I will start this post with a simple statement…
The IED is not going to go away any time soon
Whether we engage in asymmetric conflicts or those against traditional state actors the likelihood of the IED being used is extremely high, the genie is out of the bottle and cannot be pushed back in. This presents a significant challenge because traditional armoured vehicle design tended to concentrate on direct fire and shell fragmentation as the main threats; these of course don’t go away. We have covered the IED and vehicular design strategies in a couple of previous posts here and here but to summarise; passive vehicular design is just one facet of a diverse approach to defeating the threat.
I am planning a separate post on IED’s and specifically route clearance (where is Talisman?) but this post is about vehicles so will concentrate on this aspect for now.
A Mechanised Brigade will utilise four principle vehicle types, light and medium weight protected mobility, FRES and ‘others’, the others section includes everything from quad bikes to 15 tonne trucks and combat engineering vehicles. FRES is going to be built on the ASCOD2 base platform, we have rehearsed the arguments for and against but the fact is, ASCOD2 it is. One of the problems with FRES, amongst many it must be said, is that it was too ambitious, trying to replace most of the established vehicles with a single family. It has now developed into what looks like a simple and achievable set of vehicle replacements.
Operations in Iraq and Afghanistan have resulted in a wide range of UOR vehicles, from diesel quads to the Mastiff. Although the UOR process has been a success it is a fundamental admission of failure, the Army were woefully unprepared. The Snatch Land Rover issue has been covered by many blogs and online sources so doesn’t need rehashing here but if I can summarise, great vehicle, wrong time and place. The Army now has a wide range of disparate vehicles so the challenge will be to create some form of medium to longer term strategy that reduces this logistically challenging diversity, whilst still meeting contingent requirements.
For an idea of the wide range of vehicle types have a look here
In our ideas for restructure the Warrior and Challenger are moved out of the Mechanised Brigades and into square Armoured Brigades. Although air mobility is sometimes overstated the Mechanised Brigade must be able to have the bulk of its equipment moved by the A400 with some of the heavier types by C17. Generally speaking, most movements inter and intra theatre will be carried out by sea and road but the flexibility to deploy small units by air should be retained. The proposal called for 3 Mechanised Infantry Battalions and 1 Medium Armour Support/Reconnaissance Regiment per Brigade.
What vehicle types for these Mechanised Infantry Battalions, going back a few years one can start to see a few ideas beginning to form…
The length of time it took to deploy heavy ground forces to Kosovo led to calls to make armies more deployable i.e. lighter so they could be delivered by fast aircraft, not by slow ships and be self deployable by ground over strategic distances.
The fact that the Russians embarrassingly beat NATO to the airport at Pristina using wheeled, vehicles driven from Bosnia further reinforced the medium weight argument. It was argued that the problem was the existing tracked vehicle fleet; it being too heavy. Protection could be sacrificed to make vehicles lighter as this reduction in capability could be more than compensated for by the improved situational awareness and information superiority afforded by network centric capabilities and integrated sensor platforms.
The so called Revolution in Military Affairs was born.
Lighter more deployable forces, with less protection and manpower backed up by increasingly sophisticated precision strike all wrapped up in a ‘network’ would be the answer to the problems encountered in Kosovo and the predicted future conflicts. Talk was now of effects rather than weapons.
A whole new range of management speak was born, we would move away from platform based solutions and move to effects based solutions, a new paradigm. Paradigm is an over-used word in defence planning, deployability would be crucial for these expeditionary concepts and the ‘network’ would produce a step change akin to the invention of gunpowder.
At about the time the Revolution in Military Affairs / Future Combat System / FRES / Cure for Cancer fashion was being debated on both sides of the Atlantic, wheels seemed to gain the upper hand.
As operations in Afghanistan and Iraq have unfolded the wheeled argument has grown stronger because with wheeled vehicles one can use hull shaping to massively increase survivability against buried IED’s.
The debate about protection v mobility is also an interesting one with many arguments on both side.
Of course, the other RMA and subsequent FRES/FCS concepts have more or less been consigned to the dust bin of military fashion but that as they say, is another post!
Most armed forces have used a mix of tracked and wheeled military combat vehicles for some time but the larger 6×6 and 8×8 types have generally been limited to specific roles or in nations with less demanding military requirements.
Is the tracked vehicle a design Cul-de-sac?
What are the arguments?
Deployability – Inter theatre deployability favours neither a wheeled or tracked solution. Intra theatre is a different matter; wheeled vehicles do not need transporters and can self deploy from theatre entry points, in many regards, tracked vehicles are a transport headache.
Survivability – As mentioned above, the IED as a weapon will continue to be a major threat. Wheeled vehicles can use hull shaping and other techniques to improve protection against buried mines and IED’s but tracked vehicles, generally speaking, have a flat belly, so are much less survivable against this threat.
Protection against direct fire and shell fragments can be applied to either but tracks provide much more manoeuvrability so vulnerable points can be avoided. However, the scope for utilising these additional capabilities afforded by tracks can be limited in some terrain where no amount of ground mobility will make a difference.
The vehicles with the heaviest armour are main battle tanks and it is no coincidence that these are tracked.
In order to carry extra armour it’s weight must be distributed across the surface contact points, which bring us on to the next factor.
Combat Mobility – Mobility equals tactical advantage which contributes to survivability.
Higher speed on roads is generally easier to achieve with wheeled vehicles, unless one is driving a CVR(T) around the Nurburgring!
In difficult off road conditions, tracked vehicles can usually achieve greater speeds. Large vehicles like Mastiff are heavy and no matter how many wheels or centralised tyre pressure management systems are added the ground pressure is going to be significantly greater and traction significantly poorer than for a comparable tracked vehicle. A track has a much greater surface contact area than wheels so the weight is distributed across a larger area, this results in a lower ground pressure and in turn, greater off road mobility.
As armour is added to improve protection against direct fire then this issue becomes acute, higher ground pressure and a limit on wheel size means there is a practical ceiling for wheeled armoured vehicles off road mobility.
The lack of off road mobility means wheeled vehicles spend more of their time on road and have to move in or through vulnerable points. These vulnerable points are predictable and can be mined or covered by direct fire weapons.
If a wheeled vehicle is immobilised by terrain then it and any recovery units become exposedto fire.
Multi wheeled vehicles can usually continue to drive with a couple of wheels destroyed but if a tracked vehicle looses a track then it is immobilised.
Artificial obstacles in urban areas such as barricades, walls and cars etc present challenges to wheeled vehicles, not always insurmountable challenges but tracked vehicles, with their greater surface area on the ground, power to weight ratio and traction can more easily overcome these obstacles. The infamous US operation in Mogadishu showed that even old fashioned tracked vehicles like the M113 could deliver winning effects in an urban environment, pushing through rubble and other obstacles.
In the aftermath of the special forces capture in Basra, Operation Thyme was mounted against the Serious Crimes Unit in Jamiat police station. The outer wall was breached by a Medium Wheeled Tractor of 38 Engineer Regiment and through/over the resultant rubble a number of Warriors from the Staffordshire Regiment entered the compound. The shock delivered by this breach might have been impossible to conduct with a wheeled vehicle, instead of going through a breach a wheeled vehicle might have had to go through the entrance.
In the video below the Warriors can be seen entering the compound and pushing other vehicles out of the way.
Large wheeled vehicles are unable to execute changes of direction in close confines easily, requiring a ’23 point turn’ unlike a tracked vehicle, that can turn on the spot.
8×8 wheeled vehicles like the Boxer for example, have a high centre of gravity, meaning high speed turning or evasive manoeuvres can be hazardous. After several accidents, US Stryker’s are speed limited.
The video below shows a very impressive off road mobility demonstration for an early model LAV. Although the tests involving the removal of wheels have those axles conveniently chained in the up position it is still a striking video.
But in videos below, the extra weight of turrets, additional armour and electronic systems imposed on a similar chassis design, by later models, degrades mobility even in what might be reasonably considered to be only mild off road conditions (sorry for the author of the videos by the way but they do prove a point)
This is a clip of a Canadian unit in Afghanistan, skip forward to 2 minutes 40
So although wheeled vehicles generally have greater road mobility than tracks, as soon as the terrain becomes mixed or challenging then their mobility rapidly deteriorates. A cynic might that the FRES Utility Variant Trials of Truth exposed some of these mobility issues with the very heavy Boxer, Piranha and VBCI.
Technology moves on though and industry is always looking at alternative solutions. Whilst I am not saying that the videos below represent practical military options for improving combat wheeled vehicle mobility it does show that innovation can address wheeled vehicle mobility.
TheTrack Truck from AP Van den Berg
The Iveco Trakker Hovertrack from Veldhuizen. The Hovetrack even gets a mention in Parliament, here. I like the approach they have taken here and with some of the other vehicles the driver is positioned centrally in the cab, this means that a protective shape can be much more easily applied.
Maybe a military future beckons!
Support – Fuel consumption is an increasing concern, with asymmetric conflicts the need for combat logistics as opposed to logistics becomes a greater problem, absorbing valuable combat power.
Every litre of fuel or spare part places a considerable strain on logistics and support arrangements. The larger protected patrol vehicles have increased fuel consumption enormously over previous types.
Tracks generally have poorer fuel economy than wheeled vehicles but as soon as difficult terrain is encountered or in stop start activity this is reversed. Run flat tyres are very expensive and the US experience in Iraq with Stryker’s has shown that running costs are more expensive for wheeled vehicles than tracks (fuel and tyres).
The inherent complication of an 8×8 like drive train is inevitably going to be more maintenance intensive than the very simple arrangements of a tracked vehicle.
Weapons Platform Suitability – For small calibre weapons such as machine guns and automatic grenade launchers there isn’t any real difference. In the protected mobility role, light automatic weapons are all that is needed. However, when large calibre weapons are fitted the stability and low centre of gravity of tracked vehicles favours them. Large weapons on wheeled vehicles create recoil handling problems from both an accuracy and service life perspective. These problems aren’t insurmountable though, especially with advanced low recoil weapons.
Growth Potential – The ability to up armour, add extra weapons, communications or sensor equipment is now seen as a key requirement for combat vehicles. There is no real difference between wheels and tracks on this but in general, tracked vehicles have more space for a given set of dimensions, because of the simplicity of drive train and transmission for tracked vehicles.
Other Considerations – It could be reasonably argued that wheeled vehicles pose a less aggressive stance than tracked ones and this is a large concern in counter insurgency or lower intensity operations. Tracked vehicles can damage fragile infrastructure such as roads and bridges, totally counter productive in some operations.
On the other hand, tracked vehicles do signal ‘intent’
A low acoustic signature provides advantages in a number of areas and this clearly favours the wheeled vehicle, the US Stryker experience in Iraq has shown this to be a significant combat advantage in built up areas.
Engine noise can still be significant in either type but as hybrid engines are developed then the near silent operation of a wheeled vehicle could potentially deliver a range of tactical advantages.
Rubber band tracks are in constant development and might eventually see them being suitable for larger vehicles. This type of track is in widespread use on commercial plant vehicles and the BV series of all terrain vehicles, in an earlier post we examined the use of covered the use of Soucy band tracks on the LANCER and SIKA demonstrators.
Advantages of band tracks include much reduces sound signature, greater traction, less weight and long life but if they are damaged it is not an easy field repair although industry has produced a number of field repair systems.
As tracked technology matures the noise disadvantages of tracks may be negated.
So from the above, tracks and wheels are complimentary, each has advantages and disadvantages.
The question we asked at the beginning, wheels or tracks, is more or less a nonsense.
When approaching vehicle design these factors must be considered and relative priorities applied.
In the next couple of posts I am going to look at the protected mobility and fighting vehicles of our proposed Mechanised Infantry Brigade structure.