From: gherbert@gw.retro.com (George William Herbert)
Newsgroups: uk.people.disability,us.military.army,alt.folklore.military,
	sci.military.naval
Subject: Re: Disabled in the Military
Date: 4 Jan 2001 16:38:26 -0800

Brian  <brian_ross_665@my-deja.com> wrote:
>> Just what is your point?  What's the big deal with using an
>> autoloader?  Western armor seems to have gotten along just fine
>> without one.
>
>Well, we seem to be moving away at the moment from the use of disabled
>people in the military towards a general discussion about the utility or
>not of an autoloader but I'll make the point (again) that the major
>determinant of the height of an MBT is the height that the vehicle is
>designed to accomodate a standing human loader.  If, as the US Army
>does, it designs for the "average" loader, that means approximately 2
>metres must be allowed for.  Providing adequate armour to cover a volume
>that large means the MBT has started to become unacceptably heavy.  This
>is but one more means to reduce the height of the vehicle and hence its
>weight.  Furthermore, as a new 140mm gun has been proposed for future
>development and replacement of the 120mm, it will mean that an
>autoloader _is_ required.

This is an interestingly simplified version of tank design reality.

Tank height is driven by a number of simultaneous issues:
a) ground clearance
b) hull height around driver
c) engine / transmission height
d) suspension system internal height
e) suspension system external height
f) turret height to clear b, c, and e in rotation
g) gun system height including allowance for elevation and depression
h) loader height

You appear to be largely ignoring a-g and concentrating soley on h.

You basically need 0.4 to 0.5 meter for ground clearance.

You need 0.8 to 1.0 meter for the driver, even in a supine position.

If you use torsion bars, you need 0.15 to 0.2 meter internal height or
more for those and their end fittings and such.  You can nestle fuel
and driver and other odd shaped gear between the bars, but you can't do
that with the turret basket.

The shortest engines are 0.6 meter tall, but typical installations
including transmission and cooling radiators are more than a meter.

Gun systems are 0.65 meter or so tall without any allowance for depression;
if you figure 1.2 meter trunnion-gun rear distance and 0.4 meter recoil
distance, you're talking another 0.4 meter or so at 15 degrees depression.

You can use a reduced frontal area turret design of one variant or another
to get the bulk of the turret frontal area down but keep the gun height,
if you have to, but minimum height stays about the same.

Similarly, your (other postings) analysis of making tanks shorter if you
use drivers who are legless is overly simplistic, too.  It's not like
modern tanks aren't using the volume for equipment and stores.
If you look at the M-1 Abrams, what's occupying the rest of the front
of the tank besides the driver area is fuel.  It carries 1.9 cubic meters
of fuel (figure 2 cubic meters of tank).  If you chop the hull front depth
in half by using legless drivers, that's a whole cubic meter of volume
used for fuel tanks that goes away.  Where else on the vehicle do you
move the fuel to?  The Leopard II has tank main gun rounds stowed up
there next to the driver.  Including space to get them in and out,
they take up nearly the same linear distance as the driver does.

There's this simplistic idea that the hull length is driven only by
the drivers reclined length (legs plus torso plus head) plus the
turret diameter plus the engine and transmission length.  That's not
the case at all; the overall configuration is a careful balance of
volume allocation and layout.  If you reduce the drivers length by
0.75 meter then sure you can shorten the drivers compartment that
much, but the other volume constraints (which are significant and
inflexible) remain.  You need fuel volume.  You need ammo volume.
You need crew space and mobility volume, even if you use an autoloader
and legless drivers.  You need engine volume.  You need gun fixed
and swept volume.  You need electronics and suspension.

As a number of tanks have proven (US T-92, Merkava) you can put the
engine next to the driver and thus overlap those distances quite
effectively if you want to.  That saves overall hull length too,
if you want it to: the T-92 was pretty short; the Merkava's only long
because they have the ammo storage compartment at the aft end of the
hull with 40-ish rounds oriented horizontally and in quad round
independent storage containers with attendant volume penalties.

The 140mm gun was designed to counter a threat that is now nonexistent:
a supposed (probably real on paper, but never prototyped) 60-ton Soviet
heavy tank with about the same volume and layout of a T-80 but 50% thicker
armor or better.

We have gotten about 3/4 of the way to the origional penetration spec
with more advanced long rod penetrators in 120mm guns.  They can more than
adequately kill anything out there except possibly other modern western
MBTs with Burlington (Chobham) armor, which so far aren't showing any
sign of fighting each other.  By the time new threats actually requiring
better tank guns arrive, one or more of electromagnetic guns, liquid
propellant guns, or electrothermal-chemical guns should be available.
The odds that the 140mm will ever see service now are extremely low.

>> I'd prefer not to have one at all, actually.
>
>I'd like to see how many people you could find who were capable of
>lifting the proposed new 140mm rounds without getting a hernia.

The proposed 140mm rounds are two-part, 18-kilo per section rounds
(40 lbs or so), each part weighing almost exactly the same as the 120mm
whole rounds it was proposed to replace.  If you can accept a 12 second
firing cycle instead of 8 seconds then you could manually load them in
two seperate steps, as the British 120mm L11 and L30 rifled guns in the
Chieftan, Challenger I, and Challenger II use today and have for around
40 years now.

If you unified the 140mm ammo, I personally (when in good shape, which I am
not this month but have been in the last year) can lift 80 lbs at my
chest height, move it 5 feet and ram it without getting a hernia.
I am admittedly 6'5" and 240 lbs, but I am certainly not the best
and strongest out there.  You'd find suitable loaders.  You'd want
average trending on short weightlifters as your typical loader, but
those people are out there.

The tradeoff here is a couple of cubic meters and loader operations
height versus losing 1/4 of your crew, half your eyes-up observation
capability, 1/4 your maintenance crew, etc.  So far, the west has
judged that the loader is useful (except the LeClerc tank from France,
which went autoloading).  Those tradeoffs are true even if you want
to upgun or downsize or both.  There are some arguments for a 4 man
autoloaded tank to try and get the best of both worlds; if the loader
isn't routinely hefting rounds around their volume drops to about what
the commander takes up now, so they can be a second set of eyes / maintenance
person / MG gunner and load the main gun manually and awkwardly in an
emergency if the autoloader craps out, and it only costs you 1.2 cubic
meters of tank or so.

>> > [...]
>> >Yeah, sure, whatever.  I take it you're another of the "Soviet == crap"
>> >school of thinking?
>>
>> No, not all Soviet military equipment is crap.  But when making direct
>> comparisons, it wasn't until the late 80s/early 90s that they really
>> started to catch up technologically.
>>
>> Basically, Western military equipment has been more advanced than
>> Soviet military equipment.
>
>Except in the areas of armour technology, optronics, submarines, V/StOL
>aircraft design, dogfighters, small arms, small nuclear reactors, etc.
>
>Give it away, the Soviets led the western in many areas, before the fall
>of the fUSSR.  If anything, the west has only just started to play catch
>up, now and often by buying it from them.

There are a number of areas where in the 60s, 70s, and 80s there was
common western belief about the quality of Soviet weapons systems that
put them at parity or above western equivalents, due to having to work
with intelligence estimates and disinformation rather than direct field
testing and analysis.

Now that for the most part that is all history, we've gone back and talked
to their designers, taken some of them apart, looked at plans, and pretty
much come to the conclusion that while a few limited areas were roughly
at parity (and a very very few such as a couple of corners of materials
science and production engineering advanced concepts were ahead).


-george william herbert
gherbert@retro.com

From: gherbert@gw.retro.com (George William Herbert)
Newsgroups: uk.people.disability,us.military.army,alt.folklore.military,
	sci.military.naval
Subject: Re: Disabled in the Military
Date: 4 Jan 2001 16:50:34 -0800

Glenn Dowdy <glenn_dowdy@agilent.com> wrote:
>George William Herbert wrote in message <933522$c5r$1@gw.retro.com>...
>>Brian  <brian_ross_665@my-deja.com> wrote:
>>>I'd like to see how many people you could find who were capable of
>>>lifting the proposed new 140mm rounds without getting a hernia.
>>
>>The proposed 140mm rounds are two-part, 18-kilo per section rounds
>>(40 lbs or so), each part weighing almost exactly the same as the 120mm
>>whole rounds it was proposed to replace.
>
>The 155mm artillerty HE round is 96 pounds, and I had no problem, as did any
>other male cadet, lifting and loading that round.

It's a bit more difficult doing it within the limited volume
available inside a tank, and doing it repeatedly and rapidly
with seconds counting quite a lot.  But yes, this is well within
what humans are capable of doing.


-george william herbert
gherbert@retro.com

From: gherbert@gw.retro.com (George William Herbert)
Newsgroups: uk.people.disability,us.military.army,alt.folklore.military,
	sci.military.naval
Subject: Re: Disabled in the Military
Date: 4 Jan 2001 23:40:30 -0800

Though I'm not going to set followups that way as I moderate
the newsgroup, I think that followups to sci.military.moderated
only rather than the laundry list of: uk.people.disability,us.military.army,
alt.folklore.military,sci.military.naval would be appropriate...

Brian  <brian_ross_665@my-deja.com> wrote:
>George William Herbert wrote:
>> Brian  <brian_ross_665@my-deja.com> wrote:
>> >> Just what is your point?  What's the big deal with using an
>> >> autoloader?  Western armor seems to have gotten along just fine
>> >> without one.
>> >
>> >Well, we seem to be moving away at the moment from the use of disabled
>> >people in the military towards a general discussion about the utility or
>> >not of an autoloader but I'll make the point (again) that the major
>> >determinant of the height of an MBT is the height that the vehicle is
>> >designed to accomodate a standing human loader.  If, as the US Army
>> >does, it designs for the "average" loader, that means approximately 2
>> >metres must be allowed for.  Providing adequate armour to cover a volume
>> >that large means the MBT has started to become unacceptably heavy.  This
>> >is but one more means to reduce the height of the vehicle and hence its
>> >weight.  Furthermore, as a new 140mm gun has been proposed for future
>> >development and replacement of the 120mm, it will mean that an
>> >autoloader _is_ required.
>>
>> This is an interestingly simplified version of tank design reality.
>>
>> Tank height is driven by a number of simultaneous issues:
>> a) ground clearance
>> b) hull height around driver
>> c) engine / transmission height
>> d) suspension system internal height
>> e) suspension system external height
>> f) turret height to clear b, c, and e in rotation
>> g) gun system height including allowance for elevation and depression
>> h) loader height
>>
>> You appear to be largely ignoring a-g and concentrating soley on h.
>
>h is considered by most designers the major determinant.  All others
>follow on from there.  If there is insufficient height for the human
>loader to operate, then life becomes very difficult for him and the time
>required for him to accomplish his task increases disproportionately.
>Early Soviet vehicles had the loader either crouching or kneeling for
>the most part.  Their rates of fire were considerably lower than their
>comparable western vehicles.

h is considered by most designers to be a determinant, but not the
dominating one by any means.  Certainly the ergonomics of the loader
position are a serious issue.  However, note that if you add ground
clearance plus torsion bar depth in hull plus assume 5'10" for typical
american male loader height, you come up with a sum lower than the
height of any western tank in recent memory.  Would you like to perhaps
make an educated guess at what other factors might be in play?

>> You basically need 0.4 to 0.5 meter for ground clearance.
>
>Yes.
>
>> You need 0.8 to 1.0 meter for the driver, even in a supine position.
>
>Yes, but that can be "telescoped" into the height required for the
>loader.

Does one have to explicitly state that tanks since oh, the first
one with a turret basket, have had a basket which protuded down
into the hull?

To review what I wrote:
>> a) ground clearance
>> b) hull height around driver
>> c) engine / transmission height
>> d) suspension system internal height
>> e) suspension system external height
>> f) turret height to clear b, c, and e in rotation
>> g) gun system height including allowance for elevation and depression
>> h) loader height

g and h obviously extend downwards from the turret ring as allowed
by hull depth and suspension system internal height as required.

>> If you use torsion bars, you need 0.15 to 0.2 meter internal height or
>> more for those and their end fittings and such.  You can nestle fuel
>> and driver and other odd shaped gear between the bars, but you can't do
>> that with the turret basket.
>
>Yes but its from the floor of the turret basket to the top of the turret
>which is the height required for the loader.
>
>> The shortest engines are 0.6 meter tall, but typical installations
>> including transmission and cooling radiators are more than a meter.
>
>Immaterial to the discussion.  That factor is taken into account by
>"telescoping" it into the height required for the loader.

No.  That height is significant because (in all modern tanks) you
need to be able to do 360 degree traverses with the turret and gun,
which sets a base minimum height for the turret ring and turret proper,
which sets a minimum height for the gun trunnions (has to be up above
the turret ring high enough to be able to elevate and depress),
which given a requirement for elevation and depression (frontal,
usually, tanks generally can't depress the gun to the rear very well)
sets turret roof height above trunnions given the gun protrusion
back from trunnions and its recoil distance, based on geometry
and the depression angle.

Again, you've got this wonderful idea that the loader height must
be the only factor which matters.  Look at the T-64 / T-72 / T-80 / T-90
profile sometime.  They have no loader.  The commander and gunner are
sitting moderately prone.  It's nearly as tall as an M-1 is anyways.
Why is that?  The gun needs to clear the hull, it needs to elevate
and depress, the hull height is limited by the driver height and
engine height.

>> Gun systems are 0.65 meter or so tall without any allowance for depression;
>> if you figure 1.2 meter trunnion-gun rear distance and 0.4 meter recoil
>> distance, you're talking another 0.4 meter or so at 15 degrees depression.
>
>Again, "telescoped" into the height required for the loader.  You're
>also suggesting that the gun must always be contained within the
>armoured envelope.

No, it's *not* telescoped into the height required for the loader.
If you take the loader out entirely and replace him with magic
autoloader *you*still*need*to*geometrically*accomidate*the*gun*
*and*its*elevation*and*depression*and*recoil*.

The loader *may* be the tallest item in the combined factors.
I honestly can't recall a modern western tank where they were,
though I am willing to listen to specific arguments.

I am extremely aware of cleft turrets, remote turrets,
and elevated remote gun pod type turrets.  See "reduced frontal
area turret design" immediately below, the experimental US T-92
light tank, the Expeditionary Tank and its elevated gun pod
2-man turret concept, the whole series of AAI LAV elevated and
remote and lift and traverse turrets of the 70s and 80s...
Read R.P. Hunnicutt's "Sheridan" for a good overview.

>> You can use a reduced frontal area turret design of one variant or another
>> to get the bulk of the turret frontal area down but keep the gun height,
>> if you have to, but minimum height stays about the same.
>
>Only if a human loader is included.  The use of an elevated gun or a
>cleft turret means that the height can be reduced considerably, as can
>the frontal area.

Cleft turrets don't actually require an autoloader; the T-92 was
semi-manually loaded even though it had one (albeit with a 76mm gun,
not a larger one).

Elevated guns (and to a lesser degree cleft turrets) introduce a terrible
tactical problem to the tank.  They put the commander below the top
of the vehicle.  That means that the tallest part of the tank is no
longer the person looking around for opposing vehicles and anti-armor
missile sites and such.  That gives a (possibly tactically critical)
edge to the opposing force, who can see the top of the tank before
the tank sees them.  You can put a remote sight (CITV or equiv.)
on top of the gun, but that isn't as good in many situations as
having someone up there with eyeballs.

>> Similarly, your (other postings) analysis of making tanks shorter if you
>> use drivers who are legless is overly simplistic, too.  It's not like
>> modern tanks aren't using the volume for equipment and stores.
>> If you look at the M-1 Abrams, what's occupying the rest of the front
>> of the tank besides the driver area is fuel.  It carries 1.9 cubic meters
>> of fuel (figure 2 cubic meters of tank).  If you chop the hull front depth
>> in half by using legless drivers, that's a whole cubic meter of volume
>> used for fuel tanks that goes away.  Where else on the vehicle do you
>> move the fuel to?  The Leopard II has tank main gun rounds stowed up
>> there next to the driver.  Including space to get them in and out,
>> they take up nearly the same linear distance as the driver does.
>
>If you move to a piston engine then less fuel is required.  If utilise
>external, jettisonable tanks, then its not taking up space inside the
>armoured volume.

The Abrams is not moving to a piston engine, it's moving to a (better
and lower fuel use) new turbine.  That said, the Army now says it needs
the full fuel still to deal with getting log load / replenishments per
unit combat time down.

What would you do with say the Leopard II?  It's got its non-ready
ammo there.  Get rid of its non-ready ammo rounds?

Tanks need hull volume.  These components, fuel, ammo, engines,
systems, they all need to be there.  You have to accomidate them.
You can only juggle things around so much without a completely
new design, and a new design still requires fitting in its component
set somehow.  You can't get a functional armored vehicle without
putting all the parts in.

>> There's this simplistic idea that the hull length is driven only by
>> the drivers reclined length (legs plus torso plus head) plus the
>> turret diameter plus the engine and transmission length.  That's not
>> the case at all; the overall configuration is a careful balance of
>> volume allocation and layout.  If you reduce the drivers length by
>> 0.75 meter then sure you can shorten the drivers compartment that
>> much, but the other volume constraints (which are significant and
>> inflexible) remain.  You need fuel volume.  You need ammo volume.
>> You need crew space and mobility volume, even if you use an autoloader
>> and legless drivers.  You need engine volume.  You need gun fixed
>> and swept volume.  You need electronics and suspension.
>
>No, I did not say hull length was "driven only by the drivers reclining
>length".  As we were talking about the need to armour the length of hull
>required to house the driver's legs, that was discussed.  Of course
>there are other factors which govern the total hull length but I have
>not discussed them.  As the primary determinant of the hull length in
>front of the turret (assuming the traditional driver's position) is the
>distance from the rear of the driver's compartment to its front,
>reclining the driver will obviously make the compartment longer, not
>shorter.  In fact, if the driver was seated, his compartment consumes
>less volume but complicates the problem of hull height.

Welcome to the wonderful world of armored vehicle design!
Everything you want to do is a tradeoff!  There are geometric
concerns everywhere!  Things are a finite size and weight and
don't appreciate being squeezed!

Reclining the driver makes the compartment longer, but reduces
hull height in front of the turret.  You are trading off frontal
area and hull height with side armor.  You pays your money and
you takes your chances.  You still have to fit the components in.

>> As a number of tanks have proven (US T-92, Merkava) you can put the
>> engine next to the driver and thus overlap those distances quite
>> effectively if you want to.  That saves overall hull length too,
>> if you want it to: the T-92 was pretty short; the Merkava's only long
>> because they have the ammo storage compartment at the aft end of the
>> hull with 40-ish rounds oriented horizontally and in quad round
>> independent storage containers with attendant volume penalties.
>
>I've come across several references to the US post-war T-90 series of
>development vehicles but they are usually mentioned in passing.  Do you
>have any further references to them?

Buy everything that R.P Hunnicutt ever wrote, or find them all in libraries.
It will cost you several hundred dollars to buy them, but it's worthwhile
if you can't find them otherwise and need to see how the evolution
and features worked their ways out.

Buy or borrow several things that Richard Ogorkiewicz wrote (particularly
_Technology of Tanks_, though _Design and Development of Fighting
Vehicles_ is somewhat useful as well...).

Note that my collection to date is already well into four figures in
cost and is yet highly incomplete; armor design is not a cheap hobby.

>While you're partially correct about "telescoping" the hull length by
>position the engine to the front, this actually increases the hull
>_width_ (albeit relatively marginally compared to the overall width of
>the vehicle).  This can introduce problem in itself with
>maneauvreability (tracked width to length ratio).

The M-41 was 126 inches wide with 102 inch track.
The T-92 was 124 inches wide with 108 inch track.
The Sheridan was 110 inches wide with 92 inch track.
The XM-8 AGS was 104 inches with an 85 inch track.

The AGS was designed specifially to fit in the C-130.  The Sheridan
sort of fit inside the C-130, the M-41 and T-92 weren't expected to
have to when designed.  The T-92 had a transversely mounted engine
and could have been redesigned a foot to a foot and a half narrower
(and perhaps a couple of feet longer, but the hull was only about 16
feet long to start with) to 112 to 106 inch widths with a non-
transverse engine mounting.

The modern MTU 880 series engines are only 3 feet wide, if you assume
a 2 foot width for the driver and bulkhead, then you can fit everything
internal to the hull side armor wall within 5 feet wide.  A modern MBT
is (in rough terms) 12 feet wide, 4 feet of which are tracks and
another half foot to foot of which is suspension, giving you 7 to 7.5
feet of hull width to work with.  That gives you 2 to 2.5 feet for the
side armor (1 to 1.25 feet on each side, 12 to 15 inches, 300 to 375mm).
Plenty to work with for even spaced non-frontal composite armors.

>> The 140mm gun was designed to counter a threat that is now nonexistent:
>> a supposed (probably real on paper, but never prototyped) 60-ton
>> Soviet heavy tank with about the same volume and layout of a T-80
>> but 50% thicker armor or better.
>
>Except now they've discovered that the Russians have armour which is as
>effective on their normal vehicles, such as their T-80/90 series.

If you exclude the (unproven) ERA, the Russians have composite ceramic
alumina insert armor in older domestic T-64s and T-72s and T-80s,
and a very very crude attempt at Chobham like armor in the most modern
T-72s, T-80s and T-90s.  This has been analyzed to death; neither the
thickness nor technology of these armors are anywhere near enough to
resist even long range shots with modern DU or tungsten monobloc
120mm rounds such as the M829A2 or DM-43 or equivalent French or
Israeli or English rounds.

The thick plate ERA Kontakt-5 *may* effectively disrupt long rod
penetrators of that design range.  You can sit with the explosive
dynamics equations and flying plate equations and known dimentions and
weights of Kontakt-5 and various long rod penetrators and get answers
that go either way.  The mid-90s firing trials the west has conducted
were not publically discussed.  The DM-53 and M829A3 are next
generation rounds designed after detailed analysis of Kontakt-5 became
available and there's a reasonable guess to be made that they're
specifically designed to counter it effectively (as there is otherwise
no particular technology driver for better rounds than the DM-43 or
M829A2 level of performance), though the details are still classified
on both rounds.

>> We have gotten about 3/4 of the way to the origional penetration spec
>> with more advanced long rod penetrators in 120mm guns.  They can more than
>> adequately kill anything out there except possibly other modern western
>> MBTs with Burlington (Chobham) armor, which so far aren't showing any
>> sign of fighting each other.  By the time new threats actually requiring
>> better tank guns arrive, one or more of electromagnetic guns, liquid
>> propellant guns, or electrothermal-chemical guns should be available.
>> The odds that the 140mm will ever see service now are extremely low.
>
>I'd suggest then that you aquaint yourself with the reported
>acknowledgement by the US Army that even the T-72m3 is more than well
>enough armoured in the frontal quarter to withstand the present
>penetrators utilised in the 120mm gun.  I agree, the stop gap is further
>development of the 120mm and that is being undertaken with longer tubes
>and better penetrators however the time will come and relatively soon
>when the 120mm cannot be taken any further, then what?

Without Kontakt-5, no Russian tank can withstand any of the US issued
120mm KE rounds and is at best marginal against the earliest foreign
non-DU 120mm KE rounds.

The "reports" are not entirely inaccurate, but are taken out of
context by a lot of people.

>> >> I'd prefer not to have one at all, actually.
>> >
>> >I'd like to see how many people you could find who were capable of
>> >lifting the proposed new 140mm rounds without getting a hernia.
>>
>> The proposed 140mm rounds are two-part, 18-kilo per section rounds
>> (40 lbs or so), each part weighing almost exactly the same as the 120mm
>> whole rounds it was proposed to replace.  If you can accept a 12 second
>> firing cycle instead of 8 seconds then you could manually load them in
>> two seperate steps, as the British 120mm L11 and L30 rifled guns in the
>> Chieftan, Challenger I, and Challenger II use today and have for around
>> 40 years now.
>
>Yes, but then you could do it more efficiently with an autoloader
>anyway.  I'm surprised, the last I'd heard about the 140mm gun was that
>it was to utilise a fixed round.  That was what was agreed in the MOU
>signed between the NATO members when it was finalised as a design.

Well, all I can tell you is that all the 140mm guns used the same chamber
and ammo specification, and it's two part ammo.  This is the US XM-291
gun, Bitish DRA and Royal Ordnance guns, the Swiss 140mm gun, and
the Rhienmetall 140mm gun (plus what little is known of the Israeli 140mm
gun as well).  All of them are in the same ammo standard, as far as is
known so far (the Israeli gun is not well understood yet).  It's two
part ammo, a base with 10 kilos of propellant and casing and base and
igniter assembly, and a KE round with 5 kilos more propellant attached
or a HEAP round with no additional propellant as the two nominal rounds.

>> If you unified the 140mm ammo, I personally (when in good shape, which I am
>> not this month but have been in the last year) can lift 80 lbs at my
>> chest height, move it 5 feet and ram it without getting a hernia.
>> I am admittedly 6'5" and 240 lbs, but I am certainly not the best
>> and strongest out there.  You'd find suitable loaders.  You'd want
>> average trending on short weightlifters as your typical loader, but
>> those people are out there.
>
>Yes, but how long can they keep that sort of manauvring up in the
>confined space of a tank compartment whilst its loading?  Already we are
>starting to get though into the same sort of territory where I was
>severely criticised for reducing the pool of potential "average"
>manpower.  If those criticism are equally true for my proposal, they are
>just as true for your proposal for a particular physiogomy.

As has been pointed out, it's standard for military officer cadets
to help out on an artillery gun as part of their training in the west,
those are 40 kilo plus (90 lbs or more) shells, and people lift them
just fine.

The ergonomics details vary far too much from design to design to
be able to address accurately in this forum.

>> The tradeoff here is a couple of cubic meters and loader operations
>> height versus losing 1/4 of your crew, half your eyes-up observation
>> capability, 1/4 your maintenance crew, etc.  So far, the west has
>> judged that the loader is useful (except the LeClerc tank from France,
>> which went autoloading).  Those tradeoffs are true even if you want
>> to upgun or downsize or both.  There are some arguments for a 4 man
>> autoloaded tank to try and get the best of both worlds; if the loader
>> isn't routinely hefting rounds around their volume drops to about what
>> the commander takes up now, so they can be a second set of eyes / maintenance
>> person / MG gunner and load the main gun manually and awkwardly in an
>> emergency if the autoloader craps out, and it only costs you 1.2 cubic
>> meters of tank or so.
>
>Compromises, compromises.  As I keep suggesting, compromises are the
>order of the day.  You seem to think the need for a fourth crew member
>at the expense in height is acceptable whereas most other armour
>designers are suggesting otherwise in all the journal articles I've read
>on the subject.

Look at the LeClerc MBT from France for a moment.
It's got an autoloader on its 120mm gun, three man crew.
It is 2.53 meters high to turret roof.

The M-1 is manually loaded, four man crew, stands 2.4 meters to turret roof.

The Leopard II is manually loaded, four man crew, stands 2.5 meters to
its turret top.

The Japanese T-90 is autoloaded, three man crew, stands 2.33 meters to
turret roof (with statistically slightly smaller crew).

Oddly enough, the autoloader doesn't seem to make the problem
of height go away.

Until you go to a cleft turret or podded gun, which are valid options,
you don't get your height down a lot.  You may see tanks going as
far as lift-traverse guns which are hull-down but elevate up to
traverse to flank targets.

>> >> > [...]
>> >> >Yeah, sure, whatever.  I take it you're another of the "Soviet == crap"
>> >> >school of thinking?
>> >>
>> >> No, not all Soviet military equipment is crap.  But when making direct
>> >> comparisons, it wasn't until the late 80s/early 90s that they really
>> >> started to catch up technologically.
>> >>
>> >> Basically, Western military equipment has been more advanced than
>> >> Soviet military equipment.
>> >
>> >Except in the areas of armour technology, optronics, submarines, V/StOL
>> >aircraft design, dogfighters, small arms, small nuclear reactors, etc.
>> >
>> >Give it away, the Soviets led the western in many areas, before the fall
>> >of the fUSSR.  If anything, the west has only just started to play catch
>> >up, now and often by buying it from them.
>>
>> There are a number of areas where in the 60s, 70s, and 80s there was
>> common western belief about the quality of Soviet weapons systems that
>> put them at parity or above western equivalents, due to having to work
>> with intelligence estimates and disinformation rather than direct field
>> testing and analysis.
>>
>> Now that for the most part that is all history, we've gone back and talked
>> to their designers, taken some of them apart, looked at plans, and pretty
>> much come to the conclusion that while a few limited areas were roughly
>> at parity (and a very very few such as a couple of corners of materials
>> science and production engineering advanced concepts were ahead).
>
>Armour technology is primarily "materials science and production
>engineering advanced concepts."  The Soviets led the world in the
>advanced use of composites and ceramics in their armour.

We just did this argument in sci.military.moderated a couple
of months ago.  Exactly this argument.  Why are we doing it
again in of all places sci.military.naval plus these poor
unrelated newsgroups?

This is in fact false.  The Soviets led the world in deploying
composites and ceramics in production vehicles.  In fact, alumina,
quartz, and various other composite armor was widely investegated
in the US, Germany, and Russia as far back as WW II, and the US
did firing trials on a quartz based composite turret armor add
on to the Sherman tank in 1945.

Though extremely effective in test armor boxes, it proved
difficult and expensive to develop cost effective production
versions (on all sides) until around 1962 when Russia introduced
the Objekt 432 prototype for what was to become the T-64 tank.
It used compressed sintered alumina inserts within cast steel turret
armor.  It's interesting to note that similar armor using silica
instead of alumina was used on the US T-95 experimental tank in the
same time period but was not used in production with the more
conventional steel armored M-60 tank.  Prior to that, there had again
been firing trials on glass insert armor for the M-48 tank series
and silica inserts as well, throughout the 1950s, though none
moved to productin.  No western tank moved to production with more
advanced armor than that until the British Chobham (more properly
Burlington, but everyone calls it after the research institute)
armor in the early 1970s.

I suggest pp 370-371 in Ogorkiewicz' "Technology of Tanks" for the
curious novice, though that just sets the stage for detailed
investegations of the history (which I've launched in to and am
in the confused muddled state on at this time 8-).

>Indeed, in their uninvited bid for the Challenger II competition way
>back in 1989 they proposed a variant on the T-90 utilising a completely
>ceramic hull.  This was at at ime when the US was only just exploring the
>concept of utilising carbon fibre and gave up in the end because of
>expense and difficulty (and questionable utility).

This has never been properly clarified, but the most evidence available
that I've seen indicates that in fact this was not a ceramic hull, but
was in fact a ceramic composite (boron nitride fiber or alumina fiber
or equivalent in epoxy matrix) hull similar but somewhat superior to US
and English work on glass fiber and aramid fiber vehicle hulls.  The
popular reporting of that incident has warped it beyond any accurate
recognition.  No bulk ceramic today in the US or Russia or anywhere
else is tough enough to avoid shattering under the sorts of operational
and combat terminal ballistics stresses to be expected in a tank hull.

> I just get very
>tired of reading on usenet the same old conservative opinions that
>anything the Soviets did was automatically a piece of crap.  Its
>bullshit and time the people making it recognised it as such.  It was,
>as you noted based around erroneous conclusions drawn from estimates,
>disinformation and in many cases IMO hubris.

It is important both to give them credit for what they did do
(figure out how to produce affordable large quantities of certain
relatively advanced technologies) as well as not credit them for
miracle technologies they never in fact posessed.  The design
innovation in their tanks was quite impressive at a number of
levels, but a great variety of fundamental flaws showed up in
practice both in the Persian Gulf and in Chechenya.  Soviet tank
design took what was arguably a wrong turn when Kruschev killed
further heavy tank development but the west went to using heavy
"main battle" tanks typically 35-60 percent heavier (and correspondingly
better armored in many cases) than the Soviet medium tanks.
On the plus side, their introduction of autoloaders was innovative
(if problematic) and they started the smoothbore gun revolution.

Some references used throughout tonight's little post...
_Soviet/Russian Armor and Artillery Design Practices: 1945 to Present_,
	Hull, Markov, and Zaloga, Darlington Press, 1999
_Technology of Tanks_, Ogorkiewicz, Janes, 1991
_Design and Development of Fighting Vehicles_, Ogorkiewicz, Doubleday, 1968
_Sheridan_, Hunnicutt, Presidio Press, 1995 (and snippets from _Bradley_ )
_Janes Armor and Artillery 1998_, ed. Foss, Janes, 1998
_Janes Armor and Artillery Upgrades 1998_, ed. Foss, Janes, 1998


-george william herbert
gherbert@retro.com

From: gherbert@gw.retro.com (George William Herbert)
Newsgroups: uk.people.disability,us.military.army,alt.folklore.military,
	sci.military.naval
Subject: Re: Disabled in the Military
Date: 5 Jan 2001 14:00:16 -0800

Matt Clonfero  <matt.clonfero@ntlworld.com> wrote:
>>Again, you've got this wonderful idea that the loader height must
>>be the only factor which matters.  Look at the T-64 / T-72 / T-80 / T-90
>>profile sometime.  They have no loader.  The commander and gunner are
>>sitting moderately prone.  It's nearly as tall as an M-1 is anyways.
>>Why is that?  The gun needs to clear the hull, it needs to elevate
>>and depress, the hull height is limited by the driver height and
>>engine height.
>
>Note that the depression angle on most former-Soviet tanks is very
>limited when compared with Western tanks. Not a problem if you're always
>planning on using your tanks on the offence.

That's what people keep saying, but western tanks keep finding it useful
both on the offense and defense...

>>This has never been properly clarified, but the most evidence available
>>that I've seen indicates that in fact this was not a ceramic hull, but
>>was in fact a ceramic composite (boron nitride fiber or alumina fiber
>>or equivalent in epoxy matrix) hull similar but somewhat superior to US
>>and English work on glass fiber and aramid fiber vehicle hulls.  The
>>popular reporting of that incident has warped it beyond any accurate
>>recognition.  No bulk ceramic today in the US or Russia or anywhere
>>else is tough enough to avoid shattering under the sorts of operational
>>and combat terminal ballistics stresses to be expected in a tank hull.
>
>You have, of course, seen DERA's Tupperware tank. Before I get laughed
>off the newsgroup, it's a composite hull designed to carry armour packs
>for the environment it's in.

Yeah.  The XM-8 AGS had the same general concept; a baseline AP MG
proof hull with armor packs in three threat levels which added
progressively more and more passive and active armor resistance.
The DERA vehicle using a composite hull was lighter, though.


-george william herbert
gherbert@retro.com

From: gherbert@gw.retro.com (George William Herbert)
Newsgroups: uk.people.disability,us.military.army,alt.folklore.military,
	sci.military.naval
Subject: Re: Disabled in the Military
Date: 5 Jan 2001 15:40:40 -0800

Brian  <brian_ross_665@my-deja.com> wrote:
>George William Herbert wrote:
>> Brian  <brian_ross_665@my-deja.com> wrote:
>> >George William Herbert wrote:
>> >> Brian  <brian_ross_665@my-deja.com> wrote:
>> >> [...]
>> >> You appear to be largely ignoring a-g and concentrating soley on h.
>> >
>> >h is considered by most designers the major determinant.  All others
>> >follow on from there.  If there is insufficient height for the human
>> >loader to operate, then life becomes very difficult for him and the time
>> >required for him to accomplish his task increases disproportionately.
>> >Early Soviet vehicles had the loader either crouching or kneeling for
>> >the most part.  Their rates of fire were considerably lower than their
>> >comparable western vehicles.
>>
>> h is considered by most designers to be a determinant, but not the
>> dominating one by any means.  Certainly the ergonomics of the loader
>> position are a serious issue.  However, note that if you add ground
>> clearance plus torsion bar depth in hull plus assume 5'10" for typical
>> american male loader height, you come up with a sum lower than the
>> height of any western tank in recent memory.  Would you like to perhaps
>> make an educated guess at what other factors might be in play?
>
>Many, such as the thickness of components, track height itself, as
>you've mentioned, trunnion height and so on.  If it is not the dominant
>one, why is that in virtually every article/book that I've read on the
>subject, it is mentioned as being the main one for determining height?
>Are you suggesting that Ogorkiewicz, Foss, et al in International
>Defence Review, various Janes' journals, Military Technology magazine
>and so on are wrong?

I don't think you're reading them carefully enough.
Especially as autoloaded tanks have been demonstrated to
not get much if any shorter than manually loaded tanks.

I am quite sure that Ogkorkewicz and Foss et al are intimately
familiary with the LeClerc and Russian tank interiors.
They demonstrate that you don't make the height go away
just by autoloading.  To really reduce height you need more
extreme measures involving gun height, trunnions, etc such
as remote or cleft turrets or gun pods.

>> Does one have to explicitly state that tanks since oh, the first
>> one with a turret basket, have had a basket which protuded down
>> into the hull?
>
>No, but you are attempting to suggest this is a factor which must be
>considered in the overall height of the vehicle when in reality, it
>simply occupies part of the space which the loader already occupies.

I didn't say that you had to add a+b+c+d+e+f+g+h to arrive at the
overall height.  That should be obvious from basic understanding of
tank layouts.  It's roughly something like:
	f = (greater of b or c or e) + small factor
	H = a + (greater of (f + g) or h) + small factor

If f + g (i.e., greater of hull height around driver, engine height,
or suspension system external height (roadwheel diam + bump + track
height + small factor) plus gun system height above those obstructions)
is greater than or equal to h loader height, then autoloading will
not lower tank roof height.

>>  Look at the T-64 / T-72 / T-80 / T-90
>> profile sometime.  They have no loader.  The commander and gunner are
>> sitting moderately prone.  It's nearly as tall as an M-1 is anyways.
>> Why is that?  The gun needs to clear the hull, it needs to elevate
>> and depress, the hull height is limited by the driver height and
>> engine height.
>
>Yes, but again, you've chosen a closed turret design, which holds the
>gun within the turret.  Further, I'd suggest that a mojor determinant
>for that series of vehicles in the height required, within the hull of
>the carousel autoloader.  Also, the ratio of turret to hull in most
>Russian vehicles is the reverse of that in most western vehicles.
>Clearly, that means its case of the vehicle height being determined in
>that style of autoloader on what can be fit into the hull, below the
>turret right, rather than needing to be in the turret.

Where are you proposing to fit the ammo if you don't put it there?

Pod the gun with the ammo up above the hull?  We've already gone over
the problems with commander-not-on-top.  You can do that, but so far
nobody's seriously proposing it that I know of.

At some point you have to stop arguing about geometry and think volume.
You can't shrink vehicle volume beyond a certain point: the components
have specific requirements.  You seem to be forgetting again that you
need to fit all the components, not just minimize their height.

>> [...]
>> The loader *may* be the tallest item in the combined factors.
>> I honestly can't recall a modern western tank where they were,
>> though I am willing to listen to specific arguments.
>>
>> I am extremely aware of cleft turrets, remote turrets,
>> and elevated remote gun pod type turrets.  See "reduced frontal
>> area turret design" immediately below, the experimental US T-92
>> light tank, the Expeditionary Tank and its elevated gun pod
>> 2-man turret concept, the whole series of AAI LAV elevated and
>> remote and lift and traverse turrets of the 70s and 80s...
>> Read R.P. Hunnicutt's "Sheridan" for a good overview.
>
>I've yet to purchase that and the Bradley works by Hunnicutt but have
>read his works on WWII works but am intending to do so in the near
>future, so you're one up on me there.  However, back to the case in
>point, with a cleft turret, suddenly the gun no longer needs to be
>contained within the turret to achieve greater levels of depression,
>which is a major determinant on its ability to take up hull down
>positions.  If the gun is elevated above the hull/turret completely,
>again it can achieve much greater levels of depression, so therefore, to
>claim that the trunnion height must be contained within the turret and
>that trunnion height is a determinant of vehicle armoured volume is
>false IMO.

You just did it again.  Cleft turrets only marginally save on overall
vehicle volume.  They save on *height*.  Height != volume.  Again,
you need to fit all the components in.  If you lower the gun and turret
roof, something else needs to get larger, or you need to leave some
other component out.

Leave the loader out?  Great.  Except you save less than a cubic meter
doing so (autoloaders strangely need a large amount of space too...
and store ammo less efficiently than manual loaders can, because the
feed paths have to be more clear).  Where do you fit the volume for
the autoloader and increased ammo volume?  Larger hull or turret,
or less ammo supply.  In the end you can end up with no savings at
all on height, weight, volume, or complexity.

>> Elevated guns (and to a lesser degree cleft turrets) introduce a terrible
>> tactical problem to the tank.  They put the commander below the top
>> of the vehicle.  That means that the tallest part of the tank is no
>> longer the person looking around for opposing vehicles and anti-armor
>> missile sites and such.  That gives a (possibly tactically critical)
>> edge to the opposing force, who can see the top of the tank before
>> the tank sees them.  You can put a remote sight (CITV or equiv.)
>> on top of the gun, but that isn't as good in many situations as
>> having someone up there with eyeballs.
>
>I agree, its a compromise which still has to be addressed.  One way to
>do that is to adopt IMO, with a cleft turret or even an elevated gun, a
>turret style similar to the abortive M60a2, placing the commander
>_behind_ the gun, rather than to one side. That way, its possible to
>extend the turret upwards, without necessarily increasingly
>substantially the silouhette of the turret from the front, and the gun
>itself provides increased protection to him, from that quarter.  From
>the sides, he's more vulnerable but not substantially so and you can add
>extra armour purely to his position if its felt necessarily, without
>necessarily unbalancing the turret.

One would assume it's necessary.  Balancing the turret is easy, you
just move the trunnions forwards as required.  With a pod that becomes
trivially easy.

This has been proposed before, but again introduces some complications
in vehicle operation.  Either the commander is then cut off from
the rest of the interior of the vehicle, or the loader / autoloader
path becomes a nightmare.  Even if there is an internal path,
the commander and gunner are seperated enough that they can't
operate as closely as they do on current tanks, so you lose some
efficiency, and the intercom becomes mission critical equipment.
You also have to worry about what happens to the commander if the
main gun fractures its mounts and comes back into the turret
on firing, etc.

>The only other alternative is to accept other means of battlefield
>observation than the use of direct eyesight.  With the proliferation of
>lasers, this could well become necessary, anyway.

Fancy sunglasses can deal with lasers.  So far, though interesting,
nobody has done successful remote presence battlefield observation
for the tank commander role.  It's a set of experiments I'd love
to see someone try (say, stick a bunch of good cameras up on a
MBT turret roof, and try commanding from an internal position with
full surround high resolution video flat planel displays...).
You'd have to demonstrate the tactical viability of such a concept
before assuming you can design a vehicle around it, though.
It's a worthwhile experiment, but hasn't been done yet.
Until it is done and succeeds, we can't assume that we're at
a reasonable tech level to make that work yet.

This does introduce a possible interesting solution to some
of these problems, though; a hull-less tank.  Rather than move
the crew down, you move them *up*; the one crewman who already
has a limited field of view and has to deal with vision blocks
on a regular basis already is the driver.  The Germans have
installed an apparently very successful remote TV system in
the rear of their Leopard IIA5 tanks to facilitate backing
the tank up.  Go a step further and install similar systems
forwards rather than just aft, and put the driver up in
the turret.  Move all the ammo up, all the crew up, don't
have a turret basket but have a solid bulkhead at the bottom
(and supine crew).  This avoids the driver-in-turret problems
with the MBT-70 vehicles (which had rotating driver positions
offset in the turret doing wierd gymnastics and confusing their
sense of direction and orientation).  The hull height then is
only high enough to match the suspension system's external
height; you put fuel and engine and transmission down in
the hull, but relatively lightly armored and with lots of
internal bulkheads to deal with any penetrations.  You can
shrink hull depth to 18" or so, perhaps a bit less.
All the hull is then is a propulsive platform, with the
turret containing the crew, (seperated) ammo, gun, and
sensors and electronics.

>> The Abrams is not moving to a piston engine, it's moving to a (better
>> and lower fuel use) new turbine.  That said, the Army now says it needs
>> the full fuel still to deal with getting log load / replenishments per
>> unit combat time down.
>
>The Abrams might not be but future proposals for an MBT usually include
>the use of a piston, rather than a turbine engine.  Indeed, the US Army
>has funded some quite considerable studies in that direction over the
>years.  As the Gulf proved, the use of a turbine places a substantial
>load on the logistics required to support such a force.  The British
>Army was quite derisive of the US's tanks because of their poor range
>during that conflict and IMO with good reason.

I actually suspect electric drive and fuel cells will beat diesel into
the US tank fleet, but any such change is 10 years out or more, and
predicting that far ahead is dangerous even for the best professionals.

>> What would you do with say the Leopard II?  It's got its non-ready
>> ammo there.  Get rid of its non-ready ammo rounds?
>
>If necessary.  Why retain them there and not simply put them in the
>autoloader, anyway?

Put them where in the autoloader?  Volume, man.  Find the volume.
Then come and tell me where to move them.  That will involve making
something else bigger, and you've stated you don't want to do that...

>> Tanks need hull volume.  These components, fuel, ammo, engines,
>> systems, they all need to be there.  You have to accomidate them.
>> You can only juggle things around so much without a completely
>> new design, and a new design still requires fitting in its component
>> set somehow.  You can't get a functional armored vehicle without
>> putting all the parts in.
>
>No disagreement there.  I've merely been suggesting one means by which
>that volume could be reduced, nothing more.  Most of the major
>components, cannot be changed very easily in order to reduce that
>volume, which leaves of course the crew.   I'd actually prefer to see
>perhaps the selection of tank crew specifically for their size, as
>occures in the Russian/fSoviet one but I take it you've seen the howls
>when that came up as part of this thread.  Legless crew simply carries
>that concept to its logical conclusion, thats all.

The US is already having problems finding enough qualified
volounteers for the Army.  If you suddenly require that all
tank crews be 5'8" or shorter then you cut back by 2/3 the
total potential crewman pool.  Somehow the minor details of
manning your forces loom large in the US Army's planning,
though I'm not sure why...

Legless crew carries that to a ridiculous conclusion, really.
You seem to be under this simplistic assumption (and numerous
people telling you otherwise seem unable to get through to you...)
that tank crew spend their entire lives inside their tank in
fighting conditions.

In reality, tank crews have to do a number of things inside and
outside the tank.  For one, they have to do maintenance.  Treads
get thrown, suspensions break, engines pop, transmissions grind,
the turret jams, the electronics barf up error codes and your
crew heater freezes up.  Much of that sort of repair work is
made more difficult if you're not fully able.

For another thing, they have to be able to escape the tank
rapidly in case of penetration, fire, flooding during a
river ford operation, etc.

For another thing, they have to make camp in the woods,
carry heavy things around (main gun rounds, spare track
parts, etc).  They have to do umounted security and patrols
when their tank groups stop.

None of these things are things which disabled crew would be
unable to do, but they are largely things which disabled crew
will be less capable of, in some cases very badly though in
some cases not very affected.

>> Reclining the driver makes the compartment longer, but reduces
>> hull height in front of the turret.  You are trading off frontal
>> area and hull height with side armor.  You pays your money and
>> you takes your chances.  You still have to fit the components in.
>
>Which is what I suggested two days ago.

And yet you still aren't adequately addressing where those other
components go when you start shuffling things around... you can't
shrink one thing without making something else bigger, or leaving
some existing internal component out.

>>>> The 140mm gun was designed to counter a threat that is now nonexistent:
>>>> a supposed (probably real on paper, but never prototyped) 60-ton Soviet
>>>> heavy tank with about the same volume and layout of a T-80 but 50% thicker
>>>> armor or better.
>>>
>>>Except now they've discovered that the Russians have armour which is as
>>>effective on their normal vehicles, such as their T-80/90 series.
>>
>> If you exclude the (unproven) ERA, the Russians have composite ceramic
>> alumina insert armor in older domestic T-64s and T-72s and T-80s,
>> and a very very crude attempt at Chobham like armor in the most modern
>> T-72s, T-80s and T-90s.  This has been analyzed to death; neither the
>> thickness nor technology of these armors are anywhere near enough to
>> resist even long range shots with modern DU or tungsten monobloc
>> 120mm rounds such as the M829A2 or DM-43 or equivalent French or
>> Israeli or English rounds.
>> The thick plate ERA Kontakt-5 *may* effectively disrupt long rod
>> penetrators of that design range.  You can sit with the explosive
>> dynamics equations and flying plate equations and known dimentions and
>> weights of Kontakt-5 and various long rod penetrators and get answers
>> that go either way.  The mid-90s firing trials the west has conducted
>> were not publically discussed.  The DM-53 and M829A3 are next
>> generation rounds designed after detailed analysis of Kontakt-5 became
>> available and there's a reasonable guess to be made that they're
>> specifically designed to counter it effectively (as there is otherwise
>> no particular technology driver for better rounds than the DM-43 or
>> M829A2 level of performance), though the details are still classified
>> on both rounds.
>
>I'd debate the "not publically discussed" part, as it was discussed
>briefly, in International Defence Review when the announcements were
>made.  Further, Ogorkiewicz in several articles in the same journal, in
>about 1997, if memory serves me correctly made points about the
>superiority of fSoviet armour manufactur and technology as against
>comparable western armour with the explicit point that he believed it to
>be superior.

The details and penetration values weren't discussed.
The fundamentals of the Russian passive armors are well
known and modelable now, and as I stated the current rounds
perforate them fine.  I have to tiptoe around what makes
Chobham so nifty here, but short of its special design feature,
one can credibly say the Russian passive armors are in fact
among if not the best available in passive armor today.
But they don't have Chobham's special feature, and can't
(though they appear to have figured it out, the geometry
and layout of the vehicles makes retrofit impossible).
And pure passive armor no matter how good it is isn't
magic and on the Russian tanks just isn't think enough
to avoid 120mm perforation.

The Kontakt-5 results are a different question altogether.

>> Without Kontakt-5, no Russian tank can withstand any of the US issued
>> 120mm KE rounds and is at best marginal against the earliest foreign
>> non-DU 120mm KE rounds.
>>
>> The "reports" are not entirely inaccurate, but are taken out of
>> context by a lot of people.
>
>If the US Army declares it cannot penetrate the vehicle, then I'll take
>that as being true.  You?

The "US Army declaration" was not official nor entirely clear or specific.
The statements which were made public can be read in several different
ways, and the analysts consensus read for what they meant currently is
that Kontakt-5 makes penetration at long range (and possibly medium range)
iffy but at close range even the front half of a long rod will still
perforate frontally even if the Kontakt-5 breaks the rod.

>> Until you go to a cleft turret or podded gun, which are valid options,
>> you don't get your height down a lot.  You may see tanks going as
>> far as lift-traverse guns which are hull-down but elevate up to
>> traverse to flank targets.
>
>The Swedes rejected this concept when proposed as an alternative for the
>replacement of the Strv-103.  Instead they chose to go with, initially
>the UDE-XX concept with an articulated vehicle with an elevated gun, and
>then later with a conventionally turreted vehicle.  Personally I think
>it addes far too much complexity for little real gain and perhaps
>substantially longer reaction times for off beam targets.

People keep coming back to it though; mechanical complexity can
be lived with (if you think about it, a full turret ring, the transmission
and suspension of any tank, the tread system, any of these are of huge
complexity).  It's the only design so far which avoids tactical problems
with a low-height commander head but still gives good 360 degree gun
coverage.  The reaction times for flank targets aren't much worse
than traditional turrets (and could be faster, if the lift isn't
very long and the traverse is faster than a conventional tank since
only the gun weight is being rotated, not a full turret...).
If you put an autoloader and a few (4-10) rounds behind the gun up
in the lift pod, then you can deal with a typical flank ambush long
enough to find tactical cover and pop the pod down to reload it.
The proposals with a lift-traverse gun but hull mounted autoloader
and ammo feed probably aren't practical due to that reason.

>[...]
>Ogorkiewicz discusses this also in his various articles in IDR but makes
>the claim, if memory serves me correctly that the glass armour inserts
>did reach production but were never issued on the M-48.  According to
>those articles, the west basically abandoned such composites until the
>advent of Chobham.  The Soviets however continued with their development
>and utilised them extensively.  I believe that means their, "materials
>science and production engineering advanced concepts," were superior and
>therefore their armour for a good part of the 1970's and 80's.

No, for a good part of the 1960s and 70s their production units
had a moderate per-unit-armor-weight efficiency advantage.  As stated,
the west had equivalent technology it chose not to deploy.
These add on boxes and inserts at best are a 2.0 gain over
equivalent steel weights, but typically were much less
efficient when you consider the face and backing plates
(more typically 1.25 to 1.5 over RHA).

Chobham was developed in the early 1970s and in volume
production on the M-1 and Leopard II by early 80s.

The materials science was about the same, the production
engineering was better on the Russian side in that timeframe.

>>[...]
>The reports which I remember simply claimed it was a "ceramic hull".  I
>have always assumed that it was what it claimed to be but have wondered
>about those very same points that you raise.

Some day someone will ferret their internal documentation on that
proposal out (along with their other work on ceramics and ceramic
composites...) and we'll see.  Until then, it's probably wise to
assume they didn't invent unobtanium 8-)

>> The design innovation in their tanks was quite impressive at a number
>> of levels, but a great variety of fundamental flaws showed up in
>> practice both in the Persian Gulf and in Chechenya.  Soviet tank
>> design took what was arguably a wrong turn when Kruschev killed
>> further heavy tank development but the west went to using heavy
>> "main battle" tanks typically 35-60 percent heavier (and correspondingly
>> better armored in many cases) than the Soviet medium tanks.
>> On the plus side, their introduction of autoloaders was innovative
>> (if problematic) and they started the smoothbore gun revolution.
>
>Yep.  You also forgot to mention Reactive and Active armour, tube
>launched missiles as well.

Reactive / active armor goes back a long ways too.  The US was
working on doppler radar active antimissile defenses in the 1950s.
The Israeli "Blazer" reactive armor deployment dates back into the 1970s;
the Russian development program for reactive armor arguably dates to
1949 with the first publications of theoretical analysies of how
it might work, and lab firing trials in the 1950s.  It was considered
for the T-64 initial armor package in the early 1960s but there was
a major accident in testing and it was ruled out in the initial design
by the lead designer.  It was developed into usable form in the early
1970s (NII Stali Kontakt-1), but wasn't deployed for quite some time
after that.  In fact the decision wasn't made until 1983 after
detailed reports of the Israeli Blazer reactive armor came in
from Lebanon, according to contemporary Russian accounts.

The west did tube launched missiles quite early on as well,
flirting with them throughout the 1960s and 70s.  The 152mm gun
launcher on the Sheridan was in firing tests in 1961, and the
M-60A2 had a 165mm gun/launcher as well.  The MBT-70 and XM-803
programs looked at this weapon but in the end we passed and went
to the 105mm gun for the M-1 (and 120mm in later models).
The Russians now have gun launched missiles with about the
same effective range as western tanks have with basic gun
projectiles, an advantage which is of dubious measure.


-george william herbert
gherbert@retro.com

From: gherbert@gw.retro.com (George William Herbert)
Newsgroups: uk.people.disability,us.military.army,alt.folklore.military,
	sci.military.naval
Subject: Re: Disabled in the Military
Date: 5 Jan 2001 14:05:15 -0800

Matt Clonfero  <matt.clonfero@ntlworld.com> wrote:
>Brian <brian@connect.comdek.net.au> wrote:
>>> I doubt we'll be seeing a 140mm main gun anytime soon.
>>
>>I expect to see one fielded within the next 10 years.
>
>Interesting. Who by? No current tank chassis has a turret diameter big
>enough to take a 140mm main gun. No western country is developing a new
>tank to take a 140mm weapon. Russia's latest tanks (the T-90 and the
>Black Eagle) are 125mm armed.

Russia's tanks have been armed with 125mm guns (essentially the
same gun) since 1964 or 1965 or so when the T-64A came out.

The Western prototype 140mm gun is dimentionally compatable
with (and slightly lighter than) the standard 120mm guns now
in tank use today.  It's already been test fired in M-1 tanks
and the Leopard II if not other western tanks.


-george william herbert
gherbert@retro.com