Ottawa: The National Research Council of Canada (NRC) has commissioned a wind tunnel to help aircraft manufacturers measure the noise levels generated by aircraft landing gear. Unique in Canada, this facility will help airline manufacturers meet internationally accepted and ever more stringent noise standards.
\nIn Ottawa, one of the eight wind tunnels operated by NRC Aerospace has been outfitted with an acoustic liner and precision noise measurement technology. This tunnel can house landing gear and simulate the wind conditions during deployment and on approach, generating wind speeds up to 150 knots. NRC aerodynamics experts take landing gear apart and reassemble it part by part, measuring the noise generated by wind flowing around each component as well as that caused by components interacting. The idea is to guide manufacturers in the design of specific components to reduce their sound impact.
\nThe body behind the research is the Green Aviation R&D Network (GARDN), a federally established business-led network of Centres of Excellence. Bombardier Aerospace, Bell Helicopter, Pratt & Whitney Canada and CMC Electronics are among the industry partners collaborating with NRC and nine universities to help manufacturers produce greener aircraft.
\nRegulations, targets and limits are set by the International Civil Aviation Organization (ICAO) and NASA\u2019s Environmental Responsibility Aviation (ERA) program. In the next ten years, regulations will aim to reduce noise generated by commercial aircraft by 32 dB relative to the current standard.
\nUntil recently, the industry had focused on measuring and reducing the noise generated by engines alone. Turbofan-powered airliners and business jets are becoming progressively quieter through higher bypass ratios, acoustic materials and nacelle design techniques, in order to meet increasingly stringent noise reduction targets.
\nYet little known is the fact that the airframe also generates significant noise because of air flow turbulence around the landing gear, wheel wells, flaps and slats.
\n\u201cTurbulent flow around landing gear generates a significant proportion of the total noise output of an aircraft in close proximity to the ground,\u201d said NRC\u2019s Stuart McIlwain, group leader of fixed-wing aerodynamics.
\n\u201cWe adapted one of our wind tunnels to measure the noise from undercarriages because it\u2019s the total footprint \u2013 not just engine noise \u2013 that is measured for \u2018Stage 4\u2019 compliance.\u201d
\nNRC Aerospace has tested a full-scale Bombardier Learjet 60 landing gear, combining many permutations.
\n\u201cWe looked at the gear struts and axles individually, but also the interaction between such components,\u201d said NRC aeroacoustics researcher Jerry Syms. \u201cThe drag strut\/main strut combination, gear doors, brake lines, wheel wells and other components generate enough noise on their own to merit attention.\u201d
\n\u201cOur job is to search for where the noise comes from and suggest ways to reduce it,\u201d added McIlwain. \u201cThe OEMs then can apply and certify their individual programs to ICAO standards.\u2019\u2019
\nAircraft equipment manufacturers can now call on NRC Aerospace for this type of acoustic assessment.<\/p>\n
Recognized globally for research and innovation, Canada’s National Research Council (NRC) is a leader in the development of an innovative, knowledge-based economy for Canada. NRC Aerospace is Canada’s national aerospace laboratory, supporting the Canadian and international industry through research and technology development in matters affecting the design, manufacture, performance, use and safety of aerospace vehicles.<\/p>\n","protected":false},"excerpt":{"rendered":"
Ottawa: The National Research Council of Canada (NRC) has commissioned a wind tunnel to help aircraft manufacturers measure the noise levels generated by aircraft landing gear. Unique in Canada, this facility will help airline manufacturers meet internationally accepted and ever more stringent noise standards. In Ottawa, one of the eight wind tunnels operated by NRC … Continue reading