Abstract: A method for cutting a blade root retention slot in a turbine engine disk element includes forming a precursor slot in the element. The precursor slot has first and second sidewalls and a base. A rotating bit is passed through the precursor slot to machine the base. The bit rotates about an axis off-normal to a direction of passing. A cutting performance of the rotating bit is modeled reflecting a chip trapping intensity parameter and a heat intensity parameter. At least one parameter of the bit and its passing is selected so as to avoid tool loading where removed chips/swarf stick onto the bit.

Abstract: A method is provided for machining a slot having a slot base in a turbine engine rotor disk. The method includes forming a preform slot that extends along a longitudinal axis through the rotor disk. The preform slot includes a preform slot endwall connected laterally between a first slot sidewall and a second slot sidewall. A cutting tool is rotated about its axial centerline, which is substantially parallel to the longitudinal axis. The preform slot endwall is machined with the rotating cutting tool to form the slot base.

Abstract: A method for cutting a blade root retention slot in a turbine engine disk element includes forming a precursor slot in the element. The precursor slot has first and second sidewalls and a base. A rotating bit is passed through the precursor slot to machine the base. The bit rotates about an axis off-normal to a direction of passing. A cutting performance of the rotating bit is modeled reflecting a chip trapping intensity parameter and a heat intensity parameter. At least one parameter of the bit and its passing is selected so as to avoid tool loading where removed chips/swafs stick onto the bit.

Abstract: A method is provided for machining a slot having a slot base in a turbine engine rotor disk. The method includes forming a preform slot that extends along a longitudinal axis through the rotor disk. The preform slot includes a preform slot endwall connected laterally between a first slot sidewall and a second slot sidewall. A cutting tool is rotated about its axial centerline, which is substantially parallel to the longitudinal axis. The preform slot endwall is machined with the rotating cutting tool to form the slot base.

Abstract: A one way isolator for high torque devices, such as alternator-starters, driven by a flexible drive means includes a hub and a sheave each of which includes at least one stop member. The hub and sheave are linked by a isolating spring and, via a bearing and/or bushing, can rotate with respect to each other to provide isolation, through the spring, from torque variations when torque is transferred from the flexible drive means to the device. When substantial amounts of torque are transferred from the device to the flexible drive means, the sheave rotates with respect to the hub to bring the stop members into contact such that the isolator then acts like a solid pulley to facilitate the transfer of the torque from the device.

Abstract: A rotor blade assembly includes a slot for mounting a rotor blade that extends partially through a rotor disk and a continuous uninterrupted hoop seal that extends about the circumference of the rotor disk. The rotor disk includes an integrally formed seal that includes at least one knife edge disposed concentrically about the rotor disk. The slot receives a root portion of a rotor blade but does not extend through the seal. As the seal remains an uninterrupted full hoop about the circumference of the rotor disk, additional rigidity and strength are realized. The increased rigidity and strength provided by the full hoop structure provides for the reduction in material and physical dimensions without compromising desired performance of the seal.

Abstract: A fluid flow control system includes a valve, in which a control element regulates flow through a metering orifice. A further control element regulates flow through an orifice downstream of the orifice and is responsive to the pressure downstream of the orifice and to an opposing control pressure on a line. The element is positioned in accordance with the pressure in a chamber controlled by an electrical valve. The pressure in line is set to provide a required pressure drop across the orifice.

Abstract: A one way isolator for high torque devices, such as alternator-starters, driven by a flexible drive means includes a hub and a sheave each of which includes at least one stop member. The hub and sheave are linked by a isolating spring and, via a bearing and/or bushing, can rotate with respect to each other to provide isolation, through the spring, from torque variations when torque is transferred from the flexible drive means to the device. When substantial amounts of torque are transferred from the device to the flexible drive means, the sheave rotates with respect to the hub to bring the stop members into contact such that the isolator then acts like a solid pulley to facilitate the transfer of the torque from the device.

Abstract: A fuel control system for reheat burners of a gas turbine engine has a plurality of metering valves for respective burners, and throttle valves in series with the respective metering valves. A pressure regulating valve is provided for introducing pressurized fuel into fuel manifolds downstream of the respective throttle valves when the metering and throttle valves are shut. The pressure regulating valve also acts to relieve pressure in low pressure parts of the system when the latter is closed down and to prevent excessive temperature rise at the inlet of a fuel supply pump. The metering valves include pressure return ports which communicate with the metering valve outlets when those valves are shut.

Abstract: A rotor blade assembly includes a slot for mounting a rotor blade that extends partially through a rotor disk and a continuous uninterrupted hoop seal that extends about the circumference of the rotor disk. The rotor disk includes an integrally formed seal that includes at least one knife edge disposed concentrically about the rotor disk. The slot receives a root portion of a rotor blade but does not extend through the seal. As the seal remains an uninterrupted full hoop about the circumference of the rotor disk, additional rigidity and strength are realized. The increased rigidity and strength provided by the full hoop structure provides for the reduction in material and physical dimensions without compromising desired performance of the seal.

Abstract: A fuel control system for a gas turbine engine includes series-connected first and second metering valves for providing a metered fuel flow to an engine supply line. A downward failure condition in either valve is detected by a detector which produces a signal representative of such failure. A changeover device operates in response to the failure signal to place the system in a condition in which a sufficient metered fuel flow is maintained via the non-failed valve.

Abstract: A fuel metering arrangement has a fuel flow metering valve, a pressure drop regulator valve arranged and operable to maintain the pressure drop across the metering valve substantially constant and a throttle device arranged and operable to regulate fuel flow upon failure of the regulator valve in an insufficiently closed or fully open position.

Abstract: A regenerative pump is provided in which an impeller is centrally located within a cavity and variable volume side channels are provided such that the pump characteristic can be varied. A control mechanism is provided for controlling the volume of each side channel in a symmetrical manner.

Abstract: A multiplexing valve is provided having a spool axially movable within a valve casing under the control fluid pressure introduced into variable volume chambers. The spool has passages formed therein such that, with appropriate positioning of the spool, fluid flow communication can be selectively established or inhibited between fluid sources and/or sinks and a given port.

Abstract: The fuel control system supplies an engine via a pressure raising and shut-off valve. The valve is operated by a piston and cylinder arrangement. A shut-off motor controls the fuel pressure in a control line of a rapid shut-down valve. The rapid shut-down valve is operable to connect the cylinder to a high pressure fuel supply (HPf) via relatively large diameter pipes. The shut-off motor also controls the fuel pressure in a second control line connected directly to the cylinder. The shut-off motor is operable to supply high pressure fuel to the cylinder via the second control line. The rate of fuel flow into the cylinder via the second control line is less than that via the rapid shut-down valve so as to provide a normal rate of shut-down.

Abstract: A gas turbine engine is supplied with fuel by way of a metering unit which includes a metering valve responsive to a servo pressure which is regulated by electrical signals from a control circuit. Failure of electrical signals to the metering unit results in the metering valve being arrested in its position at failure. A combined manually operable and shut-off valve arrangement is in series with the metering unit includes a valve which is normally biassed fully open and is operable by a manually regulated servo pressure. The manually operable arrangement also includes a device for setting the servo pressure of the valve in the metering unit to a value which maintains that metering valve fully open.

Abstract: A fuel control system for a gas turbine engine has a metering valve and a shut-off valve in series, and a spill valve for spilling fuel from upstream of the metering valve in response to an overspeed condition of the engine. The spill valve and shut-off valve are responsive to respective servo pressures, and an electrically operated valve can control both servo pressures in response to a demand to shut down the engine. The electrically operated valve can also control a third servo pressure for setting a minimum flow limiting stop in the metering valve to a lower limiting level during engine starting.

Abstract: A linear variable displacement transducer (LVDT) has a core connected to an actuator such as a torque motor. The outputs of the LVDT are demodulated and subtracted to provide a displacement signal which is compared with a desired displacement to provide closed loop control of the torque motor. The desired displacement is formed by multiplying a demand signal by the sum of the demodulated LVDT outputs so as to provide temperature compensation.

Abstract: A supply passage communicates with the inlet of a first centrifugal pump. A second, smaller centrifugal pump has its outlet connected to a delivery conduit. A valve arrangement is selectively operable to connect the inlet of the second pump either to the output of the first pump or directly to the supply passage, both the inlet and outlet of the first pump being shut off in the latter condition.

Abstract: A combined multiple memory array is disclosed which includes at least two differing types of memory arrays located next to and aligned to one another. The individual memory cells of the differing memory arrays are designed wherein the x pitches may vary in order to allow the y pitches to be substantially equal. A common set of row decoders provide common wordline decoding to the differing memory arrays. The memory arrays need not have the same number of words or bits to share the common row decoders. The column decoders may be separate for each array to account for different word sizes. A common set of column decoders is possible with equal word lengths from each array. A significant savings in silicon area may be saved by combining the multiple arrays.