<p>In a gas turbine engine a seal which minimizes blade tip clearance at a design operating condition is disclosed. In the cold engine condition the radius of curvature of the sealing surface is less than the radius of the turbine wheel at the blade tips. At the design operating condition the radius of curvature of the sealing surface is substantially equal to the wheel radius. The seal is supported by arcuate hooks which are sufficiently flexible to accommodate the changes in the radius of curvature of the sealing surface over the indicated range.</p>