Exercise TALISMAN SABRE 2017 (TS17) brought the most advanced technology of Australia and its global partners to Shoalwater Bay in a spectacle of military capability. On the receiving end of this stood a small mobile force tasked with the defence of the shores against the multinational Joint Task Force. Playing the role of the enemy in TALISMAN SABRE, the 7th Battalion (7 RAR) felt the impact of modern UAVs, offensive support and overwhelming manoeuvre forces. TS17 gave 7 RAR an insight into being hunted by surveillance and reconnaissance systems by a vastly superior force. A number of key tactical lessons were learnt and importantly exposed the limitations of our current Armoured Personnel Carriers (APC). So what might the future of protected mobility look like?
You can run, but you can’t hide
Being on the frontline of a mobile delay battle requires a constant attention to your own force signature. Superior armour and fire power were able to make short work of enemy dismounted forces, but the looming presence of enemy surveillance gave an impending sense of compromise. A contemporary example of the vulnerabilities of static armour is the rocket attack at Zelenopillya in 2014. Ukrainian mobile infantry were detected and massed artillery killed at least 36 soldiers (1).
Even the most successful offensive action on TALISMAN SABRE could be halted suddenly by aircraft identifying thermal signatures of the vehicles, and subsequent targeting. Current APCs produce such heat from their engines that thermal imagery can easily identify them up to hours after being shut off. This is further exacerbated by the requirement to constantly turn the vehicles on in order to recharge the auxiliary batteries and allow continued use of the electronic equipment inside. The ageing vehicle fleet was not designed to sustain the operation of a modern secured communications suite or Battle Management System (BMS). The battery capacity of the APC is unreliable and frequently failed – including at critical times. This prompted us to consider what solutions might exist in the future to rectify the problem.
Electric Powertrain in an Infantry Fighting Vehicle
Electric motors are inherently more efficient than Internal Combustion Engines (ICE). Energy is not wasted in heat or noise resulting in a reduced vehicle signature. For every 100 joules of energy input into an electric motor, 98 joules produce force and 2 joules are converted into heat and sound as by-products. This gives electric motors are 98 per cent efficiency, compared the average ICE with 38 per cent efficiency(2) . IFVs typically operate at slower speeds when operating tactically in the field, as they bound in pairs and move through vegetation. In these conditions electric propulsion is typically more efficient than an ICE. Unlike an ICE motor, an electric drivetrain at the halt consumes no power when idling, significantly increasing the tactical range of the vehicle.
The biggest limiting factor in converting to fully electric vehicles with no consumption of fossil fuels is the energy density of current batteries. We do not have a battery with enough capacity to fit in an IFV and sustain it for the required duration in comparison to an ICE. A solution to this is to adopt a hybrid propulsion system. The automotive industry has been using hybrid propulsion in civilian vehicles for some time. A hybrid system would involve a small battery, capable of fully electric propulsion for 30-50km. After this time a small fossil fuel generator would start to recharge the battery and power the direct drive electric motors. Although using fossil fuel, this system has still been proven to be 50 per cent more efficient than a direct drive ICE. This also has the added benefit that the generator can be placed in any location within the vehicle, as it does not require direct drive. The result is an engine that can be placed away from large heat sinks such as armour plating reducing the heat signature of the vehicle at the halt.
Reduction in Maintenance
Electric motors are inherently more reliable than ICE motors. Fossil fuel engines require multi-gear transmissions, but electric motors have a consistent torque curve – meaning a transmission is not required to keep the motor functioning at an optimal torque output. There are also no engine oils and generally less than 20 moving parts. The service life of electric propulsion is cheaper and more reliable when compared to ICE engines with 400 or more moving parts, requiring fluids and regular and specialist servicing. By transitioning our IFVs to electric propulsion, the maintenance costs per vehicle would be reduced and the vehicle fleet would spend less time under maintenance. The reduced service life cost could be used to offset the spending on development and procurement.
The end goal of electric motor integration is a 100 per cent electric propulsion system, with a rapid charge or battery swap capability. Unfortunately, the current battery capacity means that this reality is beyond the grasp of existing technology. With the proper design concepts in place early a tranche system can be used to establish a vehicle base which performs rudimentary functions within the IFV and gradually implements a greater reliance on electric energy sources.
Setting the Foundations
Realistic steps can be taken to implement electric propulsion within the existing Land 400 Project. There is an ever-expanding reliance on electronics for both mounted and dismounted troops. Everything from radios and night fighting equipment to field laptops and BMS require a sustainable power solution. Development of rudimentary functions, like start-up and idle, to be powered by an electric motor would set the groundwork for Tranche 2.
If development is started early for a compatible hybrid engine, there would be an opportunity to retro-fit the in-service vehicles at the end of their engine service life. Once the battery capacity has been developed to sustain the vehicles, a 100 per cent electric propulsion system would become the desired end state.
Conclusion
Like any vehicle procurement, the Army is investing large amounts of time and money to providing the best system possible. Early identification of future demands and a continual reflection of how we can improve our systems can save the Army its valuable resources and increase our warfighting capability. The inclusion of an electric motor may be a way Army can not only future-proof but also provide sustainable, effective and efficient vehicles to the force.
About the authors
Lieutenant Harry Wagner and Lieutenant Zac Hucker are both Platoon Commanders in Alpha Company, 7th Battalion, Royal Australian Regiment. They are also both graduates of the Australian Defence Force Academy and the Royal Military College – Duntroon. Their experiences on exercises this year inspired them to pursue this concept with the aim of starting a discussion about the future of IFVs.
References:
(1) P. A. Karber, “Lessons Learned” from the Russo-Ukrainian War, The Potomac Foundation, 2015, pp. 36-37.
(2) S. M. Lukic & A. Emadi, Modelling of electric machines for automotive applications using efficiency maps, IEEE Transactions on Power Electronics, 2003, pp. 543-550.