A rendering showing the inside of The Grid, a planned Collins Aerospace R&D lab in Rockford, Illinois, that will help usher in the next generation of high power systems required for electric aircraft. CREDIT COLLINS AEROSPACE


By Dave DeWitte

United Technologies Corp. is determined to lead the pack in an emerging race to develop hybrid electric aircraft – a prize that could provide the next leap forward in aircraft fuel savings and emissions reductions.  

Within three years, a new internal project, dubbed Project 804, aims to fly a regional turboprop aircraft with a 2-megawatt electricpowered engine replacing one of two conventionally powered engines. The goal of the project is to demonstrate a 30 percent fuel savings on a one-hour flight. 

UTC envisions an aircraft with the ability to carry 30-50 passengers on hour-long trips of between 200250 nautical miles. 

Research and development on the aircraft, a Bombardier Dash 8 Series Q100, will take place at a new power systems lab that will open in the spring of 2020 at Collins Aerospace’s Power and Controls Division in Rockford, Illinois, and at Pratt & Whitney’s engine facility in Longueuil, Quebec, Canada. Both companies are subsidiaries of UTC.  

Overseeing the project is UTC’s Advanced Projects Group (UTAP), a new R&D unit formed last year to pursue accelerated development of disruptive technologies, free from influence from the conglomerate’s other lines of business. 

No specific role in the project was mentioned for UTC’s Corridor operations, home to the Mission Systems and Avionics Systems divisions of Collins Aerospace. The project will tap talent from various areas of the company, however. 

“In the not too distant future, hybrid electric and full electric aircraft will have revolutionized aircraft as we know it, opening up new markets like urban air mobility while reinvigorating others like regional service to underutilized airports, Collins Aerospace CEO Kelly Ortberg said at an April 4 dedication event for the lab in Rockford. “They will help support a greener planet by reducing carbon emissions and help our airline customers by reducing operating costs and fuel consumption.” 

UTC studies indicate partial electric and hybrid electric propulsion could reduce aircraft noise by up to 85 percent, cut fuel consumption by up to 40 percent, reduce carbon dioxide emissions by more than 20 percent, and lower airline operating maintenance costs by up to 20 percent, Mr. Ortberg noted. 

UTC has no plans to build hybrid electric aircraft, but wants to be the supplier that equipment manufacturers in the aerospace world call on when they do. 

Project 804 “will help us understand some of these system integration challenges we would face when an OEM decides to develop a hybrid electric aircraft, so we have that knowledge ahead of time,” said Mauro Atalla, Collins Aerospace’s vice president of engineering and technology, at a press conference in Rockford. “The demonstrator is not going to result in a product that you can just sell, but would give us all the understanding of what it takes to do it.” 

The current generation of aircraft use more electric power than previous generations to replace or supplement hydraulic or pneumatic systems. UTC supplied the electric power generating and start system that provides nearly 1.5 megawatts of power for the Boeing 787 Dreamliner, the largest power source yet on a commercial airliner. The power output is the equivalent of the amount consumed by about 400 average homes, UTC officials said. 

Those demands, as well as electric and hybrid aircraft R&Dare the reasons UTC is investing about $50 million in the R&D lab, and will be investing a total of $150 million over the next three years in power systems R&D, explained Tim White, president of Power & Controls at Collins Aerospace. 

Dubbed The Grid, the Rockford lab will be the tool that enables UTC and Collins Aerospace to out-innovate competitors, he said. It will be equipped with a high-voltage DC power distribution system and dynamometers capable of testing motors, generators and electric systems at up to 2 megawatts and 1 kilovolt of power, according to the company. It will also have high-powered computers to record and analyze the terabytes of data that will be collected during testing. 

The challenges of designing such a hybrid aircraft propulsion system are many. Space and weight are near the top of the list, Collins’ Mauro Atalla explained. 

“We’re trying to make everything much more compact, carry much more power and perform as efficiently as we need to, so there is a lot of work that goes on in designing these motors, generators and distribution systems to make sure you can grow from 250 KW to a megawatt and not quadruple the volume or weight you need, but maybe just double, so you’re making things much more dense.” 

UTAP plans to use commercial off-the-shelf battery systems. Current estimates are that the battery array would weigh 4,0005,000 pounds – a little less than a typical elephant. 

Although Project 804 will use a parallel architecture pairing an electric and conventional aircraft engine, Mr. Mauro said The Grid will be used by UTAP to study a variety of configurations, including all-electric and a series hybrid configuration. 

The hybrid air race 

Other aerospace companies have already announced plans to commercialize electric aircraft, although production of a commercial passenger hybrid electric aircraft from a clean-sheet design is likely years away. 

European aerospace giant Airbus has developed at least four electric flight demonstrators in pursuit of the European Commission’s FlightPath 2050 vision for more sustainable aviation. Its most recent project, in partnership with Siemens and RollsRoyce, is the most ambitious. Dubbed E-Fan X, it involves repowering a British Aerospace 146 regional airliner with its right inboard turbofan replaced by an electric motor. 

MagniX, a maker of electric aircraft engines, announced last month that it will partner with North America’s largest seaplane airline to convert its fleet to electric propulsion using the company’s 750-horsepower all-electric motor. 

Canada-based Harbour Air carries more than 500,000 passengers per year on 30,000 commercial tours and flights between hubs like Seattle and Vancouver. 

Almost a year ago, the private jet company JetSuite announced it will become the launch customer for up to 100 hybrid electric aircraft from startup Zunum Aero. The latter company is backed by the venture capital arms of JetBlue, Boeing and Washington state’s Clean Energy Funds. 

Big potential, big challenges 

Just weeks before UTC announced The Grid, a new University of Illinois study offered valuable context for hybrid electric aircraft designs from the standpoint of reducing carbon dioxide emissions. It said making a serious dent in the commercial air transport emissions would require repowering larger-scale aircraft, like a 140-passenger single-aisle airplane, and be able to have a distance range similar to conventionally powered aircraft. 

The study published in the Journal of Aircraft found that the most feasible hybrid electric configuration for repowering that type of aircraft uses a 50 percent electrical power drivetrain, and could produce 49.6 percent less lifecycle carbon dioxide than a conventional modern aircraft with a maximum range equivalent to the average of all global flights. 

However, reducing carbon dioxide emissions depends largely on where the electricity used to power the batteries comes from, according to the study. The use of fossil fuels to generate power varies widely among different regions of the United States, and simply replacing conventionally powered aircraft with electricity generated from coal would have a limited effect on reducing CO2 emissions. 

Moreover, achieving the 50 percent electrical power drivetrain goal would require a battery energy density that doesn’t yet exist (1,000 watt-hours per kilogram). Over time, battery technology is likely to improve, study co-author Phillip Ansell said in a release, but getting close to that power density will require a lot of progress. 

“Perhaps in the next 10 years we’ll be able to have a battery that is 400 to 600 watt-hours per kilogram,” Mr. Ansell said. “If we project that out, the levels that we need for larger hybridization factors, or even fully electric commercial aircraft, might be within reach in the next 25 years.”