HAS THE LEOPARD CHANGED ITS SPOTS?

An unpublished draft for an article in ARMOR magazine by the great tank theorist, Brigadier Richard E. Simpkin. Discussion on Wolfgang Mathos and Rolf Hilmes article "LEOPARD 3 - erstes Waffensystem dei dritten Generation". A lot of criticism of German projects.

HAS  THE LEOPARD CHANGED ITS SPOTS?

Richard E Simpkin

 

The periodical WEHRTECHNIK recently published a long and seemingly authoritative article on LEOPARD 3, written by the technical project manager, Wolfgang Mathos, and the chief consultant on armored vehicle technology¹, Rolf Hilmes. This makes depressing reading indeed for anyone who believes that NATO can and must maintain a technological lead in key weapon systems over the Warsaw Pact, doubly so for those who, like myself, admired the Wehrmacht as a fighting force as heartily as they loathed the ideas of its political masters. The Federal Republic seems in danger of deliberately throwing away the world lead in armored vehicle technology it had so rapidly regained.

 

LEOPARD 2 and Ml ABRAMS

If I was still of an age to go to war, the tank I should choose would be the M1, for two reasons. The decisive one is the survivability provided by having the main armament ammunition outside the principal armored envelope. The second, which applies only to the M1/105 mm, not the M1E1, is firepower. I see the loss of 12 rounds, probable degradation of the rate of fire, and impairment of the ability to put down economical general support fire as extremely bad tradeoffs for a slender and probably superfluous gain in power of attack on armor.

If, on the other hand, I was asked which was the more advanced tank, I would have equally little hesitation in saying LEOPARD 2. My main reasons for saying this are the principle of the gun control system (gun slaved to sight), and the PERI R17 commander's sight.

Another factor would be the power train; and in terms of development potential, the German arguments about smoothbore technology are now irrefutable – more of these aspects later.

 

Politico-military background

Coming from the pen of German engineers, some of the statements in the WEHRTECHNIK article are so odd that one has to wonder whether they are cover-ups for economic pressures and/or user conservatism. In interpreting the Federal German government's very understandable demand for a forward positional defense, the 1973 Federal German Army Regulations just about scuppered the maneuver-based thinking which had sired LEOPARD 1 and, with a swing towards added armor protection resulting from the Yom Kippur War, LEOPARD 2. With the policy-making positions still held by Wehrmacht-trained officers, the promulgation of these Regulations resulted in a period of conflict, with lip service being paid to maneuver theory and high-tempo operational reserves, while more and more was pushed into the shop window and into tactical roles just behind it.

Now, with few of any Wehrmacht-trained officers still serving, the pendulum has swung. German user and designer alike seem to hold the view that modern technology can support tanks of ever greater battle mass. Recent articles and other unclassified sources tell us that MARDER's successor is to weigh 44 tonnes (almost 50 (S) tons). And, far from seeking greater mobility, the Panzergrenadiere are occupying themselves with trials of synthetic materials for dugouts.

 

The "low-profile turret"

With this background in mind, let us look at the technical solution Mathos and Hilmes offer – the "low-profile turret." This is based on the height of a seated crewman, in place of the standing loader. The swept volume of the breech with the gun in depression is taken care of by a pivoted hatch in the roof (fig 1). At first sight this looks like a flash of genius, particularly as the flap will not show to the front when it is raised and the tank is on a reverse slope. But unless this hatch is to be paper-thin, it represents a considerable mass a goodish way from the gun trunnions. This is bound to affect stabilization; and, as we shall see, the German user is proposing deliberate fire on the move as part of his tank tactics for the Nineties. With this concept in mind, let us look at the technical arguments the authors put forward.

 

"LEOPARD 2's achieved firepower will predictably be adequate for decades yet (sic!), thanks to its great current superiority in terms of penetrative performance of the main armament and system accuracy."

In 1940 the British Imperial General Staff (as it then was) pronounced after full deliberation that the 2 pr (40 mm) tank gun would satisfy requirements for performance and range in the foreseeable future. The result of this statement was to leave the British Army outgunned right through World War II, in fact until almost 1950.

I feel one can no longer question the battleworthiness of smoothbore tubes in the light of long Soviet experience of them, of the American user's ultimate acceptance of the German gun, however reluctant, and last but not least of the Swedish choice of it for UDES XX 20 and UDES 40. But it is idle to pretend that, even at the time of its introduction on LEOPARD 2, the German 120 mm was the world's most powerful tank gun. While its multipurpose (MP = HEAT/HE) round is probably in advance of the Soviet 125 mm HEFS, despite the latter's airburst capability, there is no reason whatever to suppose any significant difference in the performance of the Soviet and German kinetic energy (KE) penetrators. Even if the Germans have the better smoothbore, the excellent and extremely powerful Soviet 130 mm rifled gun is still very much in Warsaw Pact service in "SU" form. This gun’s mounting parameters appear to be broadly similar to those of the 120 mm smoothbore, and it remains a candidate gun for existing and future Soviet tanks.

The German 120 mm may currently be the West's best point of departure for further development of high-pressure gun-ammunition systems. And in fact other German sources tell of ammunition programs already well under way. Unsurprisingly, these are based on increasing the length/diameter (L/D) ratio of the KE penetrator; and on advances in explosives technology, casing materials, and fuzing to improve the general-support performance of the MP shell. With United States know-how on long rod penetrators thrown in, great things can be expected of the 120 mm smoothbore – unless of course progress is stifled by complacency.

 

"Thanks to its power train, LEOPARD 2’s mobility is far superior to that of all other known systems (Like Ml for instance?), and experience to date suggests no need to seek higher performance."

LEOPARD l's power-weight ratio of 19.6 hp/t (DIN) rose to only 27.2 hp/t (DIN) in LEOPARD 1, an 80 % increase in power being offset by a weight growth of almost 13 tonnes. As recently as 1983, no less an 2 authority than General Dr Ferdinand von Senger und Etterlin, was reasserting the long-term target of 50 to 60 hp/t (DIN), and predicting 2000 to 2250 hp (DIN) (as against today's figure of 1495 hp) from diesels of the capacity of LEOPARD 2's. This prediction, now expressed in terms of specific mass and volume, is borne out by 1 extrapolating the histograms of the WEHRTECHNIK article¹, and by the conservative end of Dobbs' and Bryzik s forecasts³. The main predictable advance in transmissions for the LEOPARD 3 timeframe is the use of retarders (electromagnetic braking) within the main brake system. This technology has been available in the Federal Republic for some time, and is now under active discussion in Soviet tank circles⁴. But it is not clear whether the LEOPARD 3 team favor this step.

As to running gear, the German love affair with the torsion bar seems as ardent as ever. The British have succeeded with hydrogas suspension at 62 tonnes, their design meeting the long-standing user requirement for bolt-on replacement, Japan (Type 74 МВТ) and the United States (eg HIMAG) have done it at around 40 t; and there is vast Swedish experience at that kind of weight. On top of this, a mass of Swedish (and German!) analytical and empirical evidence shows hydrogas to out-perform even the ideal torsion bar in terms of terrain profile following; and Mathos and Hilmes admit hydrogas to be superior in performance. But no hydrogas for LEOPARD 3!

Taking a broader look at mobility, the ballpark figuring 1 have done in the context of the von Senger "main battle air vehicle" (MBAV, alias the "bottomless tank")^5,6 does suggest that further improvement in mechanical standing start agility, related to firing exposure time, will increasingly be swamped by human decision and reaction times. But no such limitation applies to usable cross-country speed, affecting movement exposure time.

Two factors, I would have thought, make this – and ride per se - of supreme importance for LEOPARD 3. One is the German user's intention, expressed in the context of recent discussions at Munsterlager on the Panzergrenadiere of the nineties, to adopt fire on the move as an inherent part of tank tactics. The other is the likelihood that, during the period LEOPARD 3 is in service, automatic target acquisition (at least of moving hard targets) will become feasible. As 1 have demonstrated elsewhere^8,9, this would cut mean acquisition times from around 30 secs to 5 secs or less, changing the whole picture of tank survivability.

Likewise, in examining Soviet tempo⁷ and elsewhere, my studies have borne out the common-sense view that increases in road cruising speed are indeed well up the diminishing returns curve, though - at 65 kph for the MBT - by no means onto the flat (fig 2). There are many indications that the Soviets are keen to achieve 80 kph for their MBTs; and the project to lengthen the T-64 hull (perhaps for 'T85') suggests that they may achieve this in the present decade. A recent Soviet article, apparently using LEOPARD series mobility data, suggests - surely with much good sense - that the improvement in usable road and cross-country speeds from the second generation to the third is likely to be only 10 to 16 %, around one half of the improvement from first generation to second. But surely this improvement is worth having - specially for the defender, forced by the pattern of the Soviet deep battle to operate on exterior lines at both tactical and operational levels.

Yet when one recalls how the target battle mass of 30 tonnes for LEOPARD 1 was engraved on so many a German tanker's heart, the key issue has to be trafficability. The Bundeswehr may confidently affirm its ability to snorkel in a tactical setting when operating over known ground – on reconnoitered and maybe improved crossing sites, that is. But a LEOPARD that cannot swim and a marten (MARDER) that neither sinks nor swims are hardly the ideal basis for the rapid crossing of water obstacles. And even given the Federal Republic's modern communications network, a MLC40 tank, with a battle mass in the same ballpark as heavy commercial and agricultural vehicles, and an on-board flotation screen – would have an enormous advantage in trafficability over the agile monsters of the eighties.

"An optical system above the gun (of an external gun tank) looks to be technically unfeasible".

This astonishing statement determined the configuration of LEOPARD 3. Let me say at once that, if it is true, I, with my unbounded but not unfounded enthusiasm for "toplessness," have to join two of the West's best and most experienced tank designers, Sven Berge and Clifford Bradley, in the sin bin. So let us probe it.

Before we do so, though, let me be the first to say that it is the technological appraisal that I find surprising. If the German user, having been given a full and correct technological briefing on all aspects of this problem, put his foot down and said that the commander had to stay up top so that he could work head-out and "sense" the battlefield, and that this is more important than operational mobility, trafficability and amphibious capability together, designers and commentators alike must accept this without question.

The key quantifiable factor here is target detection (not, as is commonly said, acquisition) on the "dirty battlefield" in daylight with five tenths or more cloud cover. The latest data I have on this is in fact German. According to it, xl0/xl8 optics are still superior in this respect out to 1500 m, beyond which a x23 vidicon-based optronic system does better. The crucial point I do not know is whether this evaluation takes account of the fact that hard targets have a larger subtense, higher apparent contrast and more conspicuous secondary signatures at the shorter ranges.

With the German data as a point of departure, the crystal ball tells us three things. First - and experts in three countries have confirmed this to me - fiber optics already allow an image to be passed from "turret-top" height into the hull via an optical slip ring (fig 3). The  problems, if any, lie in field of vision and possibly in loss of quality and or intensity.

On the optronic side there are two problems. One is resolution. The hardware associated with the high frequencies needed for quasi-optical resolution and acuity needs to be cut down to tankworthy size. Since this is being worked on in the Federal Republic, Japan, Sweden, the United States and almost certainly in the Soviet Union, and since the spinoff ranges from aerospace through medicine to quality of life, a solution is unlikely to be far away.

The second is a touch more abstruse (fig 4). Man's natural visual perception (around 8 to 4 x 10¹⁴ Hz) represents the narrowest of slits in the span of the electromagnetic spectrum. But this has been extended downwards in frequency by          a couple of orders to far Infrared  (10 Hz¹² ) by photoelectric and thermoelectric means. Electronics offers another window ranging from the order of 10⁹ Hz up  to 10 Hz (millimeter wave (MMW) radar); and electrically produced signals up to 10¹¹ Hz, overlapping thermal imaging frequencies, are old hat in the laboratory. Evidently, then, a practical system which would join these two casements into a picture window may not be far off. The most promising approach lies, it seems, in "charge-coupled devices" (CCDs) and the microprocessor.

Given this, one can envision a "multisensor head" consisting of maybe six elements, like these for instance

a vidicon optimized for normal light level

a vidicon optimized for low light levels (image intensifier system)

a laser transceiver for range-taking and "flashing up"

a thermal imager

a MMW antenna array

and "system X" to bridge the gap.

The output from these would be transmitted digitally to an image processor in the hull, which would send an optimized image, adjustable in magnification, contrast and brightness, to the crew's monitors (fig 3).

Before ruling out such a system as too expensive, one should take account of two things. The cost of electronic hardware is "schussing" even faster than that of optical and mechanical systems is escalating. And offset against the savings in real system cost slice offered by a reduction of one third in battle mass, the multisensor vision and sighting system, along with a fiber optics backup, would be worth their weight in platinum many times over.

 

Threat analysis

The arguments put forward by Mathos and Hilmes suggest that the low-profile turret concept stems from an analysis of the anti-armor threat which is, to say the least, somewhat classical. My impression - and the evidence is too slight for it to be more - is that it is based on an exclusively surface-to-surface direct-fire threat spectrum over the classical frontal arc, analysed by Stark's system based on the "method of means. I was invited both to review and (by a third country) to translate Stark's book. Not liking either "comprehensive" models which leave the crew right out of the loop, or the model data Stark uses by way of illustration, 1 declined.

To put it bluntly, they have reduced the turret height but retained the large flat roof, and laid the turret crew out just underneath it like butterflies on a collector's board - but in fact (it appears) on top of the autoloader carousel, just to make sure they're done to a turn both sides.

 

Survivability and reliability

As some of your readers will know, 1 - in good company - have moved towards the view that system survivability based on direct (armor) protection is ceasing to be a valid concept for a turreted tank. What strikes me as the most dangerous aspect of this article is the way this issue is fudged by linking system survivability (in battle) to reliability, under the portmanteau concept of "availability." At the level of the numbers game this argument is irrefutable. Yet it is unrealistic and unsoldierly because any relative vulnerability analysis on which it is based inevitably ignores the crew. I guess I need do no more than repeat what I wrote in a recent book¹³

- "Analysts and designers who ignore the whole man may produce highly efficient fighting machines: but they are unlikely to produce machines in which men win battles."

 

The cleft turret option

The user may well insist on keeping the commander up top; if so, the gunner (or "deputy commander") needs to be up there too, with a duplicate station. Here the old "cleft turret" configuration might at last come into its own in modern dress. One might envision this in terms of the UDES 40 layout (fig 5), with a yoke-type external mounting and external           magazines and autoloader, being the yokes expanded into contoured pods (fig 6).

This configuration would greatly reduce the area exposed to overhead  attack, and allow extensive use of sloping over the remaining "roof" area. It would also significantly reduce the "fair hit" area exposed to frontal attack in hull defilade, and eliminate the conspicuous "mass center" so important to the opposing gunner's sight picture. Isolation of all three crew from one another is a painful tradeoff on the human factors side. But then again an improved chance of survival is the most potent human factor of all.

 

Conclusion

In the introduction of their article, Mathos and Hilmes very rightly say - "The development of a new generation of weapon systems arises not just from the lapse of a given time, or because the budget for the new project was planned well ahead, but only under pressure from tactical and technical realities." How right they are! That is precisely why, as 1 see it and I'm sure many other friends and admirers of the Bundeswehr will see it too, the authors have made an excellent case for returreting that superb tank LEOPARD 2 - but no kind of case for launching LEOPARD 3.

In the present state of the art, "toplessness" (the crew-in-hull configuration) offers an immense payoff for the "light mobile protected gun" (LMPG). It may well be that the fusing of the two "windows" is needed to make this concept competitive for the main battle tank (МВТ). Even then, user opinion may still, as I mentioned, insist on keeping the commander up top regardless of the penalties, and user opinion is sacred.

But surely it would be worthwhile carrying out an objective survivability analysis comparing this LEOPARD 3 concept with the Swedish UDES 40 (which mounts the same gun). For there is evidence¹⁴ that, despite their emphasis on offensive action, the Soviets are giving serious consideration to a crew-in-hull layout for "T90" or "T95." Needless to say, though, the eminently respectable Russians insist on retaining a "bra" in the shape of a turretlike weapon pod (fig 7).

 

 

NOTES AND REFERENCES

1. Mathos, W and R Hilmes; "LEOPARD 3 - erstes Waffensystem dei dritten Generation," WEHRTECHNIK, 2/84, 38-54. I have rendered the authors appointment titles descriptively rather than translating them.
2. Von Senger und Etterlin, General Dr F M; Taschenbuch dei Panzer/Tanks of the World 1983 (trans Richard Simpkin), Munich, Bernard & Graefe, 1983
3. Dobbs, COL Herbert H and Dr Walter Bryzik; "The Adiabatic Engine Revolution," ARMOR Magazine, Jan/Feb 1982, 16-21
4. Vygodskiy, S; "Podvizhnost' tankov," Tekhnika i vooruzhenie, 1/84, 10-11
5. Von Senger und Etterlin, General Dr F M; "New Operational Concepts," lecture given at RUSI, London, February 2, 1983, RUSI Journal, June 1983, 11-14
6. Simpkin, Richard E; "Topless and bottomless tanks," lecture given at (ISAAC March 22, 1984, repreinted by Art of War Colloquium, US Army War College, 1984
7. ibid; Red Armour, Oxford, Brassey's Publishers Limited (Pergamon Press Group), 1984
8. ibid; "Closing the Survivability Gap," ARMOR Magazine, Nov/Dec 1981, 19-24
9. ibid; Tank or Tank Destroyer," Military Technology, 5/83, 14-33
10. Von Senger und Etterlin, General Dr F M; in his Introduction to Tank Warfare (Simpkin), London, Brassey's Publisher Limited, 1979, and New York, Crane Russak
11. Stark, Herbert; Panzer - Qualität oder Quantity!? (2 vols, boxed), Munich, Bernard & Graefe, 1983
12. Bradley, Clifford E; "Future Close Combat Vehicles," ARMOR Magazine, Jan/Feb 1981, 36-41
13. Simpkin, Richard E; Human Factors in Mechanized Warfare, Oxford, Brassey's Publishers Limited (Pergamon Press Group), 1983
14. Babadzhanyan, Marshal of Armored Forces A Kh (ed); Tanki i tankovyy voiska (Tanks and tank forces) (new edn), Moscow, Voenizdat, 1980, Pt 1, Sect 2, Ch 1. See also Red Armour (7).

 

(figure captions)

1. Schematic of the "low-profile turret" configuration proposed for LEOPARD 3, showing the pivoted roof hatch lifted by the breech when the gun is in depression.
2. Vehicle cruising speed plotted against average completion time for tactical moves (full line) and operational moves (broken line). (courtesy of Brassey's Publishers Limited). (rough attached, see also Red Armour fig 13)
3. Schematic to indicate vision and sighting links between turret/mounting and hull - optical slip ring and multiple optronic system.
4. Extension of the human vision window, (rough attached)
5. Concept model of UDES 40, the Swedish МВТ for the nineties, (you have)
6. Schematic of a possible variant on the cleft turret concept with the commander and gunner in individual pods, (rough attached)
7. A possible Soviet crew-in-hull solution.