Abstract: An inlet door assembly for reducing air pressure loss and enhancing performance of an auxiliary power unit (APU) contained within an aircraft housing is provided. The inlet door assembly includes a duct and a diffuser. The duct, which is configured to be movably coupled to an aircraft and to move between open and closed positions, has a flow passage extending therethrough. Air external to the aircraft flows through the duct while it is in the open position, but not while it is in the closed position. The diffuser is coupled to the duct and configured to move therewith. The diffuser has a passage extending therethrough that is in fluid communication with the duct flow passage, and is configured to diffuse the air that flows therethrough.

Abstract: A muffler system is provided for use with an auxiliary power unit. In one embodiment, and by way of example only, the system includes an outer can, an annular baffle, and a tube. The outer can has a sidewall including a forward end, an aft end, and a cavity extending therebetween. The sidewall is disposed about a first longitudinal axis, and the cavity has a first cross-sectional area and a smaller second cross-sectional area. The annular baffle is coupled to and extends radially inward from the outer can sidewall and has an opening that is disposed about a second longitudinal axis that is non-coincident with the first longitudinal axis. The tube extends through the annular baffle opening and is spaced apart from the annular baffle to define a radial gap therebetween, comprises acoustic material, and has a length and a substantially uniform cross-sectional area along the length.

Abstract: A valve for the accurate control of fluid flowing through the valve. The valve has a valve body and a flow control mechanism. The valve body is a two-part body having a fluid flow section and a valve adjustment section. The fluid flow section has a fluid flow cavity. The fluid flow cavity further includes a flow control orifice area, which flow control surface being smaller in cross-sectional area than the fluid flow cavity. The flow control mechanism is able to vary the length of its major axis via a force provided by the valve actuator. As the major axis of the flow control mechanism decreases, the minor axis of the flow control mechanism increases at an amplified rate, said increase in the minor axis of the flow control mechanism accomplishes flow control and in combination with the valve actuator, flow control and fluid modulation.

Abstract: Described is a valve that is useful for the accurate control of fluid flowing through the valve. The valve comprises a valve body and a flow control mechanism. In the preferred embodiment, the valve body is a two-part body having a fluid flow section and a valve adjustment section. Necessarily, the fluid flow section has a fluid flow inlet and a fluid flow outlet. The fluid flow section further comprises a fluid flow cavity, which is in fluid communication with the fluid flow inlet and the fluid flow outlet. The fluid flow cavity further includes a flow control orifice area, which flow control surface being smaller in cross-sectional area than the fluid flow cavity in order to reduce unwanted effects such as the venturi and the like. The flow control mechanism has a flow control surface, which works in with the flow control orifice area. Because of its construction the flow control mechanism is able to vary the length of its major axis via a force provided by the valve actuator.

Abstract: For gas turbine engine mounted in an aircraft, a closed loop control system, and method therefor, for the inlet duct is provided. Under this control system the flow area of the inlet duct is varied by opening and closing a duct door. The control assures that the position of the door is such that the delta P across the engine will not inhibit the starting of the engine in flight.

Abstract: An improved drilling pipe for directional boring uses a frictionally welded threaded coupling attached to pipe ends for connecting multiple pipes in a drill string. A stress spreader of the end coupling crosses the frictionally welded region to modify stresses on the weld. A weld flash receiving groove positioned beneath the weld allows the insert to be in place during the inertial welding operation and to be closely coupled to the interior pipe surfaces to receive forces therefrom.