Abstract: An air cycle air conditioning system (10) is provided with regenerative heat exchangers (80, 110) upstream and downstream of an expansion turbine (90). A closed-loop liquid circulatory system serially connects the two regenerative heat exchangers for regeneration without the bulk associated with air-to-air heat exchange. The liquid circulatory system may also provide heat transport to a remote sink heat exchanger (150) and from a remote load (20) as well as heat exchange within the sink heat exchanger and load for enhanced compactness and efficiency.

Abstract: An air cycle air conditioning system (10) for rgulating the temperature and pressure of diverse loads includes open and closed loop sections (12) and (16). A first load (14) requiring heating or cooling with constantly supplied fresh air is provided with chilled air from first turbine (75) and warm air from first bypass valve (50). A second load (20) which can be heated or cooled with a supply of recirculating air is provided with chilled air from second turbine (130) and warm air from a second bypass valve (170). Air is supplied to the second turbine from a compressor driven by the first turbine whereby the first turbine maintains the temperature of both loads either by the direct supply of air thereto or by driving another turbo-compressor system.

Abstract: An improved jam compensating control valve (45) includes a spool (65) which blocks and unblocks a flow passage through the valve. The spool is slidably disposed within an inner sleeve (60) which, upon jammed interengagement with the spool moves therewith, thereby connecting drain passsages (180, 182, 185, 190 and 195) in the surface of the spool with outlet passages (120 and 125) communicating with an associated actuator (5) for actuator draining in response to such valve jamming.

Abstract: A water/gas separator for individual cells of an H.sub.2 /O.sub.2 fuel cell battery includes porous hydrophilic discs which transport water but block passage of the oxidant gas.

Abstract: A high efficiency air cycle air conditioning system (10), driven and charged by a gas turbine engine (15), operates in a closed-loop, Brayton cycle. The system includes a main (bootstrap) compressor (75) discharging to a sink heat exchanger (85) which in turn discharges to a regenerative heat exchanger (110). Air is ducted from the regenerative heat exchanger to an expansion turbine (120) where the air is chilled and then ducted to load (20). Air exhausted from the load is again ducted through the regenerative heat exchanger where the load exhaust air precools turbine inlet air. The capacity (operating pressures) of, and input power to the system are controlled by modulation of charge air provided to the system from the gas turbine engine and if desired, may be further controlled by selective bleeding of air from the system, selective bypassing of the system turbine with refrigerant, or modulation of shaft input power to the main compressor.

Abstract: The fuselage (cabin) (15) of a propeller (45) driven aircraft (10) is isolated from vibration associated with the wake (46) of the propeller by vibration isolators (50, 55 and 110) in the wing and tail surfaces of the aircraft.

Abstract: The accuracy of performance data obtained from instrumentation associated with a wind tunnel test facility is determined by a comparison of empirically and analytically determined performance data associated with a combustorless gas turbine engine reference model. The reference model includes a housing (30) terminating in an exhaust nozzle (85) of standard geometry for which empirical performance data exists. A plurality of apertured plates (130-145) spaced from each other and other reference model components by spacer rings (165-185) adjust airflow through the reference model to correspond to that encountered in the actual wind tunnel testing of a combustorless gas turbine engine simulator.

Abstract: A pitch control system (10) for a variable pitch propeller effects engine governor (330), control of blade pitch under normal operating conditions and automatically effects direct (beta) control of blade pitch by the power lever (305) throughout a predetermined range of power lever settings. The system is hydromechanical and comprises a pitch actuator (40) and a pair of control valves (120 and 210), a first of the valves (120) applying a metered fluid pressure from a governor controlled pilot valve to the actuator and blocking that signal and replacing it with a supply fluid pressure at the point of transition from governor to beta control. The second control valve (210) effects a controlled draining of the actuator and connection thereof with the power lever (305).

Abstract: An apparatus (10) for the storage therewithin and expulsion therefrom of a fluid medium includes a tubular tank (15) and a pair of diametrically opposed, simultaneously actuatable pistons (50) permanently sealed to the tank by a pair of rupturable seals (65). The pistons are driven by a secondary fluid the effects of which are shielded from the interior surface of the tank by a pair of flexible shields fixed at the ends thereof to a corresponding piston and the inner surface of the tank, movement of the pistons effecting an expansion of the shields to form a protective lining for the tank.

Abstract: A propeller pitch control system having a mechanical low pitch stop which includes an electrical backup therefor. The backup comprises an electrically operatable means (245) to effect blade pitch adjustment toward feather under conditions of failure of the low pitch stop indicated by propeller operation at pitch angles in the range of beta operation, but power settings in the range of normal engine speed governor pitch control. Such operating conditions actuate a pair of switches (190 and 195) connecting the means (245) to a voltage source to increase blade pitch toward feather, thereby preventing overspeed operation of the propeller.

Abstract: A system (10) of parallel hydraulic actuators (15) and (20) includes a pair of laterally spaced, longitudinally extending, discrete feedback levers (180) and (185) which independently provide feedback signals to a pair of actuator control valves (50) and (55) with enhanced accuracy and minimal lateral loading of the system.

Abstract: Elongate articles of non-circular cross section such as those of an airfoil cross section are constructed by winding filamentary material in layers about a form between a pair of spaced turnarounds generally conforming in shape to the cross sectional shape of the form. Adjacent layers are continuously wound by winding the filamentary material across the edges and outer face of each turnaround while reversing the direction of relative longitudinal displacement between the filamentary material and the form. The shape correspondence between the turnarounds and the form effect a minimization of expanse between the turnaround edge and form surface, thereby minimizing bridging of the filamentary material between those two members.

Abstract: A propeller pitch change actuation system comprises an input actuator (230) driving a ball screw (200). Operation of the ball screw rotates a torque tube (140) about the longitudinal axis thereof to drive a screw 145 and control valve 120 which controls the pressurization of pitch change actuator (87). Actuator (87) is supplied with hydraulic fluid through the interior of the torque tube.

Abstract: An improved airfoil blade for aircraft propellers and the like which exhibits high aerodynamic performance and low far and near field noise levels at a minimum weight is provided with a novel high lift and high lift to drag cross-sectional airfoil shape characterized by a blunt, generally parabolic leading edge portion (10) which fairs into a pressure surface (15) characterized by a leading convex portion (20). For thickness ratios less than approximately 0.15, the pressure surface includes a concave trailing portion (25) at one end thereof, fairing into the leading convex portion (20) and at the other end thereof, terminating at a blunt trailing edge (35). The leading edge portion also fairs into a suction surface (30) which is convex along substantially the entire length thereof to the blade trailing edge.

Abstract: In the machining of composite material, improved rates of material removal and reduced machine tool wear are achieved by a cutting fluid comprising the binder of said composite in an uncured state.

Abstract: Yaw (fishtail) oscillations in large wind turbines (10) are minimized by damping provided by a drive motor (65) connecting the turbine to the supporting tower (50) therefor at, for example, a yaw bearing (45). The drive motor drives the wind turbine in yaw and maintains desired yaw settings of the turbine. The motor is also capable of being driven by yaw oscillations of the wind turbine and in being so driven, dissipates the energy of such oscillations.

Abstract: A pressure measuring device is provided with an indicator such as a bourdon tube (10) for indicating the absolute value of the difference in pressure between fluids applied to the indicator through first and second conduits (15) and (20). Valve means (25) including an element (100) actuable in response to the pressure in conduits (15) and (20) consistently applies the higher pressure fluid to that portion of the indicator adapted to receive such higher pressure fluid and the lower pressure fluid to that portion of the indicator adapted to receive the lower pressure fluid. Optical means such as transmitter (115) and receiver (120) are provided for indication of the sign (positive or negative) of the pressure difference.

Abstract: A digital vortex shedding flow measuring transducer (10) includes an optical conductor (20) cantilevered to a conduit (15) accommodating the flow and an optical receiver (35) which intercepts an optical signal from the conductor as the conductor vibrates in response to vortices shed therefrom due to fluid flow thereover.

Abstract: In a compressed air supply system utilizing a shaft-driven compressor (10,16), the flow capacity of the compressor is changed by varying the compressor outlet stator geometry (16) by an actuator (18) which controls the outlet stator geometry to provide an optimum match between the compressor flow capacity and the requirements of the load. The result is a compressed air supply system which satisfies wide variations in demanded flow by the load, while supplying air at maximum pressure with minimum input shaft horsepower.

Abstract: In a compressed air powered refrigeration system for aircraft containing a refrigeration turbine and associated heat exchangers for supplying cool air to the aircraft cabin, air is recirculated from the cabin by a recirculation means and combined with the turbine discharge air to simultaneously melt ice present in the turbine discharge and provide cooling to the recirculated air. The lack of ice in the turbine discharge allows the use of an ice-free regenerative heat exchanger, in heat exchange relation with the mixture of the turbine discharge air and recirculated cabin air, to condense moisture from the air entering the turbine. The use of heat from the cabin air to melt ice coupled with maximum utilization of the recirculation means supplying the recirculating cabin air enables the turbine to provide air at a temperature below freezing and results in improved cycle efficiency as well as maximum possible ventilation rate to the load.