Landing gear noise reduction technology development for future green regional aircraft

Paper in proceeding, 2014

One of the main objectives of the CS-JTI GRA ITD project - Low Noise Configuration domain is the aircraft noise reduction. It is well known that landing gear is one of main sources of airframe noise and therefore several previous projects have been carried out in USA and Europe to investigate relevant low-noise technologies. Nevertheless these studies have addressed mainly wing-mounted main landing gear (MLG) architecture of low-wing large aircraft which is quite different from the fuselage-mounted MLG of high-wing aircraft. Therefore, an activity plan has been defined to address noise reduction of MLG, and of nose landing gear (NLG) as well, for high-wing turboprop regional aircraft, aimed at identifying TRL 3 technologies and increase their maturity level up to TRL 5. The plan includes both numerical and experimental activities with the participation of European industries, research centers, SMEs and universities, as either GRA ITD Members or Partners of projects in the frame of Calls for Proposals (CfP). In 2012 MLG and NLG baseline configurations, being realistic CAD models of actual architectures, have been jointly delivered by Alenia Aermacchi and Messier-Bugatti-Dowty. In the course of 2013 low-noise technologies development is performed, from state-of-art survey and preliminary studies based on semi-empirical approach, to CFD/CAA analyses and basic wind tunnel tests on simplified mock-ups. Technologies under investigation are fairings, wheels hub caps, bay and doors acoustic treatments, partial closure of bay cavity (after gear lowering), spoilers, vortex disintegrators, etc. The paper describes to-date results and the criteria adopted to down-select landing gear low noise devices leading to the choice of best solutions for WT test demonstrations.