Blade pitch varying means for use in a gas turbine engine are disclosed. The blade pitch varying means may be used on an engine with a single row or two counterrotating rows of variable pitch blades which are disposed outwardly from an annular gas flowpath and which are connected with a rotating airfoil within the flowpath. The blade pitch varying means comprise actuation means, bearing means, and gearing means. The actuation means are in a nonrotating reference frame disposed inwardly from the flowpath and deliver an axial force. The bearing means transmit the axial force from the nonrotating into a rotating reference frame which contains both the propulsor blade and the airfoil in the gas flowpath. The gearing means are located in the rotating reference frame and convert the axial force into a force for varying the blade pitch.

Blade pitch varying means

Blade pitch of variable pitch blades is changed by an actuator having first and second ac machines. The first ac machine is excited with ac power to apply a motoring torque to a control shaft of the actuator, thereby causing blade pitch to change in one direction. The second ac machine is excited with appropriate power to apply a braking torque to the control shaft, thereby causing blade pitch to change in an opposite direction. When the second ac machine is an induction machine, dc excitation will brake the control shaft. When the second ac machine is a synchronous machine, an ac excitation causing a retarding magnetic field will brake the control shaft.

Electromechanical apparatus for varying blade of variable-pitch fan blades

A plurality of spaced reed switches vertically aligned for positioning in a liquid. Each of the reed switches vertically overlaps the adjacent above and below reed switches and the longitudinal axis of the reed switches is at an angle to the vertical. A float carries magnets and is movably positioned coaxially about the plurality of switches. An electrical indicator is connected to the switches for indicating the vertical position of the float relative to the switches.

Liquid level measuring apparatus

A method for inventory maintenance and leak detection in liquid storage tanks and dispensing lines, that combines tank level measurements, tank product temperature measurements, output flow measurements, liquid product characteristics data, initial product delivery volume data, and redundantly calculates changes in the quantity of liquid product within the tank and compares these calculations to determine abnormalities in the changes in the quantities of product within the tank. Changes in the quantity of product within the tank are verified as either the delivery of additional product into the tank or the dispensing of product from the tank as with a customer sale. Changes that cannot be verified as either delivery into or dispensing from the tank are appropriately characterized as possible leak conditions in the tank or lines. The system additionally incorporates an accuracy improving process of restrapping or recharacterizing the physical conditions within the tank and recalibrating the flow meters associated with dispensing product from the tank. The combination of redundant measurements of volume changes and continuous recalibration of system measurements, along with the incorporation of product temperature measurements and product liquid/vapor state determinations, allows the system to detect with greater accuracy anomalies in the quantity of product within the tank.

Storage tank and line leakage detection and inventory reconciliation method

A plurality of propeller blades are mounted to an axially elongated tubular propeller hub (H1). Each blade is rotatable in position about a radial axis. An electromechanical linear actuator (A1) is housed within the hub for rotating the blades to change their pitch. The actuator includes a rod member (R1) fixed in position relative to the hub, a casing (C1) which can extend and retract relative to the rod member, a rotary electric motor (M1), and a planetary screw drive (SD1). The screw drive (SD1) drivingly interconnects the electric motor (M1) with the casing (C1) for causing the casing to move axially in response to operation of the motor. The actuator (A1) is connected to the propeller (P1) by a linkage (L1) so that movement of the casing causes the propellers to change their pitch. A second actuator (A2) may be housed within the hub (H1) and connected to the first actuator (A1) for providing redundancy in the event of failure of the first actuator.

Propeller pitch control system and apparatus

An actuation system is provided for the rotor of a gas turbine engine and includes an electric motor mounted for rotation with the engine rotor together with a generating system consisting of rotor windings which connect electrically to drive the motor, and stator windings which fixedly connect to the stationary portion of the engine. The stator windings may be energized in a controlled manner to induce an electromotive force in the rotor windings and thus provide a power and control signal to drive the electric motor at a controlled speed or direction.

Remote controlled actuation system for the rotor of a gas turbine engine

Electric position sensor

A FUEL MANAGEMENT SYSTEM FOR INDICATING AIRCRAFT CENTER OF GRAVITY. FUEL PROBES IN EACH FUEL TANK PRODUCE AN ELECTRICAL SIGNAL WHICH VARIES IN ACCORDANCE WITH THE FUEL LEVEL AT EACH PROBLE. THIS SIGNAL IS CONVERTED BY SCALING RESISTORS TO PRODUCE A LIQUID WEIGHT CURRENT SIGNAL AND A LIQUID WEIGHT MOMENT SIGNAL. SERVO MEANS AND AMPLIFIERS ARE ENERGIZED BY THESE TWO CURRENT SIGNALS TO OBTAIN THE TOTAL AIRCRAFT LIQUID WEIGHT AND MOMENT AND TO INDICATE THE AIRCRAFT CENTER OF GRAVITY.

Dave B Levins

Papers

Remote controlled actuation system for the rotor of a gas turbine engine

Electric position sensor

Fuel management system