Abstract: The invention provides for oxidatively resistant surface coated 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 brake for airplanes. The surface coated carbon/carbon composite or graphite-like material, which is resistant to oxidation at high temperatures comprises a fiber-reinforced carbon/carbon composite or graphite having a First Coating (A) of silicon and/or silicon carbide, and a Second Coating (B) comprising a material containing phosphorus chemically bound to oxygen which is chemically bound to silicon.

Abstract: A gas mass flow sensor or probe (35, 37, 39) of an air flow sensing and control system (17, 19, 21) based upon hot-wire type devices where flow sensing is achieved by controlling the difference between two temperature sensing elements (51 and 53) suspended in the flow stream (41, 43, 45). The first element (53) is used to measure the ambient temperature of the fluid flow and the second element (51) is maintained at a programmed temperature (121) above ambient by a current-fed heater (49). The mass flow rate density is determined from heater current (117) required to maintain the temperature difference and the total flow in the duct is inferred. To measure the flow in which the elements (51, 53) are submerged, electronic circuitry monitors the two temperature elements (51, 53) and controls the amount of current through the heater (49) such that there will always be a predetermined difference between the ambient and heated temperatures. The sensor provides an output signal (101) for use by other devices (23).

Abstract: An electrical AC-DC power conversion system featuring 18-pulse rectification and utilizing a low weight wye-connected phase shifting autotransformer (500) supplied from a 3-phase AC source (40) through a 3-phase line reactor (41). The current harmonic distortion is less that 5% and can be further reduced to 3% level by the use of additional suppression devices (eg., chokes) which are often required in aerospace applications. The transformer (500) includes three sections (501) each spaced 120° electrically apart, wherein each section (501) includes a main winding (510) and a pair of phase shift windings (540). The main winding (510) has a neutral end connected to a floating neutral point (502) and a source end (514) is connected to one phase (1, 2, 3) of the three-phase power source (40). The pair of phase shift windings (540) each include a second winding (520) and a third winding (530) connected in series and arranged to generate phase outputs (4-9) of the autotransformer (500).

Abstract: A high intensity discharge lamp (HID) (200) includes an electrically powered lamp (200) having a lamp exterior (220) and at least one lead (226) extending outside of the lamp. An electrical interface (202) includes a male connector (204) fastened at its base (302) to one of the leads (226), an insulate housing (206) having an inner contour (402) shaped to fittedly encompass therein the male connector and at least a portion of the lead, and a cement contact (208) that fastens the housing to the lamp exterior without air gaps. A boot (212) hermetically seals the insulate housing. A female connector (210) is mated to the male connector within the boot, and a feed line (501) having an insulating cover (502) is electrically connected at one end to the female connector and to a power source at the other end.

Abstract: A generator control unit (200) includes a field current modulator (212) that repeatedly switches between an ON state and an OFF state to control the flow of field current to the generator (20), a free-wheeling path (216) that feeds excitation current from the generator (20) back to the generator (20) as a field current component when the field current modulator (212) is in the OFF state, and an impedance circuit (220) that selectively and temporarily absorbs excitation current in the free-wheeling path (216) to reduce voltage overshoot of the generator (20) upon occurrence of an operating transition, such as a transition from high load to low load. In one implementation, the impedance circuit (220) is an RC circuit and a by-pass switch (222) is provided across the RC circuit. When excitation current in the free-wheeling path (216) is not to be absorbed by the RC circuit, the by-pass switch (222) is ON, thereby providing a low-impedance path for the excitation current.

Abstract: A solid state control switching and control system (200) for retractable landing lights. A control unit (208) uses an absolute position sensor (214) to monitor the position of the lighthead (210) of the retractable landing light, and actuates a motor (216), brake (217), and lamp (212) in response to command signals (220,221,223) from the flight crew. Actuation of the motor (216), brake (217), and lamp (212) with solid state switches (100) is gradual and synchronized to minimize electromagnetic interference and extend component life.

Abstract: A multi-functional AC to DC converter (100) controls AC to DC conversion as a function of at least one characteristic of a battery (200) connected to a DC power bus (300), such that the voltage output by the converter (100) to the DC power bus (300) is varied to efficiently charge the battery (200). In one implementation of the present invention, a multi-functional AC to DC converter (100) also adjusts the voltage output to the DC power bus based on a starting condition of an auxiliary power unit (400) so that the supplied voltage is suitable for starting the APU (400). The present invention is suitable for implementation in an aircraft power system to maintain the voltage output within the compliance range of the DC power bus (e.g., between 27.5 and 29 Vdc) while adjusting the output voltage to efficiently charge a battery (200) connected to the bus (300) and/or start an APU (400) connected to the bus (300).

Abstract: The invention provides for oxidatively resistant silicon carbide coated carbon/carbon composites, a method for the preparation of these materials, and their use in high temperature applications, preferably in brakes for airplanes. The silicon carbide coated C/C composite, which is resistant to oxidation at high temperatures, is prepared by a method comprising: (a) coating a C/C composite base with a reactive carbon containing composition to form a reactive carbon coated C/C composite; followed by (b) applying a silicon containing composition to the reactive carbon coated C/C composite to form a bi-layered C/C composite; (c) heating the bi-layered C/C composite to at least the melting point of silicon to form the silicon carbide coated C/C composite; and optionally (d) applying a retardant solution to the silicon carbide coated C/C composite wherein the retardant solution comprises the ions formed from the combination of the following: 10-80 wt % H2O and 90-20 wt % H3PO4.

Abstract: Actuators are described that operate as a result of double-layer charge injection in electrodes having very high gravimetric surface areas and gravimetric capacitances. The actuator output of the actuators may be a mechanical displacement that can be used to accomplish mechanical work. As a result of the non-faradaic process and the actuator materials utilized, such as carbon nanotubes, the actuators have improved work capacity, power density, cycle life, and force generation capabilities. Other benefits include low voltage operation and high temperature performance. The actuators also convert a mechanical energy input to an electrical energy output. The actuators may be used to control either thermal, electrical or fluid transport or cause either the switching, phase shift, or attenuation of electromagnetic radiation.

Abstract: A technique for reducing the likelihood of fatigue damage to a wheel rim assembly (11) of the type having an annular wheel rim (13) with a first bead flange (19), a second separable bead flange (15, 21), and a retaining ring (17) disposable within a groove (35) in the wheel rim to secure the separable bead flange to the wheel rim includes forming the retaining ring to have an annular bead (41), a portion of which has an arcuate cross-sectional configuration by shaping the annular bead, in cross-section, as at least two tangentially joined circular segments (43, 45) of unequal radii (27, 29). Contact between the retaining ring and the wheel rim is limited to the arcuate portion as the sole contact region between retaining ring and wheel rim.

Abstract: A resin transfer molding (RTM) process is disclosed for rapidly filling a fibrous preform and/or a rigid, porous body with high viscosity resin or pitch. The process is suitable for impregnated multiple porous bodies stacked in a single mold. The process uses a fibrous preform or rigid porous body which is placed into a mold matching the desired part geometry. A resin is injected into the mold at temperature and pressure. After cooling, the infiltrated component is removed from the mold. The mold is constructed from two halves fitted to form at least one mold cavity. A gate fitted with a nozzle is set into one of the mold halves, and a valve admits resin or pitch into the gate area. Venting or vacuum can be applied to the mold. The mold is held in a hydraulic press and an extruder, optionally fitted with an accumulator, supplies molten resin or pitch to the mold.

Abstract: A convertible aircraft brake assembly (10) designed as original equipment to have heat sinks comprising a steel heat sink (20) 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 with a change in the piston bushing assemblies (18, 21) of the piston housing (14), while the torque tube (12), wheel (30), piston housing (14) and other parts can be utilized with the heat sinks (20, 40).

Abstract: An electrically actuated braking system (30) of the type having a plurality of brake actuators (35, 37, 39, 41, 43, 45, 47, 49) disposed on a carrier housing (13) to selectively apply a braking force to effect the restraint of wheel rotation has the particular actuators employed during a braking event determined, at least in part, by monitored wheel motion. The system (30) reduces brake energy consumption and heat generation during slow speed operations, reduces braking induced vibration, and compensates for individual actuator failure.

Abstract: A method for manufacturing a preform having a desirably uniform distribution of structural forms (for example and without limitation, particles, flakes, and fibers) therethrough. The method according to the present invention includes using an electrical charge reaction between cationic and anionic agents (such as, without limitation, cationic and anionic polymers) to cause the structural forms to floc or clump together in a mass in which the structural forms are desirably uniformly distributed therethrough. The flocculent mass is then dewatered and/or dried to form a preform that is ready for further processing.

Abstract: A method and apparatus for combining raw fibrous and binding materials in a single mixing step (Step S3), followed by consolidation (Step S5) so as to greatly shorten the overall cycle time to a finished fiber-reinforced composite part. Chopped fibrous materials and binder materials are deposited sequentially onto a belt conveyor (Step S2) so that the materials are successively layered, one on top of each other in a predetermined ratio, and subsequently mixed (Step S3) to achieve uniform dispersion throughout. The mixed materials are then deposited into a rotating mold (Step S4) to further ensure uniform dispersion of fibrous and binder materials. Impregnation of the fibrous materials with the binder material occur in-situ as the uniformly mixed materials are heated and subsequently compacted in the mold (Step S5) to obtain the desired shape of the fiber-reinforced composite part.

Abstract: The airflow distribution of bleed air extracted from a plurality of turbine engines (11, 13, 15, 17) is equalized by an airflow sharing system having electronic airflow sensors (49, 51, 53, 55) and closed-loop control algorithm to equalize the pressure-drop characteristics of multiple bleed air branches to flow-share equally. The pressure-drop characteristic of each airflow branch is controlled to the same setpoint characteristic by negative feedback. The closed-loop control can be implemented with an electronic circuit or as a computational process in a digital controller.

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 infrared aircraft light (100) for use with night-vision imaging equipment as an anticollision light. The light uses infrared light sources (112) coupled to a fiber optic cable (114). The infrared light sources (112) are regularly switched on and off by control electronics (200) to generate bursts of infrared light, aiding the prevention of collisions between covert aircraft. The fiber optic cable (114) distributes the infrared light to create a band of light for improved visibility.

Abstract: An LED strobe light is disclosed. The strobe light (600) uses light emitting diodes (402) arranged about the circumference of an electrically insulative, thermally conductive disk (404) to form an LED light ring (400). LED Light rings (400) may be stacked as desired, with electrically conductive rings (502) placed between light rings (400). A control circuit (614) conditions voltage and current to a level with the LEDs and regulates the on-off timing of the LEDs.

Abstract: A process of enhancing repeatability of the force applied to an object by an electromechanical system having an electric motor, a rotary to linear motion converter and a gear train mechanically coupling the motor to the converter includes providing an analog signal having a magnitude indicative of the desired force, supplying the analog signal to the motor to apply force to the object, removing the analog signal from the motor and reapplying the signal before any free play motion within the converter and gear train can occur. During a command for a desired force, the sequence of supplying the analog signal to the motor to apply force to the object, removing the analog signal from the motor, and resupplying the analog signal to the motor prior to any free play motion occurring within the gear train and converter are repeated several times. The rapid reapplication of the analog signal prevents any backlash associated with the gear train and converter.