Abstract: Vibration induced compressor vane failure from tip leakage vortex bursting is eliminated or minimized. By securing the vane at opposite ends to inner and outer stationary casings, tip leakage is entirely avoided hence avoiding the mechanism for inducing vibration. By contouring the inner surface of the flow path to converge the flow in a downstream direction with a cantilevered compressor vane having a vane tip spaced from the inner casing surface, airflow lift off is precluded or minimized maintaining the flow attached to the flowpath surfaces with consequent avoidance of tip vortex induced vibration.

Abstract: A method of tuning a compressor stator blade having a base portion and an airfoil portion to achieve a desired natural frequency, includes a) identifying the natural frequency of the compressor stator blade; b) determining a different target natural frequency for the compressor stator blade; and c) removing material from the base portion of the compressor stator blade in an amount and in a configuration that achieves the target natural frequency. A frequency-tuned compressor stator blade includes an airfoil portion and a base portion, the base portion having a substantially solid rectangular shape; and a groove cut across a width dimension of the base portion, the groove having dimensions selected to obtain a predetermined natural frequency for the airfoil portion.

Abstract: Blades of increased blade angle may be retrofitted onto existing compressor rotor wheels as replacement blades whereby higher performance and efficiency without replacing the rotor wheel may be achieved. The base attachments of replacement blades are provided with lateral extensions or flanges and the rim of the compressor wheel is provided with recesses straddling the grooves to accommodate the flanges. The leading edge of the replacement blade is positioned circumferentially for support only by the platform extension thereby limiting the mean and vibratory stresses in the leading edge of the airfoil and maximizing damage tolerance.

Abstract: A microcircuit adhesion testing method and fixture for uniform placement and soldering of a preselected length of wire above a film pad on a microcircuit substrate with consistent substrate-to-wire spacing, comprising a holder for the substrate, finger spacers attached to the holder, and a member for pressing the wire against the spacers. The spacers are made of a material which is not wettable with solder of the type used to attach the wire to the film.

Abstract: A thick-film ink for forming electrically conductive areas on ceramic substrates comprising an organic vehicle and solids composed of 0.5-8% by weight cupric oxide and 99.5-92% by weight finely divided silver.