Aircraft propulsive power unit
An aircraft having a propulsive power unit supported in a fuselage mounted configuration and including an engine and a nacelle structure housing the engine. The nacelle structure is provided with upper and lower displaceable nacelle portions, such as thrust reverser cowls and fan cowl doors which are displaceable between closed dispositions which they occupy during operational conditions of the aircraft and open dispositions which they take up to provide access to engine components. The upper and lower nacelle portions are so mounted as to be displaceable to their open and closed dispositions in movements in which one is assisted by gravitational force and the other is displaced against gravitational force. A force transfer mechanism is provided for transfer during opening and closing movements of the nacelle portions of gravitational force assisting displacement of one of the nacelle portions to assist in displacement of the other nacelle portion being displaced against gravitational force.
1. An aircraft having a propulsive power unit and a propulsive power unit support means to support the aircraft propulsive power unit, the propulsive power unit including an engine and a nacelle structure housing the engine, the nacelle structure including first and second displaceable nacelle portions each of which is displaceable between a closed disposition which it occupies during operational conditions of the aircraft and an open disposition which it takes up to provide access to engine components, the first and second nacelle portions being so mounted that the first nacelle portion is displaceable to its open disposition in an opening movement in which it is assisted by gravitational force acting upon it and is displaceable to its closed disposition in a closing movement against gravitational force acting on it and the second nacelle portion is displaceable to its open disposition in an opening movement against gravitational force acting on it and is displaceable to its closed disposition in a closing movement in which it is assisted by gravitational force acting upon it and is displaceable to its closed disposition in a closing movement against gravitational force acting on it and the second nacelle portion is displaceable to its open disposition in an opening movement against gravitational force acting on it and is displaceable to its closed disposition in a closing movement in which it is assisted by gravitational force acting on it, a first pivotal mounting on the support means to provide for pivotal opening and closing movements of the first nacelle portion, a second pivotal mounting on the support means to provide for pivotal opening and closing movements of the second nacelle portion, and force transfer means provide for a predetermined transfer during opening movements of the nacelle portions of gravitational force acting on the first nacelle portion to assist displacement of the second nacelle portion to its open disposition and during closing movements of the nacelle portions gravitational force acting on the second nacelle portion to assist displacement of the first nacelle portion to its closed disposition, wherein the second nacelle portion in its open disposition is such that the second nacelle portion during its opening movement passes top dead centre in relation to its pivotal mounting on the support means, and wherein biasing means are provided to assist the second nacelle portion to reach top dead centre so as to minimise and optimise the hand load required from an operator during a closing movement in which the second nacelle portion is required to reach and pass through top dead centre;
wherein the biasing means comprises a spring which is pivotally connected at one end to one of the nacelle portions at an offset pivotal location radially offset from the pivotal mounting of that nacelle portion on the support means and which is pivotally connected at its other end at a pivotal location on the other nacelle portion or on the support means.