© F. Lert

Heli Expo, which took place at the end of February in Anaheim, California, offered Turbomeca (a SAFRAN group subsidiary) the opportunity to present a noise attenuator mounted on an Arrius 2F helicopter engine. The turbine nozzle has a twin-wall lining incorporating small resonant cavities, the dimensions of which are determined according to the frequencies to be absorbed. For now, this is simply a demonstrator, and its weight and size would be scaled down before any mass production were to take place. Yet the trail has been blazed: the installation cuts down noise emissions by around 3 decibels, representing half the engine’s noise levels. Another item that went on public display was the e-APU from Microturbo, a Turbomeca subsidiary. The "e" stands for both "electricity" and "ecology", since this new APU (auxiliary power unit) concept, on account of its performance and the systems architecture it supports, contributes to a more environmentally-conscious approach (reduced fuel consumption, lower levels of pollutant emissions, attenuated noise signature, optimized architecture). This APU has already been chosen for two programs, and its complete certification and first shipments off the production line are scheduled for 2012.

© F. Lert

>Towards ever lower consumption levels When it comes to helicopter engine design, there has been constant progress over the past few decades. In the space of 30 years, kW consumption has gone down by 60% between the Artouste 2C and the Arrius 2F engines. The progress expected in the future is even more ambitious: by 2020, carbon dioxide (CO2) emissions are expected to be reduced by 50%, and nitrogen oxide (NOx) emissions by 80% (1). Turbomeca is already working on demonstrators that will comply with these constraints, for engine ratings of between 500 and 1500 hp, or even greater as requirements dictate. Other avenues of progress are also envisaged, such as promoting the diesel engine for light helicopters with power requirements not exceeding 400 hp. There are some technical obstacles to overcome, but the potential gains to be made (40% less fuel consumption) could serve as a catalyst for the current research.

(1) Objectives set by the Advisory Council for Aeronautics Research in Europe (ACARE.