Contenders for the Future Attack Reconnaissance Aircraft – Competitive Prototype Programme
Khalem Chapman provides detailed insight into each contender in the Future Attack Reconnaissance Aircraft – Competitive Prototype (FARA-CP) programme before the US Army narrows its selection down to just two concepts.
The FARA-CP programme – part of the US Army’s Future Vertical Lift (FVL) portfolio – is a competition to design, produce and test a prototype that will replace the service’s now retired Bell OH-58D Kiowa Warrior light attack, observation and reconnaissance helicopter. The project falls under the army’s Futures Command and its subordinate Combat Capabilities Development Command (CCDC).
The CCDC’s Aviation & Missile Center’s Development Directorate leads the overall discovery, development and delivery of the technology-based capabilities required in the FARA-CP programme.
In April 2019, Col Craig Alia, Future Vertical Lift Cross-Functional Team (FVLCFT) chief of staff said: “FARA represents the leap-ahead in technology we’ve been talking about… It’s a critical [programme] in that it fills an existing capability gap created by the divestiture of the OH-58.” Since the type’s retirement in 2017, US Army AH-64D Apache Longbow/AH-64E Guardian attack helicopters are currently plugging that capability gap.
The US Army outlined mandatory requirements that the selected companies needed to incorporate into their respective concepts at a design stage. The service stated that the platform’s rotor diameter must not exceed 40ft (12m), it must have a minimum speed of 180kts (207mph or 333km/h) and allow for the integration of government-furnished equipment including a gun, rocket launcher and General Electric’s T901-900 turboshaft engine – the winner of the army’s Improved Turbine Engine Program (ITEP). Other factors included affordability, range, endurance, payload and gross weight goals.
The US Army is also looking at the companies involved, assessing whether each of the five contenders has the potential to continue with the programme all the way through to the platform’s scheduled field capability date, currently set for 2028. The service is also considering the companies’ execution plan timings, acceptable risk level and funding profile. According to reports in April 2019, the army wants its FARA platform to cost no more than the AH-64E Guardian, roughly US$30m.
The service is due to shortlist two of the five initial candidates in the very near future. Following this, the selected companies will produce airworthy prototypes in preparation for fly-off competition and then the winner of that will be attain a contract award. All five candidates have now been unveiled, after Boeing revealed its FARA-CP concept earlier this month, joining AVX Aircraft, Bell, Sikorsky and Karem Aircraft in doing so. Each respective candidate is detailed below.
AVX Compound Coaxial Helicopter (CCH)
Having teamed up with L3Harris Technologies, AVX Aircraft publicly announced its contender for the FARA-CP programme in December 2018, calling it the Compound Coaxial Helicopter (CCH). It later unveiled a mock-up during the Association of the US Army (AUSA) Annual Conference in mid-October 2019.
The company focused on incorporating a single-engine coaxial rotor with a blended fuselage as part of its design process. According to AVX/L3Harris, the inclusion of this means the CCH will need a smaller amount of power when performing traditional helicopter manoeuvres, requiring 15-20% less energy to hover and 10% less power when loitering, as well as increasing aircraft speeds. The companies claim the platform can reach speeds of more than 230kts (265mph or 426km/h), exceeding the US Army’s requirement by 50kts (58mph or 93km/h). This would also be considerably faster than advanced helicopters currently in service.
Another key feature in the CCH’s design is its inclusion of two ducted fans located behind the wings at the start of the aircraft’s tail section, one on either side of the fuselage. These provide extra forward/reverse thrust, along with asymmetrical thrust used for yaw control, improving safety, high-speed agility and endurance. They will also make the platform quieter than helicopters that fly with open propellers. To complete the smooth, blended fuselage, the CCH features a retractable undercarriage. The combination of ducted fans with a coaxial rotor results in a greater hover out of ground effect (HOGE), range, speed, aerodynamics and fuel efficiency than conventional helicopters.
Shoulder-wings provide an additional 50% of lift while flying at cruising speed, lowering the power required and operational costs while increasing range, speed and overall load. The wings are small to allow for the CCH to be employed in urban environments. The CCH’s tail boom – which has been patented by AVX – helps to offer increased range, endurance and speeds, while reducing the need for additional power for the anti-torque employed in traditional helicopters. The extended-range fuel tanks enable enhanced self-deployment and a larger operational radius.
With manually foldable wings and rotor blades, the CCH will be a compact aircraft, making it compatible with USAF C-17A Globemaster III strategic transports and US Navy guided-missile destroyers (DDGs), allowing for easy long-distance transportation.
Internally, the CCH will accommodate two pilots seated side-by-side and up to 14 troops. There is a troop entrance door on either side of the fuselage and a rear ramp, enabling access for cargo and troops at the back.
The CCH employs a fly-by-wire flight control system to reduce pilot workload and improve efficiency. The modular open systems architecture (MOSA)-based avionics and digital systems enable rapid integration of new capabilities, software and technologies as they become available. Following a MOSA-based digital/avionic backbone is beneficial as it lowers operational costs and welcomes competitive innovation. In this case, the US Army would be able to procure systems and technologies from a wider source of providers. A MOSA-based approach also allows for component re-use and presents a higher degree of commonality.
AVX/L3Harris describe the CCH as “lethal, survivable and affordable" It has a modular internal weapons bay housing sling mounts which fold in and out of the aircraft’s fuselage, located behind the cockpit. The weapons bay is 80in long x 53in high x 58in wide, giving it space for eight air-to-surface missiles, most probably the proven AGM-114 Hellfire and the in-development AGM-179 Joint Air-to-Ground Missile (JAGM). It also employs a cannon under the nose – the size has yet to be confirmed – and manual firing from a gunner seat in the cargo hold.
The CCH will be equipped with a state-of-the-art manned-unmanned teaming (MUM-T) mission equipment package (MEP) that enables the operation of remotely piloted air systems (RPAS), such as the RQ-7B Shadow, from the helicopter. There is a plan for the CCH itself to have the ability to be operated fully autonomously, conducting missions in a full-automated configuration, something that is being pioneered by developments in the FVL portfolio. It will feature Universal Ground Control Station (UGCS) interoperability, providing a platform for the US Army’s unmanned systems to be operated from a single common ground control station. This system is designed around modularly configured flight-critical hardware and software based on NATO Standardisation Agreement (STANAG) 4586 architecture.
Both AVX and L3Harris are confident the CCH platform will “meet 100% of [the] mandatory requirements and exceed 70% of them” Christopher E Kubasik, chairman, CEO and president of L3 Technologies, said: “This FARA-CP solution provides L3 and AVX an opportunity to demonstrate the agility and innovation that sets our team apart in support of the US Army’s modernisation priorities… We are collaborating to deliver a prototype that provides [a] powerful leap-ahead in capability for our warfighters at an affordable life-cycle cost.”
Bell 360 Invictus
Bell unveiled its 360 Invictus platform in October 2019, having announced its partnership with Collins Aerospace a month earlier. Having provided the OH-58D to the US Army for decades, the company is now looking to continue its relationship by providing the type’s successor.
The Invictus follows a single-rotor, blended-fuselage design and is one of the few proposals to not opt for a coaxial rotor-driven configuration. At first glance, it bears a striking resemblance to the Boeing-Sikorsky RAH-66 Comanche prototype which flew in the late 1990s. Commonalities between the two include the sleek, compound fuselage and engine intakes blended into the top of each side of the aircraft, as well as a retractable undercarriage, shrouded main rotor, internal weapons bay, forward-facing rotary cannon under the nose and a tandem-seat configuration for a pilot and weapons systems operator (WSO)/co-pilot to further reduce drag at high speeds. Unlike the Comanche, the Invictus doesn’t have stealth capabilities, instead featuring “advanced sensors, human system interface and communications to increase operational effectiveness and interoperability,” according to Bell.
Like the CCH, the helicopter features a ducted tail rotor that’s canted to save power. Its horizontal stabilisers will help reduce drag, while a lift-sharing wing is incorporated to off-load rotor lift demand in flight, providing 50% of the aircraft’s total lift at cruising speed. This allows for what Bell says is an “optimum propulsive capability without the need for complex drive solutions” The platform’s rotor is articulated, enabling the aircraft to fly at increased speeds while mitigating retreating blade stall, improving agility when transitioning from hover to high-speed flight. Retreating blade stall is caused when a rotor blade moving in the opposite direction to the aircraft’s overall trajectory has a low relative speed but a high angle of attack, resulting in a stall and loss of lift.
The Invictus is designed to operate and manoeuvre efficiently at high speeds. Bell claims a cruising speed of more than 180kts (207mph or 333km/h) in mission configurations, slower than the CCH but safely within the US Army’s requirements. A supplemental power unit will be featured, providing auxiliary power to add both additional horsepower while hovering or at cruising speed, and to give extra support during ground maintenance and routine systems checks. It’s been reported that Pratt & Whitney’s PW207D1 turboshaft will serve as the aircraft’s supplemental power unit, “mounted on the right side of the [platform], with its exhaust exiting out of the right-side infrared signature suppression system” The 360 Invictus will be powered by a single T901-900 turboshaft engine, have an operational combat range of 135nm (155 miles/250km) and the ability to loiter in the area of operations for more than 90 minutes.
A digital fly-by-wire flight control system adds autonomy and agility improvements across all flight modes. Bell/Collins Aerospace will be employing mature modern technologies to offer a path to autonomous flight, along with capability upgrades under a MOSA-based backbone. The platform will also comply with the Future Airborne Capability Environment (FACE) consortium to enable rapid integration of additional, portable capabilities throughout the operational life cycle, making it more adaptable in the face of new, emerging threats, technologies and requirements. Bell says that the Invictus will have the potential to be interoperable with MUM-T systems, presenting new capabilities in line with current, ongoing developments in that field.
The company is focusing on “reliability, adaptability and affordability.” In terms of adaptability, adding that the Invictus will have the flexibility to operate in different combat environments, including urban, confined areas. As part of its pitch, the company is offering a digital thread to enable real-time collaboration through aircraft fabrication, supply chain providers and maintenance, to ensure smoother manufacturing, increased sustainability and operational readiness while reducing costs and mitigating schedule risks. This will ultimately streamline the process of production and maintenance, repair and overhaul (MRO) tasks on operational examples. It will also enable aircraft to spend less time in MRO, boosting the platform’s operational availability. Providing sustainment in this manner will make the aircraft more affordable in terms of acquisition and operating costs while optimising reliability in the field.
The 360 Invictus will have a payload capacity of up to 1,400lb (635kg) and will feature a 20mm rotary cannon under the nose, an integrated munitions launcher accommodating both current and future ordnance, and two internal weapon bays. There will also be an option to integrate an air-launched effects (ALE) capability, alongside advanced sensors to boost situational awareness across domains. The concept art also depicts what appears to be either sighting/targeting optics or a laser designator above the cannon.
Bell is incorporating proven technology employed by its 525 Relentless commercial helicopter, optimised to fit the size and weight requirements of the FARA-CP programme. The 360 Invictus will employ a four-blade 40ft (12m) rotor rather than the Relentless’ five-bladed system. The 525 is capable of more than 200kts (230mph or 370km/h), suggesting the Invictus’s top speed could be in excess of that.
A Bell spokesperson said: “[The] 360 Invictus applies lessons learned from decades of vertical flight expertise to create a low-complexity design capable of delivering transformational, affordable capability to soldiers… Invictus provides the optimal solution to achieve the right mix of power, speed, reliability, intelligence, lethality and sustainability.”
Keith Flail, vice president of Advanced Vertical Systems at Bell, said: “[The company] is committed to providing the US Army with the most affordable, most sustainable, least complex and lowest risk solution among the potential FARA configurations, while meeting all requirements.”
The company unveiled a full-scale mock-up at the AUSA Annual Meeting and Exposition 2019 and, if selected, aims to have the first flying prototype of the 360 Invictus by 2022.
Karem AR40
Having partnered with Northrop Grumman and Raytheon, Karem Aircraft threw its hat into the FARA ring last October, when it unveiled its AR40 concept. Each will contribute different aspects to the platform’s development – Northrop Grumman is leading production and product support, while lending its avionics expertise; Raytheon will act as the AR40’s mission systems integrator and modular open systems architect; finally, Karem will provide its active variable speed rotor technologies.
The last of these has been developing these vertical take-off and landing systems in collaboration with the US Army for the last decade. Last July, Thomas Berger, Karem Aircraft’s FARA-CP programme manager, was optimistic about the competition, saying: “We look forward to leveraging the US Army’s investment by applying these innovative technologies to our FARA aircraft.”
As with the others, the AR40 follows a compound, blended-fuselage design with a retractable undercarriage, and joins the Invictus in being the only other proposal to employ a single-rotor propulsion system. However, it has some unique elements, including a three-blade rigid main rotor and swivelling tail rotor. The AR40’s 36ft (11m) main rotor will be integrated with Karem’s Optimum Speed Rotor technology, which adjusts rotor speed between vertical and horizontal flight movements, while maintaining optimal loading on the blades to maximise propulsive efficiency. It also enables each blade to be controlled individually. The swivelling tail rotor is unusual in that it is angled backwards during horizontal high-speed flight to act as a ‘pusher propeller’ producing additional thrust. Even more unorthodox is its ability to tilt 90° to the side (where it looks more like the tail rotor of a traditional helicopter) for low-speed flight, countering the torque created by the main rotor and stabilising the aircraft. The AR40’s unbalanced vertical stabilisers also provide extra compensation for the main rotor’s torque.
Lift-sharing wings of 40.02ft (12.2m) in length are also able to tilt 90° during flight, so they can be positioned horizontally to generate additional lift at high speeds, or tilted vertically when hovering to enable more of the downwash from the main rotor to pass the aircraft.
The company claims the AR40 will have a maximum speed of 220kts (253mph or 407km/h), exceeding the US Army’s requirements. Its 45ft (14m) long fuselage provides enough space for an adequately sized internal weapons bay and a small cabin behind the cockpit for the transport of four additional passengers or cargo – useful for special forces or medical evacuation operations. Two aircrew are required to pilot the AR40, flying side-by-side in the cockpit.
Sikorsky Raider X
Lockheed Martin subsidiary Sikorsky unveiled its FARA-CP candidate at the AUSA Annual Conference in 2019. The company claims its Raider X platform will be “game-changing” in its warfighting capabilities through the integration of technology gained through the development, testing and evaluation of its X2 experimental high-speed compound helicopter.
The Raider X shares many similarities with the X2, including a coaxial rigid main rotor and smooth, blended fuselage with retractable undercarriage. According to Sikorsky, the X2 technology also enhances level acceleration, braking and of -axis hover capabilities, while reducing platform vibration and its overall weight. The employment of Sikorsky’s Advancing Blade Concept uses two rotors spinning in opposite directions to mitigate loss of lift as it speeds up, which is an issue with traditional helicopters.
For some time now, Sikorsky has been testing and developing its S-97 Raider demonstrator – a platform which has influenced the company’s FARA-CP offering greatly, with the Raider X sharing a similar shape and characteristics. However, the Raider X will be 20% larger to accommodate the US Army’s requirement for the integration of the T901-900 turboshaft. Bill Fell, a senior experimental test pilot on Sikorsky’s S-97 programme and retired army pilot, said: “Every flight we take in our S-97 Raider today reduces risk and optimises our FARA prototype.”
The Raider X is the only FARA submission so far not to include wings. However, it does share some similarities with the others, including a side-by-side cockpit configuration, retractable undercarriage and a large internal weapons bay. The company has yet to detail characteristics relating to speed, service ceiling, size and armament, but it does say that it will meet the FARA-CP requirements posed by the US Army.
In developing the Raider X, Sikorsky is incorporating state-of-the-art digital design and maturing manufacturing processes to reduce acquisition costs while enabling rapid, affordable upgrades. The company is offering a MOSA-based ‘plug and play’ option to continually improve the platform’s survivability, weapons systems, sensors, avionics and mission systems to stay ahead of evolving threats and to take advantage of new technologies while benefiting from competitive add-on acquisitions and mission-specific tailoring.
Sikorsky boasts that the Raider X is designed with low sustainment and maintenance costs in mind and is integrated with self-monitoring technologies and a condition-based maintenance system. This is an effort to reduce the platform’s sustainment footprint, while enabling flexible MRO operating periods, shifting from the traditional routine inspections and scheduled maintenance periods and increasing its operational availability.
The Raider X also incorporates a fly-by-wire flight control system and its rigid coaxial main rotor provides enhanced agility at low speeds, which is a critical requirement when operating in more confined environments, such as forests and urban spaces. The system enables the aircraft to perform turns in half the distance required by helicopters currently in service, meaning it’s more manoeuvrable in an engagement scenario. Using its ‘pusher propeller’ it can apply reverse thrust while in forward flight to slow its descent, giving it a unique ability to dive on targets and change its altitude rapidly, again increasing manoeuvrability and lethality. It can also reverse pitch on its propeller to slow down while maintaining level flight, which is a benefit for pilots as it lets them keep eyes and weapon systems on target. Additionally, the aircraft can add power to its propeller and main rotor to provide rapid acceleration without having to tilt the latter, minimising exposure when under threat.
Dan Schultz, president of Sikorsky, said: “Raider X is the culmination of decades of development, and a testament to our innovation and passion for solving our customers’ needs… By leveraging the strength of the entire Lockheed Martin Corporation, we will deliver the only solution that gives the US Army the superiority needed to meet its mission requirements.”
Boeing FARA
Boeing’s subtly dubbed ‘FARA’ concept is described by the company as agile, purpose-built and “designed to meet the Army’s current mission needs while evolving as technologies and missions change.” It was the last of the concepts to be unveiled, having been revealed by Boeing on March 3.
The helicopter follows a thrust-compounded single main rotor design and employs a six-bladed rotor system, which will be powered by a single GE Aviation T901-900 turboshaft engine. The T901-900 powerplant was the winner of the US Army’s Improved Turbine Engine Program (ITEP) and will be the system to power the service’s desired FARA solution. The company also boasts that the platform will feature a modular, state-of-the-art cockpit with a reconfigurable large area display in a tandem-seated configuration. It adds that the aircraft will also have autonomous capabilities.
Mark Cherry, vice president and general manager of Boeing’s Phantom Works, said: “We’re offering more than a helicopter – we’re offering an affordable and fully integrated system for the army, the mission and the future. We’ve blended innovation, ingenuity and proven rotorcraft experience with extensive testing and advanced analysis to offer a very compelling solution.”
The most unique thing about Boeing’s FARA submission is its use of three separate rotor systems, comprising of a single main rotor, a pusher propeller and a traditional tail rotor. According to Boeing, the employment of three rotors provides greater agility and manoeuvrability. The main rotor consists of a hingeless six-bladed system, while the tail rotor follows a more conventional four-bladed system to combat torque and provide improved low-speed manoeuvrability, with the four-bladed pusher propeller providing the additional thrust needed for high-speed flight as well as low-speed manoeuvrability.
The platform also follows a fly-by-wire design, which the company says “leverages more than 65 years of rotorcraft experience, proven advanced and addictive manufacturing technology, and product commonality driving down risk and costs.” Adding that it will provide a seamless capability within the US Army ecosystem to allow for the integration of Long-Range Precision Fires and ALE. Boeing will also employ a predictive health management system which can adapt to degraded conditions using real-time diagnostics, real-time tactical maintenance and live aircraft interface capabilities.
Shane Openshaw, Boeing FARA programme manager, said: “We listened to the army, assessed all alternatives, and [optimised] our design to provide the right aircraft to meet the requirements… We are offering a very reliable, sustainable and flexible aircraft with a focus on safety and the future fight.”
Boeing FARA is the company’s first all-new helicopter design in years; but the company has not been absent from the rotorcraft field, routinely managing its CH-47 Chinook and AH-64D/E Apache products and working with Bell in producing the V-22 Osprey tiltrotor. It has also partnered with Sikorsky to develop the SB>1 Defiant – which will be the two companies’ submission into FARA’s sister project, the Future Long-Range Assault Aircraft (FLRAA) programme, that will kick-start soon.
Among the contestants, there is no shortage of new technologies and innovation to provide the US Army with its next-generation light attack/scout/reconnaissance helicopter. Each offers new capabilities that were not available for the OH-58D. The involvement of unproven companies such as AVX and Karem alongside a consortium of well-established defence contractors is something relatively rare in such a major programme. The question remains as to whether the US Army will down-select offerings from mainstream companies or gamble on lesser-known contractors.
The FARA-CP programme demonstrates new objectives for the US Army, which is going through a modernisation drive itself. The focus on following MOSA-based approaches across all contenders will enable the service to remain ahead of the fight. New, more streamlined MRO systems seek to increase operational readiness and the provision of new technologies and abilities – such as autonomous flight – will provide the US Army with capabilities it has never employed before, bringing the service further into the modern age.
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