Light helicopter demonstrator with high-compession engine: flight test results

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Mercier, C.
Gierczynski, A.
Hanappier, N.
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In the frame of the GRC4 program of Clean Sky’s Green Rotorcraft Integrated Technology Demonstrator (ITD), Airbus Helicopters led the development of a flying demonstrator based on the H120 serial helicopter and fitted with a reciprocating engine running on kerosene. This engine is called HCE for High-Compression Engine. Airbus Helicopters worked on this research project with TEOS Powertrain Engineering, France, and AustroEngine GmbH, Austria, under the HIPE 440 Consortium. Bench tests started in March 2013. Ground tests were completed in March 2015. The Maiden Flight occurred on November 6th 2015 and the flight test campaign lasts until the end of 2017. The HCE needed to be built from scratch. This paper explains its specifics. It presents the achievements of the research project regarding engine mass-to-power ratio, power output, fuel consumption, torque oscillations, engine movements, rotor speed control and lastly emphasizes on the cooling system performance. The flight tests validated the achievements on these subjects, concluding to full applicability of HCE kerosene piston engine technology to light helicopters with benefits on fuel consumption (-42%), DOC (-30%), hot and high performance and engine price.