Abstract: A method of controlling the oil flow in an engine is provided. In preferred embodiments, the method comprises: flowing oil to a first oil pump upstream or downstream of a fuel oil heat exchanger and flowing oil to a second oil pump upstream or downstream of an air oil heat exchanger. One of two control functions to control the oil mass flow rate through the first oil pump is selected wherein the first control function minimizes specific fuel consumption (“SFC”) by the engine and the second control function minimizes average oil temperature. Preferably, the oil pumps are electric and the total combined oil mass flow rate of the first and second oil pumps is maintained constant.

Abstract: A heat exchanger that comprises a plurality of small channels that are arranged around a cross-sectional perimeter such that the sides of the small channels are touching to create bigger channels running parallel to the small channels. To this end, embodiments of the present invention have a heat exchanger matrix where the structure of the large channels is entirely comprised by the structure of the smaller channels resulting in a more compact, more efficient heat exchanger.

Abstract: Brake wear sensors for the brake disc stacks commonly used in aircraft brake systems are disclosed. An ultrasonic transducer is employed to transmit signals to a reflective surface and to receive the reflected signals in return. The time that elapses between the transmission of the ultrasonic signal and the reception of its reflection correlates with the separation between the transducer and the reflective surface. The reflective surface is operatively connected to a pressure plate of the associated brake disc stack such that, as the stack wears, the reflective surface is displaced along with the pressure plate. That displacement correlates with brake wear. In one embodiment, the ultrasonic brake wear detector is an independent unit mounted to the brake housing, while another embodiment includes the detector as an integral portion of a brake actuator connected to such housing.

Abstract: Brake wear sensors for the brake disc stacks commonly used in aircraft brake systems are disclosed. An ultrasonic transducer is employed to transmit signals to a reflective surface and to receive the reflected signals in return. The time that elapses between the transmission of the ultrasonic signal and the reception of its reflection correlates with the separation between the transducer and the reflective surface. The reflective surface is operatively connected to a pressure plate of the associated brake disc stack such that, as the stack wears, the reflective surface is displaced along with the pressure plate. That displacement correlates with brake wear. In one embodiment, the ultrasonic brake wear detector is an independent unit mounted to the brake housing, while another embodiment includes the detector as an integral portion of a brake actuator connected to such housing.

Abstract: A hubcap for an aircraft wheel comprises a generally cup-like body for covering, in use, a free end of an axle. The cup-like body has an end wall, a side wall and an open end opposite the end wall. The hubcap further comprises one or more elongate formations protruding from an outer surface of the side wall and extending from close to the end wall towards the open end of the body, wherein the height of the or each elongate formation varies or tapers continuously or discontinuously from a maximum to a minimum along at least a portion of its length in a direction towards or away from the closed end of the cup-like body.

Abstract: A carbon article shaped as a brake disc, the brake disc being coated with an anti-oxidant coating obtained by applying as a primer coat a composition including orthophosphoric acid, aluminum hydroxide, demineralized water, and a wetting additive; curing the primer coat; applying as a barrier coat a composition including orthophosphoric acid, aluminum hydroxide, demineralized water, colloidal silica, silicon hexaboride, boron, and a wetting additive; and curing the barrier coat.

Abstract: A brake apparatus (1) and method of operating the apparatus are disclosed. The apparatus (1) has a plurality of brake elements (2, 3, 4, 5, 6) with a combined thickness of Y. At least one of the brake elements (2, 3, 4, 5, 6) has a wear portion (22a, 22b) for tribological interaction with a wear portion (52b, 62a) of an adjacent element (5, 6) and is formed in two separable parts (21a, 21b) having thicknesses A1 and A2. The method includes operating an actuator (8) at an actuation extension length less than a maximum actuation extension length to cause the wear portions (22a, 22b, 52b, 62a) of the brake elements (2, 5, 6) to tribologically engage and thereby wear. This tribological engagement is such that as the elements (2, 5, 6) wear to a combined thickness of less than Y the extension length of the actuator is increased.

Abstract: Upgrading existing aircraft braking systems to accommodate replacement of existing brake units employing sintered friction materials with brake units employing carbon-carbon composite friction materials is often desirable. However, when upgrading the braking systems it is necessary to ensure that the integrity of the existing airframe is not compromised by the use of the new brake assemblies employing the carbon-carbon composite friction materials. Consequently, the present invention replaces existing pressure control valves of existing braking systems with an electronic control unit (126) coupled to a pressure control servovalve (128), thereby ensuring proper application of hydraulic pressure to brake assemblies (122). An advantage of this invention is that the pressure profile of the hydraulic fluid is controllable and hence the integrity of the airframe is maintained.

Abstract: An electrically actuated aircraft brake with a carbon-carbon composite heat pack and an electrical actuator for engaging the heat pack and operating the brake. When the brake is not being applied, the brake actuator is adjusted in dependence upon temperature, for example, by controlling the actuator to maintain a temperature regulated position.

Abstract: An aircraft braking control system for an aircraft braking system that comprises at least one first side braking unit (30L) for braking a respective wheel (22L) positioned on a first side of a longitudinal axis of an aircraft and at least one second side braking unit (30R) for braking a respective wheel (22R) positioned on a second side of said longitudinal axis, said braking control system comprising a brake control unit (40) operable to process respective measurements of performance of the braking units (30L, 30R) and according to the process results to provide command signals for controlling respective braking forces applied by said first and second braking units (30L, 30R) to reduce any difference between a first side braking force applied on the first side of the longitudinal axis by said at least one first side braking unit (30L) and a second side braking force applied on said second side by said at least one second side braking unit (30R).

Abstract: In the field of avionics, it is difficult to justify initiation of new aircraft programmes for replacement of small numbers of niche aircraft. Instead, in many cases, retrofitting existing aircraft is preferred for economic reasons. In this respect, upgrading existing braking systems to accommodate replacement of existing brake units employing sintered friction materials with brake units employing carbon-carbon composite friction materials is desirable. However, when upgrading the braking systems it is necessary to ensure that the integrity of the existing airframe is not compromised by the use of the new brake assemblies employing the carbon-carbon composite friction materials. Consequently, the present invention replaces existing pressure control valves of existing braking systems with an electronic control unit (126) coupled to a pressure control servovalve (128) thereby ensuring proper application of hydraulic pressure to brake assemblies (122).

Abstract: A method for charging an aircraft braking system for use includes monitoring actuations of an aircraft braking system to identify where generating usage and non-wear generating usage of the aircraft braking system, and charging the aircraft braking system for use based on the identified usage of the aircraft braking system. An apparatus for monitoring usage of aircraft brakes and charging the aircraft brakes for usage includes at least one sensor for sensing a brake output parameter when the aircraft brakes are actuated and providing signals indicative of values of the sensed brake output parameter. The apparatus further includes a processing system for processing the signals and determining whether an actuation of the aircraft brakes is a wear generating usage or a non-wear generating usage and operating a pricing scheme based on actuation of the aircraft brakes and the associated usage.

Abstract: A composite article for use in an aircraft brake heat pack, the article comprises a core layer having a face portion and a wear layer attached to the face portion, wherein the wear layer has a density lower than the core layer. The core layer is preferably formed from impregnated C—C and the wear layer is preferably formed from C—C. The article may be used as a brake disc.

Abstract: A system and method for monitoring the usage of brake members of an aircraft braking system. The system makes a separate record of each brake actuation in which there is relative movement of the brake member's facing friction surfaces which causes wear, determines the types of brake usage and operates a pricing/payment scheme to charge for brake usage.

Abstract: An aircraft braking control system for an aircraft braking system that comprises at least one first side braking unit (30L) for braking a respective wheel (22L) positioned on a first side of a longitudinal axis of an aircraft and at least one second side braking unit (30R) for braking a respective wheel (22R) positioned on a second side of said longitudinal axis, said braking control system comprising a brake control unit (40) operable to process respective measurements of performance of the braking units (30L, 30R) and according to the process results to provide command signals for controlling respective braking forces applied by said first and second braking units (30L, 30R) to reduce any difference between a first side braking force applied on the first side of the longitudinal axis by said at least one first side braking unit (30L) and a second side braking force applied on said second side by said at least one second side braking unit (30R).

Abstract: Method and apparatus for monitoring electrically-actuated aircraft brakes includes measuring the break heat pack thickness to determine wear of the brake discs and adjusting the measurement so as to give ongoing compensation for temperature variations and hence expansion of the heat pack.

Abstract: A hubcap for an aircraft wheel comprises a generally cup-like body for covering, in use, a free end of an axle. The cup-like body has an end wall, a side wall and an open end opposite the end wall. The hubcap further comprises one or more elongate formations protruding from an outer surface of the side wall and extending from close to the end wall towards the open end of the body, wherein the height of the or each elongate formation varies or tapers continuously or discontinuously from a maximum to a minimum along at least a portion of its length in a direction towards or away from the closed end of the cup-like body.

Abstract: A system and method for monitoring the usage of brake members of an aircraft braking system. The system makes a separate record of each brake actuation in which there is relative movement of the brake member's facing friction surfaces which causes wear, determines the types of brake usage and operates a pricing/payment scheme to charge for brake usage.

Abstract: A system and method for monitoring the applications of carbon-carbon brakes of an aircraft to determine brake condition and operate a brake maintenance program or charge a brake system user. The system and method includes monitoring each actuation of the brakes and making a separate record of each actuation of the brakes in which there is relative movement of the facing friction surfaces that cause wear, and from that separate record determining brake usage. The monitoring may include measuring changes and processing the signals to distinguish between those which fall below and those which are above a threshold value. The method and system may comprise sensing a plurality of braking parameters having values dependent upon the wear in the system and different faults of the system, and identifying and recording wear and faults based on combinations of values of the parameters.