Abstract: The present invention relates to detectors used in X-ray tomographic imaging. The invention describes a multi-element detector array which detects ionization events in a xenon dielectric, and also describes a pressure vessel for containment of the xenon and detector.

Abstract: An energy recovery system is provided for an aircraft gas turbine engine of the type in which some of the pneumatic energy developed by the engine is made available to support systems such as an environmental control system. In one such energy recovery system, some of the pneumatic energy made available to but not utilized by the support system is utilized to heat the engine fuel immediately prior to the consumption of the fuel by the engine. Some of the recovered energy may also be utilized to heat the fuel in the fuel tanks. Provision is made for multi-engine applications wherein energy recovered from one engine may be utilized by another one of the engines or systems associated therewith.

Abstract: In one form of the present invention, a plurality of serovalves are connected to a common manifold. The manifold transmits fluid pressure from the servovalves to a modulator piston which controls the fluid pressure applied to a hydraulic actuator piston. The servovalves are designed such that, if the fluid pressure provided by any one of them to the manifold falls below a threshold, then the servovalve disconnects itself from the manifold, allowing control of the modulator piston to be assumed by the remaining, functioning servovalves. The present invention can be used in control surface actuators of short takeoff and landing (STOL) aircraft.

Abstract: An open-ended acoustic impedance tube is abutted against a material having a known acoustic impedance and a standing wave pattern is established in the tube. A first apparent impedance of the material is derived based on the standing wave pattern. A correction factor is computed based on the known impedance and the first apparent impedance. The open-ended impedance tube is then abutted against a sample material and a second apparent impedance is derived. The actual impedance of the sample is inferred from the second apparent impedance and the correction factor.

Abstract: A swirler for a gas turbine engine combustor is disclosed for simultaneously controlling combustor flow rate, swirl angle, residence time and fuel-air ratio to provide three regimes of operation. A first regime is provided in which fuel-air ratio is less than stoichiometric, NOx is produced at one level, and combustor flow rate is high. In a second regime, fuel-air ratio is nearly stoichiometric, NOx production is less than that of the first regime, and combustor flow rate is low. In a third regime, used for example at lightoff, fuel-air ratio is greater than stoichiometric and the combustor flow rate is less than in either of the other regimes.

Abstract: An invention is disclosed for the attachment of a yoke to a laminated material composed of a medial matrix laminated between first and second skins. Two elongated parallel brackets are attached to the laminated material, the brackets each having a first segment fastened to the first skin, a second segment fastened to a first region of the second skin, and a third segment fastened to a second region of the second skin. The first and second regions are separated by a cavity in the second skin. The yoke is positioned in the cavity and fastened to the two brackets to provide a thrust point approximately coplanar with the second skin. The invention can be used to attach an actuator rod at the thrust point when the laminated material is that used in a cowling associated with a thrust reverser in a gas turbine aircraft engine.

Abstract: An invention is disclosed in which a signal indicating a rate of fuel flow desired for a gas turbine engine is bounded between limits imposed by maximal- and minimal-fuel rates allowed under the current operating conditions of the engine and between limits imposed by maximal- and minimal-accelerations allowed under the same operating conditions. The fuel rate limits are constantly modified by feedback information about the actual acceleration experienced by the engine. This feedback information about acceleration is obtained without directly measuring acceleration itself.

Abstract: In one form of the present invention, an apparatus for tightening a bolt stores information relating to an allowable relationship between change in bolt length and torque. A wrench applies a time changing torque to the bolt, the change in bolt length is measured by timing a traveling acoustic pulse in the bolt, and comparison means ascertains whether the torque-length behavior of the bolt exhibits the allowable relationship.

Abstract: In one form of the invention, means are provided for sensing changes in electrical power demanded from an electrical generator driven by a gas turbine engine. In response, other means change the rate of fuel and air delivery to the engine in proportion to the demand changes and keep the combustor fuel-air ratio substantially constant.

Abstract: A multiple-impingement cooled structure, such as for use as a turbine shroud assembly. The structure includes a plurality of baffles which define with an element to be cooled, such as a shroud, a plurality of cavities. Impingement cooling air is directed through holes in one of the baffles to impinge upon only the portion of the shroud in a first cavity. That cooling air is then directed to impinge again upon the portion of the shroud in a second cavity.

Abstract: An invention is disclosed in which a light source provides light beams of different wavelengths which are projected to an object to form images thereon at substantially the same degree of focus and magnification. The reflected images are received by two photosensors, each responsive to one of the wavelengths, which produce signals indicative of surface features of the object. Increased resolution of small surface features is obtained through the similarities of focus and magnification.

Abstract: The invention defines a boundary in space and optically determines the crossing of it by an object and at the time of crossing measures the distance between a point located on the object and the boundary. More particularly, the invention establishes the boundary with respect to an amount of light eclipsed in a light beam positioned in space. In one embodiment, an examination zone containing the boundary is illuminated by two light beams, one of which is produced by inverting and reflecting the other after the other passes through the examination zone with the result that the rate of change in light intensity which occurs during the eclipsing is greater than that in the case of a single beam.

Abstract: A shear-type, fail-fixed servovalve is disclosed which includes a piston whose piston head is movably disposed in one chamber of a multi-chamber housing. A piston rod is attached to the piston head and extends into the other chambers. Two passages extend through the piston rod and communicate with the chamber on opposite sides of the piston head. A pair of input orifices are located proximate each other at one end of the piston rod, each corresponding to one passage. An angularly movable jet pipe emits fluid directed at the input orifices. The jet pipe has a null angular position disposed at a predetermined offset angle with respect to the axis of the piston rod, and directs fluid towards the pair of orifices. Means responsive to a selectively variable control signal for changing the angular position of the jet pipe is provided which is effective to produce a magnified linear piston displacement by varying the relative amounts of fluid supplied to the input orifices.

Abstract: An invention is disclosed for positioning an object wherein three point supports provide three contact points which define a first plane. Three additional point supports provide three additional contact points which are not coplanar with the first plane and which define a second plane. The first and second planes are nonperpendicular. The point supports accurately and repeatably position the object for optical measurement of a dimension of the object. The invention can be used in connection with the quality control testing of weldments which attach blade tips to gas turbine engine blades.

Abstract: The hysteresis of an inductive proximity probe is reduced by repeatedly switching off and on a feedback network in the probe which causes the hysteresis. Such a probe can be used in a fixturing device for the grinding of dovetails on gas turbine engine blades.

Abstract: Gas turbine engines are used as powerplants for aircraft. When the aircraft are parked on the ground, the wind can blow through the engines and set fans and rotors into motion, i.e., windmill them. Given that the blades of the fans and rotors are loosely fastened to their rotors, the low speed rotation caused by windmilling causes the blades to clatter or clank, thus causing wear. The present invention provides means for clamping blades into position during this low speed rotation for reducing clanking.

Abstract: A balancing method is provided for dynamically balancing parts intended for use in rotating machines. The method is most advantageous when used on parts that are originally cut on a numerically controlled cutting machine or are easily defined by a part cutting program. The method begins with rotating the part and producing electrical error signals proportional to the part's imbalance. The error signals are used to determine in digital format an amount and location of material that must be removed from the part to render it rotationally balanced. The part cutting program is then appropriately modified so that if the part is remachined, the necessary material will automatically be removed. The part is then properly positioned in a numerically controlled cutter, remachined using the modified part cutting program, and the necessary material is automatically removed.

Abstract: An overload protection circuit for an electrical signal source is disclosed in which an overcurrent in the signal source is sensed and the source is disabled for a predetermined time interval. If the overcurrent condition persists beyond the predetermined time interval, the turn-off cycle is repeated. The system is immune to overcurrent transients and the amplitude of the current which triggers turn-off, as well as the length of the predetermined time interval, may be selectively set.

Abstract: A switch is disclosed having a plurality of conductors entering a chamber containing a movable contact element. Air pressure applied to the contact element moves it into contact with at least one of the conductors.

Abstract: A centrifugal pump is provided for degrading antimisting fuel. The centrifugal pump has a rotary impeller closely surrounded by a vaned diffuser for receiving fuel therefrom. The diffuser includes a plurality of recirculation channels disposed along its inner circumferential surface for directing some of the fuel which passes from the impeller to the diffuser back to the impeller for enhancing the degradation of the fuel. Other embodiments are disclosed.