Jump to content
Sturgeon's House

N-L-M

Forum Nobility
  • Content Count

    549
  • Joined

  • Last visited

  • Days Won

    10

Reputation Activity

  1. Funny
    N-L-M reacted to Collimatrix in General AFV Thread   
    I've never seen a color picture of a Tiger II being recovered and towed before.
  2. Tank You
    N-L-M reacted to SH_MM in Polish Armoured Vehicles   
    You seem to have a very incorrect idea about the Main Ground Combat System. it is not a design by Rheinmetall (or KMW), but a state-run or state-managed program, just like the Leopard 2 for example wasn't a design from one company, but a project managed by the German state, where components were sub-contracted and a main contractor (i.e. Krauss-Maffei) was chosen after the design was finished. The MGCS will be similar.
     
    For this at first a concept has to be developed and chosen. This work consists of multiple steps: at first several companies focused on analysis and consultation such as Industrieanlagen Betriebsgesellschaft mbH (IABG) of Germany and the Franco-German institute in Saint-Louis (ISL) were tasked with wrok for a pre-design analysis and conception phase - i.e. the IABG was tasked to create studies about potential use scenarios and theoretical threats encountered in these. The German and French militaries then accessed these scenarios and based on these come up with a weighing system and requirements. The specified tank threat reference for the MGCS is the Russian T-14 Armata main battle tank.
     
    If Rheinmetall presented anything to Poland, then this is not directly related to the MGCS - simply because it has not been defined how the MGCS will look. At the time of Eurosatory 2018 it was still not decided which armament concept out of four being considered is to be chosen; aside of different guns (130 mm & 140 mm smoothbore guns, ETC technology), other concepts suggest that a relatively large autocannon (bigger than the usualy 30 x 173 mm) with missiles (either top-attack or hypervelocity missiles) might be adequate armament. At this point of time no decision had/has been made regarding combat weight (at some point a 35 tonnes tank was considered to be more air-deployable, but also heavier tanks with ~60-70 tonnes of weight) or crew configuration (two men, three men or four men crew per MGCS tank?).
     

     
    Above is the schedule shared between MGCS and CIFS. As you can see the concept studies last until mid 2018, but it seems that it had been extended by a few weeks given the late signature of a Franco-German agreement. Technology demonstrators will be made for the different concepts, as no final decisions for one specific concept has been made. At the same time studies regarding the available technologies and production capacities are made. When a concept has been chosen and key technologies have been demostrated, a first set of system demonstrators will be made. A first proper prototype follows later, it is expected by 2025, but KMW/Nexter claimed that they could finish one by 2023, if nice enough funding is approved for this.
     
     
    Rheinmetall has only shown concepts of its own MBT suggestions, which they want to use as basis to propose for the MGCS. Rheinmetall - and KMW & Nexter - are probably keeping their R&D department busy with creating such next-gen tanks, given the potential contract value. That Rheinmetall did not offer Poland to join the MGCS, is very simple to see in this topic. I posted an interview of Defence24.pl with Otmar Schultheis, who is currently COO of the recently funded subsidairy Rheinmetall Polska. Just listen and see him confirm that they did suggest a different tank for Poland only:
     
    The fan-art is completely bullshit. Most of the MGCS are either turretless or have an unmanned turret, as achieving the desired protection levels is not possible with a manned turret, unless the a very high weight limit is chosen.
     
     
    First of all: yes. The MGCS will feature next generation thermal sights and sensors. The electric drives for turret and hull of the Leopard 2PL are made by Jenoptik in Germany.
     
    Aside of that, PCO S.A. wasn't the only Polish company having issues. Before they even started, Bumar Łabędy S.A.had to upgrade its facility, as they lacked the machinery to handle the upgrade, delaying the whole program by multiple weeks.This can happen again, for example if the MGCS design uses a turret construction similar to the Puma's.
  3. Tank You
    N-L-M reacted to D.E. Watters in Gun Science Library   
    Back in 2009, I stumbled across a site hosting the annual command histories for the Commander in Chief Pacific (CINCPAC) from 1960 through the mid-'80s. I found an interesting tidbit in the 1974 history regarding an examination of establishing South Vietnamese production of the Lazy Dog munition for the VNAF.
     
     
  4. Funny
    N-L-M reacted to LoooSeR in The fragile and transitory nature of humour   
    @Sturgeon
    @N-L-M
     
  5. Tank You
    N-L-M reacted to Jeeps_Guns_Tanks in Competition: Tank Design 2239   
    The Judges are now reviewing the entries. 
  6. Tank You
    N-L-M reacted to LoooSeR in Syrian conflict.   
    S-300PM2 that participated in Victory parade, was transfered to Syria.

     
    Very likely to be manned by Russians. PM2 is most advanced version of S-300, and it is not an export version, but systems that were very recently in active service.
     
  7. Tank You
    N-L-M got a reaction from That_Baka in WoT v WT effort-thread   
    My personal experience was that the early Panzer IVs kick ass if you know how to use them. PzGr. Rot is a mini nuke, and there isn't much that can resist it. What can resist it is usually small vehicles vulnerable to crew losses from Hl 38B/C. The large internals and 5 crew members mean fairly good survivability if you aren't ammo-racked.
    37mm guns are generally suffering.
  8. Tank You
    N-L-M reacted to Ramlaen in United States Military Vehicle General: Guns, G*vins, and Gas Turbines   
    The Griffin II that is GDLS's MPF contender has the modified Abrams turret and a 105mm gun.
     
    The 50mm gun on the Griffin III can elevate to 85 and depress to -20 degrees. It's GVW is just under 40 tons. The hexagonal camo tiles are called called Tacticam and are made by Armorworks. The turret's size is a result of the 50mm ammo. The turret is also equipped with Iron Fist APS, Switchblades and an MX-GCS sight.
     
     
    https://www.shephardmedia.com/news/landwarfareintl/ausa-2018-general-dynamics-swoops-50mm-equipped-gr/
  9. Tank You
    N-L-M reacted to skylancer-3441 in United States Military Vehicle General: Guns, G*vins, and Gas Turbines   
    and from this page http://achatespower.com/achates-power-and-cummins-develop-leap-ahead-capability-for-the-us-army-ground-combat-fleet/ some info on this engine:
     
  10. Tank You
    N-L-M reacted to Willy Brandt in StuG III Thread (and also other German vehicles I guess)   
    "Ready Now"
    haha sure.
    After the development Hell the Puma went through i would say it would only be ready after the S1 and S2 upgrades and then some.
    For me the Lynx looks too clean for being ready.
    Like how do you get ontop of and not slip and break your neck and where do you stow your shit?
    And i only can imagine the problems they will have with the thing.
    The Puma already has some mind-boggling bugs.
     
    But maybe Rheinmetall did a good job. Who knows.

    Also what could Raytheon contribute to the thing?
    Doesnt Raytheon do the M113 on Steroids?
  11. Tank You
    N-L-M reacted to Bronezhilet in Bronez' place to dump interesting things he stumbles upon   
    @Collimatrix@N-L-M
     
    More:
     

     
     
  12. Tank You
    N-L-M reacted to Bronezhilet in Bronez' place to dump interesting things he stumbles upon   
    @N-L-M@Collimatrix
     

     
    Presentation about big caliber guided shells from an AC-130. This isn't the complete presentation but I wasn't going to screencap and upload 52 sheets. This is most of the interesting stuff anyway.
  13. Metal
    N-L-M reacted to Collimatrix in Bash the J-20 thread.   
    Now with serrated nozzles!


     

  14. Metal
    N-L-M reacted to ApplesauceBandit in Competition: Tank Design 2239   
    pew

  15. Tank You
    N-L-M reacted to SH_MM in Contemporary Western Tank Rumble!   
    A few days ago the folks from Warthunder went to Minnesota and measured some details regarding the physical thickness of the armor of an original M1 Abrams tank, something which was already mentioned in the United States Military Vehicle General topic.
     
     
    The English version of the article can be found here. I decided to take these values and combine them with the schmatics of the original composite armor (aka "Chobham", "Burlington" & "BRL-1") fielded on this version to estimate the overall armor thickness. The scan quality of these schematics is low (the paper wasn't flat when scanned, so the lines are not always straight), but I tried to adjust for this as good as possible. It seems that these schematics are not for scale or the measurements were wrong (though that doesn't seem likely).
     
    Overall it seems that the armor thickness has been exaggerated quite a bit; some people said it would be 700 mm or even 750 mm, but most results end up being below 600 mm. I guess the most damning argument against the overall thickness being in the 650-750 mm range is the claim, that the distance between weld lines on the hull floor is just 22 inches (558 mm). Even though it isn't clear wether this includes or excludes the weld lines, it more or less means that overall cavity thickness is way below 558 mm. Add to this a 101 mm backplate and a 31.75 mm frontplate (both sloped) and 700-750 mm armor thickness becomes impossible, IMO 650 mm aswell, but I've never seen exact angles for the LFP and the hull floor.
     

     
    WT also measured the thickness of the turret's armor cavities, but they didn't mention if that includes slope and they didn't mention the exact thickness of backplate, but it also doesn't seem to warrant the 700-800 mm thickness sometimes claimed. Armor cavity thickness was 19.5 inches on an unspecified side of the turret (the horizontal slope of the turret front is assymetrical), but the front plate is 1.5 inches (38.1 mm) thick.
  16. Tank You
    N-L-M reacted to LoooSeR in What are we playing?   
    After deleting Unreal 2 i saw that there is nothing to play now for me, and i had enough of terrible Russian/CIS made games. So it is time for EndWar, to roleplay as Glorious Warrior of New Russia and Supreme Leader Vladimir!
    @Collimatrix
    @N-L-M
    @Bronezhilet
    You may enjoy this.
     
       Game allows you to start WW3 immediately or to have short foreplay instead.

     
    Timeline of EndWar's version of reality
     
    English voices make me angry as they say "Spetsnaz" as "Sh-petsnaz". 
     
     
       During first missions i forgot to check graphics option, and game put them on "low" (although putting them on "high" didn't changed perfomance at all). So sorry for not so great quality of graphics.
       1st pre-WW3 missions is for Euroweaklings (each of those missions is about 4-5 minutes long)
     
    Eurocopters
     
    After victory
     
    2nd is for US
     
    "terrorists" brought their AA weapons from American division of Jihad design bureau
     
    After Victory of Trump forces vs terrosits
     
    Hard to learn "TACTICS" of this game

     
    3rd mission is again for Eurowealkings. Finally remembered to put graphics to the max.
     
  17. Tank You
  18. Funny
    N-L-M reacted to Collimatrix in Post Election Thread: Democracy Dies In Darkness And You Can Help   
    I personally theorize that Trump lured Lindsey Graham into his office on some pretext.
     
    Suddenly, three of Trump's old WWE wrestler buddies sprang out and locked the door.  Then they put Graham into a sleeper hold and suplexed him into the floor.  Then, for good measure, they hit him with folding chairs for a while.
     
    Then two held him down on the ground while one of them yelled in his face.  "DO YOU FEEL WEAK?!  ARE YOU ANGRY YET?!  AM I GOING TO HAVE TO HIT YOU SOME MORE SO YOU CAN UNDERSTAND THE NATURE OF THE PAIN?!"
     
    And Lindsey Graham cried and maybe wet himself a bit.
     
    The yelling wrestler continued.  "YOU ARE ESTRANGED FROM YOUR PRIMAL NATURE?!  WHERE IS YOUR FORCEFUL WILL?!  WILL YOU MERELY ACCEPT THE COLD HAND OF OBLIVION?!"
     
    The wrestler started slapping the senator and shaking him.
     
    "YOU WOULDN'T LIFT A FINGER IF I KILLED YOU RIGHT NOW BECAUSE IN YOUR GUTS YOU ARE ALREADY DEAD?!  WHY DIE A THOUSAND TIMES IF YOU CAN'T EVEN LIVE ONCE?!  WHY DO YOU TORMENT YOURSELF THIS WAY?!"
     
    By this point the senator could only make muffled choking sounds.
     
    "WELL GUESS WHAT LITTLE BUDDY?!  IT'S TIME TO FIGHT?!  I'M GOING TO MAKE A REAL BERSERKER OUT OF YOU?!"
     
    The wrestler pulled out a syringe and a cotton pad swabbed in rubbing alcohol.
     
    "THIS IS A SALINE SOLUTION OF COCAINE AND STEROIDS?!  WE'RE GOING TO REPEAT THIS LITTLE PROCEDURE UNTIL YOU ARE MAD ENOUGH AND BAD ENOUGH TO UNLEASH YOUR FIGHTING SPUNK ON THE UNSUSPECTING MASSES?!  DO YOU GET ME?!"
     
    Trump just sat silently for this entire episode, smirking above steepled fingers.
  19. Tank You
    N-L-M reacted to ApplesauceBandit in Competition: Tank Design 2239   
    Not a submission
     
    Didn't go hard on making this a serious submission this time around since I've got classes to worry about right now and a lot of those classes already have me doing stuff similar to some aspects of this (mostly the number crunching).
     
    Just made this mostly for practice, though it's stuff that won't show up in the final model (hotkeys, cloning objects along a path, fancy details of the meshsmooth modifier, etc.).  The model itself isn't really in a finished state.  Turret is mostly placeholders still, hull still needs some more detail passes done to it.  I want to make some minor layout tweaks as well, mostly in regards to the turret's base and roof.  If this were to be serious, I would make myself a second turret that relies less on casting and would hopefully have a smaller frontal profile.  While I would like to eventually get this finished, that all depends on how lazy I end up.
     


     
  20. Tank You
    N-L-M got a reaction from EnsignExpendable in Documents for the Documents God   
  21. Tank You
    N-L-M got a reaction from Lord_James in Competition: Tank Design 2239   
    FINAL SUBMISSION:
    XM-2240 RED FOX

    [Fullbore autism warning]
    Upon receipt of the technical requirements for the light tank competition, the design team at GF&M once more decided that the spec was extremely conservative. It was decided that a light vehicle, capable of being used in direct wars of maneuvering and in the assault against Deseret forces, as well as in a defensive ambush role against Californian forces, was more than possible.
    To allow good strategic mobility, and low maintenance for long-range independent operations, a lightweight wheeled chassis was chosen, based on pre-war experiences by South African forces in Angola and Namibia. Combined with the success of pre-war French armored cars (AML, EBR, ERC, VBC, AMX-10), and the export and service success of the pre-war British vehicles (Saladin, Fox, Ferret), it is clear that wheeled vehicles have the ability to operate in rocky desert and mountainous terrain (as long as the going doesn’t get too sandy), with limited support or maintenance.
    For armament, it was quickly determined that the minimum calibre gun which would remain relevant against high-end threats throughout the life of the vehicle is prohibitively large at roughly 100-110mm, forcing the tank to be bigger and heavier than it otherwise needed to be. The minimal calibre to remain relevant against light vehicles (such as light tanks, APCs, IFVs and older tanks), however, is much more reasonable: a 30-35mm autocannon. To defend against the high-end threat, a pre-war invention is resurrected: the anti-tank guided missile (ATGM).
    Systems and crew comfort features were inspired by (and in some cases shared with) those in development for the Norman medium tank, saving time and development money.
    Mobility:
    Suspension is double wishbone on the front 2 axles, with steering; the front-most axle steers all the way, the second axle only steers roughly half.
    The rear axles have Christie-style suspension, with the springs tucked away in the groove on the outside of the hull.
    All axles are powered through drive systems reminiscent of that of the ERC; the engine and transmission sit in the rear of the vehicle.

    Survivability:
    Armor is 10mm high hardness steel facing on 60mm aluminium LOS throughout the 60 degree frontal arc for both hull and turret; for the sides, 5mm steel facing on 30mm aluminium LOS; and the rest (sides, back and belly) 30mm aluminium. The belly is V-shaped, at 10 degrees from the horizontal, to allow good performance against mines.
    Smoke grenade launchers as on Norman, 24+24 for 4+4 salvoes of instantaneous smoke.
    The entire vehicle has a very low profile, and is capable of firing ATGMs from turret-down positions with only the optics and box launcher exposed.
    Automatic IR-detection fire suppression fitted as standard; room for spall liners is available. Mounting points for light-weight ERA when available are also integrated onto the vehicle.
    Thin sheet-steel (2mm) stowage boxes over front and above wheels, around left and rear of turret, set off HE rounds at sufficient standoff to avoid having the armor cave in. [not in model]
    Firepower:

    A.     Armament.
    1.      The main gun is, basically, a Bushmaster III, chambered in 35x230mm, with full dual-feed first-round-select semiauto/automatic fire capability, at around 200 RPM. Ammunition is belted in 2 boxes underneath the turret crew seats; 100 rounds of AP and 500 rounds are carried (50/250 ready).
    Ammo types: AP, HE/HEI (APDS, APFSDS in development)
    2.      1 M240 coax. The coax has a ready box with ~2500 rounds ready, with an additional 2500 stowed.
    3.      1 M240 commander’s MG. Commander’s MG has 600 rounds on mount with extras stowed on the sides of the turret in unarmored boxes [not pictured]
    4.      The main armament elevates from -10 to +30 degrees, and is fully stabilized in a similar manner to the Norman’s armament.
    5.      The ATGM box is raisable, and carries 4 missiles; it is armored against light arms fire (10mm steel) and can elevate and depress to the full extent of the main sight. Additional missile canisters can be stowed on the sponsons (not ready to load from within)
    6.      There are in fact 2 different versions of the basic MCLOS missile on offer, differing by the details of the guidance system.
    B.     Optics. Same as Norman, minus loader.
    C.     FCS.
    1.      Same as Norman for guns. Smaller hydraulic unit needed for the much smaller and lihter turret.
    2.      For missile:
    Missile is controlled in current variants by gunner using a joystick. Space has been allocated for a reticle seeker feeding off of the gunner’s optics and electronics to allow SACLOS systems to be fitted. Details on missile system expanded in later section.
    It is not recommended that a firing mechanism be fitted for the commander to fire the missiles in MCLOS versions.
    For best accuracy it is recommended to point the launch tube directly at the target before launch.
    D.     Radio.
    A more powerful radio is fitted in the Red Fox, with more options. It is suggested that this radio also be fitted in command variants of the Norman.
    Crew comfort: As on Norman, with smaller water tank and reduced power AC unit.
    Upgradeability:
    1.      Same as on Norman, minus ammo.
    2.      Missile easily upgraded to SACLOS.
    3.      Gun very capable of accepting newer advanced ammunition types.
    4.      Main armament can be replaced with low-pressure 90mm gun (styled after the pre-war Cockerill) to create an infantry fire support platform. Estimated stowage: 30-40 rounds, HE/HEP/HEAT.
     
    [I ran out of time so the modelling is woefully incomplete on the vehicle, but the general outline is available].
     
    Mass of turret: 0.8 tons
    Mass of hull: 2.2 tons
    Engine: ~200HP diesel.  Features as on Norman (air compressor/starter, large radiators)
    Estimated mass: 0.6 tons.
    500L fuel, 0.4 tons.
    Transmission: smaller version of that on the Norman, 4 speeds forwards, 4 reverse.
    mass: probably around 2 tons (including drive shafts).
    Suspension: Probably around 2 tons. (including tires)
    Armament mass: probably around 2.5 tons including mantlet, ammo and ATGM box.
    Mass of extras: 3 tons.
    Total estimated mass: 15 tons.
    Dimensions:
    Length, gun forwards: 6.0m
    Length, hull: 5.0m (wheel to wheel, maximum)
    Width, OA: 2.75m with ATGM launcher.
    Width over tracks: 2.5m
    Ground clearance: 450mm to bottom of V, 580mm to top of V hull.
    Height, turret roof: 1.95m
    Height, overall: 2.3m to top of commander’s sight
    Wheel diameter: 1.1m
    Wheel hub diameter: 0.5m
    Wheel width: 300mm
     
    As an additional note, the secrets of multi-alkali photocathodes and cascade image intensifiers are known to the engineers of the EL-OP subsection of the Electronics Division. The Cascader Mark 1 is expected to be in field trials soon. While too large for infantry weapons, tank gunnery integration is expected to proceed rapidly.
    (This refers to first-generation image intensifier equipment, intended for integration in both tanks)
    Likewise, IR detectors and spin scan reticles are being developed; conscans will soon be in development as well. Their use in SACLOS systems as well as anti-air applications will be apparent soon.
    (These reticle seekers will be used for automatic missile detection and aiming in SACLOS, and target detection in anti-aircraft applications)
    And now, the moment you’ve all been waiting for:
    MISSILE TECH EXPLAINED
    As a forewarning, this is going to be fullbore autism, and I strongly recommend you read up on gyros, control theory, and missile guidance before you read the explanation.
    Useful links:
    http://www.shorlandsite.com/images/landroversmissileselliott.pdf
    Contains useful info on the development of British first generation ATGMs. And missiles on Land Rovers, which are cute.
    http://www.dtic.mil/dtic/tr/fulltext/u2/b807471.pdf
    Scientific Advisory Commission report on guided and homing weapons, May, 1946.
    http://www.tpub.com/neets/book15/63e.htm
    Gyro basics.
    https://sci-hub.tw/https://ieeexplore.ieee.org/document/1104289
    Non-minimum-phase dynamic systems.
    The following is based on my knowledge of control systems and missile guidance, as well as basic knowledge of human reactions and as-built 1st gen ATGMs.
    The problem is as follows: we want a missile to fly along the line of sight, to the target, despite target maneuvers and outside disturbances.
    For this, we track the missile, and send commands to the missile to correct for its heading, to maintain the missile along the line of sight to the target. As long as the missile can be made to always be on the line of sight, and is moving faster than the target, a hit is guaranteed.
    This is the basic premise of CLOS guidance.
    To ensure aerodynamic stability and direction-keeping despite manufacturing flaws and inconsistencies, the missile is lightly spun around its axis throughout flight by its fins. These are on an adjustable base, so as part of the SACLOS upgrade the spin can be disabled.
    There are a few points to address in this regard-
    1.       How is the missile tracked?
    2.      How are the commands given? What do they mean?
    3.      How are the commands sent and how are they interpreted?
    4.      How are the commands carried out?
    The answers will be given for 3 systems-
    a. classic MCLOS
    b. classic SACLOS
    c. The BGM-1A and BGM-1B missiles
    let’s start.
    1.A: operator tracks target and missile through sight.
    1.B: Operator tracks target by centering sight on it; guidance system detects missile location relative to crosshairs through spin or later conscan reticle similar to those in early A2A missiles.
    1.C. Same as traditional MCLOS
    2.A. Manual Joystick, usually acceleration command to the missile, command intensity proportional to joystick deflection; force feedback.
    2.B. automatic, often bang-bang, to center of crosshairs, usually acceleration.
    2.C. Manual Joystick, proportional, velocity control.
    3.A. From joystick take-off, through amplifier, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.B. From detector output, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.C. BGM-1A: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile),  to actuators on open loop.
     BGM-1B: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile), to autopilot in missile; autopilot operates actuators on closed loop with horizontal and vertical rate gyros to achieve fixed angle for given command.
    4.A. TVC or rear control surfaces.
    4.B. aerodynamic control surfaces, front or rear.
    4.C. Front control surfaces.
     
    The disadvantages of classic MCLOS are that it was difficult to use, and required great skill, as the acceleration commands combined with rear steering missiles. These missiles exhibit extremely unintuitive steering mechanics, with delayed response, and inverse response: rear steering throws the aft end of the missile in the opposite direction to point the missile towards the target, which means the whole missile moves the wrong way until sufficient wing lift can be generated to push the missile in the intended direction. This is extremely unintuitive for the user and takes a lot of practice to accurately predict; frontal control on the other hand is minimum-phase and intuitive- the missile goes where you want it to, and goes there faster for the same control authority.
    Likewise, acceleration feedback is not intuitive for human beings; we are not used to it. Speed feedback is however within the abilities of humans to handle reliably, and therefore the autopilot has been chosen to perform this duty, greatly easing the use of the missile system by humans and thereby improving accuracy, within the limits of established technology.

    Example of front vs. rear steering. Note the rear-steered missile going the wrong way initially. This is very confusing and leads to overcompensation in all except the well trained and highly skilled.
    The differences between the flight control of the BGM-1A and BGM-1B are as follows:
    The BGM-1A has a single inertia gyro, spinning on a horizontal axis normal to the missile’s axis. This gyro stabilizes the commutator to allow the proper splitting of command to the surfaces despite missile spin.
    Velocity control is achieved through matching to an internal simulator in the flight control box. This receives the command, and relays it to both the missile and the internal missile flight estimator (a reduced 3-variable (local sideslip angle, turn rate, and heading) first order differential solver. The system is linked to an internal PID controller aimed at bringing the missile velocity across the line of sight to the value dictated by the command joystick input. The missile itself, in flight, is controlled on open loop, and therefore velocity errors are liable to accumulate throughout flight. With a flight time of only around 20 seconds to maximal range (4000m), however, this is not considered to be too great a risk.
    This flight control box also forms the basis of the built-in missile simulator; hooked up to a driven mirror assembly with HUD-style reflector plate in the gunner’s sight, it can be used to project a dot representing the gunner’s view of the missile tracer flare onto the gunner’s sight. This can be used to practice missile firings as many times per day as is desired, to maintain high skills with minimal support and minimal live-firings of practice missiles.
    The BGM-1B has an additional gyro in the missile, this one a displacement gyro with its rotation axis aligned with the missile body. The angle take-offs from the 2 gimbal frames are fed through the (larger) commutator, to allow the missile to know what its attitude is compared to that it had at launch. When firing this missile, the flight control box only controls the gain of the joystick (less sensitivity at short range as speeds across the line of sight have greater angular rates), and the missile itself contains a PID autopilot, controlling the servomechanisms by gyro feedback to maintain constant bearing displacement relative to launch. The size of the bearing displacement is linear as a function of the control input, as that results in proportional velocity control along the line of sight.
    The BGM-1B is a slightly more expensive missile, but the increased accuracy thanks to reduced drift more than justifies the cost difference.
    The BGM-1B, thanks to its design, retains a modicum of accuracy in case of a wire break, as it seeks to maintain a 0 bearing relative to launch in that plane. For this reason it is highly advised to point the launcher directly at static targets before launch.
    Both missiles are fairly modular; the warheads are easily removeable and upgradeable, as are the rocket motors, flares, and batteries.
     
    MCLOS missile tech better than was available pre-war is possible with the current industrial ability, as it involves no tech not present in the 1946 survey, and transistors improve reliability and significantly shrink the volume needed for guidance electronics. The better understanding of the control problems involved and the man-machine interface allows the design of more reliable more accurate missiles than were available pre-war.
     
    TL;DR: Missiles work and better than any MCLOS missile built IRL.
     
     
    Tech Specs of the missile:
    Diameter: 160mm
    Length: 1300mm
    Length of launch tube (including launch gas generator): 1500mm
    Wingspan: 550mm
    Wing type: wrap-around fin, thin sheet steel with forming springs; sprung fold-out Monobloc canards. (As on AT-4 Spandrel and AT-5 Spigot)
    Gyros: 1 free for commutator inertial stabilization, BGM-1B: extra displacement gyro for angle feedback control.
    Gyro spin-up mechanism: Compressed air start, no sustain.
    Servo actuation mechanism: Electrical servo-controlled compressed air actuators.
    Velocity: ~200-250m/sec [ss.11 was 220 m/s, clearly this is a controllable speed]
    Range: 4000m, wire limited.
    Time to max range: 16-20 sec.
    Warheads:
    Antitank: Precursor 60mm HEAT, main 160mm HEAT, precision formed, crush-cone fuze, base detonated with wave shapers.
    Anti-structure/ Anti-ship:
    Precursor: none.
    Main: 160mm blast-frag.
     
    Current development of variants includes:
    a. CEV (light breaching equipment, smoke screening equipment, fascines, light digging equipment)
    b. ARV (winches, light crane)
    c. APC/IFV (similar in concept to Alvis Saracen with small cannon/MG turret)
    d. SPAA (VADS-like turret, with twin 20mm autocannon, 1 Vulcan cannon or 1 35mm revolver cannon, and basic air search and ranging radars; missile pod replaced with SAMs (Sidewinder-style) when available).
    e. Fire support vehicle- 90mm low pressure main gun.
     
     
     
  22. Tank You
    N-L-M got a reaction from Zyklon in Competition: Tank Design 2239   
    FINAL SUBMISSION:
    XM-2240 RED FOX

    [Fullbore autism warning]
    Upon receipt of the technical requirements for the light tank competition, the design team at GF&M once more decided that the spec was extremely conservative. It was decided that a light vehicle, capable of being used in direct wars of maneuvering and in the assault against Deseret forces, as well as in a defensive ambush role against Californian forces, was more than possible.
    To allow good strategic mobility, and low maintenance for long-range independent operations, a lightweight wheeled chassis was chosen, based on pre-war experiences by South African forces in Angola and Namibia. Combined with the success of pre-war French armored cars (AML, EBR, ERC, VBC, AMX-10), and the export and service success of the pre-war British vehicles (Saladin, Fox, Ferret), it is clear that wheeled vehicles have the ability to operate in rocky desert and mountainous terrain (as long as the going doesn’t get too sandy), with limited support or maintenance.
    For armament, it was quickly determined that the minimum calibre gun which would remain relevant against high-end threats throughout the life of the vehicle is prohibitively large at roughly 100-110mm, forcing the tank to be bigger and heavier than it otherwise needed to be. The minimal calibre to remain relevant against light vehicles (such as light tanks, APCs, IFVs and older tanks), however, is much more reasonable: a 30-35mm autocannon. To defend against the high-end threat, a pre-war invention is resurrected: the anti-tank guided missile (ATGM).
    Systems and crew comfort features were inspired by (and in some cases shared with) those in development for the Norman medium tank, saving time and development money.
    Mobility:
    Suspension is double wishbone on the front 2 axles, with steering; the front-most axle steers all the way, the second axle only steers roughly half.
    The rear axles have Christie-style suspension, with the springs tucked away in the groove on the outside of the hull.
    All axles are powered through drive systems reminiscent of that of the ERC; the engine and transmission sit in the rear of the vehicle.

    Survivability:
    Armor is 10mm high hardness steel facing on 60mm aluminium LOS throughout the 60 degree frontal arc for both hull and turret; for the sides, 5mm steel facing on 30mm aluminium LOS; and the rest (sides, back and belly) 30mm aluminium. The belly is V-shaped, at 10 degrees from the horizontal, to allow good performance against mines.
    Smoke grenade launchers as on Norman, 24+24 for 4+4 salvoes of instantaneous smoke.
    The entire vehicle has a very low profile, and is capable of firing ATGMs from turret-down positions with only the optics and box launcher exposed.
    Automatic IR-detection fire suppression fitted as standard; room for spall liners is available. Mounting points for light-weight ERA when available are also integrated onto the vehicle.
    Thin sheet-steel (2mm) stowage boxes over front and above wheels, around left and rear of turret, set off HE rounds at sufficient standoff to avoid having the armor cave in. [not in model]
    Firepower:

    A.     Armament.
    1.      The main gun is, basically, a Bushmaster III, chambered in 35x230mm, with full dual-feed first-round-select semiauto/automatic fire capability, at around 200 RPM. Ammunition is belted in 2 boxes underneath the turret crew seats; 100 rounds of AP and 500 rounds are carried (50/250 ready).
    Ammo types: AP, HE/HEI (APDS, APFSDS in development)
    2.      1 M240 coax. The coax has a ready box with ~2500 rounds ready, with an additional 2500 stowed.
    3.      1 M240 commander’s MG. Commander’s MG has 600 rounds on mount with extras stowed on the sides of the turret in unarmored boxes [not pictured]
    4.      The main armament elevates from -10 to +30 degrees, and is fully stabilized in a similar manner to the Norman’s armament.
    5.      The ATGM box is raisable, and carries 4 missiles; it is armored against light arms fire (10mm steel) and can elevate and depress to the full extent of the main sight. Additional missile canisters can be stowed on the sponsons (not ready to load from within)
    6.      There are in fact 2 different versions of the basic MCLOS missile on offer, differing by the details of the guidance system.
    B.     Optics. Same as Norman, minus loader.
    C.     FCS.
    1.      Same as Norman for guns. Smaller hydraulic unit needed for the much smaller and lihter turret.
    2.      For missile:
    Missile is controlled in current variants by gunner using a joystick. Space has been allocated for a reticle seeker feeding off of the gunner’s optics and electronics to allow SACLOS systems to be fitted. Details on missile system expanded in later section.
    It is not recommended that a firing mechanism be fitted for the commander to fire the missiles in MCLOS versions.
    For best accuracy it is recommended to point the launch tube directly at the target before launch.
    D.     Radio.
    A more powerful radio is fitted in the Red Fox, with more options. It is suggested that this radio also be fitted in command variants of the Norman.
    Crew comfort: As on Norman, with smaller water tank and reduced power AC unit.
    Upgradeability:
    1.      Same as on Norman, minus ammo.
    2.      Missile easily upgraded to SACLOS.
    3.      Gun very capable of accepting newer advanced ammunition types.
    4.      Main armament can be replaced with low-pressure 90mm gun (styled after the pre-war Cockerill) to create an infantry fire support platform. Estimated stowage: 30-40 rounds, HE/HEP/HEAT.
     
    [I ran out of time so the modelling is woefully incomplete on the vehicle, but the general outline is available].
     
    Mass of turret: 0.8 tons
    Mass of hull: 2.2 tons
    Engine: ~200HP diesel.  Features as on Norman (air compressor/starter, large radiators)
    Estimated mass: 0.6 tons.
    500L fuel, 0.4 tons.
    Transmission: smaller version of that on the Norman, 4 speeds forwards, 4 reverse.
    mass: probably around 2 tons (including drive shafts).
    Suspension: Probably around 2 tons. (including tires)
    Armament mass: probably around 2.5 tons including mantlet, ammo and ATGM box.
    Mass of extras: 3 tons.
    Total estimated mass: 15 tons.
    Dimensions:
    Length, gun forwards: 6.0m
    Length, hull: 5.0m (wheel to wheel, maximum)
    Width, OA: 2.75m with ATGM launcher.
    Width over tracks: 2.5m
    Ground clearance: 450mm to bottom of V, 580mm to top of V hull.
    Height, turret roof: 1.95m
    Height, overall: 2.3m to top of commander’s sight
    Wheel diameter: 1.1m
    Wheel hub diameter: 0.5m
    Wheel width: 300mm
     
    As an additional note, the secrets of multi-alkali photocathodes and cascade image intensifiers are known to the engineers of the EL-OP subsection of the Electronics Division. The Cascader Mark 1 is expected to be in field trials soon. While too large for infantry weapons, tank gunnery integration is expected to proceed rapidly.
    (This refers to first-generation image intensifier equipment, intended for integration in both tanks)
    Likewise, IR detectors and spin scan reticles are being developed; conscans will soon be in development as well. Their use in SACLOS systems as well as anti-air applications will be apparent soon.
    (These reticle seekers will be used for automatic missile detection and aiming in SACLOS, and target detection in anti-aircraft applications)
    And now, the moment you’ve all been waiting for:
    MISSILE TECH EXPLAINED
    As a forewarning, this is going to be fullbore autism, and I strongly recommend you read up on gyros, control theory, and missile guidance before you read the explanation.
    Useful links:
    http://www.shorlandsite.com/images/landroversmissileselliott.pdf
    Contains useful info on the development of British first generation ATGMs. And missiles on Land Rovers, which are cute.
    http://www.dtic.mil/dtic/tr/fulltext/u2/b807471.pdf
    Scientific Advisory Commission report on guided and homing weapons, May, 1946.
    http://www.tpub.com/neets/book15/63e.htm
    Gyro basics.
    https://sci-hub.tw/https://ieeexplore.ieee.org/document/1104289
    Non-minimum-phase dynamic systems.
    The following is based on my knowledge of control systems and missile guidance, as well as basic knowledge of human reactions and as-built 1st gen ATGMs.
    The problem is as follows: we want a missile to fly along the line of sight, to the target, despite target maneuvers and outside disturbances.
    For this, we track the missile, and send commands to the missile to correct for its heading, to maintain the missile along the line of sight to the target. As long as the missile can be made to always be on the line of sight, and is moving faster than the target, a hit is guaranteed.
    This is the basic premise of CLOS guidance.
    To ensure aerodynamic stability and direction-keeping despite manufacturing flaws and inconsistencies, the missile is lightly spun around its axis throughout flight by its fins. These are on an adjustable base, so as part of the SACLOS upgrade the spin can be disabled.
    There are a few points to address in this regard-
    1.       How is the missile tracked?
    2.      How are the commands given? What do they mean?
    3.      How are the commands sent and how are they interpreted?
    4.      How are the commands carried out?
    The answers will be given for 3 systems-
    a. classic MCLOS
    b. classic SACLOS
    c. The BGM-1A and BGM-1B missiles
    let’s start.
    1.A: operator tracks target and missile through sight.
    1.B: Operator tracks target by centering sight on it; guidance system detects missile location relative to crosshairs through spin or later conscan reticle similar to those in early A2A missiles.
    1.C. Same as traditional MCLOS
    2.A. Manual Joystick, usually acceleration command to the missile, command intensity proportional to joystick deflection; force feedback.
    2.B. automatic, often bang-bang, to center of crosshairs, usually acceleration.
    2.C. Manual Joystick, proportional, velocity control.
    3.A. From joystick take-off, through amplifier, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.B. From detector output, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.C. BGM-1A: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile),  to actuators on open loop.
     BGM-1B: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile), to autopilot in missile; autopilot operates actuators on closed loop with horizontal and vertical rate gyros to achieve fixed angle for given command.
    4.A. TVC or rear control surfaces.
    4.B. aerodynamic control surfaces, front or rear.
    4.C. Front control surfaces.
     
    The disadvantages of classic MCLOS are that it was difficult to use, and required great skill, as the acceleration commands combined with rear steering missiles. These missiles exhibit extremely unintuitive steering mechanics, with delayed response, and inverse response: rear steering throws the aft end of the missile in the opposite direction to point the missile towards the target, which means the whole missile moves the wrong way until sufficient wing lift can be generated to push the missile in the intended direction. This is extremely unintuitive for the user and takes a lot of practice to accurately predict; frontal control on the other hand is minimum-phase and intuitive- the missile goes where you want it to, and goes there faster for the same control authority.
    Likewise, acceleration feedback is not intuitive for human beings; we are not used to it. Speed feedback is however within the abilities of humans to handle reliably, and therefore the autopilot has been chosen to perform this duty, greatly easing the use of the missile system by humans and thereby improving accuracy, within the limits of established technology.

    Example of front vs. rear steering. Note the rear-steered missile going the wrong way initially. This is very confusing and leads to overcompensation in all except the well trained and highly skilled.
    The differences between the flight control of the BGM-1A and BGM-1B are as follows:
    The BGM-1A has a single inertia gyro, spinning on a horizontal axis normal to the missile’s axis. This gyro stabilizes the commutator to allow the proper splitting of command to the surfaces despite missile spin.
    Velocity control is achieved through matching to an internal simulator in the flight control box. This receives the command, and relays it to both the missile and the internal missile flight estimator (a reduced 3-variable (local sideslip angle, turn rate, and heading) first order differential solver. The system is linked to an internal PID controller aimed at bringing the missile velocity across the line of sight to the value dictated by the command joystick input. The missile itself, in flight, is controlled on open loop, and therefore velocity errors are liable to accumulate throughout flight. With a flight time of only around 20 seconds to maximal range (4000m), however, this is not considered to be too great a risk.
    This flight control box also forms the basis of the built-in missile simulator; hooked up to a driven mirror assembly with HUD-style reflector plate in the gunner’s sight, it can be used to project a dot representing the gunner’s view of the missile tracer flare onto the gunner’s sight. This can be used to practice missile firings as many times per day as is desired, to maintain high skills with minimal support and minimal live-firings of practice missiles.
    The BGM-1B has an additional gyro in the missile, this one a displacement gyro with its rotation axis aligned with the missile body. The angle take-offs from the 2 gimbal frames are fed through the (larger) commutator, to allow the missile to know what its attitude is compared to that it had at launch. When firing this missile, the flight control box only controls the gain of the joystick (less sensitivity at short range as speeds across the line of sight have greater angular rates), and the missile itself contains a PID autopilot, controlling the servomechanisms by gyro feedback to maintain constant bearing displacement relative to launch. The size of the bearing displacement is linear as a function of the control input, as that results in proportional velocity control along the line of sight.
    The BGM-1B is a slightly more expensive missile, but the increased accuracy thanks to reduced drift more than justifies the cost difference.
    The BGM-1B, thanks to its design, retains a modicum of accuracy in case of a wire break, as it seeks to maintain a 0 bearing relative to launch in that plane. For this reason it is highly advised to point the launcher directly at static targets before launch.
    Both missiles are fairly modular; the warheads are easily removeable and upgradeable, as are the rocket motors, flares, and batteries.
     
    MCLOS missile tech better than was available pre-war is possible with the current industrial ability, as it involves no tech not present in the 1946 survey, and transistors improve reliability and significantly shrink the volume needed for guidance electronics. The better understanding of the control problems involved and the man-machine interface allows the design of more reliable more accurate missiles than were available pre-war.
     
    TL;DR: Missiles work and better than any MCLOS missile built IRL.
     
     
    Tech Specs of the missile:
    Diameter: 160mm
    Length: 1300mm
    Length of launch tube (including launch gas generator): 1500mm
    Wingspan: 550mm
    Wing type: wrap-around fin, thin sheet steel with forming springs; sprung fold-out Monobloc canards. (As on AT-4 Spandrel and AT-5 Spigot)
    Gyros: 1 free for commutator inertial stabilization, BGM-1B: extra displacement gyro for angle feedback control.
    Gyro spin-up mechanism: Compressed air start, no sustain.
    Servo actuation mechanism: Electrical servo-controlled compressed air actuators.
    Velocity: ~200-250m/sec [ss.11 was 220 m/s, clearly this is a controllable speed]
    Range: 4000m, wire limited.
    Time to max range: 16-20 sec.
    Warheads:
    Antitank: Precursor 60mm HEAT, main 160mm HEAT, precision formed, crush-cone fuze, base detonated with wave shapers.
    Anti-structure/ Anti-ship:
    Precursor: none.
    Main: 160mm blast-frag.
     
    Current development of variants includes:
    a. CEV (light breaching equipment, smoke screening equipment, fascines, light digging equipment)
    b. ARV (winches, light crane)
    c. APC/IFV (similar in concept to Alvis Saracen with small cannon/MG turret)
    d. SPAA (VADS-like turret, with twin 20mm autocannon, 1 Vulcan cannon or 1 35mm revolver cannon, and basic air search and ranging radars; missile pod replaced with SAMs (Sidewinder-style) when available).
    e. Fire support vehicle- 90mm low pressure main gun.
     
     
     
  23. Tank You
    N-L-M got a reaction from Toxn in Competition: Tank Design 2239   
    FINAL SUBMISSION:
    XM-2240 RED FOX

    [Fullbore autism warning]
    Upon receipt of the technical requirements for the light tank competition, the design team at GF&M once more decided that the spec was extremely conservative. It was decided that a light vehicle, capable of being used in direct wars of maneuvering and in the assault against Deseret forces, as well as in a defensive ambush role against Californian forces, was more than possible.
    To allow good strategic mobility, and low maintenance for long-range independent operations, a lightweight wheeled chassis was chosen, based on pre-war experiences by South African forces in Angola and Namibia. Combined with the success of pre-war French armored cars (AML, EBR, ERC, VBC, AMX-10), and the export and service success of the pre-war British vehicles (Saladin, Fox, Ferret), it is clear that wheeled vehicles have the ability to operate in rocky desert and mountainous terrain (as long as the going doesn’t get too sandy), with limited support or maintenance.
    For armament, it was quickly determined that the minimum calibre gun which would remain relevant against high-end threats throughout the life of the vehicle is prohibitively large at roughly 100-110mm, forcing the tank to be bigger and heavier than it otherwise needed to be. The minimal calibre to remain relevant against light vehicles (such as light tanks, APCs, IFVs and older tanks), however, is much more reasonable: a 30-35mm autocannon. To defend against the high-end threat, a pre-war invention is resurrected: the anti-tank guided missile (ATGM).
    Systems and crew comfort features were inspired by (and in some cases shared with) those in development for the Norman medium tank, saving time and development money.
    Mobility:
    Suspension is double wishbone on the front 2 axles, with steering; the front-most axle steers all the way, the second axle only steers roughly half.
    The rear axles have Christie-style suspension, with the springs tucked away in the groove on the outside of the hull.
    All axles are powered through drive systems reminiscent of that of the ERC; the engine and transmission sit in the rear of the vehicle.

    Survivability:
    Armor is 10mm high hardness steel facing on 60mm aluminium LOS throughout the 60 degree frontal arc for both hull and turret; for the sides, 5mm steel facing on 30mm aluminium LOS; and the rest (sides, back and belly) 30mm aluminium. The belly is V-shaped, at 10 degrees from the horizontal, to allow good performance against mines.
    Smoke grenade launchers as on Norman, 24+24 for 4+4 salvoes of instantaneous smoke.
    The entire vehicle has a very low profile, and is capable of firing ATGMs from turret-down positions with only the optics and box launcher exposed.
    Automatic IR-detection fire suppression fitted as standard; room for spall liners is available. Mounting points for light-weight ERA when available are also integrated onto the vehicle.
    Thin sheet-steel (2mm) stowage boxes over front and above wheels, around left and rear of turret, set off HE rounds at sufficient standoff to avoid having the armor cave in. [not in model]
    Firepower:

    A.     Armament.
    1.      The main gun is, basically, a Bushmaster III, chambered in 35x230mm, with full dual-feed first-round-select semiauto/automatic fire capability, at around 200 RPM. Ammunition is belted in 2 boxes underneath the turret crew seats; 100 rounds of AP and 500 rounds are carried (50/250 ready).
    Ammo types: AP, HE/HEI (APDS, APFSDS in development)
    2.      1 M240 coax. The coax has a ready box with ~2500 rounds ready, with an additional 2500 stowed.
    3.      1 M240 commander’s MG. Commander’s MG has 600 rounds on mount with extras stowed on the sides of the turret in unarmored boxes [not pictured]
    4.      The main armament elevates from -10 to +30 degrees, and is fully stabilized in a similar manner to the Norman’s armament.
    5.      The ATGM box is raisable, and carries 4 missiles; it is armored against light arms fire (10mm steel) and can elevate and depress to the full extent of the main sight. Additional missile canisters can be stowed on the sponsons (not ready to load from within)
    6.      There are in fact 2 different versions of the basic MCLOS missile on offer, differing by the details of the guidance system.
    B.     Optics. Same as Norman, minus loader.
    C.     FCS.
    1.      Same as Norman for guns. Smaller hydraulic unit needed for the much smaller and lihter turret.
    2.      For missile:
    Missile is controlled in current variants by gunner using a joystick. Space has been allocated for a reticle seeker feeding off of the gunner’s optics and electronics to allow SACLOS systems to be fitted. Details on missile system expanded in later section.
    It is not recommended that a firing mechanism be fitted for the commander to fire the missiles in MCLOS versions.
    For best accuracy it is recommended to point the launch tube directly at the target before launch.
    D.     Radio.
    A more powerful radio is fitted in the Red Fox, with more options. It is suggested that this radio also be fitted in command variants of the Norman.
    Crew comfort: As on Norman, with smaller water tank and reduced power AC unit.
    Upgradeability:
    1.      Same as on Norman, minus ammo.
    2.      Missile easily upgraded to SACLOS.
    3.      Gun very capable of accepting newer advanced ammunition types.
    4.      Main armament can be replaced with low-pressure 90mm gun (styled after the pre-war Cockerill) to create an infantry fire support platform. Estimated stowage: 30-40 rounds, HE/HEP/HEAT.
     
    [I ran out of time so the modelling is woefully incomplete on the vehicle, but the general outline is available].
     
    Mass of turret: 0.8 tons
    Mass of hull: 2.2 tons
    Engine: ~200HP diesel.  Features as on Norman (air compressor/starter, large radiators)
    Estimated mass: 0.6 tons.
    500L fuel, 0.4 tons.
    Transmission: smaller version of that on the Norman, 4 speeds forwards, 4 reverse.
    mass: probably around 2 tons (including drive shafts).
    Suspension: Probably around 2 tons. (including tires)
    Armament mass: probably around 2.5 tons including mantlet, ammo and ATGM box.
    Mass of extras: 3 tons.
    Total estimated mass: 15 tons.
    Dimensions:
    Length, gun forwards: 6.0m
    Length, hull: 5.0m (wheel to wheel, maximum)
    Width, OA: 2.75m with ATGM launcher.
    Width over tracks: 2.5m
    Ground clearance: 450mm to bottom of V, 580mm to top of V hull.
    Height, turret roof: 1.95m
    Height, overall: 2.3m to top of commander’s sight
    Wheel diameter: 1.1m
    Wheel hub diameter: 0.5m
    Wheel width: 300mm
     
    As an additional note, the secrets of multi-alkali photocathodes and cascade image intensifiers are known to the engineers of the EL-OP subsection of the Electronics Division. The Cascader Mark 1 is expected to be in field trials soon. While too large for infantry weapons, tank gunnery integration is expected to proceed rapidly.
    (This refers to first-generation image intensifier equipment, intended for integration in both tanks)
    Likewise, IR detectors and spin scan reticles are being developed; conscans will soon be in development as well. Their use in SACLOS systems as well as anti-air applications will be apparent soon.
    (These reticle seekers will be used for automatic missile detection and aiming in SACLOS, and target detection in anti-aircraft applications)
    And now, the moment you’ve all been waiting for:
    MISSILE TECH EXPLAINED
    As a forewarning, this is going to be fullbore autism, and I strongly recommend you read up on gyros, control theory, and missile guidance before you read the explanation.
    Useful links:
    http://www.shorlandsite.com/images/landroversmissileselliott.pdf
    Contains useful info on the development of British first generation ATGMs. And missiles on Land Rovers, which are cute.
    http://www.dtic.mil/dtic/tr/fulltext/u2/b807471.pdf
    Scientific Advisory Commission report on guided and homing weapons, May, 1946.
    http://www.tpub.com/neets/book15/63e.htm
    Gyro basics.
    https://sci-hub.tw/https://ieeexplore.ieee.org/document/1104289
    Non-minimum-phase dynamic systems.
    The following is based on my knowledge of control systems and missile guidance, as well as basic knowledge of human reactions and as-built 1st gen ATGMs.
    The problem is as follows: we want a missile to fly along the line of sight, to the target, despite target maneuvers and outside disturbances.
    For this, we track the missile, and send commands to the missile to correct for its heading, to maintain the missile along the line of sight to the target. As long as the missile can be made to always be on the line of sight, and is moving faster than the target, a hit is guaranteed.
    This is the basic premise of CLOS guidance.
    To ensure aerodynamic stability and direction-keeping despite manufacturing flaws and inconsistencies, the missile is lightly spun around its axis throughout flight by its fins. These are on an adjustable base, so as part of the SACLOS upgrade the spin can be disabled.
    There are a few points to address in this regard-
    1.       How is the missile tracked?
    2.      How are the commands given? What do they mean?
    3.      How are the commands sent and how are they interpreted?
    4.      How are the commands carried out?
    The answers will be given for 3 systems-
    a. classic MCLOS
    b. classic SACLOS
    c. The BGM-1A and BGM-1B missiles
    let’s start.
    1.A: operator tracks target and missile through sight.
    1.B: Operator tracks target by centering sight on it; guidance system detects missile location relative to crosshairs through spin or later conscan reticle similar to those in early A2A missiles.
    1.C. Same as traditional MCLOS
    2.A. Manual Joystick, usually acceleration command to the missile, command intensity proportional to joystick deflection; force feedback.
    2.B. automatic, often bang-bang, to center of crosshairs, usually acceleration.
    2.C. Manual Joystick, proportional, velocity control.
    3.A. From joystick take-off, through amplifier, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.B. From detector output, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.C. BGM-1A: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile),  to actuators on open loop.
     BGM-1B: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile), to autopilot in missile; autopilot operates actuators on closed loop with horizontal and vertical rate gyros to achieve fixed angle for given command.
    4.A. TVC or rear control surfaces.
    4.B. aerodynamic control surfaces, front or rear.
    4.C. Front control surfaces.
     
    The disadvantages of classic MCLOS are that it was difficult to use, and required great skill, as the acceleration commands combined with rear steering missiles. These missiles exhibit extremely unintuitive steering mechanics, with delayed response, and inverse response: rear steering throws the aft end of the missile in the opposite direction to point the missile towards the target, which means the whole missile moves the wrong way until sufficient wing lift can be generated to push the missile in the intended direction. This is extremely unintuitive for the user and takes a lot of practice to accurately predict; frontal control on the other hand is minimum-phase and intuitive- the missile goes where you want it to, and goes there faster for the same control authority.
    Likewise, acceleration feedback is not intuitive for human beings; we are not used to it. Speed feedback is however within the abilities of humans to handle reliably, and therefore the autopilot has been chosen to perform this duty, greatly easing the use of the missile system by humans and thereby improving accuracy, within the limits of established technology.

    Example of front vs. rear steering. Note the rear-steered missile going the wrong way initially. This is very confusing and leads to overcompensation in all except the well trained and highly skilled.
    The differences between the flight control of the BGM-1A and BGM-1B are as follows:
    The BGM-1A has a single inertia gyro, spinning on a horizontal axis normal to the missile’s axis. This gyro stabilizes the commutator to allow the proper splitting of command to the surfaces despite missile spin.
    Velocity control is achieved through matching to an internal simulator in the flight control box. This receives the command, and relays it to both the missile and the internal missile flight estimator (a reduced 3-variable (local sideslip angle, turn rate, and heading) first order differential solver. The system is linked to an internal PID controller aimed at bringing the missile velocity across the line of sight to the value dictated by the command joystick input. The missile itself, in flight, is controlled on open loop, and therefore velocity errors are liable to accumulate throughout flight. With a flight time of only around 20 seconds to maximal range (4000m), however, this is not considered to be too great a risk.
    This flight control box also forms the basis of the built-in missile simulator; hooked up to a driven mirror assembly with HUD-style reflector plate in the gunner’s sight, it can be used to project a dot representing the gunner’s view of the missile tracer flare onto the gunner’s sight. This can be used to practice missile firings as many times per day as is desired, to maintain high skills with minimal support and minimal live-firings of practice missiles.
    The BGM-1B has an additional gyro in the missile, this one a displacement gyro with its rotation axis aligned with the missile body. The angle take-offs from the 2 gimbal frames are fed through the (larger) commutator, to allow the missile to know what its attitude is compared to that it had at launch. When firing this missile, the flight control box only controls the gain of the joystick (less sensitivity at short range as speeds across the line of sight have greater angular rates), and the missile itself contains a PID autopilot, controlling the servomechanisms by gyro feedback to maintain constant bearing displacement relative to launch. The size of the bearing displacement is linear as a function of the control input, as that results in proportional velocity control along the line of sight.
    The BGM-1B is a slightly more expensive missile, but the increased accuracy thanks to reduced drift more than justifies the cost difference.
    The BGM-1B, thanks to its design, retains a modicum of accuracy in case of a wire break, as it seeks to maintain a 0 bearing relative to launch in that plane. For this reason it is highly advised to point the launcher directly at static targets before launch.
    Both missiles are fairly modular; the warheads are easily removeable and upgradeable, as are the rocket motors, flares, and batteries.
     
    MCLOS missile tech better than was available pre-war is possible with the current industrial ability, as it involves no tech not present in the 1946 survey, and transistors improve reliability and significantly shrink the volume needed for guidance electronics. The better understanding of the control problems involved and the man-machine interface allows the design of more reliable more accurate missiles than were available pre-war.
     
    TL;DR: Missiles work and better than any MCLOS missile built IRL.
     
     
    Tech Specs of the missile:
    Diameter: 160mm
    Length: 1300mm
    Length of launch tube (including launch gas generator): 1500mm
    Wingspan: 550mm
    Wing type: wrap-around fin, thin sheet steel with forming springs; sprung fold-out Monobloc canards. (As on AT-4 Spandrel and AT-5 Spigot)
    Gyros: 1 free for commutator inertial stabilization, BGM-1B: extra displacement gyro for angle feedback control.
    Gyro spin-up mechanism: Compressed air start, no sustain.
    Servo actuation mechanism: Electrical servo-controlled compressed air actuators.
    Velocity: ~200-250m/sec [ss.11 was 220 m/s, clearly this is a controllable speed]
    Range: 4000m, wire limited.
    Time to max range: 16-20 sec.
    Warheads:
    Antitank: Precursor 60mm HEAT, main 160mm HEAT, precision formed, crush-cone fuze, base detonated with wave shapers.
    Anti-structure/ Anti-ship:
    Precursor: none.
    Main: 160mm blast-frag.
     
    Current development of variants includes:
    a. CEV (light breaching equipment, smoke screening equipment, fascines, light digging equipment)
    b. ARV (winches, light crane)
    c. APC/IFV (similar in concept to Alvis Saracen with small cannon/MG turret)
    d. SPAA (VADS-like turret, with twin 20mm autocannon, 1 Vulcan cannon or 1 35mm revolver cannon, and basic air search and ranging radars; missile pod replaced with SAMs (Sidewinder-style) when available).
    e. Fire support vehicle- 90mm low pressure main gun.
     
     
     
  24. Tank You
    N-L-M got a reaction from Collimatrix in Competition: Tank Design 2239   
    FINAL SUBMISSION:
    XM-2240 RED FOX

    [Fullbore autism warning]
    Upon receipt of the technical requirements for the light tank competition, the design team at GF&M once more decided that the spec was extremely conservative. It was decided that a light vehicle, capable of being used in direct wars of maneuvering and in the assault against Deseret forces, as well as in a defensive ambush role against Californian forces, was more than possible.
    To allow good strategic mobility, and low maintenance for long-range independent operations, a lightweight wheeled chassis was chosen, based on pre-war experiences by South African forces in Angola and Namibia. Combined with the success of pre-war French armored cars (AML, EBR, ERC, VBC, AMX-10), and the export and service success of the pre-war British vehicles (Saladin, Fox, Ferret), it is clear that wheeled vehicles have the ability to operate in rocky desert and mountainous terrain (as long as the going doesn’t get too sandy), with limited support or maintenance.
    For armament, it was quickly determined that the minimum calibre gun which would remain relevant against high-end threats throughout the life of the vehicle is prohibitively large at roughly 100-110mm, forcing the tank to be bigger and heavier than it otherwise needed to be. The minimal calibre to remain relevant against light vehicles (such as light tanks, APCs, IFVs and older tanks), however, is much more reasonable: a 30-35mm autocannon. To defend against the high-end threat, a pre-war invention is resurrected: the anti-tank guided missile (ATGM).
    Systems and crew comfort features were inspired by (and in some cases shared with) those in development for the Norman medium tank, saving time and development money.
    Mobility:
    Suspension is double wishbone on the front 2 axles, with steering; the front-most axle steers all the way, the second axle only steers roughly half.
    The rear axles have Christie-style suspension, with the springs tucked away in the groove on the outside of the hull.
    All axles are powered through drive systems reminiscent of that of the ERC; the engine and transmission sit in the rear of the vehicle.

    Survivability:
    Armor is 10mm high hardness steel facing on 60mm aluminium LOS throughout the 60 degree frontal arc for both hull and turret; for the sides, 5mm steel facing on 30mm aluminium LOS; and the rest (sides, back and belly) 30mm aluminium. The belly is V-shaped, at 10 degrees from the horizontal, to allow good performance against mines.
    Smoke grenade launchers as on Norman, 24+24 for 4+4 salvoes of instantaneous smoke.
    The entire vehicle has a very low profile, and is capable of firing ATGMs from turret-down positions with only the optics and box launcher exposed.
    Automatic IR-detection fire suppression fitted as standard; room for spall liners is available. Mounting points for light-weight ERA when available are also integrated onto the vehicle.
    Thin sheet-steel (2mm) stowage boxes over front and above wheels, around left and rear of turret, set off HE rounds at sufficient standoff to avoid having the armor cave in. [not in model]
    Firepower:

    A.     Armament.
    1.      The main gun is, basically, a Bushmaster III, chambered in 35x230mm, with full dual-feed first-round-select semiauto/automatic fire capability, at around 200 RPM. Ammunition is belted in 2 boxes underneath the turret crew seats; 100 rounds of AP and 500 rounds are carried (50/250 ready).
    Ammo types: AP, HE/HEI (APDS, APFSDS in development)
    2.      1 M240 coax. The coax has a ready box with ~2500 rounds ready, with an additional 2500 stowed.
    3.      1 M240 commander’s MG. Commander’s MG has 600 rounds on mount with extras stowed on the sides of the turret in unarmored boxes [not pictured]
    4.      The main armament elevates from -10 to +30 degrees, and is fully stabilized in a similar manner to the Norman’s armament.
    5.      The ATGM box is raisable, and carries 4 missiles; it is armored against light arms fire (10mm steel) and can elevate and depress to the full extent of the main sight. Additional missile canisters can be stowed on the sponsons (not ready to load from within)
    6.      There are in fact 2 different versions of the basic MCLOS missile on offer, differing by the details of the guidance system.
    B.     Optics. Same as Norman, minus loader.
    C.     FCS.
    1.      Same as Norman for guns. Smaller hydraulic unit needed for the much smaller and lihter turret.
    2.      For missile:
    Missile is controlled in current variants by gunner using a joystick. Space has been allocated for a reticle seeker feeding off of the gunner’s optics and electronics to allow SACLOS systems to be fitted. Details on missile system expanded in later section.
    It is not recommended that a firing mechanism be fitted for the commander to fire the missiles in MCLOS versions.
    For best accuracy it is recommended to point the launch tube directly at the target before launch.
    D.     Radio.
    A more powerful radio is fitted in the Red Fox, with more options. It is suggested that this radio also be fitted in command variants of the Norman.
    Crew comfort: As on Norman, with smaller water tank and reduced power AC unit.
    Upgradeability:
    1.      Same as on Norman, minus ammo.
    2.      Missile easily upgraded to SACLOS.
    3.      Gun very capable of accepting newer advanced ammunition types.
    4.      Main armament can be replaced with low-pressure 90mm gun (styled after the pre-war Cockerill) to create an infantry fire support platform. Estimated stowage: 30-40 rounds, HE/HEP/HEAT.
     
    [I ran out of time so the modelling is woefully incomplete on the vehicle, but the general outline is available].
     
    Mass of turret: 0.8 tons
    Mass of hull: 2.2 tons
    Engine: ~200HP diesel.  Features as on Norman (air compressor/starter, large radiators)
    Estimated mass: 0.6 tons.
    500L fuel, 0.4 tons.
    Transmission: smaller version of that on the Norman, 4 speeds forwards, 4 reverse.
    mass: probably around 2 tons (including drive shafts).
    Suspension: Probably around 2 tons. (including tires)
    Armament mass: probably around 2.5 tons including mantlet, ammo and ATGM box.
    Mass of extras: 3 tons.
    Total estimated mass: 15 tons.
    Dimensions:
    Length, gun forwards: 6.0m
    Length, hull: 5.0m (wheel to wheel, maximum)
    Width, OA: 2.75m with ATGM launcher.
    Width over tracks: 2.5m
    Ground clearance: 450mm to bottom of V, 580mm to top of V hull.
    Height, turret roof: 1.95m
    Height, overall: 2.3m to top of commander’s sight
    Wheel diameter: 1.1m
    Wheel hub diameter: 0.5m
    Wheel width: 300mm
     
    As an additional note, the secrets of multi-alkali photocathodes and cascade image intensifiers are known to the engineers of the EL-OP subsection of the Electronics Division. The Cascader Mark 1 is expected to be in field trials soon. While too large for infantry weapons, tank gunnery integration is expected to proceed rapidly.
    (This refers to first-generation image intensifier equipment, intended for integration in both tanks)
    Likewise, IR detectors and spin scan reticles are being developed; conscans will soon be in development as well. Their use in SACLOS systems as well as anti-air applications will be apparent soon.
    (These reticle seekers will be used for automatic missile detection and aiming in SACLOS, and target detection in anti-aircraft applications)
    And now, the moment you’ve all been waiting for:
    MISSILE TECH EXPLAINED
    As a forewarning, this is going to be fullbore autism, and I strongly recommend you read up on gyros, control theory, and missile guidance before you read the explanation.
    Useful links:
    http://www.shorlandsite.com/images/landroversmissileselliott.pdf
    Contains useful info on the development of British first generation ATGMs. And missiles on Land Rovers, which are cute.
    http://www.dtic.mil/dtic/tr/fulltext/u2/b807471.pdf
    Scientific Advisory Commission report on guided and homing weapons, May, 1946.
    http://www.tpub.com/neets/book15/63e.htm
    Gyro basics.
    https://sci-hub.tw/https://ieeexplore.ieee.org/document/1104289
    Non-minimum-phase dynamic systems.
    The following is based on my knowledge of control systems and missile guidance, as well as basic knowledge of human reactions and as-built 1st gen ATGMs.
    The problem is as follows: we want a missile to fly along the line of sight, to the target, despite target maneuvers and outside disturbances.
    For this, we track the missile, and send commands to the missile to correct for its heading, to maintain the missile along the line of sight to the target. As long as the missile can be made to always be on the line of sight, and is moving faster than the target, a hit is guaranteed.
    This is the basic premise of CLOS guidance.
    To ensure aerodynamic stability and direction-keeping despite manufacturing flaws and inconsistencies, the missile is lightly spun around its axis throughout flight by its fins. These are on an adjustable base, so as part of the SACLOS upgrade the spin can be disabled.
    There are a few points to address in this regard-
    1.       How is the missile tracked?
    2.      How are the commands given? What do they mean?
    3.      How are the commands sent and how are they interpreted?
    4.      How are the commands carried out?
    The answers will be given for 3 systems-
    a. classic MCLOS
    b. classic SACLOS
    c. The BGM-1A and BGM-1B missiles
    let’s start.
    1.A: operator tracks target and missile through sight.
    1.B: Operator tracks target by centering sight on it; guidance system detects missile location relative to crosshairs through spin or later conscan reticle similar to those in early A2A missiles.
    1.C. Same as traditional MCLOS
    2.A. Manual Joystick, usually acceleration command to the missile, command intensity proportional to joystick deflection; force feedback.
    2.B. automatic, often bang-bang, to center of crosshairs, usually acceleration.
    2.C. Manual Joystick, proportional, velocity control.
    3.A. From joystick take-off, through amplifier, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.B. From detector output, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.C. BGM-1A: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile),  to actuators on open loop.
     BGM-1B: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile), to autopilot in missile; autopilot operates actuators on closed loop with horizontal and vertical rate gyros to achieve fixed angle for given command.
    4.A. TVC or rear control surfaces.
    4.B. aerodynamic control surfaces, front or rear.
    4.C. Front control surfaces.
     
    The disadvantages of classic MCLOS are that it was difficult to use, and required great skill, as the acceleration commands combined with rear steering missiles. These missiles exhibit extremely unintuitive steering mechanics, with delayed response, and inverse response: rear steering throws the aft end of the missile in the opposite direction to point the missile towards the target, which means the whole missile moves the wrong way until sufficient wing lift can be generated to push the missile in the intended direction. This is extremely unintuitive for the user and takes a lot of practice to accurately predict; frontal control on the other hand is minimum-phase and intuitive- the missile goes where you want it to, and goes there faster for the same control authority.
    Likewise, acceleration feedback is not intuitive for human beings; we are not used to it. Speed feedback is however within the abilities of humans to handle reliably, and therefore the autopilot has been chosen to perform this duty, greatly easing the use of the missile system by humans and thereby improving accuracy, within the limits of established technology.

    Example of front vs. rear steering. Note the rear-steered missile going the wrong way initially. This is very confusing and leads to overcompensation in all except the well trained and highly skilled.
    The differences between the flight control of the BGM-1A and BGM-1B are as follows:
    The BGM-1A has a single inertia gyro, spinning on a horizontal axis normal to the missile’s axis. This gyro stabilizes the commutator to allow the proper splitting of command to the surfaces despite missile spin.
    Velocity control is achieved through matching to an internal simulator in the flight control box. This receives the command, and relays it to both the missile and the internal missile flight estimator (a reduced 3-variable (local sideslip angle, turn rate, and heading) first order differential solver. The system is linked to an internal PID controller aimed at bringing the missile velocity across the line of sight to the value dictated by the command joystick input. The missile itself, in flight, is controlled on open loop, and therefore velocity errors are liable to accumulate throughout flight. With a flight time of only around 20 seconds to maximal range (4000m), however, this is not considered to be too great a risk.
    This flight control box also forms the basis of the built-in missile simulator; hooked up to a driven mirror assembly with HUD-style reflector plate in the gunner’s sight, it can be used to project a dot representing the gunner’s view of the missile tracer flare onto the gunner’s sight. This can be used to practice missile firings as many times per day as is desired, to maintain high skills with minimal support and minimal live-firings of practice missiles.
    The BGM-1B has an additional gyro in the missile, this one a displacement gyro with its rotation axis aligned with the missile body. The angle take-offs from the 2 gimbal frames are fed through the (larger) commutator, to allow the missile to know what its attitude is compared to that it had at launch. When firing this missile, the flight control box only controls the gain of the joystick (less sensitivity at short range as speeds across the line of sight have greater angular rates), and the missile itself contains a PID autopilot, controlling the servomechanisms by gyro feedback to maintain constant bearing displacement relative to launch. The size of the bearing displacement is linear as a function of the control input, as that results in proportional velocity control along the line of sight.
    The BGM-1B is a slightly more expensive missile, but the increased accuracy thanks to reduced drift more than justifies the cost difference.
    The BGM-1B, thanks to its design, retains a modicum of accuracy in case of a wire break, as it seeks to maintain a 0 bearing relative to launch in that plane. For this reason it is highly advised to point the launcher directly at static targets before launch.
    Both missiles are fairly modular; the warheads are easily removeable and upgradeable, as are the rocket motors, flares, and batteries.
     
    MCLOS missile tech better than was available pre-war is possible with the current industrial ability, as it involves no tech not present in the 1946 survey, and transistors improve reliability and significantly shrink the volume needed for guidance electronics. The better understanding of the control problems involved and the man-machine interface allows the design of more reliable more accurate missiles than were available pre-war.
     
    TL;DR: Missiles work and better than any MCLOS missile built IRL.
     
     
    Tech Specs of the missile:
    Diameter: 160mm
    Length: 1300mm
    Length of launch tube (including launch gas generator): 1500mm
    Wingspan: 550mm
    Wing type: wrap-around fin, thin sheet steel with forming springs; sprung fold-out Monobloc canards. (As on AT-4 Spandrel and AT-5 Spigot)
    Gyros: 1 free for commutator inertial stabilization, BGM-1B: extra displacement gyro for angle feedback control.
    Gyro spin-up mechanism: Compressed air start, no sustain.
    Servo actuation mechanism: Electrical servo-controlled compressed air actuators.
    Velocity: ~200-250m/sec [ss.11 was 220 m/s, clearly this is a controllable speed]
    Range: 4000m, wire limited.
    Time to max range: 16-20 sec.
    Warheads:
    Antitank: Precursor 60mm HEAT, main 160mm HEAT, precision formed, crush-cone fuze, base detonated with wave shapers.
    Anti-structure/ Anti-ship:
    Precursor: none.
    Main: 160mm blast-frag.
     
    Current development of variants includes:
    a. CEV (light breaching equipment, smoke screening equipment, fascines, light digging equipment)
    b. ARV (winches, light crane)
    c. APC/IFV (similar in concept to Alvis Saracen with small cannon/MG turret)
    d. SPAA (VADS-like turret, with twin 20mm autocannon, 1 Vulcan cannon or 1 35mm revolver cannon, and basic air search and ranging radars; missile pod replaced with SAMs (Sidewinder-style) when available).
    e. Fire support vehicle- 90mm low pressure main gun.
     
     
     
  25. Tank You
    N-L-M got a reaction from Belesarius in Competition: Tank Design 2239   
    FINAL SUBMISSION:
    XM-2240 RED FOX

    [Fullbore autism warning]
    Upon receipt of the technical requirements for the light tank competition, the design team at GF&M once more decided that the spec was extremely conservative. It was decided that a light vehicle, capable of being used in direct wars of maneuvering and in the assault against Deseret forces, as well as in a defensive ambush role against Californian forces, was more than possible.
    To allow good strategic mobility, and low maintenance for long-range independent operations, a lightweight wheeled chassis was chosen, based on pre-war experiences by South African forces in Angola and Namibia. Combined with the success of pre-war French armored cars (AML, EBR, ERC, VBC, AMX-10), and the export and service success of the pre-war British vehicles (Saladin, Fox, Ferret), it is clear that wheeled vehicles have the ability to operate in rocky desert and mountainous terrain (as long as the going doesn’t get too sandy), with limited support or maintenance.
    For armament, it was quickly determined that the minimum calibre gun which would remain relevant against high-end threats throughout the life of the vehicle is prohibitively large at roughly 100-110mm, forcing the tank to be bigger and heavier than it otherwise needed to be. The minimal calibre to remain relevant against light vehicles (such as light tanks, APCs, IFVs and older tanks), however, is much more reasonable: a 30-35mm autocannon. To defend against the high-end threat, a pre-war invention is resurrected: the anti-tank guided missile (ATGM).
    Systems and crew comfort features were inspired by (and in some cases shared with) those in development for the Norman medium tank, saving time and development money.
    Mobility:
    Suspension is double wishbone on the front 2 axles, with steering; the front-most axle steers all the way, the second axle only steers roughly half.
    The rear axles have Christie-style suspension, with the springs tucked away in the groove on the outside of the hull.
    All axles are powered through drive systems reminiscent of that of the ERC; the engine and transmission sit in the rear of the vehicle.

    Survivability:
    Armor is 10mm high hardness steel facing on 60mm aluminium LOS throughout the 60 degree frontal arc for both hull and turret; for the sides, 5mm steel facing on 30mm aluminium LOS; and the rest (sides, back and belly) 30mm aluminium. The belly is V-shaped, at 10 degrees from the horizontal, to allow good performance against mines.
    Smoke grenade launchers as on Norman, 24+24 for 4+4 salvoes of instantaneous smoke.
    The entire vehicle has a very low profile, and is capable of firing ATGMs from turret-down positions with only the optics and box launcher exposed.
    Automatic IR-detection fire suppression fitted as standard; room for spall liners is available. Mounting points for light-weight ERA when available are also integrated onto the vehicle.
    Thin sheet-steel (2mm) stowage boxes over front and above wheels, around left and rear of turret, set off HE rounds at sufficient standoff to avoid having the armor cave in. [not in model]
    Firepower:

    A.     Armament.
    1.      The main gun is, basically, a Bushmaster III, chambered in 35x230mm, with full dual-feed first-round-select semiauto/automatic fire capability, at around 200 RPM. Ammunition is belted in 2 boxes underneath the turret crew seats; 100 rounds of AP and 500 rounds are carried (50/250 ready).
    Ammo types: AP, HE/HEI (APDS, APFSDS in development)
    2.      1 M240 coax. The coax has a ready box with ~2500 rounds ready, with an additional 2500 stowed.
    3.      1 M240 commander’s MG. Commander’s MG has 600 rounds on mount with extras stowed on the sides of the turret in unarmored boxes [not pictured]
    4.      The main armament elevates from -10 to +30 degrees, and is fully stabilized in a similar manner to the Norman’s armament.
    5.      The ATGM box is raisable, and carries 4 missiles; it is armored against light arms fire (10mm steel) and can elevate and depress to the full extent of the main sight. Additional missile canisters can be stowed on the sponsons (not ready to load from within)
    6.      There are in fact 2 different versions of the basic MCLOS missile on offer, differing by the details of the guidance system.
    B.     Optics. Same as Norman, minus loader.
    C.     FCS.
    1.      Same as Norman for guns. Smaller hydraulic unit needed for the much smaller and lihter turret.
    2.      For missile:
    Missile is controlled in current variants by gunner using a joystick. Space has been allocated for a reticle seeker feeding off of the gunner’s optics and electronics to allow SACLOS systems to be fitted. Details on missile system expanded in later section.
    It is not recommended that a firing mechanism be fitted for the commander to fire the missiles in MCLOS versions.
    For best accuracy it is recommended to point the launch tube directly at the target before launch.
    D.     Radio.
    A more powerful radio is fitted in the Red Fox, with more options. It is suggested that this radio also be fitted in command variants of the Norman.
    Crew comfort: As on Norman, with smaller water tank and reduced power AC unit.
    Upgradeability:
    1.      Same as on Norman, minus ammo.
    2.      Missile easily upgraded to SACLOS.
    3.      Gun very capable of accepting newer advanced ammunition types.
    4.      Main armament can be replaced with low-pressure 90mm gun (styled after the pre-war Cockerill) to create an infantry fire support platform. Estimated stowage: 30-40 rounds, HE/HEP/HEAT.
     
    [I ran out of time so the modelling is woefully incomplete on the vehicle, but the general outline is available].
     
    Mass of turret: 0.8 tons
    Mass of hull: 2.2 tons
    Engine: ~200HP diesel.  Features as on Norman (air compressor/starter, large radiators)
    Estimated mass: 0.6 tons.
    500L fuel, 0.4 tons.
    Transmission: smaller version of that on the Norman, 4 speeds forwards, 4 reverse.
    mass: probably around 2 tons (including drive shafts).
    Suspension: Probably around 2 tons. (including tires)
    Armament mass: probably around 2.5 tons including mantlet, ammo and ATGM box.
    Mass of extras: 3 tons.
    Total estimated mass: 15 tons.
    Dimensions:
    Length, gun forwards: 6.0m
    Length, hull: 5.0m (wheel to wheel, maximum)
    Width, OA: 2.75m with ATGM launcher.
    Width over tracks: 2.5m
    Ground clearance: 450mm to bottom of V, 580mm to top of V hull.
    Height, turret roof: 1.95m
    Height, overall: 2.3m to top of commander’s sight
    Wheel diameter: 1.1m
    Wheel hub diameter: 0.5m
    Wheel width: 300mm
     
    As an additional note, the secrets of multi-alkali photocathodes and cascade image intensifiers are known to the engineers of the EL-OP subsection of the Electronics Division. The Cascader Mark 1 is expected to be in field trials soon. While too large for infantry weapons, tank gunnery integration is expected to proceed rapidly.
    (This refers to first-generation image intensifier equipment, intended for integration in both tanks)
    Likewise, IR detectors and spin scan reticles are being developed; conscans will soon be in development as well. Their use in SACLOS systems as well as anti-air applications will be apparent soon.
    (These reticle seekers will be used for automatic missile detection and aiming in SACLOS, and target detection in anti-aircraft applications)
    And now, the moment you’ve all been waiting for:
    MISSILE TECH EXPLAINED
    As a forewarning, this is going to be fullbore autism, and I strongly recommend you read up on gyros, control theory, and missile guidance before you read the explanation.
    Useful links:
    http://www.shorlandsite.com/images/landroversmissileselliott.pdf
    Contains useful info on the development of British first generation ATGMs. And missiles on Land Rovers, which are cute.
    http://www.dtic.mil/dtic/tr/fulltext/u2/b807471.pdf
    Scientific Advisory Commission report on guided and homing weapons, May, 1946.
    http://www.tpub.com/neets/book15/63e.htm
    Gyro basics.
    https://sci-hub.tw/https://ieeexplore.ieee.org/document/1104289
    Non-minimum-phase dynamic systems.
    The following is based on my knowledge of control systems and missile guidance, as well as basic knowledge of human reactions and as-built 1st gen ATGMs.
    The problem is as follows: we want a missile to fly along the line of sight, to the target, despite target maneuvers and outside disturbances.
    For this, we track the missile, and send commands to the missile to correct for its heading, to maintain the missile along the line of sight to the target. As long as the missile can be made to always be on the line of sight, and is moving faster than the target, a hit is guaranteed.
    This is the basic premise of CLOS guidance.
    To ensure aerodynamic stability and direction-keeping despite manufacturing flaws and inconsistencies, the missile is lightly spun around its axis throughout flight by its fins. These are on an adjustable base, so as part of the SACLOS upgrade the spin can be disabled.
    There are a few points to address in this regard-
    1.       How is the missile tracked?
    2.      How are the commands given? What do they mean?
    3.      How are the commands sent and how are they interpreted?
    4.      How are the commands carried out?
    The answers will be given for 3 systems-
    a. classic MCLOS
    b. classic SACLOS
    c. The BGM-1A and BGM-1B missiles
    let’s start.
    1.A: operator tracks target and missile through sight.
    1.B: Operator tracks target by centering sight on it; guidance system detects missile location relative to crosshairs through spin or later conscan reticle similar to those in early A2A missiles.
    1.C. Same as traditional MCLOS
    2.A. Manual Joystick, usually acceleration command to the missile, command intensity proportional to joystick deflection; force feedback.
    2.B. automatic, often bang-bang, to center of crosshairs, usually acceleration.
    2.C. Manual Joystick, proportional, velocity control.
    3.A. From joystick take-off, through amplifier, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.B. From detector output, through wires, direct to gyrostabilized commutator (in spun missile), to actuators on open loop.
    3.C. BGM-1A: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile),  to actuators on open loop.
     BGM-1B: From joystick take-off, to flight control box, Through wires, direct to gyrostabilized commutator (spun missile), to autopilot in missile; autopilot operates actuators on closed loop with horizontal and vertical rate gyros to achieve fixed angle for given command.
    4.A. TVC or rear control surfaces.
    4.B. aerodynamic control surfaces, front or rear.
    4.C. Front control surfaces.
     
    The disadvantages of classic MCLOS are that it was difficult to use, and required great skill, as the acceleration commands combined with rear steering missiles. These missiles exhibit extremely unintuitive steering mechanics, with delayed response, and inverse response: rear steering throws the aft end of the missile in the opposite direction to point the missile towards the target, which means the whole missile moves the wrong way until sufficient wing lift can be generated to push the missile in the intended direction. This is extremely unintuitive for the user and takes a lot of practice to accurately predict; frontal control on the other hand is minimum-phase and intuitive- the missile goes where you want it to, and goes there faster for the same control authority.
    Likewise, acceleration feedback is not intuitive for human beings; we are not used to it. Speed feedback is however within the abilities of humans to handle reliably, and therefore the autopilot has been chosen to perform this duty, greatly easing the use of the missile system by humans and thereby improving accuracy, within the limits of established technology.

    Example of front vs. rear steering. Note the rear-steered missile going the wrong way initially. This is very confusing and leads to overcompensation in all except the well trained and highly skilled.
    The differences between the flight control of the BGM-1A and BGM-1B are as follows:
    The BGM-1A has a single inertia gyro, spinning on a horizontal axis normal to the missile’s axis. This gyro stabilizes the commutator to allow the proper splitting of command to the surfaces despite missile spin.
    Velocity control is achieved through matching to an internal simulator in the flight control box. This receives the command, and relays it to both the missile and the internal missile flight estimator (a reduced 3-variable (local sideslip angle, turn rate, and heading) first order differential solver. The system is linked to an internal PID controller aimed at bringing the missile velocity across the line of sight to the value dictated by the command joystick input. The missile itself, in flight, is controlled on open loop, and therefore velocity errors are liable to accumulate throughout flight. With a flight time of only around 20 seconds to maximal range (4000m), however, this is not considered to be too great a risk.
    This flight control box also forms the basis of the built-in missile simulator; hooked up to a driven mirror assembly with HUD-style reflector plate in the gunner’s sight, it can be used to project a dot representing the gunner’s view of the missile tracer flare onto the gunner’s sight. This can be used to practice missile firings as many times per day as is desired, to maintain high skills with minimal support and minimal live-firings of practice missiles.
    The BGM-1B has an additional gyro in the missile, this one a displacement gyro with its rotation axis aligned with the missile body. The angle take-offs from the 2 gimbal frames are fed through the (larger) commutator, to allow the missile to know what its attitude is compared to that it had at launch. When firing this missile, the flight control box only controls the gain of the joystick (less sensitivity at short range as speeds across the line of sight have greater angular rates), and the missile itself contains a PID autopilot, controlling the servomechanisms by gyro feedback to maintain constant bearing displacement relative to launch. The size of the bearing displacement is linear as a function of the control input, as that results in proportional velocity control along the line of sight.
    The BGM-1B is a slightly more expensive missile, but the increased accuracy thanks to reduced drift more than justifies the cost difference.
    The BGM-1B, thanks to its design, retains a modicum of accuracy in case of a wire break, as it seeks to maintain a 0 bearing relative to launch in that plane. For this reason it is highly advised to point the launcher directly at static targets before launch.
    Both missiles are fairly modular; the warheads are easily removeable and upgradeable, as are the rocket motors, flares, and batteries.
     
    MCLOS missile tech better than was available pre-war is possible with the current industrial ability, as it involves no tech not present in the 1946 survey, and transistors improve reliability and significantly shrink the volume needed for guidance electronics. The better understanding of the control problems involved and the man-machine interface allows the design of more reliable more accurate missiles than were available pre-war.
     
    TL;DR: Missiles work and better than any MCLOS missile built IRL.
     
     
    Tech Specs of the missile:
    Diameter: 160mm
    Length: 1300mm
    Length of launch tube (including launch gas generator): 1500mm
    Wingspan: 550mm
    Wing type: wrap-around fin, thin sheet steel with forming springs; sprung fold-out Monobloc canards. (As on AT-4 Spandrel and AT-5 Spigot)
    Gyros: 1 free for commutator inertial stabilization, BGM-1B: extra displacement gyro for angle feedback control.
    Gyro spin-up mechanism: Compressed air start, no sustain.
    Servo actuation mechanism: Electrical servo-controlled compressed air actuators.
    Velocity: ~200-250m/sec [ss.11 was 220 m/s, clearly this is a controllable speed]
    Range: 4000m, wire limited.
    Time to max range: 16-20 sec.
    Warheads:
    Antitank: Precursor 60mm HEAT, main 160mm HEAT, precision formed, crush-cone fuze, base detonated with wave shapers.
    Anti-structure/ Anti-ship:
    Precursor: none.
    Main: 160mm blast-frag.
     
    Current development of variants includes:
    a. CEV (light breaching equipment, smoke screening equipment, fascines, light digging equipment)
    b. ARV (winches, light crane)
    c. APC/IFV (similar in concept to Alvis Saracen with small cannon/MG turret)
    d. SPAA (VADS-like turret, with twin 20mm autocannon, 1 Vulcan cannon or 1 35mm revolver cannon, and basic air search and ranging radars; missile pod replaced with SAMs (Sidewinder-style) when available).
    e. Fire support vehicle- 90mm low pressure main gun.
     
     
     
×
×
  • Create New...