Abstract: A lay shaft assembly for a speed reduction gearbox in a geared turbofan gas turbine engine, the lay shaft assembly having an output gear formed on a lay shaft as a single piece, and an input welded gear formed as a separate piece that is welded to the shaft in close proximity to the output gear. The output gear is machined and precision-ground prior to welding the input welded gear to the lay shaft so that the two gears can be located in close proximity. The input welded gear is precision-ground after the gear has been welded to the shaft.

Abstract: A gas turbine engine in which a long length-to-diameter (L/D) flexible shaft is used to connect two high speed shafts in order to tolerate misalignment. In order to reduce the overall system length, a smaller diameter flexible shaft is contained within but not in contact with a larger diameter primary turbomachinery shaft such that the smaller flexible shaft adjoins to the primary shaft aft of the primary shaft bearing. This design reduces a length of the overall system and reduces additional cost associated with a flex bellows or spline.

Abstract: A turbopump is formed from a metal additive manufacturing process in which both the housing and the impeller are formed as a single piece with the impeller trapped within the single piece housing. The impeller is formed with an axial bore and a shaft is secured by a tie bolt on one end to secure forward and aft bearings within the housing after the impeller and housing have been formed.

Abstract: A self-metering hydrostatic thrust bearing for a small gas turbine engine. The thrust bearing can provide thrust capacity in the fore and aft directions of a hydrostatic thrust bearing using a single source of air. The air supply is directed towards the loaded bearing and away from the unloaded bearing by the self-metering mechanism operated by the thrust load.

Abstract: A turbomachine such as a turbocharger with an air journal bearing and an air thrust bearing arrangement with a fixed air journal bearing connected in series with a floating air journal bearing connected by a hollow spring to supply compressed air from the fixed air journal bearing to the floating air journal bearing, and a forward air thrust bearing and an aft air thrust bearing connected in parallel to a source of compressed air. An air vent cavity is formed between the forward bearing and the aft bearing in which compressed air from all four bearings can be collected and discharged from a housing. Some of the compressed air from the forward thrust bearing is discharged with a compressor outlet, and some of the compressed air from the aft thrust bearing is discharged into a turbine inlet.

Abstract: A turbopump such as a liquid oxygen (LOX) turbopump for a liquid rocket engine is formed using a metal additive manufacturing process in which a single-piece impeller is formed within a single piece housing, the impeller being trapped within the single piece housing. The impeller is formed with an axial bore in which a shaft is inserted after the impeller and housing have been formed. The turbopump includes a protective coating that forms a reaction resistant surface on the base metal in areas of the base metal that are exposed to an oxidizer during pumping. The protective coating may be an enamel glass, a superalloy layer beneath an enamel glass layer, a composite layer of a mixture of enamel glass and superalloy, a composite mixture of oxide and superalloy, or a composite layer of a mixture of enamel glass, superalloy, and oxide.

Abstract: An apparatus and a process for removing a support structure from a 3D printed part, where the 3D printed part along with the support structure is placed in an acid solution and the part is surrounded by an induction heater. The acid solution is recirculated through the acid tank to prevent the acid solution from heating up too much. Small surfaces of the part are heated up by the induction heater before larger pieces are heated so that the acid will remove the smaller pieces first. After enough time, all of the support structure is removed by the acid and the heater to leave the finished 3D printed part with the support structure removed.

Abstract: A turbopump for a liquid rocket engine in which an oxidizer is pumped, where the turbopump is formed with a single piece rotor within a single piece housing by a metal additive manufacturing process, and where surfaces exposed to the oxidizer is coated with enamel glass to provide a smooth surface over the rough printed surface and to provide burn resistance to the base metal from exposure to the oxidizer such as oxygen. A Mondaloy coating can be used below the enamel glass coating to add additional burn resistance to the base metal.