Abstract: A structure for clustered stator vanes of the type utilized in axial flow gas turbine engines is disclosed. Concepts and techniques for retaining the vanes in position within the engine are developed. The concepts are well suited to structures in which the vanes are metallurgically joined. In one embodiment the stator vanes are grouped in pairs of a first, or principal vane and a second, or secondary vane each. East secondary vane is joined to a complementary principal vane along planes which preclude radial or axial movement of the secondary vane with respect to the principal vane, in the event that the bond between the joined vanes fails.

Abstract: A turbine wheel assembly having an improved blade attachment is disclosed. Techniques for increasing the low cycle fatigue life of the components forming the attachment are developed. In one specific embodiment a "fir tree" type attachment includes interlocking root teeth and disk teeth. Correspondingly, grooves accommodate the interlocking teeth. Each groove is contoured in a first region to a first radius and in a second region to a second radius.

Abstract: A method for remanufacturing turbine vane clusters of gas turbine engines is disclosed. Concepts and techniques for salvaging undamaged vanes from a damaged vane cluster are developed. In accordance with the method taught, protective coatings on the vane clusters are removed and residual stresses in the vanes are relieved before salvageable vanes are separated from their original vane cluster.

Abstract: A thrust augmentor for a turbofan, gas turbine engine is disclosed. Techniques for mixing and burning dissimilar density gases in a thrust augmentor are developed. In accordance with one specific teaching the flame front in a swirl augmentor is stabilized by a continuously operative pilot burner. The pilot burner is positioned in the radially outward portion of the augmentor.

Abstract: A thrust augmentor for a turbofan, gas turbine engine is disclosed. Techniques for mixing and burning dissimilar density gases in a thrust augmentor are developed. In accordance with one specific teaching the flame front in a swirl augmentor is stabilized by a continuously operative pilot burner. The pilot burner is positioned in the radially outward portion of the augmentor. The pilot burner employs fuel premixing techniques and is adapted to operate at low inlet pressure levels.

Abstract: A wide channel seal for impeding the leakage of a gaseous medium between the rotor and stator of a rotary machine is disclosed. Various construction details including the use of a honeycomb facing material on the stator side of the channel and the use of a grooved cylindrical surface on the rotor side of the channel are discussed. A comparison in sealing effectiveness between a conventional wide channel seal and the wide channel seal of the present invention is made.

Abstract: A turbine vane for use in a gas turbine engine having high turbine inlet temperatures is disclosed. Film cooling is provided at the leading edge of the vane airfoil by cooling air which flows through leading edge holes from a hollow cavity in the airfoil section. Film cooling air is also provided through wall holes along the suction and pressure sides of the airfoil. A U-shaped insert having a pressure leg and a suction leg is disposed within the hollow cavity to isolate the leading edge holes from the wall holes. When the cavity is pressurized, the legs are each urged against corresponding seal ribs which extend from the cavity wall to effectively isolate the leading edge holes.

Abstract: A method and apparatus for inspecting the contour of an article is disclosed. Nondestructive viewing techniques including the projection of a light pattern onto the article to be inspected and the imaging of said light pattern to a display screen are discussed. The concepts taught enable the viewing of article regions which were formerly obstructed in conventional viewing systems.

Abstract: An outer air seal circumscribing the tips of the rotor blades of a rotary machine is disclosed. Techniques for limiting the radial clearance between the tips of the blades and the outer air seal at steady state conditions are developed. Structure independent of the machine case for isolating the thermal response of the outer air seal from the thermal response of the machine case is discussed and illustrated.

Abstract: A coolable wall element which is adapted for combined impingement and transpiration cooling in environments where the pressure differential across the wall element differs substantially with physical position along the wall is disclosed. Techniques varying the proportion of impingement to transpiration cooling along the wall are developed. The wall element is shown in one embodiment as forming a portion of the wall of an air-foil adapted for use in the turbine section of a gas turbine engine.

Abstract: Apparatus for sensing and transmitting physical intelligence is disclosed. In one embodiment the intelligence is transmittable from the sensing device to a remotely positioned, intelligence processing unit. The apparatus taught has particular applicability to gas turbine engine control systems requiring the encoding and transmission of accurate physical intelligence from a hostile environment to the remotely positioned intelligence processing unit. Techniques employing time sequencing through a fiber optic circuit of the transmitted intelligence to reduce the size, weight and complexity of the apparatus are developed.

Abstract: Apparatus for controlling the position of a parameter setting device of a gas turbine engine is disclosed. Techniques for improving the accuracy of the control system by incorporating an optical circuit for sensing physical parameters, such as linear position, pressure and temperature are developed. A fiber optic cable linking a remote intelligence processing unit with a sensing unit at the controlled device is employed in the preferred embodiment.

Abstract: A compressor rotor blade for a turbomachine is disclosed. Techniques for increasing the strength to weight ratio of the blade while maintaining adequate resistance to foreign object damage are developed. In one specific embodiment an all composite construction employs matrix materials of varied ductilities and yield strengths to improve the energy absorbing capabilities of the blade.

Abstract: A composite rotor blade for a turbomachine is disclosed. Concepts for maximizing the blade strength to weight ratio while maintaining adequate resistance to foreign object damage are developed. Techniques for maximizing the torsional rigidity of the structure are disclosed, and in one embodiment, a judicious yet effective placement of titanium sheet material on the pressure side of the blade is made.

Abstract: A seal design which is particularly suited for use between the rotating and stationary components of a machine is disclosed. Various construction details which increase the resistance to the flow of a fluid medium across the seal from a region of higher pressure to a region of lower pressure are developed. The seal design is built around conventional rotary seals, such as labyrinth or wide channel seals, and includes means for aerodynamically impeding the flow of the fluid medium approaching the upstream end of the seal.

Abstract: Apparatus for supplying fuel to the combustion chamber of a gas turbine engine is disclosed. Techniques for increasing combustion efficiency and for decreasing the percentage of noxious emissions in the effluent from the chamber are developed. Axially extending tubes are used extensively in the disclosed embodiments of the invention for premixing gaseous or vaporized fuel with air in the supply means upstream of the combustion chamber. In addition to operation on natural gas and vaporized liquid fuels, the embodiments shown are adaptable to efficiently burn gasified coal fuels having heating values as low as 80 BTU per standard cubic foot (BTU/scf).

Abstract: A rotor blade system which is adaptd for long term reliable operation in a gas turbine engine is disclosed. Techniques incorporating composite materials into the rotor system are developed. One rotor structure shown utilizes a paired blade assembly having a core of continuous fibers running from the tip of one blade to the tip of the adjacent blade. Each of said paired blade assemblies is mchanically detachable from the engine rotor.

Abstract: Methods and apparatus for depositing a coating material on an underlying substrate are disclosed. Cathode sputtering techniques for rapidly depositing a relatively thick coating on a substrate having a complex geometry are developed. The apparatus employed includes a sputtering chamber formed between a center, post cathode and a hollow, cylindrical cathode. In one embodiment a magnetic field is imposed upon the sputtering chamber to concentrate the sputtered coating material in a preferred region.

Abstract: A combustion system for a gas turbine engine is disclosed. Fluid transfer and premixing techniques are developed. The combustion system is specifically adapted, in one embodiment, to an engine having a centrifugal or an axial/centrifugal compressor including a pipe diffuser at the downstream end thereof. Flow transfer tubes are shown between the pipe diffuser and a radial inflow combustor.

Abstract: Apparatus and methods for measuring deflection of rotating fan blades of a gas turbine engine is disclosed. The measurement of bending and torsional deformation in response to integral and to nonintegral vibration as well as to structural loading is developed. Optical measuring techniques including the projection of collimated light beams into the fan section of the engine are employed. A linear readout of angular deflection is displayed on a distant screen for amplification of the actual deflection. The plurality of beams provide a deflection profile covering the full surface of the blade.