An Experimental Investigation of Hollow Turbine Blades for Expandable Jet Engines

An experimental investigation was made to determine the feasibility of using hollow turbine blades in engines designed for short service life. Airfoils were fabricated from sheet material and techniques of welding and brazing attachment were investigated. The airfoils were not intended to be cooled. A principal objective was the reduction of strategic material requirements primarily as a function of direct weight reduction. The materials considered were in the density range of 0.28 to 0.31 pound per cubic inch. Three materials were used for airfoils: N-155, Inconel-X and L-605. These were attached to J47 turbine blade bases and operated to destruction at maximum service conditions of turbine speed and temperature. It was found that L-605 airfoils brazed to suitable bases satisfied the requirements for expendable engines. Service life varied from 11 to 40 hours.