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Today’s conventional helicopters are powered by thermal engines that convert fossil fuels into energy. Long considered ideal for air travel because of their ability to generate large quantities of power with a limited mass of fuel, fossil fuels are likewise notorious for producing emissions such as nitrogen oxide and carbon dioxide (CO2).
The aviation industry contributes around two percent of global CO2 emissions. Important efforts have already been made to limit fuel consumption in aviation, but clearly much more needs to be done — and helicopters are at the forefront of this effort. Thanks to their small size and low power needs compared with most fixed-wing aircraft, helicopters are the ideal testbed for new technologies, and lessons learned can be extended to larger applications.
The solutions being tested today are many: from decreasing the emissions output of conventional thermal engines, to going for the holy grail of fully electric flight — and everything in between.
Airbus Helicopters’ long-term innovation roadmap involves exploring all options, brick by brick, and making incremental improvements towards an emissions-lighter future. Here’s a look at what’s happening now.
Becoming less conventional
“Our engineers have come a long way in making traditional technologies greener, working on a wide range of research projects that in some cases are already reducing emissions,” said Tomasz Krysinski, head of research and innovation at Airbus Helicopters. “The recently certified H160 is the cleaner and quieter helicopter in its class, paving the way for a reduced environmental footprint in helicopter operations”.
Integrating Airbus Helicopters’ latest technological innovations, the next generation medium twin H160 benefits from a 15 percent reduction in fuel burn, thanks to its Arrano engine by Safran Helicopter Engines, and a 50 percent reduction in exterior sound levels, thanks to its Blue Edge main rotor blades.
Krysinski cites other projects underway that aim to reduce fuel consumption through a combination of improved aerodynamics, weight reduction, and more efficient thermodynamic cycles, in hopes of one day integrating such improvements on other Airbus helicopter products.
According to Krysinski, the ultimate step is to go to another sort of energy, which could be hydrogen or fuel cells. This technology has made significant advances, particularly in the fixed-wing segment, but the power requirements for a helicopter remain a challenge. That being said, Krysinski expects hydrogen technologies could be mature enough to fly on a helicopter demonstrator as early as 2029.
There is also the electrically-powered “eco-mode”, which enables the pausing and restarting of a gas turbine in flight on twin-engine helicopters. Developed with Safran Helicopter Engines, and first tested on the Bluecopter demonstrator (an H135 testbed), this technology will generate fuel savings while increasing the range of helicopters. The “eco-mode” will be tested next on the Racer high-speed demonstrator currently being developed in the frame of the Clean Sky 2 European research programme, and which aims to reach a 220-knot cruise speed while cutting CO2, NOx and noise emissions by 20 percent, when compared to current helicopters.
A fully electric future
At the opposite end of the spectrum is the fully electrically powered helicopter. Dogging this ambition is the challenge of how to store electric energy efficiently, from the perspective of both mass and volume, using today’s technology. (In the simplest terms, a large quantity of batteries is required to equal the performance of fuel. This means that the battery in an electric car — let alone a helicopter — can represent approximately a third of its empty weight)