New models for quieter landing gear system
Full-scale models of the landing gears in the nose and under the wings are rarely tested. Until now, experimental research on airframe noise research has been performed using small-scale models. The difficulty in using model-scale results for full-scale noise predictions arises from the lack of details in the geometrical modelling. An EU consortium working on the ALLEGRA (Advanced low noise landing (main and nose) gear for regional aircraft) project investigated multiple advanced low-noise technologies applied to full- and half-scale landing gear models in leading European wind tunnel facilities. The project consortium utilised a range of novel low-noise technologies to achieve a noise reduction over the baseline configuration. Technologies that were extensively tested for their aeroacoustic performance in Pininfarina's Aeroacoustic Research Facility, Italy, included perforated fairings, meshes, hub caps and bay cavities. Researchers used a microphone array to assess basic measures such as directivity of the noise in 1/3 octave bands and overall sound pressure level. Experimental activities were complemented by advanced signal processing techniques to help identify the mechanisms behind noise generation of the aircraft components. The presence of full-scale main and nose landing gear models in wind tunnel testing set these tests apart from previous research. Thus, ALLEGRA outcomes present an opportunity to investigate low-cost designs for future full-scale landing gear testing.
Keywords
Landing gear, aircraft, low-noise technologies, ALLEGRA, wind tunnel
