- Pronouns
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OK, here it is. First draft. I'm open to suggestions - especially about forearm vs shoulder mounts.
The former let the mech shoot from behind cover, which does let us build it lighter in terms of armor, but requires fancier arms which might wipe out the gains in terms of lightening.
Shoulder mounts allow us to eliminate the armored motion capture arms that poke out of the suit, but mean that the mech is more likely to take fire to the torso.
Hmmmm... ok, I might have another design tomorrow that gets around a lot of the left/right switchover issues I talk about below, but I need to run it by some people first.
[X] Armoured Combat Humanoid Type 3 (Iron Tabby)
Name: Armoured Combat Humanoid Type 3
Nickname: Iron Tabby
Type: Mech
Branch: Army
Intended Role: Organic Light Artillery Support, Super-Heavy Infantry, Combat Engineering
Notable Quirks:
The former let the mech shoot from behind cover, which does let us build it lighter in terms of armor, but requires fancier arms which might wipe out the gains in terms of lightening.
Shoulder mounts allow us to eliminate the armored motion capture arms that poke out of the suit, but mean that the mech is more likely to take fire to the torso.
Hmmmm... ok, I might have another design tomorrow that gets around a lot of the left/right switchover issues I talk about below, but I need to run it by some people first.
[X] Armoured Combat Humanoid Type 3 (Iron Tabby)
Name: Armoured Combat Humanoid Type 3
Nickname: Iron Tabby
Type: Mech
Branch: Army
Intended Role: Organic Light Artillery Support, Super-Heavy Infantry, Combat Engineering
Notable Quirks:
- Mass Production Goes BRRRRRRR
- Anti-Reverse Engineering Measures
- A Maturing Technology
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- Concept of Operations
- While the Gen 1 Iron Tiger taught our engineers and military a lot about how NOT to build and use mechs and refined the theoretical doctrinal niches for them, we still haven't used them in said niches, so the new ITs are designed to be fairly flexible in terms of loadout to account for expected changed in conops from field deployment (throw stuff at the wall and hope it sticks).
- The new mechs occupy a happy medium between power armor and mecha: large enough to avoid the joint alignment and miniaturization issues of power armor, but small enough to sidestep most of the square cube law and joint maintenance issues of large mechs.
- At 2.5m tall and 1.25 tonnes in weight, the Tabby cannot readily enter residential spaces, though it will be able to navigate most industrial ones. The largest issue is ensuring that the floors can bear the load. It can however make effective use of urban terrain to break LOS from the enemy for protection.
- Shoulder mounted vs forearm mounted weapons are a bit of an open question, so the arms are designed to be modular and accept both options, with the expectation that we'll figure out what works best in actual combat.
- Specialized combat engineering units forgo most of the armor for lower cost and lighter weight.
- Armor
- Perforated steel plate on spacers with a aluminum alloy backing offering high multi-hit protection from 0.62x54mm R B-32 AP (Chicom) equivalents on the front of the torso and upper legs, (the parts the contain both pilot limbs and mobility critical actuators).
- The front and sides of the upper arm actuators and the rear of the thighs and torso are protected with laminated silicon carbide plates to reduce bulk. They can't take as many hits as the torso and thighs, but there are no operator bits inside the arms and a hit there won't mobility kill the mech. The rear of the torso and thighs in the meantime is judged to be less likely to be hit so the decision was made to trade protection for lighter weight there.
- The operator arm-sleeves are armored with titanium backed ceramic plates as a lighter and less bulky alternative to the perforated steel.
- The rest of the mech is (supposedly) proof against artillery shrapnel at 8 meters by dint of the aluminum exoskeleton or kevlar fabric covers.
- Machined aluminum exoskeleton with incomplete coverage - load bearing exoskeleton doubles as backing layer or armor while exposing internals for maintenance on less likely angles of fire (interior thigh, interior arms, back/top).
- Defenses
- Smoke dispensers can provide cover for the mech and its attached infantry.
- Shape disrupting ponchos in several camouflage patterns are meant to make it harder to identify at range.
- A breaching shield may sometimes be equipped for niche urban combat scenarios.
- Airtight seals and air filtration built into the AC unit needed for the computer allows operation in NBC environments.
- Weapons Loadouts
- To keep development time and costs down, the Tabby uses mostly off the shelf Soviet military hardware when it comes to weapons:
- In urban combat, the Tabby can be equipped with an automatic grenade launcher and light machine gun, and used as shock troops or reconnaissance in force.
- When attached to infantry units in urban combat, the grenade launcher can be used for making mouseholes for infantry to use or makes the enemy's lives miserable, while the LMG with deep ammo magazines provides covering fire.
- Swapping the grenade launcher for a recoilless rifle gives it anti armor and anti-fortification firepower that can be organically attached to infantry units, while the infantry support can be used to reload the recoilless rifle magazines.
- In rough terrain ops where longer range is a boon, the Tabby can use its arms to wield a tripod mounted, crew served 35mm cannon gives it plenty of ranged firepower to bring to bear against light vehicles.
- Organic indirect fire support can be provided when attached to infantry units by a crew served, backpack mounted 120mm mortar (120-PM-43 Samovar) fired from a kneeling position.
- Shoulder mounted 9K38 Igla launcher for short ranged anti-air capability that can be organically attached to an infantry unit operating in very rough terrain.
- Shoulder mounts are suitable for heavier weapons and are easier to balance but expose the pilot to more danger since they can't poke out behind cover as well. They're also easier to switch from left to right by spinning the shoulders 360 degrees and spinning the weapon around the shoulder joint in order to accommodate the left/right shooting around cover that makes up most of urban combat.
- Forearm mounted weapons allow the pilot to shoot around cover without exposing the mech as much, but are harder to stabilize and armor. They're also harder to reverse left/right, and require reversible elbows to do so.
- Fiberscope sights integrated into weapons for peeking around/over cover.
- Rule of thumb: you get about 5% of your curb weight as arm/handheld weapons, 10% if you can get both arms into it (remember to account for ammo weight).
- To keep development time and costs down, the Tabby uses mostly off the shelf Soviet military hardware when it comes to weapons:
- Powerplant
- Smaller size of Tabby made turbines a poor fit due to their poor scaling to smaller sizes, and their expected production numbers would have strained native production capacity to the breaking point.
- Instead, Free Piston Linear Generators were developed, mechanically coupled in pairs of two to minimize vibration. Their lesser number of moving parts compared to traditional internal combustion engines, coupled with their ability to gracefully shut down pairs of pistons in lower intensity operations made them an obvious choice - as well as their application to other hybrid electric drive vehicles.
- The power plant was also moved to a power egg akin to an insect abdomen that swings out behind the mech's buttocks, both allowing for easier servicing as well as improving stability by lowering the mech's center of gravity.
- The abdomen is also actuated and serves as a counter balance that both actively stabilizes the mech and acts as a spring-like energy recovery mechanism when walking and running, replacing the dedicated gyroscopic stabilizer of the Tigers.
- Actuation
- The transmission is the same air cooled copper used on previous ITs and aircraft.
- To better approximate the range of motion of the pilot and make it easier to pilot, the limbs have double jointed elbows and knees.
- 3-axis weapon stabilization and mirror first sights allow for firing on the move.
- Swap from straight electro-hydrostatic suspension, to hydropneumatic for better shock absorption to mitigate health effects of high acceleration, as well as faster and wider range of movement.
- Three fingered end effectors on the ends of the arms balance dexterity with reliability.
- Gortex 'coveralls' to keep debris out of high wear areas like joints.
- Control
- While it's difficult to prevent other nations from reverse engineering an IT by examining the physical hardware, the processors and (even more crucially) the software algorithms used for the dynamic balancing and gait cycle control are much easier to deal with.
- The processors and hard drive are black boxed in tamper resistant containment units with thermite charges that will melt it all to slag if anyone tries to get in or fails to provide the appropriate ID over a period of time.
- The computer is air cooled for reliability, using filtered and conditioned air from a small AC unit.
- The pilot drives it via a motion capture rig, reducing the computing load by relying on the pilot's natural sense of balance and sympathetic proprioception of the mech's limbs.
- Pilot enters and exits the mech via a top mounted hatch that the sensor cluster 'head' rests on. Its position means that it's unlikely to be blocked if the mech topples over.
- The pilots arms are encased in armored sleeves that terminate in an armored ball glove that contains a number of controls for the mech.
- Sensors
- Sensors are clustered in an armored 'head' on top of the pilot hatch:
- Fiberscope based binocular vision, with a head mounted 'eyes' connected to the pilot's headset. Said headset can switch between several fiberscopes, including gun cameras in both arms, because urban combat is a lot of side peek. (Fiberscopes have the advantage over era appropriate CCTVs in terms of bulk, unpowered operation, and image quality.)
- IR optics for nighttime operation.
- Laser rangefinder/designator for when you need to call in artillery or designate a target to get bombed with a laser guided bomb (not to self: we need a laser guided bomb).
- Information is conveyed through audio cues and minor heads up display around the fiberscope visor. For complex tasks, the pilot can flip up one of both fiberscope ends to look at a screen inside the cockpit.
- Sensors are clustered in an armored 'head' on top of the pilot hatch:
- Equipment
- Hard-wearing Goretex fabric covers for the limbs and body are standard in order to weatherproof the mech.
- Outer camouflage poncho designed to break up its silhouette and can be easily swapped based on environment.
- The new waterproofing allows it to wade through water with the aid of shoulder mounted air intakes and exhaust vents that prevent water ingestion.
- Concept of Operations
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