report  "Army's Proposed Close Combat Armored Vehicle Team" (12 dec 1977) has following thing on page 23:

    and that was BFV project manager's responce (hearings on military posture and h.r. 10929, part 2 of 7, p.183) several mounths later (somewhere in feb-apr 1978):

  12. Tank You
    N-L-M reacted to Walter_Sobchak in Turkish touch   
    So this is where we will get to post all those pictures of burned out Leo 2's belonging to Turkey?  Cool.
  13. Funny
    N-L-M reacted to Oedipus Wreckx-n-Effect in NODS are bad, urrrgh   
    Earplugs: the Alt Rights next weapon against the truth?
  14. Tank You
  15. Tank You
    N-L-M reacted to Zyklon in Bash the J-20 thread.   
  16. Tank You
    N-L-M got a reaction from Zyklon in How Not to Post in the Historical Warfare Section   
    Yamato wouldn't run, and would let the Iowa dictate the range and shrek it because it's a shittier design and has no choice. It's dead if it tries to run and dead if it stays.
    what does this even mean
    The Japs did not have any form of NV. The closest they had was well trained sharp eyed operators with binoculars with comedy-large objective lenses. Not in any way shape or form a substitute for radar. Face it, the jap ship is low energy and sad.
    What happened at Samar? you mean that battle where a Jap heavy cruiser was destroyed by the gun of an escort carrier? or where the Yamato sunk at most an escort carrier and a destroyer? Piss poor performance for a supposed top-of-the-line battleship. in a target rich environment. And you have to bring it up because it's the only case the Yamato was even partially successful, and that's with no American battleships anywhere nearby.
    So yeah, the world wonders how the Japs could possibly be so terrible at this that a heavy surface action group cannot sink a practically undefended landing force. The Japanese fleet and every ship in it was low energy and sad, and the Samurai fears the 5"/38.
  17. Tank You
    N-L-M reacted to Willy Brandt in General AFV Thread   
    Good news for all of you that dont speak our beautiful language.
  18. Tank You
    N-L-M got a reaction from Xlucine in How Not to Post in the Historical Warfare Section   
    hoo boy you are the fullest retard I've ever met. Your damping coefficient nears infinity and your Q approximates 0.
    So, one at a time:
    The USN superheavy shells more than match the IJNs shit. The IJN shells are only around 3200lb on a bore 2" greater. This means that their sectional density is worse, by a factor of roughly 7%. This basically nullifies any advantage you'd expect from a larger shell, and indeed the penetration of both guns is very similar. But the US guns are lighter, faster in both aiming and loading, and have far superior fire control layout, equipment, and technology. The Ford mk 1 Fire control computer was very good for the time and the Yamato had nothing of the kind. Optical rangefinders are fairly inaccurate, and ranging with them must be carried out in concert with salvo spotting. Radar gunnery gives very accurate ranges not only for the target but also for the shell splashes in each salvo, allowing quick and accurate correction of fire. Yamato falls WAAAAY short of the Iowa in this regard. Radar observation also works at night and in bad weather, where optical doesn't. There's a reason literally the entire world moved on to radar, and claiming otherwise is just objectively wrong no matter how you try to compensate. Read a bit about Surigao Strait and learn what integrated FCS with radars does.
    You clearly have not been educated on the classics of battleship design and optimization. A speed advantage greater than 3 knots pretty much allows the Iowa to not only dictate the range, but also maneuver to avoid fire in a stern chase without losing the Yamato. The Iowa's superior FCS, in combination with superior turret drives, allows her to maneuver while firing with little loss of accuracy, and in a stern chase the Yamato would only have one turret available. For broadside fighting, salvo dodging would keep the Iowa very safe while she controls the range, while the Yamato cannot maneuver like that without giving up any semblance of accuracy.
    The Iowa's reloading equipment was faster, not only because of the automatic gun indexing and elevating during runout- the Iowa's shell hoists lead directly into the ramming tray, and the 2-stage powder cart eases handling which again speeds the procedure, while  the whole system involves fewer, lighter moving parts and less complicated mechanisms improving reliability.
    If you don't know what makes the US 5"/38 a DP gun you have no business taking its name in vain. Protip- it's everything other than the gun itself that matters. from the semiautomatic ramming to the automatic fuze setters to the surface/AA director control to the turret drives and elevation range to the ammo scuttles and handling rooms. The USN 5"/38 is far and away the best intermediate gun of the war, even before VT became a thing. And with radar director control, vs a AoN armored ship, it's more effective than the Jap 6.1". Against destroyers as well, as they were not armored. The greater number of guns firing faster and more accurately the Iowa can bring to bear against any enemy ship or aircraft blows your Jap mess out of the water. Or at least it would had carrier aviation not gotten to it first.
    Do you know what a fineness ratio is? The Iowa has a far more efficient hull shape, and is much lighter and therefore smaller. Getting an Iowa places involves less fuel expenditure, particularly at high speeds. The Iowa has 212k SHP max, compared to the Yamato's 150k SHP. But power requirements roughly scale with the cube of the speed, and to reack 28kn, 1 knot faster than the Yamato can ever go, the Iowa needs only 110k SHP. It is a more efficient design.
    Battleships fight enemy ships at unknown ranges in rough weather, provide AA coverage to carriers and taskforces, bombard shore targets, and so on.
    In fact, let's take a look at the history of battleship actions, going backwards:
    Surigao Strait: night and poor weather.
    North Cape: Terrible weather in the early morning.
    Second Guadalcanal: Night.
    Casablanca: Clear day, supporting a landing.
    Shrekking of Bismarck: Clear Day, once the Bismarck could no longer run away after getting torpedoed (as it too was a shit design).
    Denmark Strait: morning, good visibility. Long range.
    Cape Spartivento: Day, long range.
    Beginning to get the idea? the battles are not a 2-way shooting range, they are more complex and tend to greatly degrade optical visibility.
    Battleships also support landings, in which case fire support is essential. The USN HC 16" holds 70 kg of explosive, 10 more than the equivalent IJN 18" shell. So any claims that the Jap shell is superior belong in the trash, next to your opinions. But the Iowa has 150 rounds per gun, while the Yamato only has around 100. So the Iowa has more firepower to rain down on targets. When it comes to secondaries the capacity disparity is huge- 500 RPG for the Iowa, and only 150 for the Yamato 6.1" and 300 RPG for its 5". Again, Yamato loses. It just can't compete, it is deficient in firepower and staying power.
    1v1 duel? I'd put good money on the Iowa winning. If it's during the day it can simply stay away until night, and then come in and wreck the Yamato because the Japs were bad at radar and literally cannot do anything other than fire at muzzle flashes at long range at night. In more normal conditions, the Iowa has already won.
    Americans were actually competent TDS designers, and the Japs sucked at it. Deal with it bitchboi.
    TL;DR: learn a thing or two about ships before posting about them.
  19. Funny
    N-L-M got a reaction from StrelaCarbon in How Not to Post in the Historical Warfare Section   
    >superheavy shells don't real
    >surface gunnery radar don't real
    >superior speed don't real
    >superior reloading equipment don't real
    >DP secondary battery don't real
    >actual TDS don't real
    >Panama canal trafficability don't real
    >fuel efficiency don't real
    >Judging battleships by ideal 1v1 slugfest at known range in ideal weather and visibility instead of what battleships actually do
    Newsflash: you're retarded.
  20. Tank You
    N-L-M reacted to Bronezhilet in How Not to Post in the Historical Warfare Section   
    It's almost like admins can do admin stuff.
  21. Tank You
    N-L-M reacted to A. T. Mahan in How Not to Post in the Historical Warfare Section   
    Show your work on the hydrodynamics calculations you're citing as evidence
    That'd be a good place to start
  22. Tank You
    N-L-M got a reaction from OnlySlightlyCrazy in How Not to Post in the Historical Warfare Section   
    Yamato wouldn't run, and would let the Iowa dictate the range and shrek it because it's a shittier design and has no choice. It's dead if it tries to run and dead if it stays.
    what does this even mean
    The Japs did not have any form of NV. The closest they had was well trained sharp eyed operators with binoculars with comedy-large objective lenses. Not in any way shape or form a substitute for radar. Face it, the jap ship is low energy and sad.
    What happened at Samar? you mean that battle where a Jap heavy cruiser was destroyed by the gun of an escort carrier? or where the Yamato sunk at most an escort carrier and a destroyer? Piss poor performance for a supposed top-of-the-line battleship. in a target rich environment. And you have to bring it up because it's the only case the Yamato was even partially successful, and that's with no American battleships anywhere nearby.
    So yeah, the world wonders how the Japs could possibly be so terrible at this that a heavy surface action group cannot sink a practically undefended landing force. The Japanese fleet and every ship in it was low energy and sad, and the Samurai fears the 5"/38.
  23. Tank You
    N-L-M got a reaction from Belesarius in How Not to Post in the Historical Warfare Section   
    Yamato wouldn't run, and would let the Iowa dictate the range and shrek it because it's a shittier design and has no choice. It's dead if it tries to run and dead if it stays.
    what does this even mean
    The Japs did not have any form of NV. The closest they had was well trained sharp eyed operators with binoculars with comedy-large objective lenses. Not in any way shape or form a substitute for radar. Face it, the jap ship is low energy and sad.
    What happened at Samar? you mean that battle where a Jap heavy cruiser was destroyed by the gun of an escort carrier? or where the Yamato sunk at most an escort carrier and a destroyer? Piss poor performance for a supposed top-of-the-line battleship. in a target rich environment. And you have to bring it up because it's the only case the Yamato was even partially successful, and that's with no American battleships anywhere nearby.
    So yeah, the world wonders how the Japs could possibly be so terrible at this that a heavy surface action group cannot sink a practically undefended landing force. The Japanese fleet and every ship in it was low energy and sad, and the Samurai fears the 5"/38.
  24. Metal
    N-L-M got a reaction from Sturgeon in How Not to Post in the Historical Warfare Section   
    Yamato wouldn't run, and would let the Iowa dictate the range and shrek it because it's a shittier design and has no choice. It's dead if it tries to run and dead if it stays.
    what does this even mean
    The Japs did not have any form of NV. The closest they had was well trained sharp eyed operators with binoculars with comedy-large objective lenses. Not in any way shape or form a substitute for radar. Face it, the jap ship is low energy and sad.
    What happened at Samar? you mean that battle where a Jap heavy cruiser was destroyed by the gun of an escort carrier? or where the Yamato sunk at most an escort carrier and a destroyer? Piss poor performance for a supposed top-of-the-line battleship. in a target rich environment. And you have to bring it up because it's the only case the Yamato was even partially successful, and that's with no American battleships anywhere nearby.
    So yeah, the world wonders how the Japs could possibly be so terrible at this that a heavy surface action group cannot sink a practically undefended landing force. The Japanese fleet and every ship in it was low energy and sad, and the Samurai fears the 5"/38.
  25. Tank You
    N-L-M reacted to OnlySlightlyCrazy in How Not to Post in the Historical Warfare Section   
    I would, at least, like to compliment Peasant for sticking to his guns despite being horrendously overmatched qualitatively and quantitatively, and getting slaughtered as a result. In this, he does the IJN proud.
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