A fan containment system for fitment around an array of radially extending fan blades mounted on a hub in an axial gas turbine engine, including: a fan case having an annular casing element for encircling an array of fan blades and an annular fan track liner lining a radially inner side of the casing element, including a first fan track liner panel positioned circumferentially adjacent a second fan track liner panel. An engagement arrangement engages the first fan track liner panel to the second, extending along at least a portion of adjacent sides of the liner panels, and is configured and the liner panels are shaped such that axial movement of the first fan track liner panel by a distance less than the length of the engagement arrangement, being measured in a direction parallel to the adjacent sides of the liner panels, disengages the first liner panel from the second.

A housing section of a turbine engine compressor stage or a turbine engine turbine stage that, in particular, has a closed and annular-shaped, radially outer casing. The radially outer casing has radially inwardly extending webs that are angled at a slant relative to the radius.

Fan blade containment system includes a composite fan case with an annular composite shell extending from forward flange downstream to aft flange, and circumferentially varying thickness portion of composite shell. Annular composite back sheet spaced radially outwardly of annular composite shell has annular filler layer disposed radially therebetween. Annular forward and aft seams between annular composite shell and composite back sheet may axially trap filler layer. Circumferentially varying thickness portion may include aftwardly extending fingers of composite back sheet in aft seam and first thickness of fingers thicker than second thickness of composite shell circumferentially between fingers. Composite shell may extend from forward flange to aft flange. Aft flange bolted to metallic flange of metallic fan casing aft of aft flange. Containment system may circumscribe and surround fan and fan blades of gas turbine engine fan section.

Fan blade containment systems and methods for producing the same are provided. The fan blade containment system comprise a first ballistic material configured to be wrapped in overlapping layers around a fan casing to form a containment covering of a fan containment case for the fan casing. A plurality of patches comprised of a second ballistic material are configured to be loosely disposed between adjacent overlapping layers of the first ballistic material with each patch partially overlapping a circumferentially adjacent patch.

A system and method are provided for a variable speed compressor with a control module that controls an operating frequency of the variable speed compressor. The control module stores a prohibited frequency range that includes a resonant frequency of the variable speed compressor and an allowed upper frequency above the prohibited frequency range and an allowed lower frequency below the prohibited frequency range. The control module determines a requested frequency and operates the variable speed compressor at the allowed upper frequency for an upper frequency operating time and at the allowed lower frequency for a lower frequency operating time when the requested frequency is within the prohibited frequency range. The control module determines the upper frequency operating time and the lower frequency operating time such that a time-averaged frequency output over the upper frequency operating time and the lower frequency operating time corresponds to the requested frequency.

A system and method are provided for a variable speed compressor with a control module that controls an operating frequency of the variable speed compressor. The control module stores a prohibited frequency range that includes a resonant frequency of the variable speed compressor and an allowed upper frequency above the prohibited frequency range and an allowed lower frequency below the prohibited frequency range. The control module determines a requested frequency and operates the variable speed compressor at the allowed upper frequency for an upper frequency operating time and at the allowed lower frequency for a lower frequency operating time when the requested frequency is within the prohibited frequency range. The control module determines the upper frequency operating time and the lower frequency operating time such that a time-averaged frequency output over the upper frequency operating time and the lower frequency operating time corresponds to the requested frequency.