1. Helicopter Carried Vehicles — Part 1 (Introduction)
  2. Helicopter Carried Vehicles — Part 2 (Motorcycles and ATVs)
  3. Helicopter Carried Vehicles — Part 3 (UTVs and Load Carriers)
  4. Helicopter Carried Vehicles – Part 4 (Medium Wheeled Vehicles)
  5. Helicopter Carried Vehicles – Part 5 (Tracked Utility Vehicles)
  6. Helicopter Carried Vehicles – Part 6 (Multi Axle Skid Steers) 
  7. Helicopter Carried Vehicles – Part 7 (Uncrewed) 
  8. Helicopter Carried Vehicles – Part 8 (Tractors and Trailers) 
  9. Helicopter Carried Vehicles – Part 9 (Engineering Plant and Watercraft) 
  10. Helicopter Carried Vehicles – Part 10 (Weapons and Systems) 
  11. Helicopter Carried Vehicles – Part 11 (Comparisons) 
  12. Helicopter Carried Vehicles – Part 12 (Discussion) 

Not many commonly available tracked vehicles fit within the dimensional constraints for internal carriage, but a handful do exist.

In general terms, tracks provide greater traction and lower ground pressure than wheels, but are slower.

Where high levels of mobility are required in extreme ground conditions, tracks tend to be favoured. Tracks tend to be pricier and heavier than wheels.

Modern continuous rubber tracks address many of the disadvantages of conventional linked tracks and are now the norm in small construction plant and utility vehicles.

Wheel Replacement Track Kits

Wheel replacement track kits are available from manufacturers such as Duratracks, Matracks and Camso, they provide some benefits of tracks as a retrofit, although many argue they are good for snow but not robust enough for mud (am sure the manufacturers would refute this).

That aside, the biggest issue with using track kits is they raise the height of the vehicle, and in this application, height is never in abundance.

Tracks Over Tyres

More common in the construction plant and forestry industry, track over wheels or track over tyres (perhaps more accurately) are a low-cost means of providing additional surface area and traction in poor soils.

Skid steer type multiple axle vehicles would have to disable any front and rear wheel steering.

Different widths and construction methods are used for different types of soil and snow, or where traction is favoured over flotation.

Snowmobile

An exception to the rule that tracks are slow, the Royal Marines Oversnow Reconnaissance Vehicle (ORV) is a centre drive single track snowmobile.

The newer Royal Marine models seem to be the two-seat BRP Skid-do Crossover range, the XTerrain Brutal.

Not quite in the same category, but still worth a mention, is the Widescape WS250 single-tracked snowmobile.

Obviously, not as capable as a conventional machine, but at 91 kg, 2.2m long, 800 mm wide, and 1.3m high, as transportable as a conventional motorcycle or e-bike.

Alpina in Italy manufactures work-class twin-track snowmobiles, with three models available.

The centre seat can accommodate two and the small load platform can be fitted with additional seating to bring the carrying capacity to five.

To allow easier movement on hard surfaces (and reduce the overall length), the skis can be replaced with small wheels.

A pontoon kit is available

It can be quickly fitted with a ROPS and the rear seats can be substituted with a rescue stretcher kit which has an electronic levelling system for the stretcher.

Its payload is 830 kg and its kerb weight is 623 kg.

Articulated

The well-known and well-established Bv206 from BAE Systems Hägglunds is an extremely versatile tracked articulated amphibious vehicle.

With a ground pressure of less than 14kPa/2PSI, its mobility needs no introduction, but this video shows just how good it is.

The basic vehicle weighs approximately 4.5 tonnes, with a maximum payload of 2.2 tonnes or 12 personnel and their equipment.

Although not in service with the UK, there is a folding cab version, and this has been proved as an internal load for Chinook.

Even in this configuration, internal carriage on Merlin would not be possible without disassembly.

Hopefully, the Bv206 vehicles in UK service will be replaced by BVs10 Mark 2 in the coming years as part of wider programmes.

Ravco Renegade

Ravco in the USA manufactures the Renegade 300, quite a compact machine.

It has seating for four and a total payload of 100 kg.

Litetrax

Although less capable than a Bv206, the Litetrax MTX is a two or four-seat tracked vehicle from the USA and is probably more practical and realistic for Merlin and Chinook internal carriage.

With the fitted roll bars, it is slightly too high for Merlin but like many above, a folding roll bar would enable it to easily fit.

It has an unloaded weight of 1.2 tonnes and a maximum payload of approximately 500 kg.

A cab is available, but this would make it too high for internal carriage.

The suspension provides 450 mm of ground clearance and with the tracks extending beyond the front and rear of the chassis, approach, and departure angles are excellent, although top speed is only 30kph.

Litetrax describes how the latest models have a completely sealed body with no intrusions except for a drain plug, providing easy ‘amphibiosity’.

It is compatible with the width constraint on Merlin and Chinook, although quite close to the limit for Merlin.

All Track AT-20HD

Similar to the Litetrax, but with a longer commercial heritage in the demanding oil exploration sector, is the Canadian Alltrack AT-20HD 

It has a kerb weight of just over 2,700 kg but with a payload of nearly 1,600 kg, a gross weight of 4,309 kg.

At 1.5m wide, it would also be an easier load than the Litetrax and is 4.1m long.

It would need modification to remove the cab and implement some form of folding roll bar or collapsible cab for internal carriage to be possible.

Despite being slower and without articulated suspension, the main difference between the AT-20HD and Litetrax is payload and practicality for load carriage. Its longer and flat load bed and payload of 1.2 tonnes make it a much more useful machine.

The 1.5m × 1.5m load bed could be used for a single NATO pallet or even a lightweight folding troop seating module.

At 800 mm from the ground to the load bed, it is not inconceivable that 4 such seats could be fitted back to back and side facing. These types of seats tend to be about 500 mm wide and 750 mm high, within the 1.8m height constraint of Merlin. This would result in a single vehicle with a carrying capacity of 6 personnel with some space for personal equipment.

Loglogic Softrak 75

One from the UK this time.

The Loglogic Softrak 75, one of which is actually in use as an MoD range vehicle

It has a kerb weight of 2,550 kg and a payload of 2,000 kg, with hydraulic and hydrostatic power take-off should it be needed.

With 600 mm Bridgestone tracks, the Softrak 75 is 2,100 mm wide, too wide. The length is 3.276m and the height to the top of the cab is 2.3m, also too high.

Loglogic offers a tracked trailer (more on this later) with 400 mm and 600 mm wide tracks, so I wonder if using 400 mm wide tracks on the vehicle would be possible, the 100 mm reduction bringing width down to 2.0m. With a folding ROPS, it would also be low enough.

The load bed is 1,784 mm long and 1,800 mm wide. The height from the floor to the base of the load bed is 1.2m.

With a top speed of 16 kph, it would take some to cover any distance but with a ground pressure of less than 2PSI, its terrain accessibility is excellent.

It can also be fitted with a demountable cargo module, akin to a manual DROPS style arrangement, or a crew pod.

Even with narrow tracks and a folding ROPS, it would still be challenging for Merlin internal carriage.

Tracked Dumper

Commonly used in the construction sector, tracked dumpers focus on payload and not speed.

Manufacturers of smaller models include Marooka, Cautrac, Yanmar, and Kubota.

A typical compact design is the Yanmar C30R-3, 1.55m wide and 3.28m long, top speed is a whopping 11kph.

With an operating weight of 2,650 kg, it has a payload of 2,500 kg on the 1.69m × 1.41m tipping load bed.

An older model is shown in the video below, but it shows its terrain access and load capacity.

Although the seat sits relatively high up, it swivels, and the vehicle can be driven in either position. This will make loading and unloading much easier.

Slightly smaller than the Yanmar, the Geier Series 85 Forest is as small as a quad ATV.

Probably better characterised as engineering plant than a utility vehicle, but it can be fitted with a load bed, and it is only 1.1m wide and 2.52m long.

Data Table

VehicleLength (m)Width (m)Height (m)Kerb Weight (kg)Payload (kg)
BRP Ski-Doo3.251.201.23400200
Alpina Sherpa 1.63.481.471.80623830
Lite Trax (2)3.201.952.201,200500
BRP Ski-Doo4.101.501.902,7001,600
Loglogic Softrak 75 (2)3.282.002.302,5502,000
Yanmar CR30R (1)3.251.551.752,6502,000
Geier 85 (2)2.571.102.351,5101,200

(1), height to ROPS pivot

(2), would require the cab or fixed ROPS to be replaced with folding ROPS to fit either helicopter

Load Diagrams

Merlin

Chinook


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