CGTM Develops Air Filter for Eurocopter AS 350

 - December 19, 2007, 6:07 AM

Turbomeca’s subsidiary CGTM, known primarily as the engine manufacturer’s flight-test center, plans to offer a new air filter for the Eurocopter AS 350 Ecureuil. Developed jointly with filtration specialist Pall Aerospace, the air filter should be certified by early next year. Pau, southwest-France-based CGTM plans to certify the new air filter even for inadvertent flight into icing conditions.

Its designers call the filter a “dynamic engine air particle separator.” Indeed, the separation process begins with a swirl motion applied to the contaminated air entering each tube. The filter is made of dozens of small tubes, each fitted with a vortex generator. The swirl motion causes the heavier dirt particles (or water droplets) to be thrown outward radially. A small portion of the inlet air then scavenges the dirt overboard. The pressure drop is small and constant, the company claimed in its product brochure.

Engine durability is multiplied 20-fold in comparison with an unprotected engine in adverse conditions, Philippe Rowell, CGTM’s marketing and sales manager, told AIN at the Heli Trade show.

The filter was designed to address concerns operators have voiced about current filters. According to the company, these concerns include difficulties accessing air intakes for preflight checks and the systems’ inability to handle large amounts of ingested sand. CGTM also said that reliability and performance have been issues on other systems.

Last January, an AS 350 equipped with the system logged some 100 flight hours and made 98 landings in the Sahara Desert. In addition, the company tested the filter system during this year’s Paris-Dakar rally, where the AS 350 spent most of its time filming close to the ground. At the end of the test, “hardly any erosion” was found on the axial compressor of the Arriel turboshaft engine. And no more than 0.6 gram of contaminants was found in the hollow shaft.

According to Rowell, the new air filter is only the first product in a planned CGTM catalog.