摘要 |
<p>A propulsion engine for an aircraft, the propulsion engine comprising: one or more fans (1, 2) rotatably linked to one or more respective shafts (11); a driving means arranged to drive the one or more fans; and a first hydraulic pump-motor (10) connected to one of the fan shafts, the first hydraulic pump-motor comprising a cam (12) disposed about the shaft and one or more radially extending pistons (13) arranged to engage a surface of the cam, the cam and pistons being arranged such that the pistons reciprocate due to the rotation of the cam, wherein the first hydraulic pump-motor is arranged to selectively transfer a variable amount of power to or from the one or more fans so as to control the rotational speed of the one or more fans.</p> |