Farnborough Air Show

UTAS Lifts Veil on New Products and Hybrid/Electric Propulsion R&D

 - July 17, 2018, 3:21 AM
UTAS will provide the environmental control systems, air turbine starter, flow-control valve, and main electrical power system for KAI’s KF-X fighter.

UTC Aerospace Systems (UTAS, Outside Exhibit 4) is launching a new range of aerospace vehicle management computers (VMCs) which will have much greater processing power than any other VMCs available in the market, according to the company.

Tim White, president of UTAS’s Electrical, Environmental, and Engine Systems business, said that its newly launched VMCs will have multi-core processors to support customers needing huge processing capability both for fly-by-wire control needs and, more importantly, to provide massive processing capability for autonomous unmanned aerial systems (UASs). Providing autonomous systems with much greater processing power will help allow UASs to obtain civil certification, he explained, “as we prepare to get autonomy in the civil-certified environment because they’re not civil-certified right now."

In addition to providing the environmental control system, air turbine starter, and flow-control valve for KAI’s KF-X fighter (a contract win UTAS announced on February 6 at the Singapore Airshow), UTAS has also won a contract in partnership with Korean company KAES Hanwha (Chalet B24) to provide the aircraft’s main electrical power generation system. It will include a new variable-speed constant frequency (VSCF) generator, which will be the first new military-aerospace generator of its kind in more than a decade, according to White.

He said UTAS’s new VSCF generator offers 10 percent more power density than its existing VSCF generators flying today and is also more efficient, continuously producing 65 kilowatts of power at a constant 400 Hertz frequency. The generator has an integrally packaged converter and control unit that electronically converts the variable speed output of the generator into the desired constant-frequency output power.

UTAS’s hybrid/electric power R&D

Formerly the head of UTAS’s Electrical Systems business, White now oversees an expanded range of activities for the company as a result of its decision to combine the Electrical Systems, Environmental Systems, and Engine Systems businesses into one much larger unit. UTAS chose to combine the three because, he said, “As we look into the future of hybrid-electric propulsion and sixth-generation fighters, the consequences of controlling and managing power systems, and thermal management, and integrating these with propulsion, puts us in a position where we can provide integrated systems rather than the federated systems” the company offers now.

As a direct consequence, much of UTAS’s R&D effort is focusing on key areas of product development intended to enable aircraft manufacturers to design commercial aircraft with more-electric systems architectures and/or with hybrid turbine-electric propulsors, as well as military aircraft with greatly improved thermal-management capabilities and small civil aircraft that are completely electrically powered.

Ubiquitous on virtually all modern commercial aircraft as the supplier of their electrical power-generation and distribution systems, emergency power systems, and environmental control systems, UTAS provides both the environmental control system for the electric-architecture Boeing 787 and the power generation and control system for the Lockheed Martin F-35 sixth-generation fighter.

“We see those product lines being applied to the hybrid-electric propulsion market,” said White. “We have been quite active in developing products and meeting clients [involved in] hybrid-electric and electric propulsion [projects]. We certainly see a market for hybrid-electric propulsion [but] in our view it is not broadly applicable across the entire range of aircraft, for reasons to do with the specific power storage of jet fuel compared with batteries.”

Because jet fuel has 50 times the power density of today’s batteries, fully electric and hybrid-electric propulsion won’t be viable anytime soon for large, long-range aircraft, according to White. However, the electric-propulsion situation for smaller aircraft is better, because they can fly lower and slower to save energy. For a 500-nm mission with 12 passengers, battery power-density capability will need to improve by a factor of approximately six over the state of the art today to be all-battery powered. There is hope, said White: because so many companies are investing in battery R&D—UTAS isn’t one of them, because it wants to let other companies concentrate on battery technology while it concentrates on systems technology—power density will soon improve. Current projections show the power density of batteries improving by a factor of three over the next 10 years, according to White.

“We see hybrid-electric solutions that supplement the engines with some batteries,” he said. “We see a sub-30-passenger aircraft as the first commercially viable market” for hybrid-electric propulsion. Many customers are interested in developing such aircraft. Electric and hybrid-electric propulsion would offer OEMs and operators various benefits, according to White. They would take less time to build, because their aircraft wiring runs would be reduced in scale, and they would have operating and maintenance costs 20 percent lower than aircraft with traditional propulsion systems because they would offer higher reliability and repairs would be less costly.

Such aircraft would also provide improved fuel consumption by means of more efficient power extraction and control, be up to 85 percent quieter, offer reduced carbon emissions, and they would not leak hydraulic fluid. If operators could implement quick battery exchanges for small electrically powered or hybrid-electric aircraft while they were on the ground, turnaround times could be reduced as well, because they would require less refueling, according to White.

Specific R&D Efforts

A key R&D requirement for UTAS in supporting the development of hybrid/electric aircraft propulsion is to develop new, integrated systems hardware. The company is establishing a new lab that will allow it to integrate all the electrical-power systems for electrically and hybrid-electric powered aircraft, according to White. It is also developing technologies to improve the power density of its electric actuation motors and motor controls. UTAS’s motors for the 787 offer five kilowatt-per-kilogram power density, but it has an R&D effort in place to increase the motors’ power density to 10kW/kg. At the same time, UTAS is working on megawatt-class motors for hybrid-electrically powered aircraft.

“It’s our understanding that these will be higher-voltage systems,” said White. “They will be in the kilovolt range, whereas today commercially available systems are 150 to 235 volts. But kilovolt systems present challenges on protection and control,” and UTAS is working hard on both those areas. “We’re spending significantly on controlling power as it is being generated or distributed by hybrid-electric propulsion systems. That will be essential for civil certification of such systems. We think we can offer a lot of domain knowledge,” because of UTAS’s extensive experience with military-aircraft power and thermal management.

Future electrically/hybrid powered commercial aircraft and military aircraft will have megawatt-class electrical power requirements; the 1.5-megawatt-class Boeing 787 already does. But megawatt-class aircraft “present thermal management problems,” said White. “We see a confluence between the higher power required for hybrid-electric propulsion and the higher electric-power needs for advanced military aircraft,” which will result in a requirement to reject waste heat from the aircraft. UTAS is working on half a dozen U.S. government-funded projects researching this area and is running “thermal-management labs to test and validate high-temperature heat exchangers in much more difficult environments than today’s commercial systems,” he said. These heat exchangers will be “placed in higher-temperature areas of engines to provide thermal management.”

In parallel with its R&D efforts focusing on aircraft electrical propulsion, electrical-power aircraft systems architectures, and improved thermal management, White’s business unit is performing R&D aimed at accelerating the development of more intelligent and connected aircraft systems. It is doing so to help aircraft operators improve operational efficiency and also to give UTAS new insights that will allow it to design and manufacture highly reliable aircraft systems. To this end, UTAS has established a new Intelligent Aircraft Technologies Lab in Rockford, Illinois. This lab will initially focus on developing health-monitoring solutions for generators, air compressors, fans, and motor controllers, but its health-monitoring R&D activities are planned to expand quickly to include many other components.