Abstract: A turbine engine and method of operating includes an engine core with a compressor, a combustor, and a turbine in axial flow arrangement. A flow path extends through the engine core from the compressor to the turbine to define a flow direction for a working airflow through the engine core.

Abstract: The surface hardness of material is tested by the extent of penetration of a tool thereinto by moving the tool onto the surface from a low to a high value of compressive force and then back to the low value by reversible rotative movements with the penetration being determined from the difference between the two rotative movements, in which the movement may be related to incremental rotative steps with the difference in the number of steps determining the extent of penetration and in which the movement may be automatically performed. The improvements comprise differential thread means comprising a rotatable part and means for revolving the rotatable part to effect linear movement of the penetrating end, and flexure means allowing free axial motion but preventing rotation of the rod (21) therebetween.

Abstract: An exhaust passageway is provided with a sound muffler comprising an orifice, and means operable against a spring in response to sudden increase of fluid exhaust pressure for relatively restricting the orifice thus to abate the sound of exhausting high pressure gas flow. As the gas pressure to be relieved diminishes in a first stage, the spring automatically enlarges the orifice, in effect, whereby the second stage exhausting is rapidly completed at unobjectionable noise level to permit recycling of a pneumatic machine or tool.