Abstract: An aircraft brake control system accommodates desired yaw for steering, while substantially eliminating undesired yaw. The system assesses brake command signals from the pilot, signals corresponding to aircraft parameters, and signals based on brake control parameters, and determines therefrom an amount of yaw desired by the pilot. The instantaneous yaw rate is monitored and compared to the desired yaw rate. An error signal corresponding to the difference between instantaneous and actual yaw rates is calculated and that error signal is employed to modify a braking differential between right and left brakes to eliminate or substantially reduce the undesired yaw.

Abstract: A system and associated method for achieving both force and position control of motor-driven electrical brake actuators for a brake disc stack that has, and seeks to maintain, a characteristic built-in clearance among the discs. The system employs both force feedback and motor turns position feedback associated with the actuator during a braking operation in order to obtain a motor turns position that achieves the characteristic built-in clearance following braking action or the like.

Abstract: A method of diagnosis and prognosis for various operative systems is provided so that maintenance can be efficiently and effectively scheduled and provided. The invention is applicable to a broad range of systems, but particularly to aircraft brake systems and tires. An aircraft brake may be modeled by attributing brake wear factor values to various parameters associated with the aircraft brake that impact wear. Over the course of time and during braking events, the brake wear factor values are summed and a running total of that sum is kept over the life of the brake. At a point in time when the sum of weighted factors exceeds a preset threshold, an indicia is generated that service is required.

Abstract: Various embodiments of aircraft brake assembly structures are provided for achieving noise reduction during braking activity. In certain embodiments of the invention, the actual application of force to the pressure plate is regulated such that a different number of actuator pistons are used during low-energy stops than during high-energy stops. In other embodiments of the invention, the pressure plate or endplate is augmented as to surface area in some instances and as to a taper angle in others, again to achieve a desired increase in effective pressure application during low-energy stops. In other embodiments of the invention, the stator and/or rotor disks are characterized by slots to break up the propagation of noise waves.

Abstract: A flexible wheel drive for aircraft onboard taxi systems is provided. In association with an aircraft wheel assembly there is provided a drive gear assembly that is adapted to be driven by a motor mounted to an aircraft. A flexible drive flange is secured about an inboard rim of the aircraft wheel assembly and a flexible ring is interconnected between the drive gear assembly and the flexible drive flange. Preferably, the flexible ring is made of a metal textile or high-temperature composite and the drive flange is of a high-strength stainless steel.

Abstract: An electric brake power conversion and distribution system for use in aircraft is provided. An array of DC-DC converters is interposed between a DC power source and a plurality of aircraft electric brake actuators. Each of the DC-DC converters has a characteristic output voltage. The DC-DC converters are interconnected in an additive series of connections to provide an output voltage to the plurality of aircraft electric brake actuators that comprises the sum of the characteristic voltages of the DC-DC converters that are enabled at a particular point in time. A controller manipulates an array of switches interconnected with the array of DC-DC converts, such that the controller can selectively enable or inhibit selected ones of the DC-DC converters, as desired. Accordingly different voltages can be made available for the electric brake actuators depending upon aircraft activity, such as landing, taxiing, parking, or in flight.

Abstract: A method and apparatus for making carbon/carbon composite disks for braking applications that employs a continuous feeding of fiber strands into a mold. The fibers are then compressed to form a mat or preform. The fibers are then needled such that the fibers within the mat interlock and extend in various directions. The mat or preform is then subjected to densification processing. In order to enhance the effectiveness of the densification process and/or to speed up the processing time, a filler is added to the preform during the manufacturing process. The fillers are added by way of a dry powder or as a liquid slurry. The filler may be aluminum oxide, boron carbide, silicon carbide, pitch, or a variety of carbonic or noncarbonic performance enhancers.

Abstract: A process for fabricating a carbon composite structure that is lightweight, structurally sound, and characterized by high heat capacity. A carbon structure is devised with cavities therein receiving a phase change medium. The phase change medium demonstrates both high energy absorption capacity and high thermal conductivity and is formed from a carbon fiber to establish a high porosity medium having a large volume fraction. The surface energy of the carbon fibers is enhanced in various ways as by deposition of a carbide former, a metallurgical coating or a precursor liquid or by electroplating or etching the surfaces of the carbon fibers. The enhanced surface energy allows for the retention of phase change material.

Abstract: A brake control system for a wheeled vehicle includes a field programmable gate array configured to perform the algorithm of brake control subsystems in a typical brake control system for a wheeled vehicle. The brake control subsystems typically include anti-skid control, brake temperature monitoring, built-in tests, and, in the case of an aircraft, nose wheel steering. The system also includes wheel speed sensors, brake temperature monitors, brake valves and associated control circuits, and brake valve monitors respecting brake valve current and voltage. The use of field programmable gate arrays to configure a brake control system avoids the obsolescence and shortened life of control systems previously dependent upon microprocessors and the like.

Abstract: A torque tube and conical back plate for aircraft brakes including a torque tube having a truncated back plate of thin metal construction extending from the outboard end thereof. The conical back plate is characterized by inner and outer reinforcing rings, such rings providing a compressive force at opposite ends of the truncated cone of the back plate, thus allowing the back plate to resist bending and deflection. In accordance with the invention, the cross sectional centers of mass of the inner and outer reinforcing rings are shifted outboard from a projection of the center plane of the conical back plate, such positioning enhancing the stiffening and reinforcing capabilities of the reinforcing rings.

Abstract: A beam key and wheel assembly for aircraft brakes is presented. A beam key is pinned at one end to the aircraft wheel and is engaged proximate an opposite end to a pad on an outrigger flange of the wheel. The pad has a milled arcuate surface which is congruent with and nestingly receives a similar arcuate surface of a foot member. The foot has a channel formed therein on a side opposite the arcuate surface, the channel matingly receiving a base on a bottom surface of the beam key. A bolt passes through the beam key, foot, and pad on the outrigger flange to secure the elements together.

Abstract: An inflation valve having overpressure protection has an inflation core which is coaxial with an exhaust port, both of which are coaxial with an exhaust plenum maintained within a body portion of the inflation valve. The inflation core communicates with a circular chamber which also communicates with radial passages extending within the base portion to an annular chamber which communicates with radial passages which interconnect with the wheel entry port. The exhaust plenum is sealed from the wheel entry port and the pressure of the associated tire by a rupture disk. Exhaust ports extend through the body portion of the valve from the exhaust plenum to atmosphere. When an overpressure condition exists within the tire, exceeding the characteristic pressure of the rupture disk, the rupture disk opens and allows the pressure within the tire envelope to escape through the wheel entry port, exhaust plenum, and exhaust ports.

Abstract: A metallic aircraft brake disk having thermal relief slots therein is provided. The brake disk is of an annular shape with force bearing slots in one of the circumferential surfaces thereof to engage the disk with a portion of the aircraft. A plurality of thermal relief slots extend from an opposite circumferential surface of the annular brake disk. The thermal relief slots are in the shape of a dual armed hook anchors and are configured to minimize the amount of material removed to form each slot, while maximizing certain radii of the slot head. Particularly, an elongated radial slot terminates in a slot head, the slot head being formed of a number of interconnected curvate surfaces. The radii of the curvate surface opposite the end of the radial slot is maximized.

Abstract: Brake disc assemblies and methods for making the same which allow for increased carbon utilization. In one embodiment of the invention, worn or spent discs from a carbon brake disc assembly are used to fabricate new brake discs. The separate discs, individually unsuited for further use in a brake assembly, are secured together with like wear material and subjected to chemical vapor infiltration to configure a disc suitable for use as a new disc. In other embodiments, previously used discs or new carbon material is employed to configure wear pads or wear discs which are affixed to opposite sides of a carrier plate and then subsequently used in a brake disc assembly. In all of the embodiments, carbon screws or threaded rods are employed to hold the components of the disc together. Such carbon screws or threaded rods are fabricated from otherwise worn or spent carbon discs or from new carbon.

Abstract: An apparatus for making carbon discs for brake disc assemblies by feeding continuous strands of fibrous carbon material from spools into a die, the volume of the carbon material so dispensed being continuously monitored. A cutter terminates the dispensing operation and a debulking plate urges all of the fibrous carbon material so dispensed into the die alone. The material is compressed within a cylindrical annular die and, in one embodiment, is submitted to a convection curing oven where the preform is cured. Subsequently, the preform is carbonized, densified, and machined to form a final carbon disc brake. In another emobodiment, a dry preform is fabricated, obviating the need for curing and carbonizing.

Abstract: A brake disk for an aircraft brake assembly, the assembly comprising a multi-disk stack of alternating stator and rotor brake disks wherein each disk is comprised of a carbon composite material and a specific volume of a phase change material is encapsulated within the core of the disk between its brake wear faces and distributed so as to function to enhance brake energy capacity in the operation of the brake assembly.

Abstract: A wheel and brake assembly is provided for use with an aircraft. A landing gear strut depends from the aircraft and an axle is mounted to the strut. At least one brake assembly housing is mounted to the axle, on either side of the strut. One or more torque take-out pins are provided on the strut to be received in mating sockets provided in the brake assembly housing. Torque from the brake assembly housing is transferred to the strut or a stationary member by way of the pins and sockets. At least one tie rod member engages lug members provided on at least one brake assembly housing and the strut or stationary member. At least two brake assembly housings mounted on opposite sides of the strut may be interconnected by at least one tie rod member. Thus, the brake assembly housing is interconnected and may be drawn toward the strut or stationary member by selective adjustment of a turnbuckle incorporated into the tie rod member.

Abstract: A torque tube for an aircraft wheel and brake assembly is characterized by an annular, substantially cone-shaped, radially-extending backplate flange having a plurality of stiffening ribs which extend axially inboardly as radial extensions of various key surfaces, the key surfaces being adapted for engagement with alternating disks of a brake disk stack of the assembly. The stiffening ribs exhibit an axial dimension as may be defined by a pair of acute angles, a first acute angle establishing an outboard straight line surface of revolution which is continuous about the outboard end of the tube while a second acute angle establishes an inboard straight line surface of revolution in only the areas of the stiffening ribs. The backplate flange exhibits an axial dimension between the ribs as may be defined by a third acute angle which establishes a straight line surface of revolution between the adjacent ribs.

Abstract: A thermally balanced brake disc stack provides brake discs of greater mass at the center of the stack and of lesser mass at the opposite ends of the stack. The temperature of the high mass discs in the center of the stack will rise to a lower level than the thinner discs at the ends of the stack. However, the heat dissipation rate at the ends of the stack exceeds that at the center of such that all of the discs cool to a predetermined temperature concurrently.

Abstract: This invention provides an improved aircraft wheel rim wherein a demountable tire bead flange has an annular chamfer within the outboard end of the flange bore, and a split lockring which cooperates to maintain the flange on the wheel rim body has an outer surface chamfer which matches the flange bore chamfer, the angle of the flange bore and lockring surface chamfers being determined by the coefficient of friction of the material comprising the wheel rim assembly such that a compressive wedge-locking load force exists at the chamfer joint as may be imposed by inflation of a rim-mounted tire.