Abstract: A turbine disk and blade arrangement having a plurality of turbine blades mounted circumferentially around a disk. Each blade has a fir tree root which provides a series of fore-to-aft-extending projections and grooves. The disk has a plurality of radially extending posts which define fir tree recesses therebetween. Each fir tree recess also provides a series of fore-to-aft-extending projections and grooves allowing each fir tree root to engage with a respective fir tree recess. On each pair of facing sides of the fir tree root and the fir tree recess, one or more projections of the fir tree roots and/or the fir tree recesses are truncated to form fore-to-aft-extending cooling passages. The arrangement has lock plates which cover forward and/or rearward surfaces of the posts and of the fir tree roots and define feed channels therebetween which feed cooling air to the respective cooling passage.

Abstract: A turbine disk and blade arrangement for a gas turbine engine has a plurality of turbine blades mounted circumferentially around a disk. Each blade has a fir tree root which provides, on circumferentially spaced sides thereof, a series of fore-to-aft-extending projections and grooves. The disk has a plurality of circumferentially spaced, radially extending posts which define fir tree recesses therebetween. Each fir tree recess also provides, on circumferentially spaced sides thereof, a series of fore-to-aft-extending projections and grooves. Each fir tree root is slidable into a respective fir tree recess with the projections and grooves on facing sides of the fir tree root and the fir tree recess interengaging with each other. On each pair of facing sides of the fir tree root and the fir tree recess, one or more of the projections of the fir tree roots and/or the fir tree recesses are truncated to form fore-to-aft-extending cooling passages between facing sides of the fir tree roots and fir tree recesses.