Abstract: An active filter (100) suppresses current harmonics generated in a dc bus (300) by generating a compensating current that is approximately equal-but-opposite in polarity to the current harmonics. In one implementation, the active filter (100) includes: an energy storage capacitor (103); a choke (104); a switch circuit (120); and a controller (150). The controller (150) receives a current harmonics measurement for the dc bus (300) and generates switch gating signals (156a, 156b) as a function of the current harmonics measurement. The switch circuit (120) receives the switch gating signals (156a, 156b) from the controller (150) and is operatively connected to the energy storage capacitor (103) and the choke (104) to selectively discharge the energy storage capacitor (103) to inject current into the dc bus (300) and to selectively draw current from the dc bus (300) via the choke (104).

Abstract: A wheel (11) having a rim (12) with a pair of flanges (17, 19) including a peripheral potential roll surface (33) on at least one flange for contacting the ground in the event of tire failure has a convexly contoured roll surface with a finite cross-sectional radius of curvature (42) at the outermost radius of the wheel to provide an optimized shape of the contact surface and an enhanced contact area without introducing any flat regions in the contact area. The roll surface is formed to have a finite radius of curvature throughout the potential roll surface. The roll surface radius of curvature and may be formed in cross-section as a central circular segment (40) blending smoothly into two circular segments (44, 50) of lesser radii at the central circular segment extremities, or may be formed in cross-section as a portion of an ellipse (57) having a semi-minor axis (63) extending generally radially along the respective annular rim portion.

Abstract: The invention provides for oxidatively resistant carbon/carbon composites and other graphite-like material, a method for the preparation of these materials, and their use in high temperature applications, preferably in brakes for airplanes. The carbon/carbon composite or graphite-like material, which is resistant to oxidation at high temperatures comprises a fiber-reinforced carbon/carbon composite or graphite in contact with a phosphoric acid based penetrant salt solution which contains the ions formed from the combination of the following: 10-80 wt % H2O, 20-70 wt % H3PO4, 0-25 wt % MnHPO4.1.6H2O, 0-30 wt % Al(H2PO4)3, 0-2 wt % B2O3, 0-10 wt % Zn3(PO4)2 and 0.1-25 wt % alkali metal mono-, di-, or tri-basic phosphate.

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a fuel pump (13), a metering valve (15) and a pressurizing valve (17) to a plurality of engine fuel manifolds (31a, 31b, 33) includes an ecology valve (43) for withdrawing fuel from the engine fuel manifolds (31a, 31b, 33) during cessation of engine operation and for returning fuel to the engine fuel manifolds (31a, 31b, 33) to be burned during normal engine operation. The ecology valve (43) includes a valve housing (44) having a plurality of ecology ports (50, 52, 54) adapted to be coupled to corresponding ones of the engine fuel manifolds (31a, 31b, 33) and a control port (46) adapted to be connected to a corresponding control port (45) of the fuel pressurizing valve (17).

Abstract: A turbine engine (49) fuel delivery system of the type including a pneumatic governor has an electronic governor and an engine excess stress avoidance feature which disable the pneumatic governor (70) so long as the engine speed exceeds a prescribed value and an electronic control unit (45) continues to function properly. The system transfers governing responsibility to the electronic control unit (45) which controls a torque motor and solenoid valve fuel diversion line (22). The system monitors an engine (49) operating parameter such as gas generator speed (37), power turbine speed, engine output torque, or engine temperature and further diminishes fuel flow to the engine (49) when the monitored parameter exceeds a threshold value. The system resumes normal speed governoring flow when that parameter returns to an acceptable level.

Abstract: A split monopole antenna that provides for simultaneous transmission of 121.5, 243 and 406 MHz emergency signals using a simple, lightweight structure that can be stowed in an aircraft in a compact manner during non-deployment, and after deployment enables the beacon to float in water in an upright orientation. The monopole antenna comprises three radiating elements. The first radiating element is electrically coupled to a transmitting unit and radiates a 406.025 MHz signal; the second radiating element is electrically coupled to the first radiating element by way of a first band rejection filter and both elements radiate at 243 MHz; and the third radiating element is electrically coupled to the second radiating element by way of a second band rejection filter and all three elements radiate at 121.5 MHz.

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a fuel pump (13), a metering valve (15) and a pressurizing valve (17) to a plurality of engine fuel manifolds (31a, 31b, 33) includes an ecology valve (43) for withdrawing fuel from the engine fuel manifolds (31a, 31b, 33) during cessation of engine operation and for returning fuel to the engine fuel manifolds (31a, 31b, 33) to be burned during normal engine operation. The ecology valve (43) includes a valve housing (44) having a plurality of ecology ports (50, 52, 54) adapted to be coupled to corresponding ones of the engine fuel manifolds (31a, 31b, 33) and a control port (46) adapted to be connected to a corresponding control port (45) of the fuel pressurizing valve (17).

Abstract: A carbon/carbon (C/C) composite comprising crystalline silicon carbide which is essentially uniformly distributed on both internal and external surfaces of the composite in a low concentration, as well as a process for producing the composite and the use of the composite in brake materials for industrial roll goods, automotives, trucks, trains and aircrafts. It has been discovered that small amounts of crystalline silicon carbide uniformly distributed throughout the carbon/carbon composite results in reduced wear with either no change or a slight increase in the friction coefficient.

Abstract: A turbine engine fuel delivery system (10) and method has, in addition to the conventional fuel bypass (20) for diverting fuel exiting a fuel control (17) away from the engine (49) and back to a fuel pump (15) to maintain a relatively constant pressure differential across the fuel control (17), a separate controllable flow fuel bypass (21) for selectively diverting fuel exiting the fuel control (17) away from the engine (49) and back to the fuel pump (15) to decrease the rate of fuel flow to the engine (49) and correct an overtemperature condition, and an arrangement for enabling the controllable fuel flow bypass (21) during engine (49) start-up and disabling the controllable fuel flow bypass (21) when the engine (49) reaches normal idle speed. Once an engine (49) start or light off is detected, the system (10) automatically prevents turbine outlet temperature exceedences by reducing metered fuel flow to the engine nozzle. The controllable fuel bypass (21) includes a solenoid operable valve (29).

Abstract: A carbon-carbon composite material is made by providing an open-celled carbon foam preform, and densifying the preform with carbonaceous material. The open-celled carbon foam preform may be oxygen stabilized prior to carbonization, and the foam preform densified by CVD, HIP, PIC, VPI, pitch and resin injection, or any combination thereof. The carbon carbon composite material can be heat treated to provide thermal management materials, structural materials, or a friction material for use in a brake or clutch mechanism.

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a fuel pump (13), a metering valve (15) and a pressurizing valve (17) to a plurality of engine fuel manifolds (31a, 31b, 33) includes an ecology valve (43) for withdrawing fuel from the engine fuel manifolds (31a, 31b, 33) during cessation of engine operation and for returning fuel to the engine fuel manifolds (31a, 31b, 33) to be burned during normal engine operation. The ecology valve (43) includes a valve housing (44) having a plurality of ecology ports (50, 52, 54) adapted to be coupled to corresponding ones of the engine fuel manifolds (31a, 31b, 33) and a control port (46) adapted to be connected to a corresponding control port (45) of the fuel pressurizing valve (17).

Abstract: An unbalance compensated bypass valve (14, 21, 23) for a gas turbine engine fuel supply system is responsive to the fuel pressure differential across a fuel metering valve (15) to open and close a bypass orifice (37, 39, 41; 89, 91, 93; 99, 101, 103). The bypass valve (14, 21, 23) selectively supplies high fuel pressure to a compensating cavity (45, 95, 120) providing a counterbalancing force against an annular area (47, 97, 124) of the bypass valve piston (34, 81, 83, 111, 112) to compensate for increased restorative forces of a helical reference spring (57, 112, 125) as that spring is collapsed as well as to compensate for other unbalance conditions within the valve (14, 21, 23). The compensating cavity may include a variable orifice inlet (37, 39, 41), (99, 101, 103), or (89, 91, 93) and a variable orifice outlet (105, 107, 109) or the inlet orifice may be variable while the outlet orifice (43, 96, 99) is fixed.

Abstract: A convertible aircraft brake assembly (10, 60, 77, 78, 83, 85, 96, 120, 130) designed as original equipment to have heat sinks comprising a steel heat sink (20, 70, 80, 90, 91, 100, 110, 122) aircraft brake assembly and a carbon-carbon composite heat sink (40) aircraft brake assembly. When the aircraft brake assembly is converted from one type of heat sink to the other, the conversion is accomplished with minimal changes in component parts. The conversion can be accomplished without any changes in the piston housing (14), torque tube (12), and wheel (30) because the heat sinks include therein respective components which enable each heat sink to be utilized with the commonly used piston housing (14), torque tube (12), and wheel (30).

Abstract: A carbon-carbon composite material is made by providing an open-celled carbon foam preform, and densifying the preform with carbonaceous material. The open-celled carbon foam preform may be oxygen stabilized prior to carbonization, and the foam preform densified by CVD, HIP, PIC, VPI, pitch and resin injection, or any combination thereof. The carbon-carbon composite material can be heat treated to provide thermal management materials, structural materials, or a friction material for use in a brake or clutch mechanism.

Abstract: A mesophase pitch material having a melting point in excess of 350° C. has a solvent added thereto to provide a solvated mesophase pitch. A low molecular weight solvent is used so that the melting point can be brought low enough to create a carbon foam at a convenient temperature. The solvent is then removed by heat and/or vacuum and, consequently, the pitch reverts to a high melting point of approximately greater than 350° C. The pitch can then be heated or carbonized without an oxidative stabilization step. Alternatively, a solvated mesophase pitch material may be used initially for foaming.

Abstract: A fuel control system for supplying metered quantities of fuel from a fuel supply (11), through a fuel pump (13), a metering valve (15) and a pressurizing valve (17) to a plurality of engine fuel manifolds (31a, 31b, 33) includes an ecology valve (43) for withdrawing fuel from the engine fuel manifolds (31a, 31b, 33) during cessation of engine operation and for returning fuel to the engine fuel manifolds (31a, 31b, 33) to be burned during normal engine operation. The ecology valve (43) includes a valve housing (44) having a plurality of ecology ports (50, 52, 54) adapted to be coupled to corresponding ones of the engine fuel manifolds (31a, 31b, 33) and a control port (46) adapted to be connected to a corresponding control port (45) of the fuel pressurizing valve (17).

Abstract: An electronically controlled, programmable searchlight (1), particularly useful for mounting on helicopters. The searchlight (1) uses a digital electronic control circuit (30) in conjunction with rotary potentiometers (32), (34) to control movement of the searchlight (1). Adjustable trimpots (22) are employed to provide the searchlight (1) with preset positions, each preset position having an easily alterable operating envelope. The searchlight (1) may have light sources (50, 52) of varying type, which may also be controlled by the electronic control circuit (30).

Abstract: A convertible aircraft brake assembly (10, 60, 77, 78, 83, 85, 96, 120, 130) designed as original equipment to have heat sinks comprising a steel heat sink (20, 70, 80, 90, 91, 100, 110, 122) aircraft brake assembly and a carbon-carbon composite heat sink (40) aircraft brake assembly. When the aircraft brake assembly is converted from one type of heat sink to the other, the conversion is accomplished with minimal changes in component parts. The conversion can be accomplished without any changes in the piston housing (14), torque tube (12), and wheel (30) because the heat sinks include therein respective components which enable each heat sink to be utilized with the commonly used piston housing (14), torque tube (12), and wheel (30).

Abstract: A turbine engine (49) fuel delivery system of the type including a pneumatic governor has an electronic governor and an engine excess stress avoidance feature which disable the pneumatic governor (70) so long as the engine speed exceeds a prescribed value and an electronic control unit (45) continues to function properly. The system transfers governing responsibility to the electronic control unit (45) which controls a torque motor and solenoid valve fuel diversion line (22). The system monitors an engine (49) operating parameter such as gas generator speed (37), power turbine speed, engine output torque, or engine temperature and further diminishes fuel flow to the engine (49) when the monitored parameter exceeds a threshold value.

Abstract: The integrated aircraft wheel, brake and axle comprises a hollow wheel and brake axle (16, 116) having longitudinal splines (17, 117) about its outer periphery, the longitudinal splines (17, 117) engaging splines (62, 162) of a piston housing (60, 160) to effect a non-rotatable connection therebetween. In one embodiment, the piston housing (60) is connected by way of a spline sleeve (70) with a backing plate (80). A wheel (45) is rotatably mounted upon an end of the brake axle (16) and includes a drum drive (52) which extends axially to a drum drive end (52A) having at its inner diameter a bearing assembly (55, 56) between the drum drive end (52A) and an outer diameter of the piston housing (60). In another embodiment, the drum drive (152) may include a thrust flange (151) engaging a rotor disc backing plate (192A).