Re: [FYI] World's Longest page on tracks vs wheels

At 8:20 PM +0100 1/9/02, Oerjan Ohlson wrote:
>
>To summarize, the ranter has three main gripes with the LAV-III 8x8:
>
>1) It is too heavy to carry in a C-130, at least for long distances. 
>True. How the former Swedish Coastal Artillery (they've changed 
>their name after a recent reorganization, but I always forget their 
>new name) manage to transport their LAV-III 10x10 up and down the 
>length of Sweden in the old RSwAF C-130s I don't know; I suspect 
>they're cheating somehow <g>

Is it perhaps of lighter construction and limited armor thickness? If 
anything is Airportable in a C-130, its going to be light. My Daimler 
Ferret (yes folks, I own a real armored car) is air portable and air 
droppable at 4 tons, but I'd not want to do anything but sneaking 
around if there were heavies around looking to kill me.

>2) Wheeled vehicles don't have the cross-country mobility of tracks. 
>Also true, though I find the ranter's repeated comparisons of the 
>LAV-III's mobility with that of French armoured cars from the early 
>1950s quite amusing. Technology has advanced somewhat during the 
>past half century, even in the wheeled-vehicle transmission field <g>

Well, the ground pressure issue is still the same. 50's and 60's 
Armoured cars are a good comparison to the M113 given their relative 
common 'birth dates'.

>3) The gripe which gets the most attention on the page is the claim 
>that the LAV-III has vastly inferior protection than the vehicle the 
>ranter pits as its rival, the M113A3. Here he is quite wrong, and 
>presents an impressive array of misleading data; I hope that he is 
>being misled by them rather than attempting to mislead others. Let's 
>take a closer look at this gripe:

I agree here. You can make a more heavily armoured Armoured Car. ie 
the Italain Centauro (25 Tons) and South Africa's105mm armed Rooikat 
AC. They aren't MBT class, but better than the M113 or the LAV for 
that matter.

The maintenance issue with tracks vs wheels has come way down with 
the newer technology tracks. Tensioning a bunch of tracks wouldn't be 
so bad, but they still take a lot of work when you have to change one 
or replace one. I could probably change a tire on the Ferret if I had 
to by myself. I couldn't do a M113's track by myself. I do however 
wonder about how many lubrication points the M113 has vs each wheel 
station on the LAV. If the LAV has lots of bevel boxes, that's a lot 
of stuff to keep topped up.

As far as mine resistance, I'd point to the South African's as 
experts in survivable Wheeled vehicles. The Ratel and Buffels both 
are very mine resistant. A properly set up Armored car can also 
operate with multiple wheel stations destroyed. For example, the 
Alvis Saracen/Saladin family can operate with two wheels destroyed 
and up to one corner station destroyed. I don't think an M113 can 
operate with the corner wheel road wheels blown away or the 
drive/idler sprockets.

[snip]

>In other words, all it tells us is that somewhere in the LAV-III 
>hull there is at least one steel plate which is 14mm thick. It 
>doesn't say *where* this plate is, nor does it say that the entire 
>hull is made from a single thickness of such plate. In fact, this 
>*proof* doesn't tell us *anything* about the armour configuration of 
>the LAV-III.

Probably the sides or rear. My ferret has 12mm armour on the sides 
and 16mm on the front glacis/turret face.

National Defense Magazine lists it as 14.5mm ballistic defense.

"Another feature that the Army agreed to trade off by selecting the 
LAV was armor protection, Yakovac explained. He said the Army is 
satisfied with the 14.5 mm ballistic protection-7.62 mm in the basic 
steel hull and a ceramic appliqué added on top."

Thats protection level, not thickness.

>But OK; let's assume that the entire LAV-III hull *is* made of a 
>single thickness 14mm steel plate. It could be true, though 
>personally I suspect that the front plates are thicker than this. 
>The next quote says:

Its not going to be.
>

>If you follow the link you'll find that these AP rounds are made by 
>a company called "Bofors Carl Gustaf". Hm, wonder where I've heard 
>that name before... <g> These rounds were designed by some of the 
>guys sitting down the corridor from my office, though we no longer 
>produce small arms ammo ourselves - Nammo does that nowadays. But I 
>digress.
>
>A penetration of 12-15 mm sounds rather scary when you only have a 
>14mm plate protecting you, doesn't it? Trouble is, you can't compare 
>these numbers straight away.
>
>Armour penetration is usually measured in mm RHA, ie. the distance 
>which the projectile penetrates into a standard Rolled Homogenous 
>Armour plate with a Brinell hardness number in the 350-380 range - 
>I've seen several definitions :-/ The higher the number, the harder 
>the metal; the harder the metal, the harder a bullet has penetrating 
>it - very simplified, but essentially correct for the plate 
>thicknesses and projectile calibers we're talking about.

*mumble about slope of the armor face*

>But look at the above quote: "...penetrates 12mm armor plate of 300 
>HB..." Not sure why the page says "HB" rather than "BHN", but 
>according to my collegues these AP rounds were indeed tested against 
>steel plates with Brinell hardness 300. Against harder steels, they 
>don't penetrate as far.
>
>So, how hard is the steel used in the LAV-III hull? 300 BHN, 380, 
>or...? Well, according to Jane's Armour & Artillery the LAV-III is 
>built of "high hardness steel", but it doesn't say exactly which 
>steel. Doesn't matter all that much; high hardness steels typically 
>have a BHN around 550. This is quite a bit harder than than the 300 
>BHN the AP rounds were tested against, reducing the penetration by 
>at least 15% - so the 5.56 round only penetrates ~10mm, and the 7.62 
>round only 13mm into this harder plate. Suddenly the margin is on 
>the LAV's side... still narrow against the 7.62, but on the right 
>side.

Again, national defense magazine states something about ceramic above 
the 7.62mm protection layer.

>In other words, while the ranter does have a point about the 
>cross-country capabilities of the LAV, the Russians in the above 
>ambush wouldn't have been any better off if they had been riding in 
>a heavily armoured tracked MBT than they were in their thin-skinned 
>wheeled APC...
>
>"Will they [LAVs] stay mobile after enemy fires hit their tires? Why 
>should we be
>any different? Because we have a computer screen inside?"
>
>Yes, the LAVs will stay mobile over most types of terrain after 
>enemy fires hit the tires. Why? Because the modern western run-flat 
>tires are vastly better than the older Russian no-run-flat tires. 
>The LAV is capable of moving even if you blow some of the wheels 
>clean off and puncture the rest; if you break even a single link on 
>the track of a tracked vehicle it becomes immobilized. Against 
>smaller mines (ie., not the 100+ kg command detonated variant shown 
>in the video clip), the LAV is actually less likely to be 
>immobilized than a tracked vehicle is. (I've seen a demonstration 
>where a Piranha-III 8x8 (ie., a Swiss-built LAV-III) with three 
>wheels *removed* and the other five flat completed a rough-terrain 
>course... it didn't go as fast as its "undamaged" comrades, but it 
>didn't get stuck either.)

Just like the Saladin.

I agree that this fellow isn't fair and leaves lots of counter 
arguments against the M113 out. I'm mostly in favor of the M113 
though for the following reasons.

1. Common with the M2/M3 family as well as the MLRS and other United 
defense systems based on the M113.
2. Smaller and more compact, thus smaller target.
3. Tracks allow better mobility with lower ground pressure in nasty
conditions
4. Long time history in the Inventory allows for better institutional 
knowledge and history. (if it ain't broke, don't fix it).
5. Band tracks have fixed most of the complaints against tracks.

Armor protection is pretty much common with both, so I don't really 
see the armor issue being a major factor. If its light and air 
droppable then it isn't going to be that well armored or that easy to 
make float (look at the M2/3 Bradly/Devers).

I'd would however like to see an increase in the use of medium and 
heavy wheeled armor for the US Army for some situations. Perhaps in a 
Med division format that is very Cavalry oriented. The self 
deployable design would be good. A common design based off of either 
the HEMMT chassis or one of the other OshKosh Tactical logistics 
vehicles would make a lot of sense and keep cost down.

-- 
Ryan Gill	  |	   |	     rmgill@mindspring.com
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