USMC Marine Personnel Carrier

Grey Havoc

Grey Havoc

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[IMAGE CREDIT: PEO LS]​

MarinePersonnelCarrierDemonstrator.jpg

Original caption: A demonstrator model of the Marine Personnel Carrier. It was built at the Nevada Automotive Test Center in Carson City, Nev., and is in testing there.
[IMAGE CREDIT: USMC via Wikipedia Commons]​

The demonstrator was built by the Nevada Automotive Test Center, a contractor facility in Carson City, Nev., that has tested several other experimental vehicles, including an early version of the JLTV, said Dave Branham, a spokesman with Program Executive Office-Land Systems, which oversees the MPC project. Photographs released to Marine Corps Times show an armored eight-wheeled vehicle stripped of weapons rolling over rocky terrain on the test center’s property.

The Corps is testing everything from the demonstrator’s drivetrain and suspension system to the electronics that assess how well the vehicle is running. Program managers will make changes as necessary to the long-term plans for the vehicle as they assess the one they have, Branham said.

The demonstrator is about 8½ feet wide and 28 feet long, with a height of 8-9¼ feet, depending on how it is adjusted to ride over terrain, Branham said. He declined to release the speeds at which the vehicle can travel, saying they are currently under evaluation. Existing Strykers weigh between 19 and 26 tons and can travel at least 60 mph on highways. They commonly deploy with an M151 weapons station that can include a .50-caliber machine gun and a 7.62mm M240 machine gun.

The Corps plans to adopt the MPC to fill a perceived shortfall in providing protected mobility to troops. Marine officials have decided the vehicles will be assigned to assault amphibian battalions, although they will not be able to float. Two MPCs will be able to transport one reinforced infantry squad.

April 6th, 2010, Marine Corps Times
Click to expand...

I thought it might be time for a thread on the US Marine Corps' ongoing MPC program. To start off, here's some interesting speculation on what form the entry from General Dynamics will take: http://snafu-solomon.blogspot.ie/2012/08/general-dynamics-i-figured-out-your.html

Your thoughts on this?
 
Why are they building a new vehicle? Surely they could just use Strykers? ::)
 
Going off topic for a minute: http://www.upi.com/Business_News/Security-Industry/2013/06/06/Chile-to-buy-surplus-US-armored-amphibious-vehicles/UPI-14211370534653/

'Spare' stocks of AAVs? At this moment in time?
 
The general shape of the vehicle reminds me of the another prototype, Lazar BVT.
http://www.youtube.com/watch?v=0_EVS1rs_p0
 

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http://news.usni.org/2015/04/01/marine-corps-releases-amphibious-combat-vehicle-rfp


https://www.fbo.gov/index?s=opportunity&mode=form&id=db5842973e52f3694c49e0514382bb0f&tab=core&_cview=0
 
The rear door on that Lazar BVT looks like it was designed by the same engineer as the Canadian Bobcat APC.
That engineer clearly never served in the infantry! The tiny rear door was one of the reasons that Bobcat was cancelled. The narrow double doors may be wide enough for advertisements, but a heavily-armed and armoured infantryman - wearing full winter clothing - would have as much difficulty squeezing through them as the rear doors of a LAV 1. Which is why LAV 2 has a wide ramp similar to M-113. Even double doors - minus the centre-post - would be easier to enter.
Both vehicles also suffer from a door sill that is way too high for a heavily-laden infantryman to enter after a long, hard day of killing fascists ... er ... communists ... er ... who are we fighting this week?

Which is why APC designers should start with a fully-equipped infantryman and build the APC around him.
 
They corrected that mistake on Lazar 2, which has both double doors and ramp.
 

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http://news.usni.org/2015/09/28/marine-acv-competitors-show-off-prototypes-as-program-downselect-nears
 
Is the new LockHeed Martin ACV 1.1 a wholly new design or still based partially on their Havoc from their partnership with Finland that ended back In July?
1st:New
2nd:Old
 

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http://breakingdefense.com/2015/11/win-marine-amphibious-combat-vehicle-it-swims/
 
http://www.defensenews.com/story/defense/show-daily/eurosatory/2016/06/20/prototypes-marine-corps-new-amphibious-combat-vehicle-coming-together/86131020/
 
I wonder why the use of rivets reappears. I thought they had been removed from armoured vehicle use in the 40s.
 
Those are not rivets. Those are bolts holding the add-on applique armor panels. I guarantee that the main hull is all-welded. Rivets would be a total no-no for mine resistance, being a source of shrapnel inside the crew compartment.
 
TomS said:
Those are not rivets. Those are bolts holding the add-on applique armor panels. I guarantee that the main hull is all-welded. Rivets would be a total no-no for mine resistance, being a source of shrapnel inside the crew compartment.
Click to expand...

During WWII, Rivets and Bolts were found to be a "no-no" for when they were hit with AP fire, the heads on the inside would come off and fly around the crew compartments.
 
Armoured rivets were developed back when battleships were fastened together with them. They could take hits that make the fires thrown at mere tanks and trucks look like wet lettuce. But you walk into any engineering shop today and ask about rivets people will be think you are something as low and base as an archetict.
 
Abraham Gubler said:
...walk into any engineering shop today and ask about rivets people will be think you are something as low and base as an archetict.
Click to expand...
In aircraft construction rivets are still widely in use.
http://aviation.stackexchange.com/questions/16995/why-are-planes-using-rivets-not-welded-construction
Why are planes using rivets & not welded construction?
[...]
Short answer: High-strength aluminium alloys are tricky to weld correctly. Aluminium is such a fine material for aircraft structures that the need to rivet it is gladly accepted.

Two things are important:

1.While steel has a temperature range in which it gets more and more runny, aluminium alloys change from solid to liquid within a few degrees. Also, heat conductivity in iron-based alloys is lower than in aluminium, so heating steel locally will keep the surrounding material cooler and more solid compared to aluminium. While welding thin sheets of steel is trivial, it needs lots of experience in aluminium. For very thin sheets, special equipment like a water-cooled copper backing on which the aluminium sheets rest, so their back is cooled, are needed. Also, the melting temperature of steel and titanium is high enough for it to glow long before it melts, while aluminium will melt without giving you any optical hint of its temperature.


2.High-strength aluminium is produced by progressively aging and precipitation hardening the material. The usual alloys use copper atoms dispersed through the aluminium matrix which locally distort the atomic lattice and strengthen it. If they are heated and rapidly cooled by welding, the copper distribution would be changed and the material would be weakened around the welding area. To harden the finished structure again is rather impractical in most cases, so riveting is the better alternative.


A third speciality is the oxide layer on aluminium, which has a higher melting temperature than the base material. You need an AC TIG welder to disrupt the aluminium oxide layer, so your choice of welding techniques is rather limited.

Also, riveted structures are easier to inspect and to repair. Most repairs need to remove aircraft structure for access, and a riveted structure is easier to disassemble and to put together again after the repair using slightly thicker rivets.

My experience with aluminium welding stopped at 4mm thick sheets; while thicker ones were easy to weld, I never managed to weld thinner ones. You sit in front of your structure and heat the spot where you want to start welding. Watching it through the darkened head screen you wait until the spot under the arc becomes glossy, which signals that the surface has started to melt. Now you need to add your welding wire like crazy to keep the spot from heating more, and get the spot moving. If you fail to do so, a second later you will have a hole under your arc, because the aluminium has molten completely and has fallen away. Doing this with 2mm sheets was a pure exercise in futility for me - the moment the surface became glossy it fell away already.
Click to expand...
 
The silliest AFVs were built in Britain up until the Second World War. They had separate chassis with armour-plate welded or bolted on late in the construction process.
 
Arjen said:
Abraham Gubler said:
...walk into any engineering shop today and ask about rivets people will be think you are something as low and base as an archetict.
Click to expand...
In aircraft construction rivets are still widely in use.
http://aviation.stackexchange.com/questions/16995/why-are-planes-using-rivets-not-welded-construction
Why are planes using rivets & not welded construction?
[...]
Short answer: High-strength aluminium alloys are tricky to weld correctly. Aluminium is such a fine material for aircraft structures that the need to rivet it is gladly accepted.

Two things are important:

1.While steel has a temperature range in which it gets more and more runny, aluminium alloys change from solid to liquid within a few degrees. Also, heat conductivity in iron-based alloys is lower than in aluminium, so heating steel locally will keep the surrounding material cooler and more solid compared to aluminium. While welding thin sheets of steel is trivial, it needs lots of experience in aluminium. For very thin sheets, special equipment like a water-cooled copper backing on which the aluminium sheets rest, so their back is cooled, are needed. Also, the melting temperature of steel and titanium is high enough for it to glow long before it melts, while aluminium will melt without giving you any optical hint of its temperature.


2.High-strength aluminium is produced by progressively aging and precipitation hardening the material. The usual alloys use copper atoms dispersed through the aluminium matrix which locally distort the atomic lattice and strengthen it. If they are heated and rapidly cooled by welding, the copper distribution would be changed and the material would be weakened around the welding area. To harden the finished structure again is rather impractical in most cases, so riveting is the better alternative.


A third speciality is the oxide layer on aluminium, which has a higher melting temperature than the base material. You need an AC TIG welder to disrupt the aluminium oxide layer, so your choice of welding techniques is rather limited.

Also, riveted structures are easier to inspect and to repair. Most repairs need to remove aircraft structure for access, and a riveted structure is easier to disassemble and to put together again after the repair using slightly thicker rivets.

My experience with aluminium welding stopped at 4mm thick sheets; while thicker ones were easy to weld, I never managed to weld thinner ones. You sit in front of your structure and heat the spot where you want to start welding. Watching it through the darkened head screen you wait until the spot under the arc becomes glossy, which signals that the surface has started to melt. Now you need to add your welding wire like crazy to keep the spot from heating more, and get the spot moving. If you fail to do so, a second later you will have a hole under your arc, because the aluminium has molten completely and has fallen away. Doing this with 2mm sheets was a pure exercise in futility for me - the moment the surface became glossy it fell away already.
Click to expand...
Click to expand...
Listen at 7:00 this was 1954

https://www.youtube.com/watch?v=t1VBMD8Paxo
 
riggerrob said:
The silliest AFVs were built in Britain up until the Second World War. They had separate chassis with armour-plate welded or bolted on late in the construction process.
Click to expand...

No sillier than any other combatant in WWII where similar construction techniques were used until the advent of monocoque chassis.

The British also pioneered BTW, the use of mixed construction techniques, particularly in their turrets, in the Churchill series. They were cast turret walls with welded roofs. Something which allowed them to tailor the armour thickness much more precisely and quicker to their needs.
 
"In aircraft construction rivets are still widely in use."

Tsssk, tsssk. They aren't rivets, they are fasteners. Rivets are set by sweaty blokes with big hammers, fasteners are set by specialists in white ovies.

Chris
 
CJGibson said:
"In aircraft construction rivets are still widely in use."

Tsssk, tsssk. They aren't rivets, they are fasteners. Rivets are set by sweaty blokes with big hammers, fasteners are set by specialists in white ovies.

Chris
Click to expand...

;D
 
CJGibson said:
"In aircraft construction rivets are still widely in use."

Tsssk, tsssk. They aren't rivets, they are fasteners. Rivets are set by sweaty blokes with big hammers, fasteners are set by specialists in white ovies.

Chris
Click to expand...
But... but... that takes out all the fun of the job! :mad:
 
Kadija_Man said:
TomS said:
Those are not rivets. Those are bolts holding the add-on applique armor panels. I guarantee that the main hull is all-welded. Rivets would be a total no-no for mine resistance, being a source of shrapnel inside the crew compartment.
Click to expand...

During WWII, Rivets and Bolts were found to be a "no-no" for when they were hit with AP fire, the heads on the inside would come off and fly around the crew compartments.
Click to expand...

That's how the story usually goes, but it was not quite the #1 issue.

The big advantage of cast or welded armour was in their weight-saving potential (as already discovered in naval shipbuilding by the 1920's).
The transition from rivets to welding allowed for saving of several hundred kg on a tank in the 15-20 ton range.
 
Also punching holes in plates reduces their strength. Rivets and other fasteners need holes wheras welds keep the plate intact (unless like me you're a crap welder). Anyway good to see my attempt to make a crap joke about Autocad Rivett the software used by architects was not understood. Keep SecretProjects architect free! Almost as bad as journalists.
 
http://www.bizjournals.com/washington/blog/fedbiz_daily/2016/09/saic-forges-ahead-on-marine-vehicle-programs.html
 
What has the expeirence been of hits to these bolts? Are they driven into the vehicle armour plates?
 
https://news.usni.org/2016/09/21/bae-systems-completes-first-production-acv-will-display-modern-day-marine
 
I only see a reference to welding, not how hits to bolts for additional armour units effects the bolts.
 
Foo Fighter said:
I only see a reference to welding, not how hits to bolts for additional armour units effects the bolts.
Click to expand...

Engineering 101: Stress = Force / Area

So if you reduce the cross sectional area of an armour plate under tensile load (caused by the impact of a shell) you reduce the ultimate tensile strength of that plate. The drilling of holes in your armour plate so as to fasten it with bolts of rivets reduces the cross sectional area available to carry the tensile load. Therefore creating a weaker plate.

As to the direct hit of a shell on the head of a bolt or rivet there is a lot less area within the head to take the load. However bolts and rivets tend to be made from much stronger material than the plates they fasten together (for shearing stress purposes) so equalising the equation. Also bolt/rivet heads that are expected to be hit by shells (ie armour) can be easily shaped to deflect forces and also fitted with protective covers and the like. You know; armoured...
 
https://www.dodbuzz.com/2017/02/21/saic-delivers-first-amphibious-combat-vehicle-marine-corps/?ESRC=dodbuzz.sm
 
Abraham Gubler said:
Engineering 101: Stress = Force / Area
Click to expand...

One follow-on comment to Abraham's explanation...I don't disagree, but there is also an interesting side note that riveted structures are often more fatigue resistant (natural crack stops built in) and can also be more forgiving in terms of failure modes.
 

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