In gas turbine engines, the operational clearances between static engine structures and the tips of rotating blades impact performance aspects such as the thermodynamic efficiency and fuel burn of the engine. It is desirable to reduce the operational clearances, while at the same time avoiding contact between the rotating blade tips and the static structure. The performance improvement value of as little as a tenth of a millimeter in clearance reduction is significant. In response to thermal excursions, the lengths of the blade tips typically vary at a different rate than that at which the static structures expand or contract. Variation in position or concentricity leads to a need for greater clearances and suboptimal performance. For example, without excess clearance, the blade tips may contact the static structure negatively impacting engine performance. Excess clearance between the blade tips and the static structure may also reduce engine performance. When engine designs result in higher temperatures such as to achieve greater efficiency, maintaining optimal clearance without excess cooling air becomes more challenging.
Accordingly, it is desirable to provide systems that effectively retain and control the position of the static structure relative to the blade tips. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.