Rotor blade retention and sealing construction

A rotor for a gas turbine engine, said rotor having a plurality of notches about its periphery, rotor blades mounted in said notches about said rotor periphery, a circumferential groove around said rotor and immediately below said notches, each rotor blade having a root and platform means above said root, said root conforming in exterior shape to said rotor notches, said platform having at one end a portion overhanging said root and an underside surface having circumferentially extending groove means, a plurality of circumferentially extending segment plates for retaining said blades in position on said rotor, the lower edge of each segment plate being contained within said rotor groove, the back face of each segment plate being adjacent a face of said blade root and the upper edge of each segment plate being adjacent the underside surface of said overhanging platform portion between said platform groove means and said blade root face, each segment plate extending between the rotor midportion between two adjacent rotor notches and the rotor midportion between two other adjacent notches and covering at least two blade roots, segment plate anti-rotation means installed at at least one rotor location between adjacent rotor notches, the ends of said segment plates adjacent said anti-rotation means being contoured about said anti-rotation means, and circumferential ring means contained in part in said blade platform groove means and covering the outer periphery of said segment plates.