The threats to Aircraft are growing at the high end of the conflict spectrum, with countries like Russia and China deploying agile and long-range air defenses, and sophisticated electronic warfare capabilities, integrated with cyber warfare operations. Existing rotorcraft might not be able to survive or fight effectively in places like Eastern Europe if war breaks out there.
The U.S. Army needs a faster, more survivable, longer range helicopter that meets its performance, cost, and schedule objectives while providing unmatched operational effectiveness on the highly contested battlefield of the future. U.S. Army launched Future Vertical Lift (FVL) program to replace its ageing rotorcraft fleet including UH-60 Black Hawk used by the Army, Navy, Air Force and Coast Guard, CH-47 Chinook and the AH-64 Apache used by the Army, in a decade of combat from Operation Iraqi Freedom and Operation Enduring Freedom.
The Army is now testing, assessing, and deliberating on two separate helicopter programs for the future. The first is the Future Attack Reconnaissance Aircraft (FARA), while the second is the Future Long-Range Assault Aircraft (FLRAA). The FLRAA is expected to double the range and speed of the current UH-60 Black Hawk helicopter. Competitors include Bell Helicopter’s V-280 Valor, a tiltrotor design, and an entry from Lockheed-Sikorsky-Boeing called the DEFIANT X.
Both models are designed to meet Army requirements for speed, range, and lift. Retired U.S. Army Lt. Gen. Ben Hodges said he’s excited about the prospects for the FLRAA program. In an interview with The National Interest, Hodges did not favor one entry over the other but was pleased with the Army’s requirements and goals for the program.
“Of course the distances are becoming greater, the loads are becoming greater and enemy air defenses are getting better, so there are so many different challenges,” Hodges said. “The U.S. is working hard to develop a capability that can put a lot of troops on the ground in a small place quickly so we can mass combat power. They are working to come up with a system that is survivable and can meet the requirements.”
Future Vertical Lift increases reach, protection, lethality, agility and mission flexibility to successfully dominate in highly contested and complex airspace against known and emerging threats. Through next-generation designs, the future vertical lift will integrate situation awareness, supervised autonomy, advanced manned/unmanned teaming and scalable and tailorable lethal/non-lethal fires and effects.
Future Vertical Lift (FVL) program
FVL officially began in 2009, and the strategic plan for the project was issued in October 2011. FVL is in a fairly early stage, and aircraft likely to result from this program’s work are not expected to be operational until the early 2030s.
Future Vertical Lift (FVL) will develop a family of helicopters for the United States Armed Forces that shall share common hardware such as sensors, avionics, engines, and countermeasures. The deadly new aircraft will be engineered to allow the helicopter to find enemies on the move, track multiple targets simultaneously, perform targeting operations during high-speed manoeuvres, and will integrate weapons unaffected by environmental effects such as wind and temperature. The goal is to create a new rotorcraft that uses new technology, materials, and designs that are able to carry heavier payloads at higher speeds for longer distances, are more reliable, easier to maintain and operate, have lower operating costs, and can reduce logistical footprints.
Increasing rotorcraft range (and speed) could conquer “the tyranny of distance,” as described in a recent Center for Strategic and International Studies panel on Future Vertical Lift. Extending the range of rotorcraft could make them “strategically self-deployable,” meaning they might cover long distances without needing to hitch a ride on a massive transport vehicle to get to a war zone. Self-deployability and range might also help the Army decrease its reliance on ground convoys, which can be vulnerable to attack, writes Torie Rose DeGhett. It will include a “fly-by-wire” technology allowing helicopter to fly along a particular course by itself in the event that a pilot is injured or incapacitated. This is the kind of technology which could, in the future, allow for unmanned helicopter operations.
The first Future Vertical Lift aircraft to be fielded by the Army will come in the medium-lift category, where attack and cargo lift helicopters reside, according to Maj. Gen. William Gayler, the new Army Aviation Center of Excellence commander at Fort Rucker, Alabama. Because the Marines and Air Force are more interested in a medium-lift, the Army has decided to focus on that weight class for the first helicopters that will be fielded starting in the early 2030s, according to Gayler. The Army is still leading the effort. Mike Hirschberg, executive director of the American Helicopter Society (AHS) International, agreed FVL could be either unmanned or optionally manned, given its diverse mission sets.
Wok with Unmanned Aerial Systems
In concert with the development of Future Vertical Lift is the development of the future family of Unmanned Aerial Systems that will work in intelligent synchronization with and complementary to future vertical lift. Army was also working to develop a next-generation drone demonstrator aircraft, which can enter hostile combat zones to allow attack helicopters to remain at a safer distance from danger.
As it stands, FVL will consist of several aircraft, starting with an advanced unmanned aerial system platform capable of delivering targeting data for long-range precision fires, said Brig. Gen. Walter Rugen, deputy commanding general of the 7th Infantry Division and director of the Future Vertical Lift Cross Functional Team. It will also be capable of electronic attack on enemy radars systems. “We want to be able to spoof those radars, jam those radars, hunt those radars and kill those radars,” he said. There will also be a future attack reconnaissance aircraft, “sized to hide in radar clutter … to operate in the urban canyons of mega cities,” Rugen said. This aircraft will be “optionally manned” with “a lot of autonomy baked into” the platform.
And these two form our advance team, and this advance team needs to deepen the interoperability between our ground force and fires team to be able detect and deliver lethal effects, assess those effects and re-attack if need be,” he said.
Future Vertical Lift and future Unmanned Aerial Systems development will outpace threat capabilities and quickly deliver future innovations to the warfighter through an open architecture and a path to autonomy that enables flexible integration of future advanced technology and capabilities. Future vertical lift’s lethality, autonomy, reach, agility and protection attributes, teamed with future unmanned systems, extends Army Aviation’s interoperability to get there, stay there, and dominate in Multi-Domain Battle. Future Vertical Lift enables the joint force to seize, retain, and exploit the initiative giving the ground force commander an asymmetric advantage against peer and near-peer adversaries.
Mission sets are to include cargo transport, utility, armed scout, attack, humanitarian assistance, medical evacuation, anti-submarine warfare, anti-surface warfare, land/sea search and rescue, special warfare support, vertical replenishment, airborne mine countermeasures, and others. The FVL family of aircraft will be required to have either optionally piloted or autonomous flight capabilities.
Helicopters are currently categorized by weight as light, medium, heavy and ultra-heavy. The Defense Department’s program to develop the next generation of rotary wing aircraft will do away with categories based on weight and will instead break them down into capabilities. The first set is the lightest variant while the fifth is the heaviest. Capability set 3 refers to the medium-lift variant.
FVL is currently looking at five basic categories (or “capability sets”) of aircraft varying in size, but the initial foci are a medium transport platform capable of succeeding the Army UH-60 Black Hawk and Marine H-1 “Huey” utility helicopters—the Future Long-Range Assault Aircraft
(FLRAA)—and a scout platform roughly in the role of the current Apache, now called the Future Attack and Reconnaissance Aircraft (FARA).Heavy-lift variants may follow.
“The trend now is to break the aircraft down into “capability sets,” he said. There will be four or five capability sets, he said. Capability set 1, for example, might encompass reconnaissance, close-air attack and direct attack. There are new categories that are going to be rolled out soon,” said Jose Gonzalez, deputy director of land warfare, munitions and tactical warfare systems. Gonzalez listed reconnaissance, close-air support, direct attack, marine interdiction, medical evacuation and urban assault and security as some of these new capabilities.
Once the capability sets are decided upon, it will be up to the services as to which ones they want to pursue first. “We should be seeing a material development decision for an Army-led future vertical lift program, leveraging the joint multi-role program, very soon,” he said. “Once a material development decision is made on the first capability set, an analysis of alternatives will be the next step. “We haven’t done an analysis of alternatives, so we don’t know where is the biggest bang for the buck.”
The two capability sets, defined by US Army Training and Doctrine Command, the service’s requirements authority, were communicated in two request for information, released in February. These were a light reconnaissance, attack and assault/lift type with a cruise speed greater than 200kt (370km/h) and 229nm unrefuelled range; or a mid-weight, general-purpose aircraft with a top speed of 230-310kt and 229-450nm range. With class 2 fulfilling the Apache’s attack role and the UH-60’s utility mission. The next-generation aircraft, which would combine the speed of a fixed wing aircraft with a helicopter’s vertical lift capabilities, could be fielded by the 2030s. While the Army will likely lead the first program, Gonzalez said, “We are really trying to do this in a joint manner.” There are six elements to the future vertical lift strategic plan, and one is “joint requirements,” he said.
“FVL is a high priority. We have identified capability gaps. We need technologies and designs that are different than what the current fleet has. It will carry more equipment, perform in high-hot conditions, be more maneuverable within the area of operations and execute missions at longer ranges,” said Rich Kretzschmar, project manager for the FVL effort. It shall have an ability to both reach high speeds and hover like a helicopter.
US Army starts work on future attack-recon helicopter
The Army is now working on two Initial Capabilities Documents (ICDs) to lay the conceptual groundwork for new weapons, munitions and a supplemental next-generation drone. The new attack-recon helicopter is intended to follow the – now much further along – FVL utility helicopter program effort; currently being developed as a Science & Technology demonstrator program, this program now includes built, airborne helicopters.
A future attack-reconnaissance helicopter, now in its conceptual phase, is a key part of a wide-spanning, multi-aircraft Army Future Vertical Lift (FVL) program. Current areas of exploration, McConville elaborated, include examinations of aerodynamics, aircraft configurations, new sensor technology and the physics of advanced attack helicopter flight.
We know that in the future we are going to need to have a lethal capability, which drives us to a future attack reconnaissance platform. The Apache is the world’s greatest but there will come a time when we look at leap ahead technology,“ Army Vice Chief of Staff Gen. James McConville told a small group of reporters.
For instance, the new aircraft will be engineered to integrate weapons and sensor systems to autonomously detect, designate and track targets, perform targeting operations during high-speed maneuvers, conduct off-axis engagements, track multiple targets simultaneously and optimize fire control performance such that weapons can accommodate environmental effects such as wind and temperature, Army officials describe. Any future attack platform will also be optimized for what’s called “high-hot” conditions, defined as 95-degrees Fahrenheit and elevations of 6,000 feet, where thinner air can make helicopter maneuvers far more challenging.
The new air vehicle itself is likely to contain composite materials, higher-resolution sensors, infrared heat suppressors and radar signature reducing configurations.
Although requirements are still being refined, new aircraft will need to have hover, speed, range, and payload and fuel efficiency characteristics “beyond any current rotorcraft”. They should fly faster reaching speeds of 230 kn (260 mph; 430 km/h) with more maneuverability, carry more payload up to 12 troops, operate in “high-hot” conditions at altitudes of 6,000 ft (1,800 m) and temperatures of 95-degrees Fahrenheit, reach further without refueling i.e. combat radius of 424 km (263 mi) and overall unrefueled range of 848 km (527 mi).
The engine will require alternative, advanced engine/power system configurations that enable enhanced mission capability, such as improved time on station, increased mission radius, and quieter operation. Due to the different configurations of the airframe, power outputs from 40 shp to 10,000 shp are being studied.
Common Hardware and Software
A key advantage of a joint FVL program is that it will engender further inter-operability between the services and, for example, allow an Army helicopter to easily be serviced with maintenance at a Marine Corps Forward Operating Base, Dan Bailey, JMR TD program director said. They are to share common hardware such as sensors, avionics, engines, and countermeasures. The commonality program could provide the aircraft-specific programs with everything from bolts and generator controls to hydraulics and maintenance toolkits.
Maintenance costs, in turn, are heavily driven by the price of parts, James Kelly, a Pentagon logistician who works on the F-35 said. If future aircraft have more parts in common and fewer unique ones, that means acquisitions officials can get bulk discounts on the parts they buy and logisticians can stock fewer different parts.
Joint Multi-Role (JMR) helicopter program
The precursor for FVL is the Joint Multi-Role (JMR) helicopter program, which will provide technology demonstrations planned for 2017. The Joint Multi-Role (JMR) phases will provide technology demonstrations. JMR-TD will develop the aerial platform; JMR Phase I will develop the air vehicle; JMR Phase II will develop mission systems. The Army plans to acquire as many as 4,000 aircraft from the FVL program.
US Army has awarded development contracts to two industry teams as part of Joint Multi-Role Technology Demonstrator, Sikorsky and Boeing with their SB>1 Defiant medium-lift helicopter based on Sikorsky’s X2TM coaxial design that features counter-rotating rigid main rotor blades for vertical and forward flight.
The second was Textron’s Bell Helicopter V-280 Valor, a tiltrotor design , a winged-aircraft with two rotor blades over each wing seeks to achieve airplane speeds and retain an ability to hover and maneuver like a helicopter. The new contracts are aimed at engineering a new fleet of aircraft for all the services by 2030.
A Helicopter Designed for the Army’s Air Assault Mission
FLRAA Bell and Sikorsky (with Boeing) have produced demonstrators for FLRAA.The two companies are taking different technology approaches to their efforts. The Bell V-280 (Figure 2) is a tiltrotor aircraft like the V-22 Osprey, with engines and rotors at the end of its wings that swivel. The Sikorsky/Boeing SB-1 is a compound helicopter, using twin coaxial rotors to provide lift and a pusher propeller to enhance speed
The Sikorsky-Boeing team’s expertise in advanced manufacturing and testing, paired with its experience in producing cutting-edge rotorcraft configurations, has refined our understanding of the Army’s mission – enabling us to provide a flexible, agile, advanced solution with adaptable software and systems for future growth across multiple missions.
To replace the Black Hawk, the Army’s next-generation helicopter must conduct air assaults from extremely long distances and evade enemy anti-aircraft systems. It is crucial that the aircraft can fly at the lowest possible altitude with a precise combination of speed and maneuverability. The aircraft needs to land quickly in tight landing zones under fire, deliver soldiers, and immediately depart.
The SB>1 DEFIANT™ is specifically designed to demonstrate technology for the FLRAA mission. The helicopter’s superior handling qualities and speed allow it to safely get to the objective, perform the complex mission and depart quickly. The SB>1 team chose this configuration featuring coaxial rotors and a rear-mounted pusher propulsor for a specific reason – to achieve the common goal that they have with the U.S. Army to design the absolute best next-generation air assault aircraft.
The SB>1 DEFIANT™ team has demonstrated revolutionary advances in engineering and manufacturing, making their FLRAA offering an affordable reality today. The team’s design and development activities have refined their understanding of the technological solutions possible for the Army. With the data gained from the wind tunnel, power system test bed (PSTB) and test flights, the Sikorsky-Boeing team is well on their way to delivering an aircraft that meets the Army’s needs. This is accomplished by:
- Integrating modern, proven technologies into our design to ensure a low-risk, low-cost offer that is scalable to a variety of military missions.
- Model-based engineering and advanced manufacturing that enhance our ability to minimize risk and program costs.
A rigorous flight test plan.
- A design that maintains commonality with:
Army’s existing facilities – It is the same size as Black Hawk / Apache.
Current Army logistics and soldier skill sets (training).
Army’s major tactics, techniques and procedures to include multi-ship operations.
- A maintenance-friendly design throughout, increasing availability and lowering lifecycle sustainment costs.
- An early and continuous focus on reliability and maintainability to create maintenance-free periods and reduce forward logistics burdens, while establishing an affordable life cycle of sustainment.
X2 Technology Brings Reach, Survivability, Lethality and Sustainment to Army Future Vertical Lift
The U.S. Army has long desired helicopters with terminal area maneuverability and agility, but with the higher speeds and longer ranges of an airplane to support a variety of military missions to address known and emerging threats. It’s now working to materialize those desires through the Pentagon’s Future Vertical Lift (FVL) program. Sikorsky’s investment in X2 Technology™ aims to provide the Army (through the FARA and FLRAA programs) with revolutionary improvements in capability, including speeds in excess of 250 knots performed in tandem with nimble combat maneuverability – significantly improving its ability to survive on modern and future battlefields.
X2 consists of an integrated package of technologies — counter-rotating rigid rotor blades, fly-by-wire flight controls, hub drag reduction, active vibration control and an integrated auxiliary propulsion system — that can be incorporated into a variety of helicopters designed for reconnaissance, attack, air assault, troop transport and medevac missions. FARA and FLRAA will remain affordable. Using the digital thread, Sikorsky has designed out most of the high maintenance drivers in the fleet and tested the X2 designs in a virtual 3D environment in addition to thousands of hours in their Systems Integration Labs (SILs). Using new manufacturing techniques, on board diagnostics and a conditions-based sustainment approach, as well as the digital thread, Sikorsky is reducing the life cycle costs to own and operate FARA and FLRAA.
With X2 Technology, Sikorsky will provide a fast and revolutionary helicopter that marks a departure point from traditional helicopters by increasing their reach, survivability, lethality and sustainability – and providing unmatched growth potential to adapt to the military’s changing needs. X2 Technology provides improved hover performance, rapid maneuverability and crisp control response due to the rigid rotor, while also maintaining the performance expected of helicopters at low speeds. The technology itself is simple in design and will be easily affordable, maintainable and sustainable for the future force. The introduction of the digital thread into the initial design forms the basis of the FVL life cycle sustainment approach by weaving design, production, upgrades, training, maintenance and sustainment seamlessly into the life cycle of the weapon system. This approach not only preserves resources, but also creates a digital aircraft twin, extends maintenance free operating periods (MFOP) and enables advanced analytics and onboard diagnostics with embedded decision tools to increase aircraft availably in mature and austere environments.
Increased terminal area agility and threat response/avoidance is significantly increased with this design as well. This ability to fly fast at low altitudes, with a high level of maneuverability, results in increased survivability and capability for the ground maneuver commander.
The unique benefits of X2 Technology are impressive:
- Precise Low-Speed Handling—Fly-by-wire control and a rigid coaxial main rotor enable high agility at low speed, including low-speed hover and off-axis hover. This is critical because it enables safe operations in complex, obstacle-laden mission environments close to the ground.
- Level Body Acceleration and Braking—In an aircraft like Sikorsky’s high-speed X2-powered Raider X, for example, power can be added to both the propeller and main rotor to accelerate without changing attitude. It can also brake by using negative thrust from the propeller. Helicopters without these capabilities require their main rotor to tilt. The rapid acceleration provided by X2 in constrained spaces increases survivability by minimizing exposure time to combat threats.
- High Turn Rate—The rigid main rotor permits tight turns in half the distance of helicopters with traditional rotors, much like a high-performance Formula 1 race car makes turns on a racetrack. This mission-critical capability decreases engagement time and increases lethality and survivability by being able to close on a target faster.
- Nose Up/Down Hover—Helicopters with a conventional single main rotor can’t point their nose up or down and maintain position at the same time. X2 nose down/nose up hover capability enables pilots to aim sensors and weapons in mountainous and dense urban environments. This is a powerful and lethal combat advantage.
- Highly Maneuverable —The X2 rigid coaxial rotor systems and 3G maneuverability provide unique agility to engage in close air support, operate in restrictive terrain, and allow unparalleled hover attitudes.
- Commonality – There are advantages to a common X2 approach to FVL utilizing common or identical sustainment, maintenance procedures, MOSA, infrastructure, ground support equipment, special tools.
Evaluation of Tiltrotor Design
It combines the vertical lift capability of a helicopter with the speed and range of a conventional fixed-wing aircraft. For vertical flight, the rotors are angled so the plane of rotation is horizontal, lifting the way a helicopter rotor does. As the aircraft gains speed, the rotors are progressively tilted forward, with the plane of rotation eventually becoming vertical. In this mode the wing provides the lift, and the rotor provides thrust as a propeller.
A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called proprotors) mounted on rotating engine pods or nacelles usually at the ends of a fixed wing or an engine mounted in the fuselage with drive shafts transferring power to rotor assemblies mounted on the wingtips. The tiltrotor’s advantage is significantly greater speed than a helicopter.
In a helicopter the maximum forward speed is defined by the turn speed of the rotor; at some point the helicopter will be moving forward at the same speed as the spinning of the backwards-moving side of the rotor, so that side of the rotor sees zero or negative airspeed, and begins to stall. This limits modern helicopters to cruise speeds of about 150 knots / 277 km/h.
However, with the tiltrotor this problem is avoided, because the proprotors are perpendicular to the motion in the high-speed portions of the flight regime (and thus never suffering this reverse flow condition), meaning that the tiltrotor has relatively high maximum speed—over 300 knots / 560 km/h has been demonstrated in the two types of tiltrotors flown so far, and cruise speeds of 250 knots / 460 km/h are achieved.
This speed is achieved somewhat at the expense of payload. As a result of this reduced payload, Experts estimate that a tiltrotor does not exceed the transport efficiency (speed times payload) of a helicopter. Additionally, the tiltrotor propulsion system is more complex than a conventional helicopter due to the large, articulated nacelles and the added wing; however, the improved cruise efficiency and speed improvement over helicopters is significant in certain uses. Speed and, more importantly, the benefit to overall response time is the principal virtue sought by the military forces that are using the tiltrotor.
Tiltrotors are inherently less noisy in forward flight (airplane mode) than helicopters. This, combined with their increased speed, is expected to improve their utility in populated areas for commercial uses and reduce the threat of detection for military uses. Tiltrotors, however, are typically as loud as equally sized helicopters in hovering flight. The Army wants future scout helicopters small enough to hover in the “urban canyons” of contested cities, and that could be tricky with a tiltrotor because the placement of its engines and rotors gives it a bigger footprint than legacy scouts.
Tiltrotors also provide substantially greater cruise altitude capability than helicopters. Tiltrotors can easily reach 6,000 m / 20,000 ft or more whereas helicopters typically do not exceed 3,000 m / 10,000 ft altitude. This feature will mean that some uses that have been commonly considered only for fixed-wing aircraft can now be supported with tiltrotors without need of a runway. A drawback however is that a tiltrotor suffers considerably reduced payload when taking off from high altitude
U.S. Army selects Rockwell Collins to support Future Vertical Lift program
The U.S. Army has contracted Rockwell Collins to conduct collaborative studies to support the future development of vertical lift military aircraft. Under the contract, Rockwell Collins will research advanced system designs and integration processes for the Architecture Implementation Process Demonstration, as well as assist Army officials with investigating new technologies and technological capabilities.
“Rockwell Collins is pioneering modeling and analysis methods for complex electronic equipment development, such as those envisioned to be required for FVL,” Rockwell Collins rotary wing director Heather Robertson explained in a press release. “These technologies automate error-prone, costly manual methods for specifying and designing products, which helps us to deliver value to our customers.”
The company went on to add the research will aim to shed light on issues regarding the affordable development of complex mission systems in addition to informing industry partners on new techniques and processes
Model Based Software Development
Army, Navy, and industry are also defining common software standards including a new “model-based” approach to software architectures that will require a culture change among programmers and defense bureaucrats alike. “Once this standard gets defined, hopefully we only write it [a piece of software] once and it can be used in all the different aircraft,” said Boeing’s Thomas DuBois, speaking alongside Hargreaves.
In model-driven development, “you actually record what the interfaces are, the semantics, and that information is available to anyone who wants to use it… down to the very end of the chain where you’re actually going to produce code,” Michael May, the associate director for software and embedded systems in the office of the assistant secretary of Defense for research and engineering said. What’s more, the model-based approach includes “formal methods” (a programming term of art) for rigorously assessing whether a particular piece of code will actually work.
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