Further Noise Reduction of Regional Jet Two-Wheel Main Landing Gear

Noise reduction design concepts have been applied to a regional jet’s two-wheel main landing gear to reduce airframe noise during the approach. Several concepts were initially developed for the main landing gear of the Japan Aerospace Exploration Agency’s research aircraft, “Hisho,” based on a Cessna Citation Sovereign business jet. The concepts were tailored to the larger regional jet main landing gear after a careful investigation of aircraft noise sources during flight and wind tunnel tests, the flowfields around the main landing gear by computational fluid dynamics simulations, far-field noise measurements with a 10%-scale wind tunnel model, and an evaluation of structural feasibility. The initial design was then improved upon by further investigations with a 20%-scale wind tunnel model and additional computational simulations. New noise reduction concepts and those applied to Hisho were also evaluated and adopted to enhance the overall noise reduction performance. Compared with a baseline configuration, significant noise reduction, 5.5 dB(A) in overall sound pressure level at a position directly below the main landing gear, was achieved in a wind tunnel test with the 20%-scale model.