| 摘要 |
<p>A changeover valve for a tandem fan type of engine is located in a duct (4) between fan stages (54,56) at either end. The valve arrangement has a butterfly flap valve (2) to selectively obstruct flow along the cut, a drop-down chute (32) to eject front fan flow and secondary inlet means (10) to induct air to the second fan stage (54) to supply the core engine. The secondary inlet means (10) comprises drop-in doors (11) hinged to pivot (50) into the duct (4) behind the flap valve (2). A tertiary airflow in a space (20) defined by the duct (4) and an engine nacelle (14) is admitted to the region at the second fan entry face which is shadowed by the secondary inlet doors (11). <IMAGE></p> |
