Abstract: A gas turbine engine has a turbine vane case, an outer combustion case and inner vane case along with an air seal located in circumferential surrounding relationship to a circumferential row of stator vanes defining a turbine nozzle assembly upstream of a high pressure turbine stage. Individual stator vanes can be replaced without removing the high pressure turbine stage by configuring an index vane to be removably secured to an inner support band by means of a spring loaded pin and configuring each of the remaining vanes in the vane row to have a side slotted base secured to the inner band and removable therefrom by rotation of each of the individual vanes in a direction opposite to the tangential gas load thereon.

Abstract: A turbine blade has a hole through the blade stalk and a controlled area in the stalk cross section on each side of the hole to assure that the blade will separate at the stalk upon overspeed of the turbine wheel. The hole is drilled and reamed and the hole surface is finally machined by chemical milling to eliminate stress risers while maintaining a controlled cross-sectional area to ensure that with selected wheel and blade materials, the blades will separate and reduce the speed of the turbine wheel.

Abstract: A turbine blade has a hole through the blade stalk and a controlled area in the stalk cross section on each side of the hole to assure that the blade will separate at the stalk upon over-speed of the turbine wheel. The hole is drilled and reamed and the hole surface is finally machined by chemical milling to eliminate stress risers while maintaining a controlled cross-sectional area to ensure that with selected wheel and blade materials, the blades will separate and reduce the speed of the turbine wheel.