Hoop seal with partial slot geometry

A rotor blade assembly includes a slot for mounting a rotor blade that extends partially through a rotor disk and a continuous uninterrupted hoop seal that extends about the circumference of the rotor disk. The rotor disk includes an integrally formed seal that includes at least one knife edge disposed concentrically about the rotor disk. The slot receives a root portion of a rotor blade but does not extend through the seal. As the seal remains an uninterrupted full hoop about the circumference of the rotor disk, additional rigidity and strength are realized. The increased rigidity and strength provided by the full hoop structure provides for the reduction in material and physical dimensions without compromising desired performance of the seal.