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History of the T-62


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#141 Interlinked

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Posted 30 July 2019 - 1720 PM

The shell body must be very thin for the squeezing effect. This prohibits excessive acceleration on firing. So the initial velocity must be relatively low.

 

It's not just that, but studies (or at least, the one study I read some time ago) showed that the effectiveness of the squashing effect using typical explosive compounds depends quite strongly on the impact velocity. Too fast (>600-700 m/s, IIRC), and the compound basically disintegrates on impact and only a fraction of the weight of explosives get detonated. The end result is almost no effect on the target. Too slow (<300-400 m/s, IIRC), and the squashed putty does not spread out at an optimal manner and the thickness of armour that can be defeated will decline by some amount.


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#142 Panzermann

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Posted 31 July 2019 - 1456 PM

And still Stuart will sing the praises of HESH despite all its drawbacks. IMHO today just using KE, HEAT and a programmable fused multipurpose HE-FRAG with a hardened tip are better for todays targets, because HESH is easily blocked with spaced armour.


 

 

Kurzgesagt: using HESH is a real challenge for the gunner  ;)

No kidding. Estimating/measuring range and leading the target is bad enough, but for the natural drift of the round to the right, requiring its own reticle - also range based - made it a chore that few US gunners wanted to entertain. And then there  were stowage issues if I remember correctly, equivalent to WP.

 


Not surprsing, both WP and HESH have a lot of dangerous filler and thin walls.


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#143 Chris Werb

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Posted 31 July 2019 - 1503 PM

If you want to try out stadia ranging yourself, Steel Beasts does a great job of simulating it in various vehicles, including the T-55. I am guessing that the new realistically undulating terrain will make it even more realistic as you will often not be able to see the entire height of the vehicle.
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#144 DB

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Posted 31 July 2019 - 1721 PM

I hope they start paying you for all this shameless promotion :D

 

I think at this point everyone realises that HESH is relegated to being an available HE round of questionable value in a "real" war. <Werb>A bit like aircraft carriers.</Werb>


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#145 DKTanker

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Posted 31 July 2019 - 1836 PM

Not surprsing, both WP and HESH have a lot of dangerous filler and thin walls.

That's not the problem, the problem is that WP has a relatively low melting point, 111F or 44C.  So what can happen is that a WP round stowed in a horizontal position might be subjected to temperatures in excess of the WP melting point.  Not a big problem if the round is fired while the WP is in a liquid state.  However, should the temperature fall below 111F, the once liquid WP, which was seeking its own level, will solidify with the WP to one side of the projectile interior.  I'm sure you can imagine just how unstable the flight of that round would be.  Stowing the rounds upright means the WP will always be symmetrically balanced around the interior circumference of the projectile.

 

While Composition B (HEP/HESH) has a higher melting point, one which wouldn't be achieved in the hottest of deserts, the concern is that that the explosive could become plastic enough to flow.  Again, seeking its own level.  And again making accurate fire impossible.


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#146 Interlinked

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Posted 31 July 2019 - 2040 PM

If you want to try out stadia ranging yourself, Steel Beasts does a great job of simulating it in various vehicles, including the T-55. I am guessing that the new realistically undulating terrain will make it even more realistic as you will often not be able to see the entire height of the vehicle.

 

Speaking of SB, I'm reminded of the appallingly slow reload speed in the T-62. I hope that gets changed soon. 


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#147 GARGEAN

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Posted 01 August 2019 - 0100 AM

And still Stuart will sing the praises of HESH despite all its drawbacks. IMHO today just using KE, HEAT and a programmable fused multipurpose HE-FRAG with a hardened tip are better for todays targets, because HESH is easily blocked with spaced armour.

Even HEAT is barely practical. MPHE-FRAG and APFSDS is essentially all you need.
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#148 Stuart Galbraith

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Posted 01 August 2019 - 0125 AM

And still Stuart will sing the praises of HESH despite all its drawbacks. IMHO today just using KE, HEAT and a programmable fused multipurpose HE-FRAG with a hardened tip are better for todays targets, because HESH is easily blocked with spaced armour.


 

 

Kurzgesagt: using HESH is a real challenge for the gunner  ;)

No kidding. Estimating/measuring range and leading the target is bad enough, but for the natural drift of the round to the right, requiring its own reticle - also range based - made it a chore that few US gunners wanted to entertain. And then there  were stowage issues if I remember correctly, equivalent to WP.

 


Not surprsing, both WP and HESH have a lot of dangerous filler and thin walls.

 

Now that is misrepresenting my position. Yes, HESH is obsolescent. My contention is, its not obsolescent enough to justify replacing the L30. It still works well at its primary mission of knocking holes in walls or killing soldiers, or very lightly armoured vehicles.

 

If we really wanted a more sophisticated round, we could easily replace FV432 mortar vehicles with a turret mounted 120mm mortar system. But we dont.


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#149 Panzermann

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Posted 01 August 2019 - 0441 AM

No, HESH is obsolete. It is not really good anymore against armoured vehicles and sucks against buildings. Just replace it with a programmable HE. Is there even a supplier for HESH left?

 

 

Replacing the L30 is not really in the budget, because that would mean completely rebuilding the turret for the then most probably chosen 120 mm smoothbore with its fixed ammunition.


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#150 bojan

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Posted 01 August 2019 - 0548 AM

 

While Composition B (HEP/HESH) has a higher melting point, one which wouldn't be achieved in the hottest of deserts, the concern is that that the explosive could become plastic enough to flow.  Again, seeking its own level.  And again making accurate fire impossible.

 

Some HESH warheads also have front part inert, made of paraffin wax or bitumen, which both have pretty low melting point.


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#151 Stuart Galbraith

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Posted 01 August 2019 - 0638 AM

No, HESH is obsolete. It is not really good anymore against armoured vehicles and sucks against buildings. Just replace it with a programmable HE. Is there even a supplier for HESH left?

 

 

Replacing the L30 is not really in the budget, because that would mean completely rebuilding the turret for the then most probably chosen 120 mm smoothbore with its fixed ammunition.

 

No, Its obsolescent, it was demonstrated as such in 2003. If it was obsolete, it wouldn't be useful for anything. As shown in 2003, it can still kill old armour, of which remains much in the world, and knock holes in walls. I would not claim its a good reason to adopt it, just that im parsimonious, and see no reason to throw something away whilst it still works.

 

Would I like a new turret, smoothbore and new rounds all the trimmings? Yes. But im also a realist. If it still goes bang and kills things, there are other things ill worry about first.


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#152 bojan

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Posted 01 August 2019 - 0725 AM

Everything HESH can do multi-fusing HE can do better. And is probably cheaper to make.


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#153 Stuart Galbraith

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Posted 01 August 2019 - 0733 AM

Again, im not disagreeing. Where im disagreeing is that the funds to rerole to a vehicle with HE shells and much else is not there for us to spend. Is it worth the extra outlay to get it? Probably not, unless we go the whole hog and replace the turret.

 

It would have been a lot smarter back in 1989 to not go with a rifled gun. But there was a lot of good reasons why we should not least we had a tank park of over a thousand tanks back then.


Edited by Stuart Galbraith, 01 August 2019 - 0741 AM.

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#154 Interlinked

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Posted 01 August 2019 - 0826 AM

Again, im not disagreeing. Where im disagreeing is that the funds to rerole to a vehicle with HE shells and much else is not there for us to spend. Is it worth the extra outlay to get it? Probably not, unless we go the whole hog and replace the turret.
 
It would have been a lot smarter back in 1989 to not go with a rifled gun. But there was a lot of good reasons why we should not least we had a tank park of over a thousand tanks back then.


HE-Frag rounds were, and still are, cheaper to manufacture than HESH rounds. Also, 120mm spin-stabilized HE-Frag shells would most likely be more effective than fin-stabilized HE-Frag shells since they don't have the added drag of the fins and don't need to carry the extra 1-2 kg of aluminium at the back which doesn't contribute significantly as fragmentation.

Concerning the use of the L30 - compatibility with the older L11 was a good reason to keep a rifled gun, yes, but compatibility with the rest of NATO was an even better reason to NOT keep a rifled gun.
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#155 Panzermann

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Posted 01 August 2019 - 1131 AM

Everything HESH can do multi-fusing HE can do better. And is probably cheaper to make.


Which makes HESH obsolete.

 

Again, im not disagreeing. Where im disagreeing is that the funds to rerole to a vehicle with HE shells and much else is not there for us to spend. Is it worth the extra outlay to get it? Probably not, unless we go the whole hog and replace the turret.
 
It would have been a lot smarter back in 1989 to not go with a rifled gun. But there was a lot of good reasons why we should not least we had a tank park of over a thousand tanks back then.


HE-Frag rounds were, and still are, cheaper to manufacture than HESH rounds. Also, 120mm spin-stabilized HE-Frag shells would most likely be more effective than fin-stabilized HE-Frag shells since they don't have the added drag of the fins and don't need to carry the extra 1-2 kg of aluminium at the back which doesn't contribute significantly as fragmentation.

 
Probably even an adapted 120 mm mortar shell albeit with a reduced load would suffice. But then a HE-FRAG or HE-PFF are rather simple projectiles and that is the type of ammuniton mostly going tpo be used the most when doing colonial expeditions to Iraq or Afghanistan or whereever else. So a production run is viable. Maybe they can even get Jordania for a group buy. For fighting the derkaderkas they have a use for such a round as well.
 

Concerning the use of the L30 - compatibility with the older L11 was a good reason to keep a rifled gun, yes, but compatibility with the rest of NATO was an even better reason to NOT keep a rifled gun.

 
The decision was made, when there were more like hundreds to a thousand Challengers planned plus expectations of exports as was the case with Chieftain. Then the Cold War ended and Whitehall had nothing better to do than cutting up the Challenger fleet as fast as possible. If the ammuniton situation had been better and more users, Greece might have gone with the CR2 as they seemed to be quite liking the vehicle for their requirements. but that was already when the UK MoD had painted itself into a corner in a dead end.
 
 
edited to add: when adopted the L30 performed easily on par with the Rh120 cannon, the RTR could keep its training pretty much the same. So imho it was a quite reasonable decision back then.

Edited by Panzermann, 01 August 2019 - 1133 AM.

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#156 alejandro_

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Posted 15 March 2020 - 0951 AM

T-62 in Chechnya, likely to belong to 160th Guards Tank Regiment (check insignia in tower):

 

QNHw1XeBIr0.jpg


Edited by alejandro_, 15 March 2020 - 1006 AM.

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#157 Ssnake

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Posted 15 March 2020 - 1201 PM



 



Just an ex-sailor trying to remember, but the more or less average firing range distance NATO and Warsaw Pact tanks were expected to meet each other in Germany was about 1K to 1.5 K?

 

In Southern Germany, the USAEUR sector, yes. But it was a lot more open in the North, you are looking something like 2000-3000 metres in places.

 

You know, I've been thinking a bit lately about this. I'm wondering how these estimations are derived.

A possible method to get such estimations is by picking a sufficiently large random sample locations and then to look into a number of random directions to calculate the average LOS. But firing positions aren't being picked at random. You rather slect them after appreciating the terrain to give you the best tradeoff between long range of fire and good concealment, and each of these positions has a preferred engagement direction. So the random sampling method may be fast, but is it accurate? (clearly not)

The next question is, what's the underlying data model of these calculations. Back in the 1970s, I'm pretty sure that they were based on a 50m grid that was the standard for all topographical survey maps (add to that, where necessary, detail maps along the path of a planned road construction or whatever). By definition, a 50m grid is devoid of all micro variations of the terrain, like drainage trenches that might run parallel to a road's embankment). But micro variations of the terrain are not only enormously important for the selection of firing positions (since they usually offer that extra bit of cover that makes a good firing position better than a bad one, duh). They also can have a substantial influence on line of sight during a mobile engagement.

I've done a few comparisons lately where I got my hands on 10m grid DTED 3 elevation data, and a high resolution LIDAR scan of the same place. In extreme cases it is, literally, a difference like day and night. In the DTED 3 model the average engagement range between a static defender and a closing enemy was about 1200m, which dropped (average!!!) to about 300m in the LIDAR scan based terrain model.

 

Gun ammo consumption dropped by 50% in the high-res terrain, simply because the targets were more fleeting, missile ammo consumption dropped by 70% with an average engagement rage of 800m (from 2200m before), simply because the predicted lines of sight (and fire) weren't there. Even the 10m grid was insufficient to accurately represent this terrain type.

 

Granted, the chosen example of a sand dune terrain is an extreme case, yes, but it got me thinking how much the "doctrine of standoff" is influenced by unsuitable data models in simulation, and then reinforced by confirmation bias as simulation results usually give an advantage to the side with standoff. Heck, I'm looking at pure junk like MASA S****d at times where units shoot each other right through a railroad embankment of 8m elevation, and that's supposedly a high quality constructive simulation (compared to other "high quality constructive simulations" in the market it may not be any worse but clearly, the results that such computer simulations calculate aren't worth the breathing air that you need to analyze them; they've all gone through a formal VVA, but if a VVA doesn't detect that a data model is unsuitable it's about as useless as I thought it was some 20 years ago when I had much less of an idea of the field of simulations than I do today).


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#158 Stuart Galbraith

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Posted 15 March 2020 - 1248 PM

BAOR had all the fire positions picked out. I talked to the guy who accompanied some senior generals surveying them in glad we learned some lessons from 1973.So did The yanks, if that file The Czechs nicked is any guide.

The main problem that affected long range engagements in Northag was West Germany's ongoing economic success and resulting urbanization. Which is when we started adopting the village strategy, where German villages were helpfully a Milan missile apart.

The pact recognized the problem too. There is a CIA foi file that suggests it was the reason for the increase of the proportion of infantry in Soviet formations from the mid 70s on.

So imho the problem wasn't map surveying, it was economic success.
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