Background on Joe Williams:
Mr. Joseph Williams entered Government service at Aberdeen Proving Ground in July 1941 as a designer and project engineer.
In a very short time, he became one of the Army's pioneers in design and analytical disciplines which are now the basic framework for scientific approach and methodology of combat vehicle design and development. Mr. Williams played a key role in the initial concepts of prototype tanks leading to the medium tank M26. He was also responsible for the conception and execution of the first postwar tank design, Model T37/M41 light tank, featuring such innovations as a single driver, quick removable powerplant, scientifically developed ballistic shape, and concentric gun recoil system.
Mr. Williams was a driving force in the initiation and development of new tank building blocks. He designed the T42/M47 gun and turret assembly, including fire control selection and installation and development of ballistic and casting sections.
He also conceived and performed most of the preliminary design and analytical work for the M103 heavy tank. He then designed the T48/M48 tank, which was later produced in large quantities and is the main battle tank for many foreign countries.
Versions of this tank are currently being modernized in the US Army and are a vital part of the tank inventory. He was a driving force in the development of the M551 and the M60A2 tanks, in both a direct-responsibility role and as a consultant.
Through his international interests and affiliations and his vast knowledge of tanks, he also played a major role in the United States/Federal Republic of Germany tank development program, a precedent-setting international endeavor. During the last 10 years of his career, Mr. Williams was recognized internationally as an outstanding leader in the design and development of combat vehicles.
Whether embodied in a tank or any other piece of equipment, the requirements for firepower, mobility and protection remain the essential ingredients of a fighting vehicle. They will remain essential as long as there is a requirement for ground combat. The largely emotional contention that tanks are on their way out is not based on an appreciation of the extraordinary flexibility for change that this vehicle possesses.
Tank technology has been only superficially exploited. The entity comprising firepower, mobility and protection, a combination of fighting requirements we call a tank, may be modulated, configured and fine-tuned to be optimally effective in any given scenario. No other ground vehicle has the capability to sustain repeated shock and abuse and cope with the full spectrum of hostile conditions from primitive opposition to the most formidable modern weapons.
By its very nature the tank lends itself to major design variations. Firepower, mobility and protection may be varied in any proportion within a given tank weight. It is possible to provide a preponderance of any one of these three characteristics with a corresponding reduction of one or the other or both.
If, for example, survivability is deemed the most essential requirement during a given era, it is possible to design a fighting vehicle (not necessarily in the classic configuration of a tank) which will provide a remarkably high level of protection against any form of attack, including active and passive nuclear radiation, chemical and bacteriological agents, kinetic energy projectiles, land mines and the spectrum of shaped charge munitions.
On the other hand, if mobility is to be emphasized, the tank also has the capacity for immeasurably greater potential in this area. Controlled variable height suspensions, higher road wheel movement and high performance power train systems will give the tank a new dimension of stability, agility and maneuverability. Taking advantage of existing ground/track potential, with future power sources the tank can far exceed its current acceleration capabilities and achieve, throughout its speed range, a constant acceleration approaching 0.8g or more.
Tanks, along with other members of the armored, mechanized equipment family, are relatively modern developments. It was not until the early 1940s that cavalry, effective for more than 2,000 years, gave way to mechanized armor. Yet, since World War II, the variety of direct fire, armored, tank-type fighting vehicles has diminished considerably, while the antitank threats have expanded to a degree which jeopardizes the tank's existence.
Modern armor emerged during World War II. It was within this period that the US developed and fielded its first noteworthy fleet of direct fire, track-laying, armored combat vehicles: the 14-ton, 37mm gun, light tanks M3 and M5; the 30 ton. 75mm gun. medium tank M3: the 35-ton class M4 series of tanks which mounted the 75 and 76mm guns, the 20-ton, 75mm gun. light tank M24; the 33-ton, 76mm gun, motor carriage M10; the 19-ton, 76mm gun, motor carriage M18; and the 34-ton, 90mm gun, motor carriage M36.
During the lost phase of the war, several heavy 46 to 65-ton tanks, mounting guns of 90, 105, 120 and 155mm size were under construction, but only the 46-ton, 90mm gun, M26 tank saw limited production and action.
Immediately following World War II, the US undertook the development of a 36-ton, 90mm gun lank, the T42. This tank was patterned after the newly developed 25-ton light tank, M41, and possessed many of the same advanced features: concentric gun recoil system, 73-inch diameter turret ring, 500hp air-cooled spark ignition engine with a cross drive transmission, small gun shield and four man crew. Although the T42 had many advantages, it was not accepted, primarily because of its poor automotive performance. However, when its turret assembly was married to an M46 chassis (product-improved from the M26 tank with an 810hp. air-cooled spark ignition engine and cross drive transmission) the entity became known as the M47 tank.
Concurrent with the T42 program, development of a 55-ton (production weight of 62 tons), 120mm gun, heavy tank, the T43 (later M103), was undertaken. This tank utilized the same engine, transmission and suspension as the M46 tank; however, it was distinguished by a quasi-eliptically shaped hull with the driver in the center of the hull, large 85-inch diameter turret ring, two-meter base optical rangefinder, small retractable shock-mounted gun shield and 28-inch wide track.
Just prior to the Korean War a program was initialed to study the development of a 45-ton, 90mm gun tank embodying the favorable features of the T43 lank. These included the air-cooled engine, cross drive transmission, track and suspension, elliptical hull. 85-inch ring, optical rangefinder and mechanical ballistic computer. Thus, the M48 tank came into being in the 1950s.
During the mid-1950s, development of a 41-ton, 90mm high velocity, smoothbore gun tank, the T95, was initiated. This tank represented a brand new concept, modern even by today's standards; only the 85-inch turret ring was retained. The tank was distinguished by its flat track suspension (no track support rollers), low silhouette and compactness. The turret provided improved turret ballistic protection, a more powerful gun (one arrangement solidly mounted without recoil and one with recoil), and OPTAR electronic rangefinder.
Largely due to the requirement for a compression ignition engine, and the unacceptable performance of the smoothbore gun and OPTAR rangefinder, the T95 tank was preempted by a product-improved M48 tank which became known as the M60. The original M60 possessed a diesel air-cooled engine, the British designed high velocity 105mni gun. and the basic M48 tank turret and hull assembly. During the early 1960s the tank again was product improved, including the introduction of a high-obliquity "Vee" frontally shaped turret. This version became known as the M60A1 tank.
Concepts of the M551 Armored Reconnaissance Airborne Assault Vehicle was initiated in 1958 to fulfill a requirement for an air-droppable, amphibious assault vehicle. The M551 replaced the standard non-amphibious light lank M41 and the unarmored non-amphibious. 8-ton, 90mm gun airborne assault vehicle M56. It also terminated the experimental development of the novel, non-amphibious 18-ton, 76mm gun light tank T92. The 17-ton M551 is distinguished by its powerful 152mm gun/missile launcher, excellent ballistic protection and amphibious and air-droppable characteristics.
A general desire by the Army for more effective approaches in tank design led to the development of the M60A2, a compact turret mounted on the standard M60A1 chassis. This concept achieves the desirable small target area characteristics of an externally mounted gun with the added advantage of full weapon protection, vision above the gun and protected manual loading. The 57½ ton tank is distinguished by its hybrid gun/missile weapon system, unmatched frontal protection, and full solution fire and gun control equipment for day and night operations by the gunner and commander.
In 1963, through an agreement with the Federal Republic of Germany, the development of a 50-ton US/FRG MBT was launched. Prior to the agreement it was the original intent of the program to first conduct exploratory component research and development in areas of national preeminence. At a later date these components were to be integrated into a new MBT. Unfortunately, due to the urgency of this international program, it was decided to conduct component research and development along with a production-aligned tank schedule. This tank, model MBT70/XM803, was terminated in December of 1971, allegedly because of excessive cost and complexity.
Lessons learned from the MBT Program are that:
The armor envelope should be configured to provide a high volume-to-armor weight ratio inasmuch as armor weight constitutes about 50 per cent of the tank's weight.
“Driver-in-the-turret” crew arrangement enhances protection for all crew members and permits a lower silhouette tank, however it introduces added componentry in a compartment already congested by crew, weapon, ammunition, gun and fire control equipment. '"Driver-in-the-turret" contributes to substantially more complexity and added cost.
The glamour of guided weapons coupled with the impressive performance of shaped charge warheads during the mid-1950s made the 152mm hybrid main armament (a sophisticated lightweight weapon system firing a guided missile as well as the multipurpose HE/HEAT round) an attractive weapon for the M551. Later it was adopted for the M60A2. Its use in the MBT70/ XM803, with broadened capabilities (HVAPDS), further compounded complexity and cost. This demonstration showed vividly that as multicapabilities of a single system increase, specific effectiveness decreases.
Inadequate allowances for vehicle weight growth are frequently made. A survey of available combat, track-laying vehicle weight growth shows that vehicles grow in weight from concept to production an average of 19.7 per cent and tanks grow an average of 12.5 per cent. This tank average is perhaps on the low side inasmuch as the available tanks sampled, exclusive of XM803 and M551, evolved from use of known standard automotive and running gear components. Foreign tank weight, exclusive of Soviet developments, has also grown a comparable measure from concept to production.
The initial concept phase of vehicle development is perhaps the most critical in the series of development phases. This is also the most glamorous and deceptive phase.
Production-aligned programs seldom lead to bold tank approaches and advancement. Scheduled commitments either abort good ideas or discourage them.
Probability of vehicle development success, within time and cost limits, varies essentially as the product of the number of unproven components to their respective probability of success. Simplified, if each of 50 unproven major components should have the exceptional high probability of success and acceptance of say, 95 per cent, then the probability that the total vehicle will perform successfully approaches zero (7.7 per cent).
There is a subtle tendency to design equipment consistent with our extravagant life-style. Our profuse technological capacity should be confined to only those areas where a simple solution will not suffice.
Current World Design Philosophy
A survey of published literature on world tank design developments shows that most MBTs weigh 37 to 43 tons. The only tanks which greatly exceed this average are the US M60 series, which weighs 53 to 57 1/2 tons, and the United Kingdom's latest Chieftain, which weighs 57 tons. The Soviets appear to achieve weight reduction not by armor reduction, but through very conservative measures in the quantity and durability of equipment. Compromises in reduced gun depression, quantity of fuel and ammunition, austere fire control and automotive durability are imposed to achieve compactness, low weight and low cost. The Federal Republic of Germany and France appear to attain weight reduction through compactness and less emphasis on armor protection while Sweden achieves it through a unique turretless configuration. Two new emerging tank producers, Japan and Israel, seem to have selected divergent approaches. The Israeli tank program appears more in line with US/UK design philosophy, while the Japanese version is in the category of German and French tanks.
The agile, sleek German, French, Swedish and Japanese tanks have a power-to-weight ratio close to 19 hp/ton; that of other countries, including Soviet tanks, amounts to 14 hp/ton or less. Gun power in all cases is not markedly different, although Soviet tanks lack the effective (sophisticated) fire control that characterizes other tanks.
Thus it appears that the major difference between the two weight groups of free world tanks is armor thickness. By adjusting and equalizing armor differences these tanks would all essentially weigh either 37 to 43 tons or 53 to 57½ tons. On the other hand, Soviet 40-ton tanks appear to possess the armor protection, mobility and, to a lesser extent, firepower of the 53 to 57½-ton free world tanks. The difference is evidently in the reduced quantity and quality of sub-systems, which produces a tank with approximately two-thirds the armored volume of most counterparts.
Judging from data contained in international publications, it would appear that in a tank-to-tank duel, the Soviet tanks would have the superiority of armor protection and smaller target with gun power being essentially the same, while their agile adversaries would exceed in firing accuracy, mobility and sustained action. Against the free world heavyweights, these Soviet tanks would have the advantage of small size and essentially equal armor and gun power, while the former would outperform the Soviet tanks in firing accuracy and kill capacity, particularly at long ranges.
Tanks are expected to undergo progressive transformation. It is difficult to predict a specific trend in view of the tank's pliant nature and changing national priorities. There is. however, a strong propensity toward reduced vehicle weight, size and cost. These, of course, are desirable goals if they can be attained without emasculating the tank's capabilities or without undue complexity.
The US now has the M60 series of tanks with its many outstanding and viable features, including some which may never be reproduced. Its few limitations will be corrected in the XM1, which is now under development and which has all the makings of a truly great tank. The unique characteristics associated with survivability and mobility promises to give this vehicle an unmatched, distinctive level of combat effectiveness for years to come. Although its weight will approach 60 US tons, automotive characteristics are engineered to produce mobile response at speed unlike any experienced today.
Technological advancements by 1990 are certain to reduce tank weight from the near 60 tons to perhaps 30 to 45 US tons. To achieve this, however, assumes relaxation of a number of traditionally accepted requirements reflected in current tanks.
CLASSES OF TANKS DEVELOPED OR STUDIED
Classes of tanks shown in the accompanying illustration have either been produced or studied. They are but a few of a large number of design approaches which offer further exploitation through latest advancements in technology.
The historic cyclic race between weapons technology and protective countermeasures is now at a stage where weapons have a distinct measure of supremacy against conventionally designed tanks. Future developments, however, are expected to transcend this advantage. They are expected to incorporate relatively simple survivability features which will greatly neutralize if not altogether abort the killing power of modern antitank weapons. It suffices to say that current tanks exhibit self-destructive characteristics which arc expected to be corrected in future concepts.
How will it be possible in the future to develop lighter, smaller, more effective tanks? Stereotyped vehicle patterns will have to be discarded and new approaches taken. Traditional requirements and policies must be reexamined and weighed, not only in the light of their specific effectiveness, but with consideration given to their impact on overall tank design objectives. Prior to undertaking future tank development programs these issues should be revolved:
Embarking on formalized, large, costly, complex vehicular development and production programs without prior logical research and experimentation to prove feasibility.
The drive toward greater and greater component reliability/durability is conducive to greater and greater vehicle weight and bulk. Is the goal one which produces an economical peacetime tank or one which produces a tank with maximum battlefield effectiveness? The tank's useful life during peacetime may exceed 20 years with periodic overhaul, but in combat its life is measured in days. Certainly a high degree of reliability within reasonable durability limits is essential, particularly for those items that have an absolute detrimental effect on firepower and mobility. However, for those items which represent redundancy or where spares are carried, such as road wheels or track shoes, too high a level of durability does not appear consistent with the attainment of other essential goals. Recent introduction of driver simulators by a number of countries is intended to reduce peacetime training and cost.
Main armament depression of minus ten degrees. Relaxation of this requirement to something less would reduce tank target size and weight. Although there are justifiable reasons for gun depression, such as firing on the move and hull defilade firing position, a lesser angle of gun depression should be acceptable by taking advantage of projected suspension capabilities.
Quantity of main armament ammunition within the armor envelope should be limited, if necessary, to 40 rounds in order to attain other important requirements such as greater secondary armament firepower.
Quantity of main engine fuel should be reduced. Where necessary, a minimal range of 250 miles (250 gallons) on secondary roads should be acceptable. If a greater range of operation is required, added fuel should be stowed externally where, if attacked, the safety of the tank will not be impaired.
Tank, weight and size are highly sensitive to variations of its internal armored volume. Although a sufficient amount of crew volume must be allocated to assure efficient battlefield-day tank operation, an overabundance of this luxury adversely affects tank size, weight and crew/tank survivability.
The US is recognized as possessing the largest of tank commander cupolas. The principal reasons for the large size are the requirements for protected firing and servicing of the machine gun, and stowage of considerable ammunition. Alternatives include externally mounted machine guns and ammunition with internal, protected mechanical controls similar to the British Chieftain's and the Swedish S-Tank's.
Inasmuch as protective armor constitutes 50 per cent of the tank's weight, the concept of protection must he critically reexamined. A clarification of the meaning of "survivability" and reordering of priorities are essential if advanced new approaches are to materialize. Most helpful to the designer is the level of protection (order of priority) placed on the crew, weapon systems, mobility and overall "K" tank kill. Tank armor distribution may be more fully exploited once these values are established.
The requirement for manual emergency loading of the main armament restricts many novel and potentially effective concepts.
Paradoxically, the modern tank exhibits seemingly crude, unrefined features, and yet its optimization depends on the very sensitive harmonization of a bewildering number of factors. Even when the best subsystems that science and technology can offer are made available, there is still the most important task of collectively modulating and integrating these elements into a well-balanced, harmonious, combat-effective entity—an entity which must reflect an optimum compromise between cost, effectively carrying out its intended mission of destructiveness, and the tank's capability to survive. And here is the difficulty—the requirement for greater and greater performance is at variance with the attainment of low weight, size, cost and a high level of survivability.
The once large team of direct fire, armored combat vehicles has diminished to essentially a single MBT. If there is anything to be deduced from our history of some two dozen production and experimental light, medium and heavy tanks, it is that very few have exhibited totally new distinguishing features. It is possible, in spite of its many constraints, to create a future MBT which will satisfy national requirements, cope with the threat of an era and dominate the battlefield. However, to facilitate this prospect, our tank development approach must be suitably realigned.
It is unlikely that we can achieve major technological advancements in the future by degree. Massive organizations, resources, and the most meticulous set of systems processes will not uncover the ultimate that technology can offer. The tempo and momentum of a production-aligned program is not conducive to selection of untried, high-risk, advanced new approaches. For this reason far greater emphasis must be placed on continued informal, flexible, relatively low cost, exploratory research and experimental programs which will surface feasible engineering and design approaches for formal development and production processing.
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JOSEPH WILLIAMS has been involved in the development of combat vehicles for the US Army since 1941 following his academic training. He has participated in a series of major combat vehicle developments including: M4 series of tanks; M47 and M48 tanks; M113 APC; M60A2 and MBT70. Mr. Williams actively participates in International programs and serves as Advanced Concept Manager for the Research, Development and Engineering Directorate, US Army Tank-Automotive Command.