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U.S. Army Defining New Multi-Role Helicopter
« Reactie #65 Gepost op: 08/04/2012 | 09:29 uur »
U.S. Army Defining New Multi-Role Helicopter

Apr 4, 2012
By Graham Warwick
It has been decades since the U.S. Army had the chance to define a clean-sheet rotorcraft. But an opportunity is approaching as the service heads toward the multi-year demonstration of configurations and technologies for next-generation utility/attack rotorcraft that could replace today’s Sikorsky UH-60s and Boeing AH-64s, beginning around 2030.

The Joint Multi-Role (JMR) concept evolved from an analysis of U.S. vertical-lift needs, which included a painful assessment of the shortfalls of current rotorcraft and gaps in industry capabilities. The conclusion was that another round of upgrades for existing platforms would not be enough, and that a technology demonstration program was needed to get industry up to speed to deliver a next-generation rotorcraft on time and on cost.

The JMR technology demonstration is intended to apply to all classes of Army rotorcraft, from armed scout to heavy lift, but is focused on the medium utility-class because replacing the Black Hawk fleet “offers the biggest bang for the buck,” says Ned Chase, JMR technology-demonstration team leader and chief of the platform technology division at the Army’s Aviation Applied Technology Directorate (AATD).

Boeing, Sikorsky, Bell-Boeing (the V-22 joint venture) and tiny AVX Aircraft are working under configuration trades and analyses contracts to define concepts for a medium-utility JMR and to decide which technologies will need to be matured through flight demonstration. AVX is studying a coaxial-rotor configuration with ducted-fan propulsion; Boeing is looking at a range of options; Bell-Boeing is focusing on tiltrotors; and Sikorsky is evaluating an advanced helicopter, tiltrotor and a compound helicopter using its X2 high-speed coaxial-rotor configuration. An independent government design team is looking at advanced and compound helicopter and tiltrotor concepts.

The goal of the configuration trades and analysis is to take the laundry list of vehicle attributes that operators say they want, and recommend concepts and technologies to meet them. The studies will evaluate specific attributes, such as higher speed and optionally manned capability, by establishing their payoff on the battlefield, and estimate the value and affordability of candidate configurations. The end product is to be a performance specification for the JMR technology-demonstrator aircraft.

The studies will help balance the often-conflicting vehicle attributes that operators want. “The community is coming to an understanding on where the trades are, but they are not a decision point yet,” Chase says. “And we are not ready yet, but there will come a time when we need to snap a line.”

The technology demonstration will be divided into two parts: Phase 1 for the air vehicle and Phase 2 for its mission system, which lags by two years, in recognition that electronics advance faster than airframes, rotors, engines and drive systems. Both phases are to be completed by the end of fiscal 2019, when the Army plans to be in position to launch the engineering and manufacturing development program for a next-generation rotorcraft.

In parallel with the configuration trades, the government is developing the Phase 1 demonstrator specification. “The trades finish in late summer and the last draft version of the spec will be out for comment soon after,” says Chase. “The next specification after that will be part of the solicitation [for Phase 1] in early 2013.”

Bidders will be asked to describe what their JMR medium-utility concept is expected to do, and what technologies critical to their design will have to be proved in flight. “They will not build to the spec, but demonstrate technologies that would enable them to achieve the spec if they built to it,” he says. The Army’s science and technology portfolio has been directed toward conventional helicopters until now, so compound helicopter and tiltrotor configurations could require additional technology maturation, he adds.

Under Phase 1, AATD plans to carry several performers through to the preliminary design review in early fiscal 2015. “At that time we will choose one or two,” Chase says. The Army has committed funds for a single air-vehicle flight demonstrator, with $187 million budgeted in fiscal 2012-16, but AATD is hopeful that funding from other services and cost-sharing by industry will enable it to afford two competing aircraft. “I think we can find a way to do two,” he says.
Phase 1 flight demonstrations are intended to verify contractor performance claims, determine the readiness of critical technologies for full-scale development and assess the value of configuration attributes. Results will feed into development of a specification for the objective JMR vehicle —whatever the Army decides that is.

Budget limitations mean the demonstrators are unlikely to be full-scale. Government studies suggest a medium-utility JMR could have a 45,000-lb. gross weight (compared with 22,000 lb. for the UH-60M). “We can’t afford to demonstrate something that big,” Chase says, although smaller vehicles will introduce the complexity of scaling up the results to objective JMR size.

In parallel, Phase 2 will get under way to demonstrate the JMR cockpit, decision-aiding software and integrated mission system—ideally in the air-vehicle demonstrators themselves, but alternatively in surrogate aircraft. This will kick off with the award of multiple contracts for mission-system effectiveness trades and analyses—equivalent to the configuration studies—to feed into the Phase 2 specification.

Proposals for the mission-system trades are due on April 1 and, as with the air-vehicle studies, contractors will be asked to identify those “game-changing” technologies that need maturing through flight demonstration to be ready for full-scale development. There are several supporting technology-development efforts under way this year. “We are having to do some things in parallel, which is not ideal,” says Keith Arnold, team leader for teaming and intelligence within AATD’s systems integration division.

The foundation for the JMR mission system is the open-system Joint Common Architecture (JCA), based on the Future Airborne Capability Environment (FACE) reusable-software standard developed by government and industry. “Based on open standards like FACE, JCA is instantiating an open systems architecture that is going to be key to any future aircraft,” says Arnold. “JCA has got to work if we are to change the way Defense Department aircraft are built and bought, and it’s a big part of what JMR is about.”

The new open standards and development tools will be used in a JCA demonstration planned for fiscal 2014-15. This will feed into the JMR Phase 2 demonstration, beginning in fiscal 2015, “which will develop specific pieces of the mission system and take others that exist and make then work together in a new architecture and airframe,” Arnold says. “We’d like to put the mission system on one of the air-vehicle demonstrators, but that injects risk,” he says. “So only the stuff that has to be will be tested in flight on the Phase 1 air vehicles. What we can, we will test in surrogate vehicles or on the bench.”

Also feeding into Phase 2 are AATD research programs developing advanced cockpit concepts and crew decision-aiding tools. Much of this work revolves around manned/unmanned teaming, vehicle autonomy and optionally piloted capability. “We are trying to take an integrated look at the battlespace. This aircraft will not be operating alone, but in a team as part of a larger battle,” Arnold says.

On the cockpit side, “there has been a lot of research into interface devices and methodologies that we would like to pull together to see what the best set of hardware is,” he says. On the decision-aiding side, work is aimed at “answering basic questions about the role of the human in future intelligent cockpits, “he says. “We have aircraft that can fly themselves, so what is the optimum allocation of tasks between the human and the machine?” The JMR demonstration will establish a baseline level of decision-aiding within the JCA architecture.

A parallel but different effort is looking at propulsion. The Improved Turbine Engine Technology (ITEP) program has two goals. One is to boost the range, payload and hot-and-high performance of the AH-64 and H-60 series by providing a drop-in replacement for the General Electric T700 family (developed 40 years ago) that is 25% more fuel efficient and 50% more powerful. The other is to prove the technology base for a JMR engine. A new requirement—added in 2011 after ITEP started—is to look at integrating dust and particle separation into the engine, doing a better job than external separators and sapping less engine performance.

GE and Advanced Turbine Engine Co. (ATEC), a Honeywell/Pratt & Whitney joint venture, are working in parallel on a science and technology phase of ITEP, which culminates this year with bench-testing of complete demonstrator engines. A Honeywell executive says ATEC expects this to be followed by a request for proposals for an initial engineering, manufacturing and development phase, involving both teams. “The Army’s strategy is to maintain two teams for as long as they can,” the executive tells DTI. In 2016, however, the plan is that one team will be selected to continue into flight tests.

ATEC’s HPW3000 is a two-spool engine (with high-pressure and low-pressure spools, plus a power turbine). which provides improved efficiency and the ability to start with a battery, eliminating the need for an auxiliary power unit.

The JMR technology demonstration will be the culmination of more than decade of science and technology work by the Army aimed at a next-generation rotorcraft. “A lot of things are coming together at the right time,” says Chase. “We put a lot of time and human capital into coming up with an investment strategy, and now the technologies are coming home to roost in the form of a demonstrator.”

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