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Introducing HUMPBAC - an armoured personnel carrier with a connecting doorway from the rear of the vehicle to walk through into the armoured passenger trailer. Tickets please!

HUMPBAC
Hinged Under-floor-Mine-Protection Battle-ready Armoured-personnel Carrier
Copyright © Peter Dow, 7th August, 2010.



HUMPBAC Features

• Trailer bolts firmly to the rim of the vehicle forming a rigid joint
• Rear section of vehicle is hinged to articulate the trailer's vertical motion
• Movement of hinged rear section accommodated by a hump in the roof
• Vehicle rear door can serve as a connecting doorway to the trailer section
• Front vehicle seats a maximum of 11 people
• Armoured passenger trailer seats a maximum of 7 people
• Vehicle with trailer seats a maximum of 18 people
• Roof mounted remote-controlled machine guns- front, top & tail gun
• Trailer wheel steering
• 6-wheel drive
• Telescopic Rear Axle & Wheels
• Rotation on the spot
• Even axle weight distribution
• 5 : 3 weight & length ratio, 5 (vehicle) : 3 (trailer)

- Joe_D

Interesting,

Looking at the design, it kinda reminds me of this thing,

Engineer vehicle with Ground Penetrating Radar

Yes I see the resemblance right away.

- Joe_D

Don't ask me the official name.

A very narrow crew compartment with "V" hull providing minimum exposure to blast. Lash two of these side by side, remove the inside set of wheels, and now you have facsimile to your Catamaran vehicle.

Pretty close Joe.

Actually that was the idea I first started with - 2 simple Vs or as I called it Y"Y

The nice thing about the first idea that would have meant that you could use the same amount of hull armour (a bit more for the inner sides, but who is counting?)



But then we got thinking over on the science forum.

www.scienceforums.net/..._p__556702

- insane_alien

and you'd also have the middle section subjected to increased blast damage due to shockwave focusing, the very thing the V hull is designed to counteract.

Which I have to tell you Joe worried me a lot (and there isn't an easy way to test how bad the effect would be) so I came up with this.

- Peter Dow

To lessen the blast forces tending to split the two V-shaped hulls apart, the Vs can be angled slightly to form a vertical blast chimney.

So the vertical blast chimney should help a lot with stopping a blast in the middle of the two hulls using a lot of its energy pushing the two hulls apart but ..

... changing the shape of the V-shaped hulls like that does unfortunately mean that they need to be bigger, cover a bigger area than just one V-shaped hull twice the size.

So with bigger armour the CATAMARAN vehicle gets heavier for the same volume to protect.

That is not to say the CATAMARAN vehicle, even if it was heavier could not be useful, but it looks like you need to trade more weight for more stability and so maybe there is another solution?

So that is why I started looking around for a second design - and I came up with the telescoping rear axle.

- Joe_D

With your idea a mine blast coming from below would have a hard time penetrating the hull, being that the inside there is no area for the blast to concentrate on.

Well that is precisely the unknown about how the two V-hulls side by side would react to a blast between them.

If the blast between the Vs was not too damaging then maybe you could use the original VVs without angling them, save weight and the CATAMARAN vehicle would win every way? Hard to know but it is a concern.

Air-Powered Steering for rotation in a vehicle

Here is an idea. If you need to, please review this diagram of a steering mechanism from Wikipedia on Steering.

OK my idea is you replace parts of the steering rod with pneumatic pistons, either side of the connection to the steering column as follows.



There is an air tank topped up by an air pump which when its valve is turned on inflates the pneumatic pistons now integral to the steering rod. (This should only ever be done while the vehicle is at rest and the driver has selected clockwise or anti-clockwise gear - some kind of safety cut out.)

The air pressure quickly rises (that is why you use air, not hydraulics, it is so much faster if you supply from an air pressure reservoir - there is not a need for huge force, just speed, so pneumatics is the driver of choice I think) and when the air pressure exceeds a critical amount, retaining catches, which normally hold the pistons firmly closed against all manner of road bumps, suddenly break open and the pressurised air forces the pistons open against a spring and the steering rod lengthens to a maximum and the wheels are turned inwards to their respective stops - hard right hand turn for the left hand wheel and hard left hand turn for the right hand wheel, ready for rotation.

It is clear to me that the 45-50 degrees or so maximum turning angle normally is limited by the steering rod at full stretch - not by the wheel bumping into the axle - so 75 degrees in this diagram looks easy.

When you want to revert to normal steering, the system simply releases the air pressure in the pistons and the pistons close with the spring and the pistons snap shut into their retaining catches ready for normal steering.

As you can see this is for rotation about a point mid-way between the rear axle. It is only when I add on my trailer to my armoured personnel carrier that the vehicle does zero turning radius, strictly speaking.

Hence I have always called it "rotation on the spot".

So do you think that would work? I would doubt that is the way that lawnmowers do zero turning radius.

- Michel_Krauss

because your design has changed, from a 2x 4x4+2x2 design to an 2x 2x2+1x1, your removeable connecting bars will have to be permanent fixed. Otherwise you will have to halve vehicle's laying sideway's

Changed? I have posted a second completely different design, a conventional mono-hull, not a catamaran at all!

Look - one hull, no connecting bars! See large image.

- Peter_Dow

Armoured Personnel Carrier Designed by Peter Dow.

Features

• Front vehicle seats a maximum of 11 people
• Armoured passenger trailer seats a maximum of 7 people
• Vehicle with trailer seats a maximum of 18 people
• Roof mounted remote-controlled machine guns
• Trailer wheel steering
• Telescopic Rear Axle & Wheels
• Rotation on the spot
• Even axle weight distribution
• 5 : 3 weight & length ratio, 5 (vehicle) : 3 (trailer)

More details ...

The second design gets stability from a telescoping rear axle! Look! See large image.

- Peter Dow

Oh I am on to my second design already Michel and you are still discussing the first!

Sorry I don't have a really cool name for my second design yet - I have just called it "Armoured Personnel Carrier by Peter Dow". I will need to think of something better so as to grab people's attention.

Sorry for the late response, did not have an change to react sooner
And I have the same (bad) habit, all mechanic engineers have: improve an (existing) design or kill it

- Peter_Dow

What I'd like to suggest Michel is that because vehicles are very often designed to have more weight on the rear axle, the designers of such "rear-axle-heavy" vehicles been able to use a lighter front axle, lighter front suspension, lighter front wheels as well. They could have made the front equally strong but since it didn't have to be, they didn't so as to save weight. Fair enough.

However, if like here, I am designing a new vehicle from scratch and I have good reasons to want equal weights on each axle (such as wanting to spread the weight around all the axles evenly to help to cope with poor quality roads which might collapse under the weight) then I can specify an equally as strong front, rear and trailer axle.

True the front axle of most "rear-axle-heavy" vehicle's is much lighter and they could have made it equally strong

The problem, to get an equally strong front axle is that the amount of material needed to realise this, will be much more then for the rear heavy axle's
This because all joints for steering, etc are weak spots so if you could reduce the load on the components this will decrease the amount of material needed
Another advantage of an lighter front axle is that "lighter parts" are easier to control, so steering systems (no matter if they are mechanical, electrical or hydraulic) can be simpler and also lighter

Before we go on, I would also like to say that your definition of heavy is an little different then mine
An Bushmaster IMV for example of 12.5 tons, is not heavy to my standards it would fit in the range of light

- About the steering.
Your solution is something mechanically, whether by a rod or a cables or whatever.
I would suggest to drop the whatever idea, because there is no other mechanical solution and the idea with the cables will be very complicated (with pulley's and a like)
Even the rods will be trouble some, better solutions would be hydraulic or electrical

- Concerning the connecting bars and the components which attach them to the Y-sides will need to be strong enough to cope.
because your design has changed, from a 2x 4x4+2x2 design to an 2x 2x2+1x1, your removeable connecting bars will have to be permanent fixed. Otherwise you will have to halve vehicle's laying sideway's

- Problem may be the overall width of the vehicle
Sorry missed that point in the text, I based my dimension on the dimensions of an average size MRAP

Michel

Perhaps a link to this thread would be sufficient...

www.physicsforums.com/...?p=2820378

I cannot help but relate to the comment about a "stream of consciousness" design style...

Armoured Personnel Carrier Designed by Peter Dow.

Features

• Front vehicle seats a maximum of 11 people
• Armoured passenger trailer seats a maximum of 7 people
• Vehicle with trailer seats a maximum of 18 people
• Roof mounted remote-controlled machine guns
• Trailer wheel steering
• Telescopic Rear Axle & Wheels
• Rotation on the spot
• Even axle weight distribution
• 5 : 3 weight & length ratio, 5 (vehicle) : 3 (trailer)

More details ...

OK well I have to admit there are a few problems with my CATAMARAN vehicle design.

• Heavier armour for the same volume protected
  
• The inner sides required to be armoured and connected together and that all adds weight. Precisely how much more weight is difficult to predict but a significant thickness of additional armour required certainly

Therefore I am now turning to a different and easier idea to solve the roll-over problem for MRAP armoured vehicles - telescopic rear axles.

Telescopic Rear Axles. Extended - Wide.


Telescopic Rear Axles. Collapsed - Narrow.


Hydraulic cylinders components are available to be adapted for this purpose.

The axles would need to be braced vertically to stop them bending under the weight of the vehicle.

Certain design concepts I have previously described for the CATAMARAN vehicle which I do want to retain for the telescopic rear axle design, such as

• Trailer wheel steering
• Armoured passenger trailer
• Rotation on the spot
• Roof mounted remote-controlled machine guns
• 5 : 3 ratio, 5 (vehicle) : 3 (trailer), weight and length distribution

Therefore the telescopic rear axle design although it is perhaps a less radical and innovative mono-hull design than the CATAMARAN Vehicle design, nevertheless it has many excellent features which greatly enhance the performance over the standard MRAP.

So I await with interest to see if anyone can identify flaws with my second major design iteration.

- Tanklord

- blackdog

I think the real question here is: will the CATAMARAN be able to carry Battle Boxes or M113 Gavins to the fight?!

Ah Hell No! Please Blackdog, you must never use the G word when talking of the M113. You have been warned!


Just kidding, but that subject is verboten here!

Not only is it verboten here (unless you enjoy being the but of continuing abuse) it is also not considered appropriate in any civilized society. Farting loudly when you have a chance to ask the President a question on Live National Television or when being introduced to Queen Elizabeth would be considered a minor gaf compared to combining M113 and the name of an Airborne general in the same phrase

Interesting,

Looking at the design, it kinda reminds me of this thing,

Engineer vehicle with Ground Penetrating Radar

Don't ask me the official name.

A very narrow crew compartment with "V" hull providing minimum exposure to blast. Lash two of these side by side, remove the inside set of wheels, and now you have facsimile to your Catamaran vehicle.

With your idea a mine blast coming from below would have a hard time penetrating the hull, being that the inside there is no area for the blast to concentrate on. The angled outside would also deflect most away at the proposed angle. The major problem I see is with side attack IED's, like an EFP, And those my friends, are real killers, having witnessed their nasty capabilities. As with MRAPS and all their kin (In fact ALL Armored vehicles), you cannot account for all angles of attack short of designing a vehicle that looks like TWO CONES MATED VERTICALLY, and the new armor packets do not take kindly to compound curves. But I do applaud your effort in trying to find a solution. Ours in 2006-07 was try not to get hit in the first place, utilizing different countermeasures, speeds, configurations, and other tactics that I won't mention, but that's like whistling in the dark .

- C_Sherman

Hi,

s0.ilike.com/play#Styx...b93c053112

You're a bad man, Chuck.

I'd print this out and run it by the folks at the local "Force Protection" manufacturing facility, but I'm afraid it would sacrifice any chances of a return visit.

Hi,

s0.ilike.com/play#Styx...b93c053112

Doug

I agree. My first impression.

Amazing that the 'G' word was evoked, I think you & I are on the same page.....

Don

- Michel_Krauss

- About the steering. Because you want to connect the vehicle's with bars, how do want to connect the steering mechanisme of the 2 vehicle's

"Mechanically" is what I have specified so far.

I have also specified "power steering" (after all if the trailer is attached, there are 8 wheels to steer!)

I have also specified that for the two rotational gears (clockwise and anti-clockwise) the steering is disengaged from the wheels, and the wheels are turned by the power steering to the appropriate positions for rotation.

I have not specified exactly how the mechanical connection between the steering of both sides is arranged, whether by a rod or a cables or whatever.

Essentially the two steering wheels would be locked together. So if you turn one steering in one driver's cabin, it turns the steering wheel in the other driver's cabin. If the two people in the driving seats disagree about who is driving it could be fun!

- Michel_Krauss

- Because all connection bars are intended to fix one vehicle rigid to the other vehicle, there will be serious trouble with overall road performance. Especialy at poor quality roads, which will give an lot of material stress at the joints;

So the connecting bars and the components which attach them to the Y-sides will need to be strong enough to cope.

- Michel_Krauss

- - Problem may be the overall width of the vehicle in dagerous locations. For each side of the catamaran will be approx 2.5m, so 5m total for the 2 vehicle's add the connection bars of 2m each, an estimated total of 6.5m overall width

No each side, as an example I have said the individual Y-sides would be 4 feet = 1 metre 22 cm wide.

I have given 3 example total widths
9 feet = 2 metres 74 cm (as wide as an MRAP)
12 feet = 3 metres 66 cm (as wide as a tank)
16 feet = 4 metres 88 cm (wide!)

So you are way out with your figures Michel.

- Michel_Krauss

- Final question: how those design perform in mountainous terrain ?
With it's narrow, bad quality roads and same quality bridge's ?

The CATAMARAN vehicle (at least the wheeled version I am considering now) is designed as an MRAP replacement, not as a tank replacement, so it performs better than an MRAP on slopes because of its lateral stability in wider configurations, not better than a tank or a tracked vehicle.

In the CATAMARAN vehicle's narrow oonfiguration, it can squeeze between any gap that a 9 feet wide MRAP can.

- Michel_Krauss

I made an check at the text at the for freedom forum also, and I would like to suggest some small corrections for the catamaran MRAP?
- first of all, the load at the steering axle is max 40% (this figure is lower for steering and driven axle's) of the GVW because the steering axle is not as strong as the non-steering one's
So the load distrubution have to be reconsidered

OK Michel you asked a number of questions and made a number of points and I hope to discuss them all in due course but for right now I'd like to post the text and image you are referring to so that others can post their opinions about it here as well.

What I'd like to suggest Michel is that because vehicles are very often designed to have more weight on the rear axle, the designers of such "rear-axle-heavy" vehicles been able to use a lighter front axle, lighter front suspension, lighter front wheels as well. They could have made the front equally strong but since it didn't have to be, they didn't so as to save weight. Fair enough.

However, if like here, I am designing a new vehicle from scratch and I have good reasons to want equal weights on each axle (such as wanting to spread the weight around all the axles evenly to help to cope with poor quality roads which might collapse under the weight) then I can specify an equally as strong front, rear and trailer axle.



The image shows some vital statistics for my proposed CATAMARAN vehicle, only one Y-side is pictured.

The front powered and driven vehicle seats a maximum of 10, 5 in either Y-side.

Each side seats 5 =

• 1 - one driver or reserve driver or front passenger +
• 2 - one front gunner and one rear gunner +
• 2 - two passengers

The trailer seats a maximum of 6, 3 in either Y-side

Each side seats 3 =

• 2 - two passengers +
• 1 - one tail gunner

So the vehicle with trailer attached seats a maximum of 16, 8 in either Y-side.

Each side seats 8 =

• 1 - one driver or reserve driver or front passenger +
• 3 - one front gunner, one rear gunner and one tail gunner +
• 4 - four passengers.

The driver can be either on the left or on the right Y-side and then the reserve driver or front passenger would be on the right or left Y-side, respectively.

Weight distribution

The image also shows the ideal weight distribution in relation to the axles.

Each square represents the same weight and length which is

• one eighth of the weight and length of the combined vehicle with trailer,
• one fifth of the weight and length of the front powered and driven vehicle and
• one third of the weight and length of the trailer.

Designing the vehicle to have this weight distribution helps to keep the vehicle well balanced in terms of equal weights over each axle which allows for the same suspension and tyres to be used through-out and maintains this balance with or without the trailer attached.