Airbus airframe noise reduction - A European harmonized research effort

Abstract

Very large aircraft - such as the planned Airbus A3XX - require correspondingly high lift forces and extended landing gear structures, thus causing potentially very high airframe noise levels during landing approach. This problem was realized by the Airbus Consortium and first relevant research initiatives date back to the early 90ies. Soon after initial research at DLR beban under contract to Airbus Industrie, dedicated to landing gear airframe noise. Recognizing the general challenge of research for aircraft noise reduction at that time, a European Noise Reduction Initiative (ENRI) was proposed, dealing with both engine- and airframe-noise. Subsequent technical discussiond, however, led to separate programmes for engine- and airframe noise research, the latter being initiated under the acronym RAIN (Reduction of Airframe and Installation Noise). RAIN encompasses analytical and experimental work to describe, predict and reduce the noise both from landing gears and high lift devices. In parallel national research programmes began: In France wind tunnel and flyover experiments relate to the whole aircraft airframe noise characteristics, while corresponding research in Germany focusses on high lift devices noise. In Great Britain noise modelling is performed for landing gear noise prediction. These national efforts are coordinated by the Airbus partner companies (3E-programme).