Turbofan case and method of making
A casing for a gas turbine includes a construction providing improved structural efficiency. Improved load paths and means for transmitting loads in the engine case are disclosed.
1. A casing for an aircraft turbofan bypass engine, the casing comprising:
a case adapted to encircle the engine and having a plurality of engine mounts thereon adapted to mount the engine to an aircraft;
an inner hub adapted to support at least one bearing supporting a main shaft of the engine, a airflow path through the engine defined by and between the inner hub and the case, the inner hub supported inside the case by a plurality of thin-walled struts each extending continuously from the inner hub to the case, the struts having a continuous leading edge which extends linearly from the inner hub to the case to thereby define a primary load path from the inner hub to the case; and
a splitter adapted to divide the airflow between a core airflow passage and a bypass airflow passage of the engine, the splitter supported intermediate the inner hub and case by the struts, the splitter having cutouts for receiving the continuous struts therein, the struts having a trailing edge with an outer trailing edge portion extending linearly from the splitter to the case to thereby defining a primary splitter load path from the splitter to the case, the struts trailing edge further having an inner trailing edge portion which extends from the splitter to the inner hub, the inner trailing edge portion misaligned with the outer trailing edge portion for interrupting a load path between the splitter and inner hub to thereby inhibit the transfer of splitter loads to the inner hub, the inner and outer trailing edge portions joined by a bend in the strut trailing edge extending between the inner and outer trailing edge portion.
2. The casing of claim 1 , wherein the bend in the strut trailing edge is an S-like double curvature bend.
3. The casing of claim 1 wherein the case is an intermediate case portion of the casing.
4. The casing of claim 1 , wherein the strut trailing edge outer portion extends substantially radially from the splitter to the outer case, and wherein the strut trailing edge inner portion extends axially forwardly from the splitter to the inner hub.
5. The casing of claim 1 , wherein the trailing edge inner and outer portions and trailing edge bend are configured to reduce the axial stiffness of the struts.