Turrets, the whole turrets, and nothing but the turrets......

Started by dy031101, December 17, 2008, 09:08:31 AM

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dy031101

First entry:

Every time I think about upgunning an AFV (armoured halftracks during this couple of weeks) from pintle-mounted .50 cal. MGs, I think about the 40/50 turret used by AAV-7.  Not knowing things about it so much as a name, I tried Googling and found something called "Cadillac Gage 1 Metre Turret".

It was mentioned that Phillipine and Canada used it to arm their M113 and Grizzly respectively, but the turret adversely affected the troop capacities of the APCs.

Questions:

1. Cadillac Gage 1 Metre Turret adversely affected the troop capacities of the carrier APC...... but by how much?

2. I also know of a 40/50 cupola built in Singapore for upgraded M113 and Bionix APCs, and a 40/50 turret built in Korea for the KAFV.  Does anyone know if those turrets/mounts would affect the troop capacities of the carrier APCs?
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deathjester

As far as I know, the upgrade turret is always fitted to the commanders station,so it doesn't impact on troop carrying capacity.

Weaver

The turret was fitted to the centre of the Grizzly (not the commander's position) and reduced the troop capacity from at least 8 to 6, IIRC.

I don't know what the impact on the M113 was, but I'd imagine that, on it's own, it wouldn't make much, since the M113 gunner stands on a box in between two rows of inward-facing benches. You might lose the backwards-facing seat on the engine bulkhead, and if the turret was really bulky, you might have to forego seating guys on the benches immediately next to it. However, that should still leave space for around 10 dismounts. If it was reduced any further, then that may be because the turret was only part of a bigger refit: one popular set of mods for the M113 is the AIFV-style one, which has sloping side armour and revised seating, giving better protection at the expense of capacity.

The generic problem is the swept volume of the under-turret gubbins, i.e any frame or cage, the ammo, a seated or "perched" gunner etc... As a rule of thumb, a one-man turret takes up as much space as two seated soldiers while a two-man turret takes up as much space as at least four. However in practice, a retro-fitted turret may leave spaces around it which although technically "free" are so small and oddly shaped as to be useless for troop carrying. Basically, you're putting a round thing in a rectangular space, and that's always inherently inefficient to some extent.

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apophenia

Weaver is right about the AVGP Grizzly turret not displacing the veh commander's position (as was the case with the fire-support AVGP Cougar). But the Grizzly 1M turret is actually offset well to port and dismounts number five.

http://www.missing-lynx.com/articles/modern/jpmgriz/jpmgriz.htm

BTW, that article is by JP Morgan the guy behind the Modern Canadian Vehicles forum and Maple Leaf Models.

http://www.network54.com/Forum/169232/  http://www.mapleleafmodels.com/main.html

For a 1/35th Grizzly which shows the turret position, see: http://forums.army.ca/forums/index.php?topic=70791.0

The modernized M113A3s/MTVLs are now called TLAVs. Some have the 1M turrets, others have Protected Weapon Stations (a Rafael Mini-Samson copy). No turret basket for the PWs, of course, but the operator's station still takes up space.

http://www.casr.ca/101-army-vehicle-rcws.htm

RotorheadTX

The second-generation turret on the AAV-7 was known as the UGWS (Up-Gunned Weapons System) - you were right on track, as here's a blurb from Janes:

Development
This one-man turret, a further development of the Cadillac Gage Textron (Textron Marine & Land Systems) twin/combination machine gun (1 m) turret, is armed with a 40 mm Mk 19 Mod 3 grenade launcher on the left and 0.50 cal (12.7 mm) M2 HB machine gun on the right.Cadillac Gage Textron made an unsolicited proposal to the US Marine Corps to install this turret on a standard BAE Systems AAV7 armoured amphibious assault vehicle for trials. The turret was armed with the 40 mm Mk 19 Mod 1 grenade launcher and the 0.50 cal (12.7 mm) M2 HB machine gun. For Development Test/Operational Test I at Camp Pendleton the Mod 1 grenade launcher was replaced by the more recent Mod 3. These trials were such a success that the Marine Corps placed an order with the company for three production turrets for DT/OT II and these were delivered in mid-1983. Early in 1986 and after a competitive procurement, the US Naval Sea Systems Command, acting for the US Marine Corps, placed an order with Cadillac Gage Textron for the supply of 240 UpGunned Weapons Stations. Production turrets were delivered during 1987 to early 1988. Total value of this contract was US$17.236 million. The US Marine Corps also took an option for an additional 100 turrets. This was exercised in January 1987 at a cost of US$5.823 million.

dy031101

Entry 2:

As I search for a 90mm gun turret to put on halftracks, I came across a MECAR KEnerga 90mm cannon...... I was initially thinking that this is one and the same as the Cockerill product line, but one particular model appears longer than the Cockerill Mk.3 but can be used to re-gun V150 90mm mobile guns.

(Illustration charts on the CMI site does NOT list V150 as capable of mounting a Mk.8, so I think it is safe to assume that this gun is not a Mk.8......)

I couldn't find any info on that gun.  Does the gun have compatibilities with the French or the American/Cockerill-Mk.8 90mm guns?  If not, does anyone know how the gun performs compared to the French guns and Cockerill Mk.3?  How many rounds of ammunitions can be carried in the up-gunned Cadillac Gage turret?
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dy031101

Entry 3:

I've come across several photos of US-made LAV-105 and LAV-600.

They both appear to use the turret of Stingray light tank.

Can the turret be used by the more-modern 8 x 8 (Pandur II, LAV-III/Stryker...... platforms like those)?

What other choices were out there prior to the introduction of CT-CV?
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dy031101

Looking through tank-related Wikipedia entries, I began to harbour a few questions about their turret design.

It seems to me that cast turrets became fashionable over welded and riveted (this one I can see why it's undesirable) turrets immediately post-WWII and early during the Cold War, only to be superseded by welded turrets again like half-way through the Cold War.

Most instances I've run into that mentioned modern welded turrets only said that they are better than cast turrets; I've never been quite enlightened on why though.

Also, I've seen egg-shaped turrets being superseded by turrets with flat faces.

So here are my questions:

#1. what exactly are the advantages of modern welded turrets over cast turrets?

#2. would my second observation be because turrets with flat faces can better-handle certain threats than egg-shaped turrets can?  If so, what are those threats?

#3. would a cast turret with flatter faces benefit in the same way as the answer of Question #2?

Thanks in advance.
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rickshaw

Quote from: dy031101 on July 15, 2010, 03:22:27 PM
Looking through tank-related Wikipedia entries, I began to harbour a few questions about their turret design.

It seems to me that cast turrets became fashionable over welded and riveted (this one I can see why it's undesirable) turrets immediately post-WWII and early during the Cold War, only to be superseded by welded turrets again like half-way through the Cold War.

Most instances I've run into that mentioned modern welded turrets only said that they are better than cast turrets; I've never been quite enlightened on why though.

Also, I've seen egg-shaped turrets being superseded by turrets with flat faces.

So here are my questions:

#1. what exactly are the advantages of modern welded turrets over cast turrets?

Easier to ensure uniform armour thicknesses, easier to manufacture, easier to upgrade, easier to design for optimum deflection angles are things which immediately spring to mind.

Quote
#2. would my second observation be because turrets with flat faces can better-handle certain threats than egg-shaped turrets can?  If so, what are those threats?

You have to understand that most modern tank turrets take a "layer-cake" approach in fabrication.  You have the turret proper, to that are welded numerous armour modules, edge on to the turret face and then over that are placed Chobham armour (or equivalent/successor) composite armour modules.  Chobham in particular is much better at defeating HEAT rounds than simple, cast armour, because of its use of ceramic layers which the HEAT jet finds difficult to penetrate.

Quote
#3. would a cast turret with flatter faces benefit in the same way as the answer of Question #2?

Nope.  See reason why in answer #2.  Turrets which are mad up of single, cohesive armour steel are more easily penetrated than composite designs.  Because its easier to weld to a flat surface and its cheaper, welded designs are preferred over the smoothly curving cast ones.

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dy031101

Quote from: rickshaw on July 15, 2010, 06:14:16 PM
Easier to ensure uniform armour thicknesses, easier to manufacture, easier to upgrade, easier to design for optimum deflection angles are things which immediately spring to mind.

I see......

Correct me if I'm wrong, but I am under the impression that for Russia and industries influenced by them, only post-Cold-War tank designs emphasized on having welded turrets.  Even T-72 and T-80, which are claimed to have composite armours, are said to use cast turrets (or were composite armours limited to just the hulls?).  That being said, some variants of the T-72 do have turrets that look a bit angular at the forward half (although, being cast turrets, they are still round at the edges).

If they did indeed stick with cast turrets, what prompted them to do so?

Do flatter faces on cast turret nontheless offer any advantage over egg-shaped turrets?  Like ease of attachment for ERA blocks (just my uneducated guess)?

Thanks in advance.
To the individual soldiers, *everything* is a frontal assault!

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rickshaw

Quote from: dy031101 on July 15, 2010, 06:34:55 PM
Quote from: rickshaw on July 15, 2010, 06:14:16 PM
Easier to ensure uniform armour thicknesses, easier to manufacture, easier to upgrade, easier to design for optimum deflection angles are things which immediately spring to mind.

I see......

Correct me if I'm wrong, but I am under the impression that for Russia and industries influenced by them, only post-Cold-War tank designs emphasized on having welded turrets.  Even T-72 and T-80, which are claimed to have composite armours, are said to use cast turrets (or were composite armours limited to just the hulls?).  That being said, some variants of the T-72 do have turrets that look a bit angular at the forward half (although, being cast turrets, they are still round at the edges).

If they did indeed stick with cast turrets, what prompted them to do so?

Do flatter faces on cast turret nontheless offer any advantage over egg-shaped turrets?  Like ease of attachment for ERA blocks (just my uneducated guess)?

Thanks in advance.


OK, what we must understand is that there are basically now two different approaches to armour design.  The Soviet/Russians and the rest of the world (usually referred to as "The West" - based around primarily British and American theory/design/practice).  The Soviets/Russians used very different ideas about how to design their vehicles to the rest of us.   They very early on tended towards (and independently to the "The West") adopted first composites then so-called "active armours".  However the Soviet/Russian method of utilising composites was very different to "The West's".   Basically the Soviets used to bake their "layercake" in a different way to "The West".   First they cast an inner shell of armoured steel and hardened it.   They then used this as the inner of a mould, on which they pour an outer-shell of armoured steel mixed with ceramic balls.  Later, they played around with it and adopted a more layered approach but essentially the sae processes were utilised.  They even experimented with explosively formed shells, apparently and complete ceramic armoured hulls/turrets (as proved by their unsolicited bid for the Challenger Mk.I in 1990 when they offered a version of the T-90 made almost completely out of ceramic armour).  This tended to be a cheaper, albeit a less effective method of creating a composite armoured shell over the method adopted in "The West".

In "The West", as I mentioned, the method adopted was to first fabricate the inner shell from flat plates to steel.  To the outer faces of that shell, were welded pieces of hardened steel, edge on, allowing significantly greater thicknesses of steel plate than if a single, uniform plate was used.  On top of that, were welded what were essentially armoured boxes, composed of what is known as "Chobham" (or Burlington) Armour, which itself is composed of layers of aluminium, rubber and ceramics.   "The West's" method has advantages in that it can be more easily repaired, upgraded or even replaced.   The Soviet/Russian method can't but that is more in keeping with their philosophy of finite life military equipment.

What spelt the end of uniform, cast armour, particularly on turrets was the widespread adoption of HEAT and HESH warheads on ATGW.   These could only be defeated by increased amounts of armour which became prohibitive.  When APFSDS rounds appeared, they needed to be deflected, rather than necessarily outright defeated (their penetration is enormous and no MBT could really carry sufficient armour to do so) and flat faces do that the best.   The result was a growing reliance on welded rather than cast turret armour.
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Henry Yeh

It's more difficult to construct perforated or layered composite armours, especially those containing ceramic matrices, into curved shapes. The slab-sided armours of Western tanks were born out of that necessity, not because of any inherent merit of their shape.

dy031101

Despite all the bumps on the turret of the M10 Tank Destroyer, is the turret cast, welded, or...... riveted?

Thanks in advance.
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Rick Lowe

The M-10 turret was welded.

The 'rivets' are the mounting bosses for the up-armouring plates that were available to be bolted onto the turret (and hull) sides, to give a fraction more thickness to the wafer-thin existing plates.
AFAIK they were never fitted, but the bolts were usually left plugging the holes in the mounts.

Cheers & HTH

Rick

dy031101

Where within itself does the AML-90 stow its main gun ammos?  Does the turret itself carry some of those shells?

Thanks in advance.
To the individual soldiers, *everything* is a frontal assault!

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