Stryker collection (merged thread)

[120mm]

And how, precisely, would you fix the M113's weakness against under-road IEDs and anti-tank mines?

The belly plate, as flat as it is, combined with the tracks, make it a deathtrap. You'd need to find someway to vent the explosion out the sides, probably a "V-shaped" hull or somesuch. That would probably mean redesigning the hull completely, and then you'd have some other vehicle, by the time you're done.

It's interesting to note that the Joseph Stalin series of heavy tank had pronounced "V-hulls", precisely in order to make them more resistent to mines.

Sorry, I didn't see page 3, when I was responding to William Owen's post vis-a-vis fixing the weaknesses of the M113.

[J Wolfsberger]

"V hull" doesn't do anything to protect against mines.

There are three things that can be done: increase standoff, reduce presented area, and increase armor at the bottom hull (belly armor).

The basic, so-called, "v hull" shape of the MRAPs actually looks like:
Hull.jpg

They work because of increased standoff and reduced presented area. The "V" shape is just incidental - it doesn't lead to any "blast deflection."

BTW, these worked well when originally designed by the South Africans because they were fighting LIC in the veldt. Who cares what the silhouette is if you can still be seen coming from 20 klicks out no matter what you're driving? They work well for us today, because we're travelling relatively predictable routes, so who cares if we can be easily seen? In a different type of conflict/mission, different terrain, different threat weapon system mix, etc., they could turn out to be unfixable death traps.

The relevant dimensions for design trades are: presented area vs. vehicle height; standoff vs. vehicle height, ride stability, mobility/agilty; belly armor vs. just about everything.

[Cavguy]

The Blog "DefenseTech" has a followup on the MGS Debate.

http://www.defensetech.org/archives/003995.html

Quote:

Some of you might remember my entry from Iraq a couple weeks ago criticizing the new Stryker vehicle version called the “mobile gun system,” or MGS. I spoke with three MGS crew, including an MGS platoon sergeant, who said the system was crap.

Well, in the interest of giving each side their due, I’m going post some comments sent to me this weekend from another MGS platoon sergeant who was quoted in the Bloomberg story I cited in my story.

At this time in my opinion am one of the most combat experienced MGS vehicle commanders in the army today. I have fired 58 rounds in a combat situation...none of them were just for fun rounds. I have used the MGS in every manner possible and used it for things it was not tatically supposed to be used for. It pisses me of that only 1 or 2 guys were asked about this vehicle in 4-9 INF, 4/2bde.

And later he wrote me...

I just want the vehicle to get a fair chance and for people who think it a waste of tax dollars to realize that we now control the battlefield both cross country and urban.

[Tom Odom]

"V hull" doesn't do anything to protect against mines.

There are three things that can be done: increase standoff, reduce presented area, and increase armor at the bottom hull (belly armor).

The basic, so-called, "v hull" shape of the MRAPs actually looks like:
Hull.jpg

They work because of increased standoff and reduced presented area. The "V" shape is just incidental - it doesn't lead to any "blast deflection."

BTW, these worked well when originally designed by the South Africans because they were fighting LIC in the veldt. Who cares what the silhouette is if you can still be seen coming from 20 klicks out no matter what you're driving? They work well for us today, because we're travelling relatively predictable routes, so who cares if we can be easily seen? In a different type of conflict/mission, different terrain, different threat weapon system mix, etc., they could turn out to be unfixable death traps.

The relevant dimensions for design trades are: presented area vs. vehicle height; standoff vs. vehicle height, ride stability, mobility/agilty; belly armor vs. just about everything.

John,

From METAR 3D Mine Resistan Ambush Protected (MRAP Entities)

MRAP systems are designed with a V-shaped hull that assists deflection of a mine or IED blast away from the vehicle’s interior. With their appropriate markings, accurate geometry, and damage states, MetaVR's 3D MRAP models can be used in counter-IED training scenarios. These models, which are in MetaVR’s model format, are included in the 3D content libraries that are delivered with the purchase of MetaVR products. Updates are available to current customers on Virtual Reality Scene Generator (VRSG) maintenance.

See also The protection of vehicles and plant equipment against mines and UXO

For example:

Principles for the protection against blast effect
The following principles can be incorporated into the design of vehicles and equipment
to render protection against the blast effect of mines:
�� absorption of energy,
�� deflection of blast effect away from the hull, and
�� distance from detonation point.

The V shape does play a role and so does standoff as well as presented area. To get the V-shape in a vehicle that could move cross country, increased stand-off, using a v-shaped hull to present less area, equated to increased height.

The heigth of the vehicles actually proved advantage in the areas where they were used. Namibia and Angola are desert like in many areas but with a heavy brush cover. The SADF vehicles were high enough that they were able to see over much of that brush, where a vehicle 50 to 100 yards is often invisible at ground level.

As for open ground making the height of a vehicle irrelevant, armored combat in Sinai, Iraq, and North Africa says otherwise (along of course with hundreds of rotations at the NTC). No ground aside perhaps from certain places like Bonneville, is that flat and even there the curvature of the earth means that taller vehicles are seen before shorter vehicles. The reason the South Africans did not care was the threat against those vehicles was not from direct fire anti-armor systems. When they had to deal with the Cubans, it was a new ball game.

I agree fully that while MRAP is a good thing in a COIN fight, it would be meat on the table in more conventional setting.

Best

Tom

[J Wolfsberger]

I didn't express myself very well in my post.

The point I was trying to make is that it isn't the "V." There are some problems now with people demanding designers try using a "shallow V."

What does buy something is standoff (i.e. ground clearance), reduced presented area, and stiffening the hull to involve as much of the structure in vehicle response as possible (the only way to accomplish absorption of energy). All that has to be balanced against impulsive load imparted to the crew, and what kind of "stroke" can be built into the seats to reduce impulsive injuries (such as ruptured disks). And that doesn't get into reliability issues of a dynamic suspension (to give a variable standoff), or vehicle mobility/agility issues associated with a higher center of gravity.

As to the tactical considerations, I think we're in agreement. I was trying to point out that in some tactical circumstances, a large silhouette is irrelevant.

When the SADF went into Angola against the Cubans, the vehicles had vulnerabilities that didn't appear in SW Africa or the COIN ops in South Africa itself. Vehicle silhouette is one of the first things designers try to reduce - smaller means lower probability of hit, which equates to better survivability. It's a lot harder to see and hit a HMMV than an MRAP at any sort of distance.

[Ken White]

are important for under vehicle explosions, no question -- but the V shape is also important as it allows the explosive force easy exit as opposed to being trapped by a flat hull -- particularly a flat hull bottom with tracks or closely spaced wheels serving as side walls which traps the force and exacerbates the intensity by reverbration as opposed to simply deflecting (or absorbing) only the initial force.

If that under vehicle explosion rises against a flat bottom, is is simply reflected right back the way it came (even if it does rip through all or part of the bottom, there's still excess force to be reflected). Vehicles can be flipped by the force as well as having bottoms penetrated. that is common with flat bottom hulls and very rare with V-bottoms.

The best V-hull designs have a minimum number of wheels and those are at extreme ands and designed to be sacrificed to aid in hull and thus crew survival.

While the V-hull and high ground clearance are beneficial in lessening the effect of buried mines or IEDs, Neither offers any protection from side or angle mounted IEDs.

It's hard to dispute that anything that keeps the troops alive is not beneficial but my sensing is that once again we have tried for a technological solution to a training and operating problem. Some were necessary and beneficial but the sheer number we're buying is probably excessive and was driven by Congressional reaction to incompetent media noise. I suspect that most will be transferred to the Iraqis. Some day...

[Tom Odom]

I didn't express myself very well in my post.

The point I was trying to make is that it isn't the "V." There are some problems now with people demanding designers try using a "shallow V."

What does buy something is standoff (i.e. ground clearance), reduced presented area, and stiffening the hull to involve as much of the structure in vehicle response as possible (the only way to accomplish absorption of energy). All that has to be balanced against impulsive load imparted to the crew, and what kind of "stroke" can be built into the seats to reduce impulsive injuries (such as ruptured disks). And that doesn't get into reliability issues of a dynamic suspension (to give a variable standoff), or vehicle mobility/agility issues associated with a higher center of gravity.

As to the tactical considerations, I think we're in agreement. I was trying to point out that in some tactical circumstances, a large silhouette is irrelevant.

When the SADF went into Angola against the Cubans, the vehicles had vulnerabilities that didn't appear in SW Africa or the COIN ops in South Africa itself. Vehicle silhouette is one of the first things designers try to reduce - smaller means lower probability of hit, which equates to better survivability. It's a lot harder to see and hit a HMMV than an MRAP at any sort of distance.

John

Thanks for that. I agree we are really saying the same things. We had issues with HMMWVs being too wide in Africa for the streets. I wonder how MRAP "fits in" under simlar circumstances.

Best

Tom

[William F. Owen]

And how, precisely, would you fix the M113's weakness against under-road IEDs and anti-tank mines?

Sorry, I didn't see page 3, when I was responding to William Owen's post vis-a-vis fixing the weaknesses of the M113.

..and that's one think you can't fix, so you don't. You apply the means and technology within a field of doctrine and teaching.

As a by-stander the level of Stryker v M-113 debate had been just embarrassing. Wheels versus tracks is a false argument, unless couched in precisely defined operational context. A combined MRAP & Modernised M-113 Brigade of even Combat Team would be a step up in capability

The M-113 design of 2008 bears no resemblance to anything currently in US Army service. The UK fluffed the FV-432 upgraded for Iraq to save money, but what we got was 100% increase in capability.

[120mm]

In addition to the above-stated benefits of "V" hulls, is the increased armor thickness afforded by any angled surface. For example, a 1" plate of steel, canted at 45 degrees, provides the equivalent of approximately 1.5" of steel armor, as the projectile (if any) has to travel 1.5 times as far due to the angle involved.