Abstract: An apparatus is disclosed for a fuel control system of a turbine engine powerplant. Various construction details have been developed which provide means to generate a backup command current for controlling the fuel flow rate to the turbine engine powerplant. In one embodiment, a means to generate a backup command current includes means to convert a fuel flow derivative to a backup command current using known hardware characteristics and an estimated null bias signal. The backup command current is input to a switch along with a command current generated by comparing a reference signal to a feedback signal from a metering valve. The switch responds to means for failure recognition which detects failures in the sensing of the feedback signal. The switch responds to a failure of the feedback signal by inputting the backup command current to a torque motor for controlling a metering valve position.

Abstract: A non-integral rotor blade platform for a rotary machine is disclosed. Various construction details are developed which disclose a one-piece, non-integral rotor blade platform retained to a live rim area of a disk. In one embodiment, a rotor blade assembly (48) is comprised of a plurality of rotor blades (54) disposed on a disk (44), a plurality of platforms (60), each platform disposed between adjacent rotor blades, and a front cover plate (56) and rear cover plate (58) which, in conjunction, retain the platforms to the disk. In an alternative embodiment, each platform (102) has a supplemental mechanical fastener means (100) to provide additional retention of the platforms to a disk (104).

Abstract: A housing assembly (14) for protection of an enclosed printed circuit board (12) with a surface mounted dome switch (18) is disclosed. Various construction details are developed which provide sealing under a variety of atmospheric conditions. In one embodiment, the housing assembly is comprised of an upper portion (22), a lower portion (26), and a one piece, continuous diaphragm (30). The upper portion has an aperture (24) for engagement of a button actuator (20) by an external force. The diaphragm, composed of an elastic material, provides a sealed cavity (32) for the housing and permits substantial equalization between the internal and external pressure of the sealed cavity.

Abstract: A switch terminal board cover 20 (FIG. 2) is molded from a non-conductive material and consists of a base 21, a spacing edge 22 with retaining latches 24,25 and an opening 23, and a plurality of projections 26 disposed on the base. The projections 26 are sized and positioned such that they form a plurality of slots which prevent excessive movement of and contact between electrical leads 10, thereby preventing electrical shorts from occurring, and help maintain the integrity of electrical terminations 12 of a switch 11 (FIG. 3).