“If the tanks succeed, then victory follows.” – Heinz Guderian
The opinion of many people today is that tanks are obsolete, losing their survivability to modern man-portable ATGMs and precision guided munitions. What must be understood is that main battle tanks are the play-ground bullies of ground warfare, they are big, intimidating, and sound of a 120mm cannon thundering across a valley saps the enemy’s moral like little else. The effectiveness of such large, high velocity cannons is well known and the concept of the “tank” in general will likely never be phased out – only improved.
During the Second World War, tanks were primarily used as infantry support and tank-on-tank battles where rare. The large majority of tank casualties were caused by anti-tank cannons. During the Yom Kippur war of 1973, the Israelis faced a barrage of Soviet AT-3 “Sagger” ATGMs of which they were simply not prepared for, causing mass panic amongst tankers. Several extractions from the CIA’s report entitled “The 1973 Arab-Israeli War: Overview and Analysis of the Conflict” outline the alarm these missile caused, however, it is important to read until the end.
“In accounts immediately after the war, however, the effect of the antitank missiles was exaggerated. Detailed information now available indicates that in the whole war the Israelis lost approximately 500 tanks; among them 119 disabled units………. at least 6 percent but no more than 25 percent, were killed by Saggers.”
The Israelis focused fire on exposed ATGM teams, and seldom moved mechanisation anywhere without cover of indirect fire. ATGM teams must not operate without being transported in a vehicle with at very least protection against shrapnel. Granted, Saggers were first generation MCLOS guided missiles that were incredibly difficult to control. Modern ATGMs are far more advanced, however they are exceptionally more expensive. A Sagger will cost a military under $1000 per unit, whereas a modern “Javelin” ATGM can costs upwards of $100,000.
MBTs are, and will continue to be a staple on the battlefield, although they are not without drawbacks. The M1 Abram’s cost is sky rocketing, and at 70 tons, it is quickly bogged down, not easy to air transport, lumbering and fuel hungry.
The Light Tank:
There is no standard definition for a “light” tank, so for the sake of this piece we will define it as the following: A tank of no more than 20 tons, capable of air transport by C-130 with an operational range similar or greater than that of an MBT. Light tanks are not a replacement for main battle tanks, to paraphrase Picard; light tanks exploit the breakthroughs of MBTs. Unlike their heavier brother’s, the light tank should have anti-tank capabilities as a secondary priority, it is first and foremost an infantry support vehicle and due to its often extremely light armour, should seldom go toe-to-toe with anything carrying more than a heavy machine gun. Perhaps a good way to think of the light tank is as a Bradley IFV, with heavier armament and no troop carriage ability.
General Dimensions: Excluding turret and appliqué armour
Height: 1.45m (4.75 feet)
Width: 2.7m (8.85 feet)
Length: 6m (19.5 feet)
Light tanks sacrifice a great deal of armour to earn their designation, and rely on heavy sloping and other methods of armouring such as protruding ribs, which have been seen on both the BMP-2 and STRV-103 of Sweden. The Swedes found that their STRV-103 was essentially impossible to penetrate with any then existing anti-tank weapon during it’s early operational history.
Armour for the light tank chassis is as follows:
Front upper glacis: Sloped at 15 degrees, fitted with protruding ribs, protection from 30mm armour piercing.
Front Lower Glacis: Sloped at 50 degrees, protection from 30mm armour piercing.
Sides: Sloped at 75 degrees, protection from 14.5mm armour piercing.
Rear: Sloped at 80 degrees, protection from 7.62mm armour piercing
Engine will be a V8 diesel, optimally the same Scania DSA 14 litre version used by the CV-90. This should give the vehicle a maximum speed on-road in the vicinity of 80km/h (50 mp/h), and an operational range of ~400km (250 miles). Extra fuel will be carried in external tanks that can be dropped when empty or if there is a danger of puncture, similar to that of Soviet tank designs. A recess may be designed into the rear of the vehicle to allow some amount of armouring, however a better idea may be to design the external fuel tanks with some amount of shrapnel protection. These tanks may not be mounted during operations within close proximity of friendly infantry so as to avoid.
A heavy main battle tank has the luxury of being able to mount heavy, powerful, high velocity cannons – something a light tank may not be able to achieve, if we examine the use of large guns on light vehicles we can see that the results are very rarely acceptable. Both the Sprut-SD (125mm HV cannon) and the US M551 (Medium velocity 152mm cannon) had recoil issues, this resulted in much discomfort from the crew, difficulty when firing on the move and in a lot of cases, the turret ring being bent irreparably (especially when using aluminium armour).
From this, we can gather that the best light tank armament will be either: a high velocity small shell, or a low velocity large shell.
We will explore both, however my preference is with the later for the following reasons:
- A small HV shell (i.e. 60mm HVMS) results in a smaller capacity for HE, and lacks the heavy APSFDS rod to penetrate heavy armour. The velocity of a 120mm APSFDS may be achieved, however the dart will not have sufficient kinetic energy due to its low weight.
- A HEAT charge does not rely on velocity to penetrate armour, and will function at the very furthest reaches of its range (where KE penetrators will not)
- The lower velocity allows us to utilise a larger diameter shell, making the HEAT charge more effective. Where a 60mm HVMS APSFDS rod will not penetrate a modern MBT, a 120mm HEAT charge has at least a fighting chance – especially against the sides, rear and top.
- The lower velocity and lack of rifling (shells should be fin stabilised) mean that we can fit far more HE into the same area – note that a 120mm mortar shell has similar, if not more destructive power then a 155mm artillery shell.
In my opinion, the best armament for this light tank would be a large diameter, breech loaded, low velocity gun/mortar – we will use a 120mm diameter gun for this project due to logistics ease (120mm shells are already in use), however the optimal diameter would be slightly larger (130-140mm).
Parallels can be drawn to the aforementioned M551 “Sheridan”, however there are numerous deviances from the design.
The cannon will fire the following four types of ammunition
Standard mortar shells:
- High explosive
- Rocket assisted (RAP)
- IR Illumination
- HEAT (Shouldn’t be too difficult to create)
Low velocity cannon round (similar to BMP-3 100m shell):
- Canister/Flechette (most importantly!)
STRIX Laser guided, anti-tank mortar-fired munition
With sufficient propellant, a mortar shell can (and will be) used for direct fire. The main reason for the addition of LV cannon shells is for using flechette shells, however this may not be necessary if a 120mm shell is developed along the lines of the 81mm Mk-120 mortar (below) used on Mk-2 Mod 0 deck mounted mortars during Vietnam. Should the LV cannon shell provide no sizeable benefit over direct fire mortar techniques, it should be deleted.
81mm Mk-120, immediate left of the 105mm APERS-T:
Alongside direct fire, the mortar will also be fired in the conventional indirect fire roll, this will prove very valuable when supporting armour advancements as the constant shelling of the advancement location will thin out any resistance before it becomes a problem, the persistence of mobile mortar-tanks will be a massive improvement over towed artillery, with its shoot-and-scoot speed, counter-battery radar will be rendered useless.
The Swedish laser guided “STRIX” shell (above) will allow the vehicle to shine in the anti-tank role. For this to be its most effective, it will be coupled with a collapsible sensor mast (example below) mounting cameras and a laser designator.
From behind cover, the vehicle will extend its sensor mast and paint the target of choice, the gunner will then fire a STRIX over the target, impacting directly downwards onto the target (where a tank’s armour is thin). This tactic will allow the vehicle to expose nothing but the tip of its sensor mast, and without the need for an engine the STRIX takes up far less space than a conventional ATGM. The main limitation is obviously the lack of direct fire capabilities; this will be solved by carrying 2-3 LAHAT missiles alongside.
This heavy cannon will be supplemented by a co-axial 40mm CTA cannon firing cased telescoping 40mm rounds. The cannon should be modified to select between 200RPM for ground targets, and >800RPM for aerial targets. The necessary elevation of the mortar means that we have an excellent platform for a “pseudo-SPAAG”. Inside the turret will be a tri-feed system for HE, APSFDs and Air-burst with an optimal capacity upwards of 100 rounds.
A light tank can be produced in larger numbers, and the flexibility of deployment is fantastic. The US lost a great advantage when they retired the M551 and cancelled the M8 Buford that cannot be measured, a solution will be extremely easy to engineer and my proposal has many aspects that can be replaced by already existing equipment to lesser, but still good effect (i.e. the new chassis may be replaced by a cut-down M113 or a Bradley).
To make use of airborne and expeditionary forces in the future, the light tank has to be explored – there is no alternative.