Vehicle Mobility Considerations

CVR(T)

This is an update of a previous post on the factors when considering vehicle design and selection, especially mobility issues.

Lighter units whose ability to move rapidly may have different needs to others and secondary roles may take on a greater importance. A light armoured vehicle may be compromised when acting in support of a heavy armoured brigade but might be just the ticket for a light role rapid reaction force.

With FRES SV and Protected Patrol Vehicles like Mastiff we have become increasingly ‘weightier’ and this will inevitably have an impact on operational agility around the area of operations. With an increasing focus on protection from operations in Iraq and Afghanistan this weight and size increase has very real implications on mobility.

The ability to quickly move a light force, equipped with a modest degree of protection/firepower, is still a capability we should strive for and enhance. Whether this is air dropping or more likely by helicopter is to some extent, detail. In the teeth of increasingly competent air defence systems this might seem an anachronism but mobility and agility allow one to advance from unpredictable locations, cut forces off and apply decisive combat power to rear areas for example. This means that some equipment has to fit in the payload and space envelope of helicopters and aircraft.

Mobility in all its guises is still a critical design factor and in the general move to favour protection in the protection/mobility/firepower triad we should still give mobility some priority.

This is a fundamental problem that Western forces face, the desire to reduce casualties by increasing protection has an adverse effect on mobility that in turn, could increase casualties.

There are of course no easy answers, just a number of sometimes uneasy trade-offs and compromises.

Arriving in Theatre

We make the assumption that the theatre of operations for land forces is not going to be in the South East of England repelling the French. Modern operations are predicated on playing nothing but away matches and so the ability to transport the personnel, stores, equipment and vehicles to distant places is the first consideration.

RAIL

For most vehicles the limitations placed on rail travel are not considerable although the weight of main battle tanks usually requires heavy duty flatbed wagons. Unless operations are to be conducted in Europe rail transportation of vehicles is unlikely, even though the British Army operate rail transportation systems in Germany and Canada with specialists from The Royal Logistic Corps and the Royal Engineers.

Rail transportation to theatre is actually very efficient; it is fast at between 30 and 50 mph and very cheap.

As heavy equipment is withdrawn from Germany back to the UK, rail transportation either to the Marchwood Sea Mounting Centre, the Channel Tunnel and other ports may become more frequent.

Standard flat-bed wagons can accommodate loads up to 2.59m high and low loaders, 2.89m high.

Land Rover and Vector Vehicles Rail Transport
Land Rover and Vector Vehicles Rail Transport

Because rail freight business is concentrated on loose bulk materials, liquids and intermodal containers the standard rail flat is the width of an ISO container, 2.44m. Vehicles that are wider can of course overhang but this may be a limiting factor on some routes and Challenger 2 and its derivatives are too wide for use on the UK rail network but CVR(T), Warrior and other vehicles can be moved by rail. Challenger 2 can be moved on some European rail networks.

The Warflat wagon was developed in WWII (images from IWM here) and has seen extensive service since but many of these are now in the hands of collectors, with a maximum payload of between 40 and 50 tonnes, depending on weight distribution, they would not be able to carry the main battle tanks of today. The Warwell is a low loader style flat wagon often used to carry Warriors and because of their width, a special platform is also sometimes used to raise them above the height a platform to avoid fouling. The older FV432 can be carried on standard flats but anything with storage bins or other equipment fitted to the roof must be carried on the low loader style Warwell.

CVR(T) on war well
CVR(T) on war well
CVR(T) Samaritan on a warwell
CVR(T) Samaritan on a warwell

The Movement Control Association has an excellent article on the use of trains in 1942, click here to view.

Modern railway flat wagons can are often fitted with quick opening tarpaulins which obviously avoid prying eyes knowing what is being carried.

If we look at the constraining factors for vehicle design and railway mobility it is the width of a vehicle that is a key issue, to a lesser extent height and even less so, weight. If a vehicle can be designed to be less than 2.35m wide and 2.39m high, the internal dimensions of a standard ISO container then it will be able to use the civilian rail container transport infrastructure in many countries.

ROAD

As with rail, there may be limited circumstances where we can deploy directly to the point of entry via road, renewed conflict in the Balkans for example. Road transportability is also important for training and UK movements, abnormal load regulations are fiendishly complex, click here, but loads (including tractor and flatbed trailer) over 44 tonnes or 2.9m width require special permissions and notifications.

Oshkosh Heavy Equipment Transport and Challenger 2 (Image Credit - Flickr Charles Dawson)
Oshkosh Heavy Equipment Transport and Challenger 2 (Image Credit – Flickr Charles Dawson)
Oshkosh Heavy Equipment Transport and Warrior Recovery Variant (Image Credit - Flickr Charles Dawson)
Oshkosh Heavy Equipment Transport and Warrior Recovery Variant (Image Credit – Flickr Charles Dawson)

Driving to a European theatre is again possible but with obvious limitations. Outside the UK these restrictions might not apply but moving from the port or point of entry via road will be the norm so road and bridge classification and the availability of suitable transport is an issue concern.

SEA

The most common form of getting to theatre will be by sea, at least for any sustained or operation excluding the light role rapid reaction units. Whether by civilian ships, the Point class RORO PFI or amphibious shipping the main limitation is vehicle length and availability of ports and offload facilities

By using RORO ships heavy equipment can be driven straight off a boat and onto waiting road or rail transport for movement to the area of operation.

The Commander's Challenger Tank of 1st The Queen's Dragoon Guards (The Welsh Cavalry) rolls down the ramp of the Russian commercial ship Vladimir Vaslyaev in Split, Croatia, during deployment in support of Operation Joint Endeavor
The Commander’s Challenger Tank of 1st The Queen’s Dragoon Guards (The Welsh Cavalry) rolls down the ramp of the Russian commercial ship Vladimir Vaslyaev in Split, Croatia, during deployment in support of Operation Joint Endeavor
Vehicles of the British 22nd Engineer Regiment, are unloaded from the Russian commercial ship Vladimir Vaslyaev in Split, Croatia, during deployment in support of Operation Joint Endeavor.
Vehicles of the British 22nd Engineer Regiment, are unloaded from the Russian commercial ship Vladimir Vaslyaev in Split, Croatia, during deployment in support of Operation Joint Endeavor.

Using ISO container flatracks to move vehicles removes reliance on RORO vessels or RORO port handling facilities and allows a deployment to take advantage of the global ISO container logistics system, ISO flatracks can utilise widely used lighterage and barge systems to move inshore.

Leyland DROPS and CVR(T) 01
Leyland DROPS and CVR(T)

The value of this should not be underestimated; a number of 105mm Light Guns were moved into the Balkans using ISO containers for example.

Domino ISO Flat Rack and CVR(T)
Domino Flat Rack and CVR(T)

Standard intermodal flatrack usage would tend to restrain width to 2.3m. Length of a single TEU is about 6m and a weight limit of 30 odd tonnes. Height is also about 2.2m but this is less critical as they can be double stacked.

AIR

Usually a last resort, most air transportation to theatre by air is for highly sensitive vehicle traffic or those that are time critical.

When discussing vehicles most people tend to dismiss air transportability as a secondary consideration, arguing that if a vehicle is going to be operating alongside heavy armoured forces there is very little point in moving them expensively by air where they will sit and wait until the big fellas arrive. There is much common sense in the position but there are certain limited circumstances where deploying by air a modest armoured force can be decisive. Rapid intervention with light forces, reinforced with light/medium armour, can be very effective. The original FRES concept was predicated on moving a medium weight intervention force by air direct to theatre by air. As we all know this was flawed in many aspects not least the amount of aircraft required but there is still some value in the concept and the weight limitations of available aircraft should be considered when designing equipment.

For the UK, those relevant future aircraft are the A400, C17 and occasionally chartered Antonov 124’s.

C17 Cargo Hold Dimensions AN124 Cargo Hold Dimensions

The C17 can lift about 70 tonnes and whilst the UK has never transported Challenger 2 by C17 other nations have done so with their main battle tanks, the capability is proven even if we don’t practice it. It’s not generally recommended though and certainly not a practical exercise for austere locations. Vehicles between 20 and 40 tonnes could be carried comfortably and the UK has transported Warrior vehicles to Afghanistan using C17’s as in the picture above.

In pitching a vehicle at the 20-30 tonne level, 2 are transportable per C17 or at a much lighter weight and depending on dimensions; up to 6 may be transported.

The A400 has yet to fully demonstrate a maximum load but the UK requirement is for 30 tonnes and the A400 website lists a maximum of 37 tonnes. Payload inevitably impacts on range and the same website lists a strategically significant range of 2,450nm at 30 tonnes and 3,450nm at 20 tonnes. The ability to move such payloads at range is one of the significant performance features of the A400, even if it will be concrete runway to concrete runway for most of the time.

A vehicle with a weight of 15 tonnes means 2 at a time or 30 tonnes means one in an A400 or 2 in a C17, there are a number of combinations that can be tried.

To fit into an A400 and C17, the width of a vehicle needs to be less than 4m wide and 3.85m high.

Weight will affect range, as the diagram below shows

A400M Atlas Load and Distance Chart
A400M Atlas Load and Distance Chart

Air dropping direct to theatre might be seen as an anachronism and easily dismissed but it is a capability we should not lightly discard, even for vehicles.

When the C130K leaves service and the A400 enters the existing Medium Stressed Platform will no longer be able to be used so a new platform is hopefully going to be obtained, the obvious choice would be Type V platform from Airlift Technologies.

The Type V can accommodate vehicles up to 19 tonnes, 19.5m long and approximately 2.3m wide.

Getting to the Action

In some locations the point of entry might also be the area of operation, Sierra Leone being a good example, but in others the area of operation might be some distance to the point or port of entry and this leg if often called ‘intra theatre’

If a vehicle is flown direct to Bastion it does not have a long way to get to the area of operation but if the said vehicle goes by a Point class RORO ship that disembarks at Karachi it has a very long and hazardous road move ahead.

Generally speaking, the same options exist except perhaps for rail although it should never be completely discounted because local rail infrastructure might be used depending on location.

AIR

Because the intra theatre journeys are shorter and end locations not always endowed with 10,000 feet runways the type of aircraft used will change, tactical airlifters and helicopters. There are a number of grey areas because both the A400 and C17 can be used in a tactical context.

in a typical hub and spoke operation, strategic aircraft will bring in personnel and supplies (sometimes vehicles) to a strategically located main operating base location and tactical airlift aircraft will bring them forward to smaller airfields, Kandahar to Bastion being a good example, at least until the new runways at Bastion were built. There are a wide variety of scenarios here that might affect vehicle design but with the A400 and C17 being more or less capable of both strategic and tactical airlift operations this hub and spoke arrangement might not always be the best model.

The same cargo hold and weight limitations would therefore apply, and equally for air despatch.

ROAD

There are two options, self-deploy or catch a lift. Self-deploying significant a distance for tracked vehicles is fuel intensive, causes a great deal of expensive track wear and therefore they tend to be carried to the area of operation on a low loader.

Wheeled vehicles can self-deploy much greater distances although segmented band tracks on light and medium weight vehicles can reduce the impact somewhat. This is one of the great attractions of wheeled vehicles, like FRES UV for example.

The UK has a small fleet of 96 Oskosh Heavy Equipment Transporters operated under a 20 year, £290 million PFI with Fasttrax. The original trailer used for transporting heavy vehicles was from King Trailers but given the poor road infrastructure in Afghanistan a number of Broshuis rough terrain trailers have also been obtained to allow the HET fleet to operate.

Another video

A lighter vehicle, like CVR(T) or Viking can be easily transported on more or less any truck, civilian or army. A simple jib can lift it onto the truck bed and move it long distances, even though CVR(T) can move quite effectively on road. DROPS have also been used quite often for deploying small vehicles including CVR(T), the Balkans especially made use of this method

Foden DROPS and CVR(T) in the Balkans 01
Foden DROPS and CVR(T) in the Balkans

One of the implications of replacing CVR(T), which can move forward under its own steam or on the back of any truck, with the 30 tonne plus FRES SV is that road moves forward will not be possible with anything but one of the 96 Heavy Equipment Transporters and specialist trailers. If we are only buying a handful this might not be so bad but given the numbers envisaged, unless we significantly increase the HET and trailer numbers in the PFI then we might have difficulty assembling a sufficiently strong force in reasonable time, this could lead to vulnerabilities as speed of deployment to a forward area is reduced.

SEA

Although less likely than road or air, vehicles can of course be moved to the area of operations by a short sea journey and landed via Mexeflotes or landing craft for example.

Cutting about the Battlefield

Freedom of movement on the battlefield is critical to effectiveness and there are many factors that influence battlefield mobility.

AIR MOBILITY

We use air mobility to rapidly move light forces.

Internal carriage in a Chinook means that slinging can be dispensed with, drag massively reduced and range and handling increased.

Supacat Extenda inside Chinook
Supacat Extenda inside Chinook

The Germans have developed the Mungo to be internally transportable in their CH53’s

German Mungo vehicle
German Mungo vehicle

For vehicles that can at least stay within the sling load limitation of the Chinook this remains a useful option.

Chinook underslung Land Rover HMS Ocean Chinook underslung BV206 Chinook underslung BV206

CVR(T) and Chinook - Operation Agricola
CVR(T) and Chinook – Operation Agricola

Chinook and CVR(T)

WEIGHT and GROUND PRESSURE

Although absolute weight is often less important than ground pressure it is still important, especially for bridges and road surfaces.

The NATO standard means of defining the ability of a surface to bear particular weights is called the Military Load Classification (MLC) system and common break points are 30 and 70, we use Class 30 and Class 70 trackway for example.

In an area with poor road and particularly, bridge infrastructure, no matter what the ground pressure, the vehicle weight will dictate tactical mobility. Existing bridges can be supplemented with military bridges and here, the classification system is important.

Most close support , general support and logistic bridges are in excess of Class 70 but for lightweight forces the kind of military bridge usually available have a lower classification.

The Air Portable Ferry Bridge currently in service with the Royal Engineers has an MLC of 35 which is close to FRES SV and UV although one might reasonably assume that neither will be in service with such light or air mobile forces.

Whilst CVR(T) could easily cross even poor bridges its replacement, the ASCOD based FRES SV Scout at a weight in excess of 30 tonnes will need more robust road and bridge infrastructure.

German BvS10 in Afghanistan
German BvS10 in Afghanistan

Ground pressure is a critical factor where the underlying surface is soft, snow, marsh or loose sand for example. Soil mechanics and ground pressure is a fiendishly complex subject that simple generalisations defy but the seemingly constant battle of tracks versus wheels is often distilled into simple statements that tracks will always be better than wheels is the soft stuff.

The videos below shows that as 8×8 designs have evolved, or gained weight form turrets, additional armour and electronic systems the degradation in mobility even in what might be reasonably considered to be only mild off road conditions is obvious.

Designs have improved greatly since the video but there are persistent concerns about the mobility of wheeled vehicles, especially the heavier 8×8’s, in soft ground conditions.

As a counter, promotional videos like these from Artec , General Dynamics, BAE and Nexter showcase the mobility of these modern wheeled armoured vehicles.

As impressive as these splashy bouncy videos are they do seem to be suspiciously on dry and firm ground, not much marsh, deep mud or snow to be seen.

Tracks do not necessarily confer immunity from the effects of soft ground

CVR(T) Stuck

Promotional videos for tracked vehicles do tend to focus on soft ground performance though.

An example of extreme mobility over soft ground is the BVs10 Viking, its articulated design, very wide tracks and high power to weight ratio provides superb off road performance.

For many years the British Army has been conducting operations in dry places but operations in the Balkans should remind us of the need for mobility over soft ground, unless of course we only plan on operating in hot and dusty places!

SIZE

One of the original design constraints for CVR(T) was the distance between rubber trees in what is now Malaysia, vehicle width was a direct response to the terrain.

CVR(T) Scimitar in the Balkans
CVR(T) Scimitar in the Balkans

The images below show a couple of instances where small vehicles can get to places that would be denied to larger vehicles.

German Fennek in Afghanistan
German Fennek in Afghanistan

This is not necessarily a bad thing in itself but if it has an impact on carrying out a given task then size becomes an issue!

ROAD DAMAGE

In a high intensity conflict this is not necessarily a concern but in counter insurgency or peace support operations heavy tracked vehicles churning up roads and counter-productive and so wheeled vehicles have a significant advantage.

Modern segmented band tracks from Diehl, Astrum and Soucy are addressing some of the traditional disadvantages of rubber pad metal tracks.

CV90 Band Tracks
CV90 Band Tracks

The image above shows BAE CV90 with segmented band tracks, they are currently in Afghanistan.

DEPARTURE AND APPROACH ANGLES

Gradients determine if the vehicle can traverse steep inclines, head or side one.

Approach angles can be determined by overhang in front of the wheels or tracks.

Contrast this image of a Warrior

Warrior MICV with 40mm CTA

With a Stryker

Strycker

This video from British Pathe shows vehicles being tested on gradient test tracks.

SPEED, ACCELERATION and DECELERATION

Top speed and high rates of acceleration and deceleration are always useful and an integral part of battlefield mobility. The general assumption is that wheeled vehicles have a higher speed and greater rates of acceleration but depending on the surface tracked vehicles can demonstrate impressive speeds and it is important to make the distinction between high speeds and useable high speeds over difficult terrain.

I seem to recall CVR(T) holds the track record at the Nurburgring for tracked vehicle and of course, any video of the Ripsaw will show that tracked vehicles are capable of extreme speed.

With wheeled vehicles the geometry of the drivetrain and payload tends to produce a vehicle with a higher centre of gravity that can be dangerous in high speed manoeuvring

PUSHING and PULLING

Although not necessarily a mobility issue per se it is still an important consideration for vehicle designers. You don’t see many wheeled bulldozers because the transferring the power of the engine to low speed pushing or pulling is greatly aided the increased ground contact area of tracks.

Pulling is usually used for recovering vehicle casualties in the absence of specialist equipment but pushing is used more often.

Pushing examples might include moving a road block or vehicle casualty out of the way or pushing over a tree.

Warrior demonstrating the tractive force of a tracked vehicle

An upgraded British Army Warrior vehicle tows a Mastiff out of a wadi
An upgraded British Army Warrior vehicle tows a Mastiff out of a wadi

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 and traction can more easily overcome these obstacles. The infamous US operation in Mogadishu showed that even old fashioned tracked vehicles like the M113 (driven by the Pakistani Army) 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.

Bulldozer or obstacle clearance blades can be fitted to wheeled vehicles, especially the larger 8×8 types but they are generally not as effective as those attached to tracked vehicles.

DAMAGE RESISTANCE

If part of the vehicle is damaged retaining some mobility to get out of danger is a very attractive feature. Once a track becomes damaged, as robust as they are, or thrown then the vehicle is effectively immobile.

Modern wheeled combat vehicles are designed to retain mobility even if one or more wheels are destroyed.

The video below shows an early model LAV without a couple of wheels still being able to move (although the running gear has been chained up to prevent it digging in to the ground)

This video from British Pathe (at about 3 minutes in) shows that even in the sixties mobility in multi wheeled vehicles with one of those wheels ‘missing’

WATER

Many water obstacles can be forded, the interesting video below shows fording in Afghanistan, at about 2 minutes 50 seconds.

Wading kits used to be relatively common on armoured fighting vehicles but have fallen out of favour and a small number of vehicles are fully amphibious.

German Leopard tank fording kit
German Leopard tank fording kit

This reduces the dependence on combat engineering but adds penalties related to complexity and weight.

GAP CROSSING

Simple ditches can be surprisingly effective vehicle barriers so the ability to cross irrigation ditches or manmade ditches is essential.

This is a driver training video (so the ditch is being crossed in slow time)

Tracked vehicles can generally cross larger gaps than wheeled and at a greater speed.

This video at about 1 minute

TURNING CIRCLE

With an increasing likelihood of operations being conducted in urban areas the ability to turn around and extricate oneself from trouble or negotiate tight streets is important.

Turning circle was one of the more challenging requirements for the Light Protected Patrol Vehicle that is being fulfilled by the Ocelot/Foxhound.

Tracked vehicles have the advantage of being able to turn on their own axis but some of the newer 8×8 wheeled combat vehicles can also perform this very neat trick.

Articulated vehicles like the Viking and Warthog cannot perform these turns although their articulation does allow relatively tight turns to be made.

FUEL CONSUMPTION and MAINTENANCE

Fuel consumption is an increasing concern, with asymmetric conflicts the need for combat logistics as opposed to logistics becomes a greater demand, 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 demonstrated that running costs are more expensive for wheeled vehicles than tracks (fuel and tyres).

If operated on hard surfaces for extended periods metal tracks tend to heat up and expand, requiring constant maintenance or running the risk of throwing a track.

The inherent complication of an 8×8 like drive train might need more maintenance than the very simple arrangements of a tracked vehicle but vibration from tracks causes many problems so whilst the wheeled drivetrain might have more parts and be more complex it isn’t necessarily more maintenance heavy.

Future systems are likely to take advantage of automotive hybrid systems, regenerative braking, fuel cells, advanced batteries and the broad technology base that is evident in the civilian sector will eventually find their way into military vehicles.

Break Points

In any design discussion there will inevitably be a series of break points.

One of the burning issues with vehicle design is to what extent we let aircraft payload factors dictate design.

There are two competing thoughts, keep to aircraft weight limitations and take what protection fits within that envelope or design a vehicle with the desired protection levels and buy aircraft to suit.

As with road and bridge classification there are a number of break points and multiples. The table below shows weight as the deciding factor (volume, floor loading and sling point load considerations are ignored)

Merlin Chinook CH53K A400 C17
5 tonnes 1 2 3 6 12
10 tonnes 1 1 3 6
15 tonnes 1 2 4
20 tonnes 1 3
30 tonnes 1 2
40 tonnes 1
60 tonnes 1

Other considerations are road transportation, landing craft and recovery capacity

Class 30 Trackway Air Portable Ferry Bridge LCVP LCU Road Special ISO Flatrack
5 tonnes YES YES YES YES NO YES
10 tonnes YES YES NO YES NO YES
15 tonnes YES YES NO YES NO YES
20 tonnes YES YES NO YES NO YES
30 tonnes YES YES NO YES YES YES
40 tonnes NO NO NO YES YES NO
60 tonnes NO NO NO YES YES NO

Stacking ISO flatracks is constrained by weight, a typical flatrack such as those manufactured by Domino can stack 9 high but only with a maximum weight of 24 tonnes, a tare weight approx 4 tonnes. ISO flatrack carriage will constrain vehicle width to just over 2.4m. The A400 has a 4m width cargo hold, the C17, 5.5m, Chinook, 2.3m and CH53K, 2.7m.

Keeping a vehicle width less than 2.4m provides the best combination; it could be carried on an ISO flat rack, the A400, CH53K and 2 abreast in the C17 but how would this affect protection, space for equipment and systems and stability?

By keeping a vehicle within the constraints of a 20foot ISO container/flatrack we can not only utilise the huge civilian infrastructure used to move them on the ocean but critically, also the intermodal facilities of ports and trucks. The main reason the UK entered into the Points Class PFI was because the international shipping market was consolidating on larger and fewer vessels, particularly pure car pure truck carriers (PCPT), availability of RORO shipping for expeditionary operations was becoming tenuous. Whilst the agreement provides for 6 vessels the flexibility and additional capacity in the civilian container shipping market could be exploited.

The sub 5 tonne weight bracket is basically for quad bikes and vehicles like the Roush LAS100, Supacat ATMP and stripped down Land Rovers.

10 tonnes is the key point for Chinook lift and 3 in a single A400 or 6 in a C17, 2 abreast

If we were to step up from the Chinook to the CH53K or the Chinook sucessor proposals the 15 tonne point becomes more realistic, 2 in an A400 and 4 in a c17. Given length issues, 2 in an A400 might be more feasible than 3. There is a constant pressure to improve helicopter lift capacity and the US and others have several studies and exploratory programmes, an evolved Chinook may be the result but ultimately, 15-18 tonnes is the likely end point for heavy vertical lift helicopters after Chinook.

Keeping a vehicle below 20 tonnes allows it to be carried on a C130 or some of the newer C130J class aircraft under development, the Embraer C-390 for example.

Beyond 20 tonnes the A400 only carries in singles and beyond 30 tonnes we start seeing mobility issues; ISO flatrack, DROPS, special load, bridges and trackways for example.

With tunable protection these hard limits can be bent a little. The German Puma, for example, uses a modular armour concept, the base vehicle is designed to be transported in the A400 with additional armour carried in follow on aircraft. It is most unlikely that a vehicle will speed down the aircraft ramp and get stuck in straight away so allowing some time to assemble the armour add-ons is a sensible and pragmatic decision.

The US M8 AGS used a scalable armour system and some of the newer Warrior UOR’s have worked on this principle.

The categories below may seem heavily biased to air transportation and when this is compared to actual airlift it might seem ludicrous but if the UK is to maintain its expeditionary capabilities we must carefully tailor equipment to available lift capacity and factors such as bridge classification or surface transportation will also be significant. Modular protection allows air transportability weight limits to be maintained whilst providing for improvements in protection when rapid transportation is not such an issue.

I know I go on a bit about ISO container constraints but if we are at all serious about moving stuff from A to B, the civilian intermodal container ecosystem has much greater capacity than any military logistics system.

With this in mind I think the following is a reasonable weight distribution (assuming we start with weight and not other requirements such as survivability or payload)

Category A; sub 5 tonnes, 1 sling load for a Merlin or 2 by a Chinook and preferably, internal carriage in a Chinook.

Category B; 7.5 tonnes maximum weight, this allows 1 to be sling loaded by a Chinook, 2 from a CH53K and 4 in an A400 or 8 in a C17 (volume permitting). Air droppable, easily carried on civilian trucks or DROPS and able to traverse most if not all bridges and trackway. Going up to 10 tonnes still allows Chinook slinging but reduces the multiples in the A400 and C17, a trade off.

Category C; 15 tonnes maximum base weight with the capacity to handle an additional 5 to 7 tonnes, this allows a base configuration to be slung loaded from a CH53K or future heavy lift helicopter. 2 could be carried in an A400 or if 4 A400’s were used, the combined payload would be 6 vehicles and 6 additional 5 tonne protection kits. A C17 could carry 4 base configuration vehicles or 3 with the protection kits already fitted. Can be carried on standard ISO flatracks, utilise all RE trackway and vehicle bridges and be carried on the back of a standard truck or DROPS. Can also be lifted by the RE Terex AC35 crane and recovered using the FRES SV recovery variant.

Category D; ideally this would be around 30 tonnes base configuration with 5 to 10 tonne additional protection kit, 1 to be carried on A400 or 2 per C17. Additional protection kits would be available but this would reduce aerial transportation to C17 only. However, this might seem too close to Category A and not deliver enough protection whilst still being constrained by the same deployment issues as the heavy equipment it will be supporting. Weight therefore becomes less of an issue because at 30 tonnes plus it is still a special load, borderline for ISO carriage and bridges and at a maximum for A400 carriage. So for this category I would be inclined to worry less about weight and concentrate on protection and firepower, true to the concept of stand up knock down fighting for information in a high threat environment as per many of our recent discussions on fighting Recce rather than sneaky recce. If you need to get the odd one or two into theatre by air, for whatever reason and however rare, as long as it is below 50-60 tonnes it can be carried by C17.

Category E; the heavy 70 tonne plus vehicles that are rarely moved by air

I will expand on vehicles to fit these categories in a future post.

Summary

The old norm that only tracked vehicles are mobile over difficult terrain is no longer the case but at higher weights and for extreme off road mobility tracks would still seem to have the edge

With all the extra equipment such as ECM, communications, air conditioning and off board power generation volumes have inevitably increased and with an increase in volume comes an increase in weight. So although, for example, a 10 tonne CVR(T) might enjoy the benefits of this low weight in mobility terms it suffers in protection and equipment terms.

FRES SV Scout, at 30 tonnes plus and the same width as an MICV like Warrior, has clearly sacrificed some aspects of strategic and tactical mobility in order to get better protection and firepower, a conscious trade no doubt, but if we look at the numerous instances where the nimbleness of CVR(T) has been useful then we might wonder what we are going to fill the gap with, Jackal perhaps or Viking.

Before we even get into issues of firepower and protection the number of factors when considering mobility is extremely diverse and inevitably there will be trade-offs and compromises.

Who would be a vehicle designer?

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