Abstract:
Isogrid structure (20) forms case (14) surrounding the fan blades (12) of the turbofan. A ballistic fabric (22) surrounds the case. Containment zones (30, 32, 34) at the forward end have isogrid ribs (38) extending other than circumferentially. In the rear support zone, ribs (76) extend circumferentially stiffening the case against collapse.
Abstract:
An airfoil (42) for a gas turbine engine (10) having an airfoil portion (52) with a leading and a trailing edge (60, 62) includes dual pressure source cooling. The trailing edge (62) of the airfoil (42) includes an internal trailing edge passage (78) and the leading edge (60) includes an internal leading edge passage (64). Compressor bleed air at higher pressure is channeled through the leading edge passage (64) whereas compressor bleed air at lower pressure is channeled through the trailing edge passage (78). The higher internal pressure in the leading edge (60) ensures that the inward flow of products of combustion does not occur.
Abstract:
A cleaning method for gas turbine engine airfoils (30) includes a step of autoclave process cleaning and a step of chelating agent solution cleaning. The cleaning method also includes water rinsing after the autoclave cleaning and after the chelating agent solution cleaning. A subsequent step of high pressure water jet spray removes the debris. The cleaning method of the present invention significantly reduces the number of cleaning cycles required to clean the airfoils (30).
Abstract:
Purge flow openings through chordwise ribs (14) are formed by making partial circular cuts at the rib edges before diffusion bonding the blade halves (10, 32). A full semi-circular is used on the pressure side, but only a segment on the suction side.
Abstract:
An automatic engine speed hold control system (430) allows an engine (420) to quickly achieve a commanded engine speed and thereafter maintain a constant commanded engine speed regardless of changes in engine loading. An engine speed error signal (444) is computed as the difference between an operator commanded engine speed (440) and actual engine speed (434, 436). The engine speed error signal (444) is scaled based on an engine speed error gain (448), and the scaled engine speed error (452) is then provided via an integral path (456) and a proportional path (454) to a summing junction (478) where it is summed with load anticipation trim signals (474, 467) to provide a final trim signal (485). The load anticipation trim signals (474, 467) are feed forward signals which anticipate engine response to changes in commanded engine loading, the combined engine trim signal (452) and load anticipation trim signals (474, 467) provide an engine speed hold throttle position command (final trim signal) (485) to control fuel flow to the engine (420) and therefore control engine speed. The engine speed error gain (448) is determined based on engine loading (450), and the error gain is thereafter limited (451) based on current engine speed.
Abstract:
A flywheel system having permanent magnets (20) embedded in a flywheel (10) rotating about a shaft (16) is provided with a stator (28) which is slidably mounted to the shaft (16) thereby allowing a gap g1 between the stator (28) and the rotor/flywheel (10) to be adjustable. When energy is being provided to (spin-up mode) or extracted from (spin-down mode) the flywheel (10), the stator (28) is positioned so the gap g1 is small to provide strong electromagnetic interaction between the stator (28) and the flywheel (10). Conversely, when the flywheel (10) is freewheeling, the stator (28) is positioned so the gap g1 is large enough to minimize electromagnetic drag on the flywheel (10).
Abstract:
A linear, bipolar-type application-specific integrated circuit includes a silicon substrate having a plurality of columns of device primitives or cells. Each cell comprises a plurality of identical NPN and PNP transistors flanking a centrally-located capacitor. Each transistor has dual emitters, bases and collectors. Open field areas are reserved on the silicon substrate on the sides of the columns of cells. Formed in these open field areas are precise thin film silicon chromium resistors. Power planes are also routed in these open field areas. A ground plane is routed in the vicinity of the centrally-located capacitor. Standard analog circuits are personalized using two layers of metallization interconnects.
Abstract:
An airfoil for a gas turbine engine includes a platform having an integral heat shield extending over a seal. Various construction details are developed that disclose a heat shield that protects the seal structure from damage due to exposure to hot gases within the gas turbine engine. In a particular embodiment, a turbine vane includes a platform having a heat shield extending from the leading edge of the platform and a recess. The heat shield extends over the outward surface of a honeycomb seal that is disposed within the recess.
Abstract:
An expandable spar filler block (10) device for use in combination with a spar member (108) of an articulated main rotor assembly of a helicopter. A preferred embodiment of the device includes first and second filler members (20, 22) and an expansion mechanism. Each filler member includes a spar engagement surface that is complementary to the inner mold line (IML) surfaces of the spar member and first and second tapered surfaces. The expansion mechanism for the preferred embodiment of the expandable spar filler block device is a pull shim (40) that includes a first segment and a constant tapered segment having tapered surfaces that are complementary to the first tapered surfaces of the filler members. The spar engagement surfaces and the tapered surfaces of the constant tapered segment are coated with a paste adhesive, and the expandable spar filler block device is inserted in the spar cavity of the spar member with the coated spar engagement surfaces adjacent the IML surfaces defining the spar cavity and the coated tapered surfaces of the pull shim adjacent the first tapered surfaces of the filler members. The constant thickness segment of the pull shim is manipulated to exert a motive force that causes the tapered surfaces thereof to slidingly interact with the first tapered surfaces of the filler members such that the spar engagement surfaces are displaced into abutting engagement with the IML surfaces of the spar member.
Abstract:
A process for electrophoretically depositing a metal oxide coating onto a substrate (16) immersing an electrically conductive substrate (16) in a sol (10) that comprises metal hydrate particles suspended in a medium comprising an alcohol and water. A direct current potential is applied between the substrate (16) and an anode (26) immersed in the sol (10) to electrophoretically deposit metal hydrate particles from the sol (10) onto the substrate (16). Simultaneously, gas bubbles are passed over the substrate (16) to remove hydrogen that forms on the substrate (16) during electrophoretic deposition. The metal hydrate coated substrate (16) is then removed from the sol (10), and heated to dry the coating and transform the metal hydrate to its corresponding metal oxide.