Eurosatory 2018: QinetiQ’s in-wheel electric hub drives on the move

Stelios Kanavakis

Senior Defence Analyst

QinetiQ is showcasing its in-wheel electric hub drives at Eurosatory 2018. The technology concept seems to be ready to move a step further in the near future. Army Recognition had the opportunity to discuss the programme status, to bring you the latest information.

QinetiQ electric hub drive 
Two mock-up vehicles with the left one depicting the increased space available inside a vehicle due to the absence of transmission,  gearboxes and the relocation of the engine. A full-scale prototype vehicle could be available after 18 months, upon the completiont of testing on an actual vehicle platform. (Picture source Army Recognition)

Hub drives are not something new. They have been in the market for a long time but the initial results had not been encouraging. The programme received a USD2,7 million funding from DARPA in 2016 in an effort to bring the technology into the testing phase.

The benefits of using hub drive are multifaceted and will revolutionize the market of wheeled military vehicles, as high power and torque density will be available. In-wheel drives allow reduction of the conventional vehicle driveline, including removal of torque converter, transmission, transfer case, prop shafts, differentials and axles. This allows volume and weight improvement, even after a generator and power converter are added to the diesel engine.

What’s equally important is that the design and manufacturing process would change, removing the requirement to penetrate the hull for the engine and transmission system to go through. That would increase not only make the manufacturing process cheaper, but it would also increase the vehicles’ protection and would give additional space to carry more people.

The weight reduction, which we found out that it would be in the range of 15%, and space availability can eventually allow room for more electronic equipment, larger weapon systems or even power-consuming laser weapons and more armour.

And the advantages do not end up here. Electric hub drives have no high-pressure hydraulic systems, they are sized and rated for a wide range of vehicles, while there is electrical generation of breaking power and integrated mechanical friction brakes.

Someone would definitely ask about the cost and the capability to support such a technology. In terms of cost, customers should expect to pay a small premium but the overall support cost (remember, no moving parts and less fuel) during a vehicle’s life will be much lower. 

As with many new technologies there is always a cultural barrier to overcome in the modus operandi. In the case of electric hub drives the results of the previous tests have not managed to open the market. Nevertheless the trend is there and this time it is not the defence industry that will diffuse the technology to the civilian sector but the exact opposite.

Tesla is leading the way for electric cars, with the rest of the automotive industry moving rapidly to the new technology too. Inevitably the defence industry will follow, albeit at a slower pace. 

Another important engineering requirement, among those that must be taken into consideration, is the batteries. Obvious in many other parts of the market, such as in the unmanned systems (especially the underwater unmanned vehicles), power density and size of the battery are two crucial factors. 

All vehicles, especially hybrid ones with electric hub drives, need battery-sourced power to keep their electronic systems running. That requirement is even higher now that an increasing number of armies are introducing digital soldier equipment. Therefore, for the vehicles to run their systems silently while stationary, it is necessary to have the right power density in small size, to add as many cells as possible.

It seems that QinetiQ’s electric hub technology is ready for the next step. As Army Recognition has found out, discussions are well underway with different defence manufacturers to add the system in their wheeled vehicle platforms and start testing them within the next 18 months.