I'm very impressed by the technical expertise on this forum, and so I'd like your feedback on my theories about what a crew-less, robot tank would be like. I wrote about it here, on my blog:
I might edit the blog entry based on any feedback I get from you guys.
Is there any way Sherman tanks could be upgraded at reasonable cost to still have a role on the battlefield? Assume that your military will never fight with a world-class army (U.S., Russia, China, etc.) and instead will only fight with second-rate armies using 1990s technology at best, or with terrorists, or go on peacekeeping missions.
I'm thinking that the Shermans could have their turrets removed and modern autoloading turrets from other armored vehicles--like the 105mm Stryker gun, or the 40mm autocannon from the CV10, or the 30mm from the BMP-2 (would any of these fit in the Sherman's turret ring?)--could be dropped in, along with their sensors and computers. ATGM launchers could be installed as well. Explosive reactive armor bricks could be attached to the outside, as is common among modern Russian tanks.
Assume that your Sherman fleet is 1,000 tanks, in various states of (dis)repair, so you have enough spare parts to last for many years.
What do you guys think? Thanks.
The idea for a design competition predates SH itself, actually going all the way back to the 2011-2012 timeframe on the World of Tanks North American Forum. Before the Exodus of 2014, there were several tank design competitions, two of which I entered. Earlier today, I found my entries to those competitions saved in various forms on my computer, and I thought I would post them here for people to reference moving forward.
Entered in: Design a Tank - 1938 Germany
The Early History of the Mittlerer Panzer Greif
In 1936, as Heinz Guderian was writing Achtung – Panzer!, he was solicited by the Heereswaffenamt Wa Prüf 6 to create a specification for light, medium, heavy, and super-heavy tanks, as part of Germany's ongoing re-armament. The tanks then in development, the Panzer III and IV, were seen as adequate for future needs, but the purpose of Wa Prüf 6's solicitation was to gain a greater understanding of upcoming panzer technologies and tactics.
Guderian's submission eliminated the heavy and super-heavy categories entirely, in favor of fast light and medium tanks requiring large engines and excellent suspensions. Wa Prüf 6 immediately began design studies on panzers to fill these needs, while still allocating some effort towards a heavy breakthrough tank design.
Early panzer designs focused on improving the existing Panzer III, but a special division of Wa Prüf 6, the Spekulativpanzerabteilung, was tasked with pushing the limits of what was possible. One design, the Mittlerer Panzer K, was selected for further study.
The original MPK design used a forged armor steel hull welded together into an elliptical shape, which the Spekulativpanzerabteilung determined would give the best internal volume to weight ratio, providing the best protection, but still maintaining the high power-to-weight ratio specified by Guderian's white paper. Armor at the front was 30mm thick, sloped at around 45 degrees, for the hull. The turret was a simple welded design, mounting the latest 5cm L/60 high velocity cannon, while the suspension was torsion bar similar to the Panzer III, but with more roadwheel travel. Sighting was with stadia reticles, and the tank was powered by a 300 horsepower Maybach HL 120TR, which gave 15 hp/tonne to the 20 tonne tank.
As Spekulativpanzerabteilung improved the design, it morphed beyond recognition. To improve the cross-country performance, the suspension was changed to an early form of hydropneumatic suspension, with more roadwheeltravel, mounted in units bolted to the side of the hull. A tank's mobility, SPA reasoned, was greatly affected by its ability to stay in repair, and thus the modular suspension was developed. Due to marginal increases in weight, the engine was modified to mount a supercharger, increasing the engine power to about 400 horsepower. A mockup was built, but a prototype was never completed.
In early 1938, Germany intercepted Russian plans to build a tank in the 100 tonne range, with upwards of 100mm of armor. A requirement was set to build, as quickly as possible, a panzer that could counter such a behemoth. SPA's medium panzer design suddenly went from a low-priority technical study, to a full procurement program. No guns in the German arsenal could reliably penetrate 100mm of armor at combat ranges without special ammunition, so immediately a new gun was sought. Eventually, it was decided that a Czechoslovakian artillery piece, the 8cm Kanon 37, would form the basis of the new medium tank's armament. Production was licensed from Skoda immediately, and it entered service as a towed anti tank gun in June of 1938 as the 7.65cm Kanone 38. The Kanone 38 differed from the K37 by firing the same projectiles as the 7.5cm KwK 37, which had been adopted a year earlier for German AFVs, but at nearly three times the velocity (900 m/s).
Fitting this monster cannon to the MPK required a total redesign. The ambitious elliptical hull was kept, but everything else changed. The turret ring swelled to a (then-enormous) 175cm, and accommodated an advanced turret, mounting a reduced-weight variant of the 7.65cm PaK 38, the 7.65cm KwK 38 to sturdy forward-mounted trunnions, with low-profile recoil recuperators. The turret was a semi-elliptical tetrahedron shape, constructed from welded forgings, with dual stabilized, stereoscopic rangefinders for both the commander and gunner, something seen only on battleships at that time. The commander's cupola sported 360-degree panoramic periscopes with a Leiteinrichtung - or slaving device, to slew the turret onto new targets. Armor on the new turret consisted of eighty millimeters of frontal armor on the mantlet, with fifty millimeters all around protection. The hull armor's slope was increased to 60 degrees, and thickened to fifty millimeters to cope with the new generation of guns. The weight of the tank ballooned to 34 tonnes, and the suspension was completely redesigned as a new compound hydropneumatic/Horstmann design, called Schwebesystem, which utilized 60cm wide tracks. The old 400 horsepower turbocharged Maybach was not deemed sufficient to power this new tank, and so the suspension was lengthened by a roadwheel to accommodate the new Jumo 250 engine, a two-stroke turbocharged diesel, which produced 650 horsepower. Transmitting this power to the roadwheels was a brand new compact Merritt-Brown-derived transmission, with an automatic planetary gearbox, which allowed the tank to steer in place, as well as travel in reverse at 30 km/h. Upon an early prototype demonstrating this ability, Guderian exclaimed "sie bauen es!" - "build it!"
The first prototypes of the newly renamed Mittlerer Panzer Greif rolled off the line in January of 1939. These new panzers were the last to be produced by Germany by the old method of batch production, and as a result, each was slightly different than the next. Full rate production would begin once testing was concluded in August of 1939, at the brand new WPW plant in Obendorf.
Specifications, Mit.PzKpfw. V Greif Ausf. A:
Weight: 34 t
Length: 6.95 m
Width: 3.00 m
Height: 2.85 m
Main armament: 7.65 cm KwK 38
Caliber length (KwK): 55
Tube length (KwK): 4.053 m
Tube life: 500 shot
Secondary armament: 1 × MG 34
Cannon ammunition: 45
MG ammunition: 2700
Upper Hull: 50 mm / 60 °
Lower Hull: 30 mm / 45 °
Rear Hull: 25 mm / 90 °
Hull Roof: 20 mm
Hull Floor: 20 mm
Turret Mantlet: 80 mm / 90 °
Turret Front: 50 mm / 90 °
Rear Turret: 50 mm / 75 °
Turret Roof: 20 mm
Engine: Jumo 250 six-cylinder turbocharged opposed two-stroke diesel, 650 hp
Displacement: 16.63 L
Gears (F / R): 7/5
Power to weight ratio: 19.2 hp / t
Top speed: 55 km / h
Fuel storage: 720 l
Reach: 525 km (road), 350 km (off road)
Track width: 65 cm
Leichter Panzer IV
(The writeup for this one appears to have vanished into the aether, but I do recall that it was armed with a short 7.5cm gun and an autocannon!)
Entered in: Design a Tank - NATO 1949
NATO Medium Tank
Concept: License-produceable medium tank "kit"
By 1949, it had become clear that not only were tensions between the Warsaw Pact and NATO going to escalate, but that Soviet-aligned countries were actively readying for a full-scale conventional conflict. Because of this, the then-new civilian Operations Research Office was tasked with development of new weapons to be proliferated throughout - and, if possible license produced by - NATO member nations. The Armored Vehicles Team of the initiative, which was dubbed Project FOUNDRY, contained a scant seven members who began brainstorming ideas for a cheap, easy to produce, and eminently maintainable NATO-wide tank.
Such a tank, it was reasoned, would not need to necessarily be the standard and only fighting vehicle of all NATO forces, but would allow less industrially capable NATO nations to defend themselves independently, as well as member nations who so chose to fast-track development of their own customized versions of the basic vehicle, without need for multiple lengthy, independent, and redundant tank development programs.
While many concepts were explored, the one that gained the most traction was for a generously roomy welded chassis, with standardized turret ring dimensions, so that turrets and hulls could be exchanged at the depot level. Running contrary to current Army thinking, which emphasized small hulls with advanced, efficient transmission layouts, the concept had a large hull rear, supporting space inefficient, but widely available automotive components.
As the AVT refined the design, they worked closely with British and American automotive engineers to try and create a design that could easily be adapted for the different automotive components then available, and projected. The design was intended from the outset to contain at least the British Meteor engine, and the Merrit-Brown Z.51.R transmission used in the Centurion. Because of this, the tank could not be made very much smaller than the Centurion, but this was deemed acceptable.
The hull design received the most attention initially, and design of the turret and armament initially languished. The AVT had to solve, satisfactorily, the problem of producing specialized fighting vehicle components - the gun, turret, and sighting systems - in a variety of nations. Eventually, it was decided that the facilities in more developed countries, such as the US, Britain, France, and Germany, that could produce armed turrets and rings for all users, to be shipped abroad and mated to locally produced hulls.
One further problem facing the AVT was ensuring the transportability of the new tanks by the various trucks, ships, and railcars that were in use at the time by member nations. The solution was to limit the weight of the new tank to 40 tonnes, enabling it to be transported by the majority of surplus wartime infrastructure.
The resulting hull design was highly convergent with, but distinct from the British Centurion tank. The armor plates were to be rolled, heat-treated, and cut to shape by industrially capable member nations with the industrial capacity, and then shipped along with automatic welding equipment, if needed, to member nations for assembly. Each welded part assembled together using dovetails - like a cardboard model - to improve the strength of the welds, allowing for somewhat expedited welding practices. The turret ring race and other senstitive contact areas were finished before the plates shipped. When assembled, the hull used a series of mounting rails for engine and transmission, which approximated very nearly the modern "powerpack" concept, albeit in a much less space-efficient form. The driver's position was accommodating, with appreciable space as well as adjustable controls and seating, and power-assisted steering levers and shifter.
Armor on the hull consisted of a two three-inch plates joined at a 60 and 45 degree from the normal, attached to side plates two inches thick set at an angle of twelve degrees, like the Centurion. Top and bottom armor plates were one inch thick, while the rear armor plate was 1.5" thick. Like the Centurion, there was provision for .25" thick standoff plates mounted to the side of the hull, encasing the suspension.
The hull was to be furnished with automotive components in-situ, so there was no standard engine or transmission. However, most studies were done with either the British Meteor engine and Merrit-Brown Z.51.R transmission of the Centurion, or the AV-1790 engine with CD-850 transmission of the T40 experimental US medium tank. Special mention, however, should be made of the design study of the tank using a Ford GAA engine and syncromesh transmission from an M4A3 Medium, intended as a backup configuration in the event that a member nation could not obtain more modern engines and transmissions. In this configuration, the mobility of the tank would be significantly decreased.
Suspension was provided via a series of mounting points to which suspension elements could be attached. The "default" suspension configuration was for an individually sprung Horstmann derivative, but the design accomodated both single and bogied forms, as well as internal and external torsion bar, Bellevile washer, and volute spring methods of suspension. Track pitch, width, and design were likewise left up to member nations, but most early scale models used standard US 6" pitch 24" wide T81 tracks.
Ancillary components, such as stowage boxes, lights, fuel tanks, and other minor details, were to be produced by the receiving nations, with stamping equipment and technical know-how distributed as needed.
With all of the allowed variation, AVT realized it would need to publish an "engineering guide" to the new tank design, by early 1950 somewhat uncreatively christened the "NATO Medium Tank". This was accomplished with the first trials of automotive pilots, and "AN ENGINEERING GUIDE TO THE NATO MEDIUM TANK" was published by ORO on July 21st, 1950, and distributed to member nations. As the document only detailed the dimensional and production aspects of the tank, it was not considered a security risk, as member nations couldn't possibly leak any sensitive information from it that they did not already possess.
By 1950, the first mild steel turret mockups had been created, giving two of the automotive pilots a "proper" look, even though they were no more combat capable than before. The turrets were cast in a single piece, and fitted with a 90mm high-and-low velocity gun based on the British 20 pdr but utilizing experience gained from the American 90mm series of cannons. It was determined that for member nations, the most common type of shot available would be solid APC shot. Because of this, a high velocity conventional AP round would be needed to deal with anticipated Soviet vehicles. The resulting round fired essentially the same T33 AP shot as the 90mm M3 gun, but at a much higher velocity of 3,200 ft/s. Testing revealed the round could penetrate a 100mm RHA plate at 60 degrees from normal 80% of the time at 500m. This was considered, initially, sufficient to defeat the anticipated armor of Soviet medium and heavy tanks.
In order to allow more fragile, and thus higher capacity HE and utility (smoke) shells, ammunition was also developed for the gun that used a foam-lined, reduced volume case loaded with a smaller charge. This high explosive round produced 2,100 feet per second with its unique 22 pound shell, loaded with 2.6 pounds of Composition B high explosive. The technical data packages for these two types of ammunition were widely disseminated to member states, for their local production.
The new 90mm gun was also compatible with any projectiles for the older M3 series of cannons, including HEAT and HVAP. Further, it was expected that the cannon would serve as the basis for a new 100-120mm gun, designed to fire a new generation of HEAT and APFSDS projectiles.
Also included with the armament were three unity periscopes for each crewman, a single-plane stabilization system for the main gun, and a gunner/commander cowitnessing system. The turret had two ready racks of five rounds a piece, with additional ammunition stowage planned to be in the floor of the vehicle, and adjacent to the driver.
The turret was cast with 3.5-3.6" all around armor, improving to six inches at the front. A large, wide mantlet/gun shield of 6" thick was provided, partially to help balance the gun in its cradle. The turret ring was 74".
NBC protection was available through a "kit" modification that was distributed to member nations upon request.
Specifications, NATO Medium Tank:
Weight: 39.4 t
Length (Hull): 7.2 m
Width: 3.4 m
Height: 3.05 m (without roof MG)
Main armament: 90mm T104E3/M56
Caliber length: 62
Tube length: 5.60 m
Tube life: 500 shot
Secondary armament: 1 × M1919, M60, MAG, MG3, etc GPMG
Cannon ammunition: 65
MG ammunition: 3200
Penetration with T53 Shot, 10.9 kg at 976 m/s:
100 m: 22.2 cm
500 m: 20.0 cm
1000 m: 17.9 cm
2000 m: 14.3 cm
Upper Hull: 76.2 mm / 30 °
Lower Hull: 76.2 mm / 45 °
Rear Hull: 38.1 mm / 90 °
Hull Roof: 25.4 mm
Hull Floor: 25.4 mm
Turret Mantlet: 152.4 mm / 90 °
Turret Front: 152.4 mm / 90 °
Rear Turret: 90 mm / 90 °
Turret Roof: 50.8 mm
Engine: Depends on variant, often AV-1790 w/ CD-850 transmission or Meteor with Merrit-Brown Z.51.R transmission. Variant with Ford GAA and syncromesh transmission also trialled.
Displacement: Depends on variant
Gears (F / R): Depends on variant
Power to weight ratio: Depends on variant
Top speed: Depends on variant
Suspension: Depends on variant
Fuel storage: Depends on variant
Range: Depends on variant
Track width: Depends on variant