Military vehicle (APC) with connecting trailer. MRAP replacement design concept.

[ViolentPanda]

Ground clearance complaint is a fair point. I created the image photoshopping from an image of an Iraq-era MRAP APC road vehicle. So it looks to have the ground clearance that vehicle has.

I would like the HUMPBAC's manufacturer's design engineers to design in a respectable ground clearance suitable an off-road vehicle; that and bigger tyres.

This is just a design concept, showing main features but poor ground clearance is not a feature I am advertising.

It's not just clearance, it's the fact that you have to channel what would usually be external features (drive shafts being the most important) through the vehicle, which takes up valuable space, and makes maintenance (even if you're using unitary assemblies so swap-out is quicker) slower.
Even then, and even with excellent ground clearance, you've still got to expect the vehicle to "bottom-out" in some situations.

 

[kyser_soze]

getting this built for the MOD as we speak...

I had that toy when I was a small. Imagine my surprise when it turned up in Judge Dredd's trek across the Cursed Earth!

 

[Peter Dow]

And if, when in e axle extended mode, one or both of them are damaged, the whole thing sags in the middle and can't go anywhere. Independent articulation of each wheel is redundant and safer.

You want HUMPBAC to lose both wheels on its middle axle and still drive? OK then.

No worries because the hinge has two modes - locked and unlocked.

Unlocked hinge is a free swinging hinge +/- 30 degrees to allow for all terrain maximum grip with each axle on the ground.

Locked hinge is a when the hinge's position is fixed by position of hydraulics and the hydraulics are strong enough to bend the HUMPBAC to any position +/- 30 degrees.

So locked hinge is handy if you have maybe had a hit on an axle and want to support the vehicle on the other two axles.

Easy enough if the middle axle is gone. Just jack up the middle and run on the two end axles.

HUMPBAC (currently) only has the 3 axles so if you lose an end axle and have to run on the other two you'd have to shift the load to one end to keep the weight on the 2 good axles.

I say "currently" because I am giving thought to whether more axles and wheels might be better.

 

[DotCommunist]

More axles and wheels are always better. Maybe some giant claws as well.

 

[Crispy]

What you really want, peter, is a tank

 

[zog]

..........and a big Scottish flag.

 

[beesonthewhatnow]

It needs more laser beams.

 

[Lemon Eddy]

I had that toy when I was a small. Imagine my surprise when it turned up in Judge Dredd's trek across the Cursed Earth!

same here!

 

[IC3D]

The Glorious Mujahadeen of Afghanistan have got wind of the diabolical HUMPBAC project and fearing a turnaround of fortune have plowed their energies into bringing back an extinct species of horse known as the 'long-horse'

The 'long-horse' is capable of carrying up to eight seekers of martyrdom equipped with a variety of rusty guns and RPG's. The long-horse was created after a competition on a jihad fantasist forum by a stoned opium farmer on a slow afternoon at his small holding in Kawasibaat province. His eight year old said angrily 'Beware the long-horse Kuffir'

 

[Peter Dow]

Replace Hinge with Articulated.

Designed what?? Lol

I worked on Alvis ATV's 20 odd yrs ago, and what we produced back then ( as a body in white 16 Wheel Drive, All Terrain W.A) was 20x better than your illustration, before the armour and artillary was attached.
Since then I have worked on Challenger tanks, P90 Robots and P12 Backhoe Loader projects.
Such info as you are showing would never be shown on an internet forum, I have had to get Military clearance for my involvement with such projects as stated above, but project numbers are all I would reveal without breaching my confidence.

You should post pictures of the vehicles you were working on.

For example here are a couple of Alvis vehicles I found right away.

Alvis Supacat ATV

Alvis Saladin

I think cramming in as many and as big wheels as possible are what we are needing for Afghanistan. Better grip for all-terrain and not so vulnerable to getting a wheel stuck somewhere either because they are big wheels and share out the weight.

It seems like the guys who designed the MRAPs just took standard trucks and put V-shaped hulls in them, whereas they might have done better starting from some of those all terrain military vehicles and putting the V-shaped hulls into them?

 

[Peter Dow]

Yes, I noticed.
Did you factor in deviation in the turning circle caused by traversing uneven terrain?
I ask, because you mat not have noticed that terrain has a significant effect, even if suspension is fully independent.

The diagram is a model, an ideal and you can't factor in many slight deviations from the ideal into diagrams, otherwise you would need an infinite number of diagrams for each possible variation.

If you want to post your own diagram factoring something in, please do.

Which means that you'll have articulation through a single plane, whether you're a human on a loo seat or a vehicle. The problem with this is that if you encounter conditions that aren't amenable to your plane of articulation, you'll be screwed.
Imagine an artillery piece articulated to a vehicle in a similar fashion. Now imagine traversing a steep hill followed by a v-type gulley. See the problem?

Why don't you post a drawing of the problem so I can see what you are talking about?

If you mean one wheel might be off the ground in some circumstances, yes, that could happen but that is why you fit a locking differential to your 4 or 6 wheel drive so you can lock the differential and drive on the wheels which are on the ground.

BTW, mine protection is a trade-off. You have to balance prevention of penetration with diffusion of blast. If you don't diffuse the blast enough, there doesn't need to be penetration to cause nasty concussion effects inside the vehicle.

The heavier the vehicle the less it and its passengers get knocked about by the blast. Hence why your lighter Humber Pig would be less safe.

 

[Cid]

The heavier the vehicle the less it and its passengers get knocked about by the blast. Hence why your lighter Humber Pig would be less safe.

Yes. And the slower it moves and the more fuel it uses and the easier it is to get stuck and the harder it is to get unstuck and the more complex maintenance is etc etc.

 

[Crispy]

If you mean one wheel might be off the ground in some circumstances, yes, that could happen but that is why you fit a locking differential to your 4 or 6 wheel drive so you can lock the differential and drive on the wheels which are on the ground.

Why not have independent suspension with lots of travel so all wheels are always on the ground and you remove a single point of failure from the design. You'll need independent suspension anyway, to deal with uneven heights in the left/right direction.



(red is the "fixed" half of the unit in your design)

The wheels in exactly the same position in each option. For the right-hand option, the largest amount of vertical travel in the suspension is half the wheel radius.

 

[beesonthewhatnow]

Please tell me that you have animated that diagram

 

[Peter Dow]

What you really want, peter, is a tank

Yes. And the slower it moves and the more fuel it uses

No gentlemen, APCs carry more passengers for less weight and fuel than tanks and bigger APCs can even carry more passengers per unit of fuel than smaller APCs.

For example, you don't need double the area of armour to enclose double the volume of passenger space.

and the easier it is to get stuck and the harder it is to get unstuck and the more complex maintenance is etc etc.

Well not if you use bigger and more tyres spreading the greater weight out over a greater area to achieve the same road / terrain surface pressure.

So not only is there safety in numbers against blast shock, also it is more efficient.

Bigger vehicles works well so long as you are not hitting IEDs and mines all the time in which case the "all your eggs in one basket" problem happens.

So I repeat the APC is for transport to somewhere yet ready for eventualities en route but you want a infantry fighting vehicle or a tank with tracks, with bigger guns, few crew, no passengers, where engagement with the enemy is likely every time.

 

[Peter Dow]

Why not have independent suspension with lots of travel so all wheels are always on the ground and you remove a single point of failure from the design. You'll need independent suspension anyway, to deal with uneven heights in the left/right direction.

View attachment 11454

(red is the "fixed" half of the unit in your design)

The wheels in exactly the same position in each option. For the right-hand option, the largest amount of vertical travel in the suspension is half the wheel radius.

Nice diagram but when comparing models it is fair to give each side the same equipment.

Therefore compare my hinged model with your rigid model if we are both allowed the same suspension units.

Then when your suspension bottoms out on the hill and has none left for further left / right potholes, mine has plenty to spare.

Also my hinged model isn't a "single point of failure" because the hinge has the ability to set a position hydraulically and lock in place to cope with a broken axle.

 

[DotCommunist]

As an aside, what is the point of APC's? Why not have a tank with room for troops as well?

That way you have a massive gun and side small guns plus a belly full of troops ready to spill out and lay down the great fire of justice as soon as it stops.

The only reason I can think of is that troops are to valuable to put into a target vehicle like a tank, but surely an APC is just as targeted.

 

[DotCommunist]

dp

 

[Pingu]

like the bmt72?


tbh that looked pretty cool

 

[Cid]

No gentlemen, APCs carry more passengers for less weight and fuel than tanks and bigger APCs can even carry more passengers per unit of fuel than smaller APCs.

Yes, obviously - tanks are designed to carry weapon systems, not people. They are also designed for deployment right on the front lines, so have to have ridiculous amounts of armour. The thing is you don't seem to understand what an APC is for; rapid deployment/evac of units to/from the front line. That means you have to find a compromise between speed and size - even the MRAPs have come under criticism for not being maneuverable enough. Your vehicle not only would be an absolute pig to handle at speed, it also presents an enormous target.

For example, you don't need double the area of armour to enclose double the volume of passenger space.

Doesn't matter.

Well not if you use bigger and more tyres spreading the greater weight out over a greater area to achieve the same road / terrain surface pressure.

Depends entirely on the nature of the terrain, and remember it has to be able to handle it at speed.

So not only is there safety in numbers against blast shock, also it is more efficient.

Well there isn't. What you've fallen here is the classic battleship conceit - make a big thing with extra stuff an we'll all be fine. Until the enemy realises they can outflank it, run rings around it, blow out its axles etc.

Bigger vehicles works well so long as you are not hitting IEDs and mines all the time in which case the "all your eggs in one basket" problem happens.

Which is exactly the problem.

So I repeat the APC is for transport to somewhere yet ready for eventualities en route but you want a infantry fighting vehicle or a tank with tracks, with bigger guns, few crew, no passengers, where engagement with the enemy is likely every time.

Yes, that's not the point.

As an aside, what is the point of APC's? Why not have a tank with room for troops as well?

That way you have a massive gun and side small guns plus a belly full of troops ready to spill out and lay down the great fire of justice as soon as it stops.

The only reason I can think of is that troops are to valuable to put into a target vehicle like a tank, but surely an APC is just as targeted.

APCs are a quick way of bring troops to an area under attack etc... The armour isn't that strong, enough to defend against small arms but not much more.

 

[Pingu]

if only there was some sort of machine... capable of flying and carrying troops at the same time.

ok it would have some vunerabilities but cant see IEDs or bridges being much of an issue for it.

if only someone would invent something like that...

 

[Wintermute]

APC takes off?

 

[fractionMan]

These guys would pay a fortune for your skillz peter

 

[Lemon Eddy]

if only there was some sort of machine... capable of flying and carrying troops at the same time.

ok it would have some vunerabilities but cant see IEDs or bridges being much of an issue for it.

if only someone would invent something like that...

I think a troop carrying dragon is the solution.

 

[Pingu]

am thinking something like this may work

 

[Lemon Eddy]

But troop carrying dragons worked out really well for us in the Napoleonic wars.

 

[ViolentPanda]

The heavier the vehicle the less it and its passengers get knocked about by the blast.

If you're only factoring in calculations of mass versus inertia then that would hold true.
Unfortunately for you it's quite a bit more complex than that. As I said earlier, concussion effects from blast have to be taken into account, and it isn't weight that's the main determinant for minimisation, it's how well the area that takes the blast can diffuse it away from the central point (this is why some multi-terrain APCs have oddly-shaped hulls, and why others have "sacrificial" armour).
If the blast isn't diffused then mass alone is not enough to minimise the "knocking about" of vehicle and passengers.

Hence why your lighter Humber Pig would be less safe.

Not necessarily. It might be rolled by a blast that wouldn't roll your HUMPBAC, but they were fairly well designed to diffuse blast effects.

 

[ViolentPanda]

No gentlemen, APCs carry more passengers for less weight and fuel than tanks and bigger APCs can even carry more passengers per unit of fuel than smaller APCs.

This actually depends on the armament and armour of the APC

For example, you don't need double the area of armour to enclose double the volume of passenger space.

Passenger compartments on APCs have never been particularly well-armoured.

Well not if you use bigger and more tyres spreading the greater weight out over a greater area to achieve the same road / terrain surface pressure.

The problem there being you then present a greater surface area to whatever your enemy has buried.

So not only is there safety in numbers against blast shock, also it is more efficient.

The brisance of most high explosives (which is what most IEDs and mines utilise) is such that tyres, even solids built around steel mesh cores, present little effective reduction to blast. They're usually vaporised by the pressure wave and the heat.

 

[ViolentPanda]

But troop carrying dragons worked out really well for us in the Napoleonic wars.

Quite literally got a bit sticky when one of the female dragons came on heat during the battle for Badajoz, though!

 

[Chester Copperpot]

This thread is awesome.