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Competition: A modern medium AFV


Toxn
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I just did a armor weight estimate on the hull, it came out at around 5 ton, which is means I will probably make the C-130J requirement.

 

And some redesign of the composite arrays:

oatPDj6.png

I say this as someone who habitually designs tanks for dwarves, but damn that thing is short.

 

What does the crew compartment look like in there?

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I say this as someone who habitually designs tanks for dwarves, but damn that thing is short.

 

What does the crew compartment look like in there?

Here is a image of when I was figuring out the layout:

k3rTwFs.png

 

Note that the crew capsule has been raised afterwards since the engine needed more height to fit. 

 

And yes, I made this vehicle as small as possible, if I switched the engine and turret I could probably make it even lower, but I see no need to. 

 

Ground clearance is 480mm by the way.

 

Total height 1,814m

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Here is a image of when I was figuring out the layout:

k3rTwFs.png

 

Note that the crew capsule has been raised afterwards since the engine needed more height to fit. 

 

And yes, I made this vehicle as small as possible, if I switched the engine and turret I could probably make it even lower, but I see no need to. 

 

Ground clearance is 480mm by the way.

 

Total height 1,814m

This doesn't give the height of the crew compartment though.

 

For reference, the compartment height in a modern hatchback is about 2.5m long, 1.3m wide and 1.2m high for 4-5 people. So a minimalist crew compartment for one should be something like 1.2x0.65x1.1 metres. If your crew is prone and doesn't mind the wheel resting on their knees, then you can maybe get it down to 1.4x0.6x1.0 metres. Any lower than 1 metre in height and you're down to firing up the Peter Dinklage cloning program.

 

Edit: again, I'm known for specifying crew compartments more suitable for clown cars than AFVs, so don't take this as blanket criticism. Just check that your dudes can all, you know, fit in the thing without having to lose appendages.

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This doesn't give the height of the crew compartment though.

 

For reference, the compartment height in a modern hatchback is about 2.5m long, 1.3m wide and 1.2m high for 4-5 people. So a minimalist crew compartment for one should be something like 1.2x0.65x1.1 metres If your crew is prone and doesn't mind the wheel resting on their knees, then you can maybe get it down to 1.4x0.6x1.0 metres. Any lower than 1 metre in height and you're down to firing up the Peter Dinklage cloning program.

 

Edit: again, I'm known for specifying crew compartments more suitable for clown cars than AFVs, so don't take this as blanket criticism. Just check that your dudes can all, you know, fit in the thing without having to lose appendages.

I know dude, lol, relax, they do fit. I use 3D models to check the dimensions. It is defiantly cramped, but they do fit. 

 

If you really really want I could give you the dimensions. 

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I know dude, lol, relax, they do fit. I use 3D models to check the dimensions. It is defiantly cramped, but they do fit. 

 

If you really really want I could give you the dimensions. 

Nah, I'm happy if you're happy.

 

Have fun with the rest of the modelling!

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Okay, here is my non-eligible submission:

 

FINAL VERSION

 

AFV-M 4 "Switchblade"

 

JF2qgLj.jpg

 

Statistics

 

Switchblade 1:

  • Length - 4.9m (hull); 5.6m (gun forward)
  • Width - 3m (compact config); 3.4m (suspension extended)
  • Height - 2.4m (stowed)
  • Weight - 15mt (bare); 18.5mt (fully loaded + addon armour)
  • Ground clearance - 0.57m (suspension extended)
  • Speed - 110km/h (on road), 20km/h (off road)
  • Armour: 100mm RHA + 250mm NERA on cab front, 50mm RHA + 200mm NERA on cab sides, 50mm RHA on cab top and bottom; 15mm RHA otherwise
  • Weapons: 75mm L40 Autoloader (45 rounds), 7.62mm MG coax
  • Ammunition (75mm L40) - APBC, HE (including programmable air burst), HEDP, HEAT, various other (training, smoke, canister, illumination etc)
  • Main gun elevation/depression - +45/-10 degrees
  • Main gun rate of fire: 40 RPM
  • Other: 2 x smoke dischargers in turret, 4 X hard kill units (mongoose) 

Switchblade 2:

  • Length - 6.0m (hull); 6.4m (gun forward)
  • Width - 3m (compact config); 3.4m (suspension extended)
  • Height - 2.4m (stowed)
  • Weight - 16mt (bare); 19mt (fully loaded + addon armour)
  • Ground clearance - 0.57m (suspension extended)
  • Speed - 110km/h (on road), 20km/h (off road)
  • Armour: 50mm RHA cab top front, 50mm RHA + 200mm NERA on cab sides, 50mm RHA on cab top and bottom; 15mm RHA otherwise
  • Weapons: 75mm L40 Autoloader (40 rounds), 7.62mm MG coax
  • Ammunition (75mm L40) - APBC, HE (including programmable air burst), HEDP, HEAT, various other (training, smoke, canister, illumination etc)
  • Main gun elevation/depression - +45/-10 degrees
  • Main gun rate of fire: 40 RPM
  • Other: 2 x smoke dischargers in turret, 4 X hard kill units (mongoose), 1.4m x 1,4m x 1m modular bay, drone launch rail, provision for ERA over crew compartment

 

Description

 

The Switchblade project was undertaken by our internal design unit as a response to the general project tender issued by exco. Here, our intent was to satisfy the stringent weight and dimensional requirements needed for air-deployability, while still providing enough firepower and protection to deal with any battlefield threats short of heavy AFVs.

 

The initial study made use of cutting-edge automation and visualisation approaches and resulted in a small, wheeled vehicle operated by two crew members inside a heavily-armoured capsule. Here a combination of conventional steel armour, add-on arrays and an integrated active protection suite was chosen in order to protect the crew. Specifically, the thickness of steel was chosen to provide full protection against heavy autocannons frontally, with side/top protection being capable of protecting against lighter autocannon firing AP or HEDP. Protection against ATGMs was provided by the add-on NERA arrays and the APS suite; which included both passive laser detection, active radar detection and hard-kill units. Mine and IED protection was provided by the double-layered hull floor, armoured seats, seat suspension system and water-filling of the tires.

 

The proposed armament was a 30-40mm autocannon (preferably in the CTA configuration), but this was later changed to a 75mm gun capable of using conventional 75x350mmR ammunition at the insistence of exco; who also authorised immediate initial low-rate production of new AP and training rounds. The penny dropped when we discovered that Terry had recently acquired a refurbished M24 Chaffee, with the upshot being that a number of live-fire tests for the new rounds were conducted by exco themselves during their monthly retreat. 

 

esBSxOz.jpg

 

Having made the initial changes to the design, we found ourselves making peace with the odd choice of armament. Although deeply unsuitable for development of an APFSDS variant (a lengthened case designed to allow for the same overall dimensions was eventually proposed to partially rectify this), the venerable 75mm had a number of distinct advantages for our project. Firstly, the existing APC and HEAT ammunition developed for the gun, although over 70 years old, was still more than enough to deal with any currently existing AFV not based on an MBT chassis. Here the APC proved especially interesting, as it was found to be almost unaffected by modern active protection systems, ERA and NERA in testing. The existing HE was also more than adequate for the purpose of infantry support, with the mount being very suitable for indirect fire and high-angle fire into buildings. The compact nature of the round also allowed for the use of a simple carousel-type autoloader, which fed the gun through a swinging feed tube assembly in the turret bustle. Finally, there was no issue of IP or licencing of the gun or ammunition technology, as any patents had long since expired. The gun, when added to a conventional coaxial machinegun, was thus felt to be more than adequate for the tasks the vehicle would face.

 

With the basic armament selected, we pressed on with more detailed changes. The gun tube was fitted with a thermal sleeve, laser alignment system, sights and 2-axis stabilization gear. A bore extractor was unnecessary, as the entire turret was unmanned. Instead, all of the systems (main gun sight, coaxial sight/wide angle sight and stowable commander's sight) were linked to the crew capsule and displayed on high-resolution displays. For the commander's sight and driver's sight, a single design was used incorporating two stabilized cameras linked to a 3-D display. This was felt to improve the spatial perception of the crew when interacting with using the system. For the driver, three viewing blocks were provided as a backup in the event that his sight was damaged or obscured.

 

QK9LjWI.jpg

 

Along with the innovative vision system, our group also grappled with the issue of automotive components for such a compact vehicle. The engine - a Scania V8 diesel unit producing up to 590kW - was housed in a modular bay and used to power a hybrid drivetrain. However, cost concerns and further design directives from exco (Dion was involved in the development of the Spinnekop mine protected vehicle in the early 1980s) lead to a hydrolic hybrid drivetrain being selected. The new system operated in series, with the reservoir, pump, accumulator and distributor being housed in the engine compartment. The wheels were again directly driven, with the motors being fed from armoured piping (including self-sealing valves in the event of rupture) that ran along steel housings located on the hull sides. The housings also served to house the electrical system, and were constructed from armour plate. The resulting drive system was compact but maintenance-intensive. This issue also plagued the suspension system, which was designed to be retracted and lowered in order to allow the vehicle to squeeze into a C-130. The process of retracting the suspension was time-consuming, and involved shortening each strut and linkage connecting the wheel to the hull. With 8 wheels to service, the process could take hours even for an experienced crew.

 

VGQeUdX.jpg

 

With preliminary design and prototyping done, the first switchblade prototype was sent for testing and evaluation. The results... were not good. Exco, which was again taking an active role in the process, was particularly unhappy with the size of the crew capsule , its resistance to mines and the overworked nature of the crew. During the development process they had also become interested in marketing a family of vehicles based on the same chassis. As such, we were instructed to change the weapon system to fit within a modular bay format.

 

After a frantic redesign process, our group came up with a compromise version of the Switchblade with a four-man crew and W-hull mine protection for the capsule. This increased the capsule size considerably and lengthened the chassis (resulting in a 10X10 drive cofiguration), but a rearrangement of the principle components allowed the overall height to remain the same at the expense of not being able to rotate the turret fully. The new placement of the capsule in the rear of the vehicle also allowed us to dispense with the thick frontal armour array, which kept the overall weight increase to a minimum. Finally, the new arrangement allowed us to solve one of the most pressing issues identified during testing: that the crew had significant difficulty exiting the vehicle in an emergency. Our initial solution had been to make the entire front hull swing forwards (aided by a powder-driven ram), but this was obviously a clunky solution.

 

A troubling aspect of the vehicle that manifestly was not improved by the redesign was the issue of auxillary sights for the driver if his main sight was not functional. Our solution was to place a number of vision ports around the crew capsule, but this did nothing for the view forwards - which was blocked by the turret. To alleviate the issue, we designed a folding periscope, which was mounted in place of the driver's top hatch. Another new issue concerned the ammunition stowage of the main gun, which was reduced somewhat in order to fit the entire mechanism within the modular weapons bay.

 

 

g311RBf.jpg

 

 

The second switchblade prototype, once finalised, was fully assembled and tested at our land developments range. Here it was deemed satisfactory for production and marketing, although a few lingering problems were discovered which we have yet to adequately solve. The most pressing of these concerns the automotive components, which are still maintenance-intensive. Suspension travel is another concern, although the ground clearance was deemed satisfactory for use. The weapons system, on the other hand, performed as expected; with crew workload being eased by the inclusion of a dedicated gunner and C3 crewman.

 

 

During qualification testing, the Switchblade proved capable of rapidly engaging targets while on the move. Provision for airburst fuzing (either programmable or radar-fuzed) allowed hits to be made on attack helicopter and CAS aircraft targets. The commander's sight, which includes provision for position marking and turret override, proved to be a useful system for spotting and handing off targets to the gunner. Protection was deemed to be satisfactory, with the crew capsule being completely isolated from ammunition stowage and other volatiles. In testing, the armour package proved to be capable of protecting the crew against ATGMs and heavy autocannon from the front, with the sides and rear being protected against lighter anti-tank weapons and standard rounds from lighter autocannon.

 

Final modifications before production commences are the inclusion and integration of communications and electronics equipment (including a hull telephone and on-board UAV operated by the C3 crewman), the improvement of automotive and drivetrain components and the development of hull modules for the weapons bay. Module variants being presently developed include a sensor mast and RWS (including a small-calibre autocannon) for scouting and light fire support; an ATGM turret for anti-armour operations; a mortar turret for short-range fire support; a MRL system for long-range fire support; a drone bay for observation and light attack missions; and an engineering suite (including hydrolic crane or digger options) for battlefield support.

 

 

rynTTBQ.jpg

Approximate component weights (Switchblade 2):

  • Hull: 9000kg
  • Addon armour: 2000kg
  • Turret, stowage, autoloading gear, crew equipment and accessories: 3000kg
  • Drivetrain (including wheels, suspension and fuel fraction): 5000kg

 

 

 

qPBBcKi.jpg

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Wait, why does your submission only show up in the first of those set of images?

I still need to actually write the text. Hence the thousand-and-one filler tags.

 

It will get bulked out with some stats and a suitably sad story soon.

 

 

Wtf were you smoking?

Regarding the design, or the layout of the description?

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eSTKgkf.png

 

Starting on the suspension some, changed the internal layout of the guns so it would all fit.  Messing with a lower turret mounting height, but that decreased depression by 1° (-11.5° now).  The gun gets some rangefinder or camera on it now too.

 

 

Edit is for newer layout.  6 bigger wheels instead of 7 smaller ones, internal layout of the guns tweaked so the MG fits properly.  Image of said layout in spoiler

 

Ehgrnxe.png

Edited by ApplesauceBandit
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General question to other people making 3D models:

 

Is making a complex curved surface like this wheel a massive pain in the ass in the programs you use too?  Stuff like this and the fat patton cupolas are good examples.

 

M113-tracks-closeup-2.jpg

I generally make the base circle (ie: the widest point), add the major details (spokes and hubs) on the base, extrude out the major portions and then work in the details. For a wheel like that, though, I'd cut it up into slices, make one slice and then copy/paste things together. That wheel looks like it would take 6 slices to make, with the rim and hub being simple extrusions.

 

Sketchup is pretty useful in that you can group objects, slide them together and then ungroup them to produce surfaces which merge into each other. So I'd probably make the rim/hub slice first, group it, make a spoke, stick it in, ungroup and perhaps smooth the result. Then I'd add any detail elements (the bolts, maybe) that I hadn't already put in.

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I generally make the base circle (ie: the widest point), add the major details (spokes and hubs) on the base, extrude out the major portions and then work in the details. For a wheel like that, though, I'd cut it up into slices, make one slice and then copy/paste things together. That wheel looks like it would take 6 slices to make, with the rim and hub being simple extrusions.

 

Sketchup is pretty useful in that you can group objects, slide them together and then ungroup them to produce surfaces which merge into each other. So I'd probably make the rim/hub slice first, group it, make a spoke, stick it in, ungroup and perhaps smooth the result. Then I'd add any detail elements (the bolts, maybe) that I hadn't already put in.

 

I should probably do it in 6 segments like you said.  I generally go about making drive wheels like that.

 

I suppose what my issue here is that it's a pain in the ass in 3ds max to get those rounded edges on the spokes to both look good and have a topography that doesn't give me cancer.  I'm fine for now with how it came out, and I only got a little cancer, but those complex curve in all 3 dimensions at once it what gets me.  Image below is what I shat out and how it's made.

b2FuYRx.png

 

What I always think of when I think of this sort of evil is the american MG tumor things.  There was one like this I tried to make, except the part where the MG mantlet goes on is part of the same casting.  Getting that extrusion there, the bumps for vision blocks, and the hatch all done without turning the mesh into a clusterfuck still eludes me.  I probably want some fancy plugin for it, since the boolean tools in max are really annoying to use on complex shapes.

 

a_2_99.jpg

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General question to other people making 3D models:

 

Is making a complex curved surface like this wheel a massive pain in the ass in the programs you use too?  Stuff like this and the fat patton cupolas are good examples.

 

 

 

 

No.  As long as the geometry can be described simply, it can be made simply:

tutorialdoohicky.jpg

 

 

This is the part that the Solidworks tutorial has you make as part of babby's first solid model.

 

 

Also, there are plenty of Solidworks gurus on this forum if you get stuck.  Sturgeon uses the program semi-regularly, both for work and for fun, and there's a guy on this forum who has designed a successful, mass-produced product in Solidworks.

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To be fair, the vast majority of what I do is cartridge design, which is literally just Sketch->Revolve.

The Baberams was seriously the first project I'd ever done in SolidWorks that was of anything like that complexity. Now, I've done some actual CNC engineering before, but I used BobCAD for that.

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