| 摘要 |
<p>A noise attenuation panel 33 used to attenuate noise in aircraft engines includes a cellular core 35 and a facing sheet 36 formed with an array of holes 31. The holes 31 may be laser drilled, and provide holes inclined in a direction normal to the facing sheet (fig 8). The hole inclination may be provided to prevent clogging of the holes with debris. Alternatively, the facing component may be fibre reinforced and the holes 31 have a polygonal cross-section with sides arranged parallel to the reinforcing fibres.</p> |
