Based on the conclusions drawn in the previous two articles, the ideal future capability would consist of both manned and unmanned rotorcraft of different sizes for maximum operational effectiveness and efficiency, and as such be hybrid in nature. For the purpose of distinction those sizes will further be designated ‘light’, ‘medium’, and ‘heavy’.
Establishing such a fleet, with different types of rotorcraft and the ground support equipment required to operate, will certainly have a large financial impact on nations interested in the development of the FBRC.
It is likely many nations within the Alliance will not be able or even willing to acquire and operate this complete array of rotorcraft. Nations might decide only to change their current inventory with the similar FBRC variant or acquire another variant to complement an updated legacy capability. However, this will come with a considerable impact on interoperability and thus capability since major differences in performance are to be expected.
Eventually, Force Commanders will require balanced, deployed fleets to execute the wide array of missions in the most effective and efficient way. Being NATO’s catalyst for the transformation of capabilities, ACT has a big role to play in this process over the next five to 15 years.
Manned Transport Rotorcraft
Manned Transport Rotorcraft will remain the backbone of the Hybrid FBRC. The light manned transport rotorcraft should be able to lift at least six fully equipped soldiers or 1,200 kg of cargo at full operational range. The medium manned transport rotorcraft should be able to lift at least 15 fully equipped soldiers or 3,000 kg of internal cargo at full operational range or 4,500 kg of total cargo, a part of which externally, at reduced operational range. The heavy manned transport rotorcraft finally, should be able to lift at least 45 fully equipped soldiers or 9,000 kg of cargo at full operational range, or 12,000 kg of total cargo, a part of which externally, at reduced operational range.
Specialized transport rotorcraft for MEDEVAC, Personnel Recovery, and Special Forces operations will more than likely be based on the medium or even heavy variant where the excess of internal space and cargo load capacity can cater for additional equipment, weapon systems, and fuel without deteriorating performance.
Unmanned Transport Rotorcraft
As an indispensable complement to the manned rotorcraft, the unmanned transport rotorcraft should come in two different sizes, ‘light’ and ‘medium’, for optimal effectiveness and efficiency. The larger one would be primarily used to execute routine resupply missions between Forward Operating Bases (FOBs) and Logistic Support Bases (LSBs). It should be designed with a modular cargo bay allowing easy loading and unloading of standardized containers, which would reduce not only the footprint of personnel and equipment involved but also decrease the required handling time. Similarly, the smaller one, which primarily would be used to execute punctual or emergency resupply missions, should boast identical design features, but on a much smaller scale to allow them to enter and leave difficult-to-reach locations within the engagement areas.
Both designs should equally allow loads to be carried externally, in the form of underslung loads, whenever the situation does not permit actual landings. Even though these unmanned rotorcraft will need to be able to operate fully autonomously, provisions should be made to allow terminal control by task force operators whenever the situation calls for it.
In 2013, the US Defense Advanced Research Projects Agency (DARPA) selected the Aerial Reconfigurable Embedded System (ARES)5 to fulfil this essential role. This project is currently in its third and final phase and aims at developing an unmanned transport rotorcraft that could transport a payload of approximately 1,360 kg at speeds in excess of 250 knots. In its current stage of development, it would virtually cover all of the required characteristics of the previously mentioned light, unmanned transport rotorcraft.
The combat variant would arguably be based on the medium or even light version of the manned transport rotorcraft. It could use the same total load capacity for a comprehensive array of defensive and offensive weapon systems. Additional fuel reservoirs could extend range or endurance, allowing it to fully execute its role as a provider of superior, Situational Awareness (SA) and Fire Support (FSp). Additionally, it will need to be able to command and control manned and unmanned combat aircraft to counter an ever-wider range of threats.
Within the framework of the (US) FVL program, the S-97 ‘Raider’ is the prototype of the first ‘next-generation’ light tactical combat rotorcraft. It is currently in the phase of flight trials and technology demonstration, preparing the introduction of the SB>1 ‘Defiant’6 as one of the two remaining contenders in the more than 100 billion USD US Army program to replace its current (medium-sized) helicopter fleet. The SB>1 is a Joint Multi-Role Technology Demonstrator (JMR-TD) based on a co-axial rotor and clutched push-propeller propulsion system. The other JMR-TD contender, the V-280 ‘Valor’,7 is expanding on the tiltrotor technology introduced by the V-22 ‘Osprey’. Both companies will eventually be requested to procure a transport and a combat variant in the new ‘medium’ size category of next-generation rotorcraft.
On Speed and Range
Although the requirements are still being refined within the FVL program, the notional concept for a ‘medium’ rotorcraft specified the capability to carry up to 12 troops in ‘hot-and-high’ conditions at altitudes of 6,000 ft (1,800 m) and temperatures of 95°F (35°C). It should have a combat radius of 230 Nm (425 km), an overall unrefuelled range of 460 Nm (850 km) at a cruise speed of 230 knots (425 km/h). Two observations need to be made while considering these requirements. First, we need to understand that they were based on recent operational experiences and consequently do not necessarily reflect future application. As pointed out in my previous article, there are arguments to support the statement that more important user requirements are not specified at all.8 Second, it is important to consider certain design choices will invariably favour some requirements at the expense of others.
Chapter Organization – The FBRC will Need to be Lean and Mean
The ‘Organization’ part of the FBRC will invariably be the result of trade-offs between operational and tactical demands, security and force protection constraints, and logistic support considerations. Traditionally, deployed helicopter units have large logistic footprints. They need sheltered infrastructure, a significant number of technicians, and a huge amount of readily available spare parts to reduce operational downtime of the different platforms. In addition, helicopters require considerable amounts of fuel to operate.
The most obvious way to circumnavigate these problems lies in the design of the different rotorcraft of the FBRC. One of the main requirements of the clients, and consequently objectives for the manufacturers, is to develop next-generation rotorcraft that would need significantly less maintenance than is the case today. Because of the mix of types and sizes expected in the FBRC, research and development of zero-maintenance components, the extensive use of easy-access Line Replaceable Units (LRU), and maximum commonality in sub-systems are of utmost importance. All of the above is far from impossible as proven by the US Marine Corps, which has been successfully operating the AH-1Z ‘Viper’ and UH-1Y ‘Venom’ for quite a number of years. Based on rather old and different helicopter designs, these two front line helicopters now share 84% of parts commonality, thus significantly reducing their logistic footprint while dramatically increasing combat effectiveness.9
To decrease the logistic footprint of deployed FBRC units further, technology and tight organization could bring easy and affordable solutions. A significant reduction of spare parts stockpiles could be achieved by the extensive use of advanced 3-D printing and, as stated before, a very high degree in the commonality of parts and sub-systems. Although the requirement for relatively large stockpiles of fuel would persist, easy solutions could be found to reduce this to acceptable levels by having the (unmanned) transport rotorcraft that are executing the routine resupply missions refuel at the LSBs and not at the FOBs, thus reducing the required fuel stocks at the FOBs.
Another organizational consideration could be to put a significant part of the unmanned rotorcraft under the command and control of the Joint Logistics Support Group (JSLG) to manage their theatre-wide use effectively, while at the same time reducing the planning burden of the deployed FBRC units.
Against the background of the Future Operating Environment (FOE)10, it would make a lot of sense if the FBRC unit(s) were stationed at one or more FOBs at relatively far distances from immediate threats and enjoying the support from other units and services partaking in the operation, while at the same time minimizing their logistic footprint. Co-locating the FBRC units with their supported combat units would allow the FBRC units to rely on them for force protection and other services. At the same time, it would facilitate planning, rehearsal, and execution of the mission tremendously.
Out of these FOBs, a number of well-defined mission types need to be synchronized with the overall battle rhythm and de-conflicted with other airspace users. The numerous routine resupply missions, mainly flown by the larger unmanned transport rotorcraft, would represent a large portion of the daily movements. MEDEVAC and QRF 24/7 stand-by missions would also be organized out of the FOBs, but the unit(s) should be prepared at all times to push these dedicated assets towards Forward Operating Locations (FOLs) either temporarily or for the whole engagement period to reduce intervention times. Finally, whenever in direct support of a specific operation, the FBRC will need to gather the required assets on the FOBs and FOLs to support task forces with their insertion, extraction, emergency resupply, and in close cooperation with other providers, the required SA and FSp.
Chapter Interoperability – Key to Mission Success
From the two above described lines of capability development, it is only a small step toward the next one. ‘Interoperability’ will, even more than today, be key to mission success. As underscored by the JAPCC, interoperability in operations is so much more than just standards for communication; it is about preserving the ability to work together.11 Interoperability is more than the flawless exchange of information but must also include a very high degree of commonality in equipment and consumables as well as tailored tactics, techniques, and procedures. Indeed, it also refers to the education and training required to fully understand the mission, capabilities, and limitations of all the participants within the operation. In the pursuit of maximum interoperability, absolute priority should be given to the direct clients of the FBRC, being the supported combat units. Equally important however are the force multipliers such as the manned and unmanned combat aircraft as well as the force enablers such as Air-to-Air Refuelling assets.
To achieve this, attention should be paid from the start of the development process to keep the different rotorcraft variants as similar as possible with regard to the design of sub-systems and components. This principle should not be limited to the different versions of the same rotorcraft model, e.g. the ‘medium-sized’ transport and combat rotorcraft, but equally to the lighter and heavier rotorcraft within the same family. Obviously, this will not be possible for all parts of the platforms such as propulsion and transmission trains but should be feasible for almost every other part of the weapon system.
An even bigger issue is the preservation of interoperability between the FBRC and the legacy platforms they will operate within deployed operations. Even though some of these legacy platforms may have received a mid-life-update, serious differences in performance are still to be expected. These differences can be technical, such as speed gaps of up to 75%, or technological, such as incompatible communication systems. There will be no easy solutions, and the end result might well be that for the planning and execution of certain missions, only one family of assets will be used to circumnavigate irreconcilable interoperability gaps.
Outlook and Conclusions
Considering the completely different design features of both JMR-TD contenders (the SB>1 Defiant and V-280 Valor); the future operating environment, which could vary from mountainous wastelands to littoral megacities; and the large diversity in future missions for the FBRC, it is likely both designs will be further developed. The author’s previous statement that a ‘one-solution-fits-all’ would be very unrealistic for the FBRC has recently been affirmed by the director of the FVL program stating that ‘a single aircraft design can’t replace the Army’s entire helicopter fleet’.12
The first steps towards a Future Battlefield Rotorcraft Capability have been taken, but there is still a long way to go before we witness Full Operational Capabilities in deployed operations. Technology is a powerful driver of this process, as will be demonstrated in the near future by the two JMR-TDs that are reaching maturity. However, it should be clear to all stakeholders that user requirements, military effectiveness and efficiency, and affordability should be equally if not more important drivers to be taken into consideration when closing the contracts and creating production lines.