Abstract: A stator vane is removed from an arcuate casing by placing a conforming mold over the vane airfoil with portions thereof extending axially on either side of the airfoil to provide driving surfaces, and repetitiously imparting a precisely directed impact to the driving surfaces to move the vane circumferentially within the casing. Impact to the driving surfaces is made by way of an elongated arm which is supported at its one end so as to be pivotable about the axis of the casing, and whose other end is bifurcated to straddle the vane row and impinge against the driving surfaces. In this way the individual vanes may be removed from a single stage without incurring significant damage thereto and without removing any vanes of adjacent stages.

Abstract: A low pressure fuel stream is injected into a carburetor by way of a fuel tube injector combination having an insulating air space provided between the internal flow path structure and the outer surface of the combination which is exposed to relatively high temperatures. The fluid stream is thus maintained at a relatively low temperature and pressure until it is discharged from the fuel injector, at which time a surrounding airstream prevents the direct contact of the fuel flow with the surface of the fuel injector, and therefore prevents any carbon build-up which would otherwise occur on or near the fuel exit orifice.

Abstract: A hydraulic pump and drive system is interconnected between the fan and compressor rotor of a turbofan engine such that the windmill speed of the core rotor can be boosted to a speed sufficient to allow a significantly increased in-flight start envelope by selectively extracting power from the windmilling fan prior to relight of the engine. Control logic is included to decouple the motor and pump whenever the engine is in the operating speed region and to selectively couple the fan-driven hydraulic pump to auxiliary machinery such as the nozzle actuators to obtain a dual-purpose function from the pump.

Abstract: A torque converter is interconnected between the fan and core rotor of a turbofan engine such that the speed of the core rotor can be boosted from windmill speed to a speed sufficient to allow an in-flight start by selectively extracting power from the windmilling fan during the start sequence of the engine. Control logic is included to automatically drain the oil from, and thereby unload, the torque converter whenever the engine is in the operating speed region. Further assurance is provided by an overrunning clutch which decouples the system when the core rotational speed exceeds the converter output.

Abstract: A pair of pressure sensing probe tubes are placed in the fan discharge of a turbofan engine, aft of the outlet guide vanes (OGVs) the tubes being circumferentially spaced by a fraction of the OGV pitch. A comparing means receives both pressures sensed by the double-barrelled probes and aerodynamically actuates to automatically select the higher of the two pressures. An accurate pressure indication representative of the mainstream pressure is therefore obtained despite the localized lower pressure turbulence area that may be caused by the presence of the upstream outlet guide vane(s).

Abstract: Fuel is selectively jettisoned through the engine of an aircraft by way of a normally closed, solenoid-operated jettison valve which is fed from the boost pump in the engine fuel system. The jettison valve is servo activated by the main fuel flow so that the engine must be running for the opening of the solenoid valve to occur. For an engine having an augmenter, other interlocks are provided to prevent the jettison of fuel when the augmenter is in use and to preclude the ignition function to the augmenter while fuel is being jettisoned.

Abstract: The disclosure shows an annular convergent-divergent plug nozzle for use with a jet engine which comprises an exhaust duct with a concentric plug spaced within the duct and cooperating therewith to form a throat which is followed by an annular exhaust outlet. Means, such as conventional primary flaps, are provided to vary the throat area, and a plurality of spaced secondary flaps are hinged to the duct downstream of the throat to form a secondary nozzle. The secondary flaps can be freely floating so that they assume a position that is determined by the pressure differential across the flaps, and the nozzle is designed so that the exit diameter defined by the secondary flaps is no greater than the maximum plug diameter. Additionally, a secondary concentric casing may be provided to handle bypass air and the secondary flaps may be hinged to the casing in a freely floating manner as above due to the pressure differential.

Abstract: A shroud closely surrounding a high thermal inertia rotor is provided with a support structure having low thermal inertia characteristics. The support structure is selectively exposed to different temperature mediums during transient operation by way of a thermal actuated valve so as to cause a rapid growth thereof during periods of engine acceleration and a slow shrinkage thereof during periods of deceleration of the engine. In this manner the clearance relationship between the shroud and enclosed rotor is maintained at a minimum during periods of steady-state and transitional operation to thereby increase the efficiency of the combination.

Abstract: A shroud closely surrounding a high thermal inertia rotor is provided with a support structure having low thermal inertia characteristics. The support structure is selectively exposed to different temperature mediums during transient operation by way of a thermal actuated valve so as to cause a rapid growth thereof during periods of engine acceleration and a slow shrinkage thereof during periods of deceleration of the engine. In this manner the clearance relationship between the shroud and enclosed rotor is maintained at a minimum during periods of steady-state and transitional operation to thereby increase the efficiency of the combination.

Abstract: An inlet guide vane for a turbofan engine comprises a principal airfoil portion fabricated of metal and a radially outward and rearward corner portion fabricated of a frangible material which is attached to the metal portion and completes the airfoil structure. When foreign objects are ingested into the airstream to cause the closely spaced fan blades to deform forwardly to impact against the inlet guide vane, the frangible rearward corner of the inlet guide vane is caused to break off into small pieces and pass through the system without causing any significant secondary damage, thereby leaving the principal portion of the inlet guide vane to function as a relatively efficient airfoil.

Abstract: An improved tip cap configuration for a turbomachinery blade includes tip cap seats formed integrally with and located on the inner sides of a hollow turbomachinery blade. Tip cap retaining members are also formed integrally with the inner wall of the blade and are spaced a short radial distance from the tip cap seats. The blade is initially provided with a flared open end and the tip caps are positioned on the seats and the flared end is crimped so as to capture the tip cap between the seats and the retaining members. The crimping operation is stopped at a point wherein a smooth outer contour is obtained for the blade in the region of the tip cap. A method of making such a blade is also disclosed.

Abstract: A hollow turbomachinery blade is formed by way of casting or the like with an open tip end except for a bridge which is formed integrally with the blade side walls at a central position with respect to the leading and trailing edges. Also formed integrally with the blade side walls, proximate the tip end openings near the leading and trailing edges, are a plurality of supporting and retaining bosses, the supporting bosses being in substantially the same plane as the cast cap, and the retaining bosses being disposed radially outward thereof. Each of the forward and rear tip caps is installed by placing it over the bridge ad then sliding it either forward or rearward to be captured by the supporting and retaining bosses and to thereby close the respective tip opening. Each of the tip caps is then brazed into position so as not to allow its sliding back out.

Abstract: An air-cooled combustor liner is constructed of a continuous, constant-thickness, annular shell having a plurality of rings attached to the inner surface thereof to direct the flow of coolant air entering the shell by way of apertures formed therein, along the inner surface of the shell to provide a film cooling function. The rings, which are fabricated to desired dimensions sufficient to prevent significant thermal distortion which would cause flow restriction, are secured to the inner surface of the shell by brazing or the like.

Abstract: An improved actuating mechanism is provided for a gas turbine engine incorporating fan blades of the variable pitch variety, the actuator adapted to rotate the individual fan blades within apertures in an associated fan disc. The actuator includes means such as a pair of synchronizing ring gears, one on each side of the blade shanks, and adapted to engage pinions disposed thereon. Means are provided to impart rotation to the ring gears in opposite directions to effect rotation of the blade shanks in response to a predetermined input signal. In the event of system failure, a run-away actuator is prevented by an improved braking device which arrests the mechanism.

Abstract: The structure which supports a rotor-surrounding shroud is composed of a material exhibiting a low coefficient of thermal expansion at low temperatures and a high coefficient of thermal expansion at higher temperatures. In this way, low alpha characteristics persist during periods of low temperature operation to provide large cold clearances and acceptable clearances during transient operation, while high alpha characteristics persist during periods of high temperature operation to provide close clearance control at maximum and part-power, steady-state operating conditions. The two-alpha material also finds use with other relatively rotating parts having close clearance relationship therebetween, such as in the stationary portion of a seal structure.

Abstract: A hollow turbomachinery blade is formed by way of casting or the like with an open tip end except for a bridge which is formed integrally with the blade side walls at a central position with respect to the leading and trailing edges. Also formed integrally with the blade side walls, proximate the tip end openings near the leading and trailing edges, are a plurality of supporting and retaining bosses, the supporting bosses being in substantially the same plane as the bridge, and the retaining bosses being disposed radially outward thereof. Each of the forward and rear tip caps is installed by placing it over the bridge and then sliding it either forward or rearward to be captured by the supporting and retaining bosses and to thereby close the respective tip opening. Each of the tip caps is then brazed into position so as not to allow its sliding back out.

Abstract: The impingement baffle insert of a turbomachinery blade is provided with a plurality of collars around a portion thereof so as to ensure a proper impingement distance between the baffle and the inside wall of the airfoil and act as a wear surface against the inside wall to thereby prevent wear to the insert wall surface. The collars are affixed to the insert in preselected positions and frictionally engage the blade inner wall in close fit relationship to position the inserts and assume any wear that may result from vibration of the insert within the chamber. The inserts may have grooves formed therein to allow equalization of pressure on both sides thereof, and they may further have chamfered edges on one end thereof so as to facilitate installation into the turbine blades.

Abstract: The impingement baffle insert of a turbomachinery blade is provided with a collar around a portion thereof, the collar having a chamfered surface on the radially inner end and adapted to be frictionally engaged by a damper which also surrounds a portion of the insert and which tends to move radially outward over the beveled surface when acted on by centrifugal forces caused by rotation of the blade. The damper is thus wedged between the insert and the blade inner wall to reduce or prevent relative movement therebetween which is normally caused by thermal and vibrational forces. The integrity of the combination is thus improved to reduce the incidence of insert and turbine blade failure.

Abstract: A shroud closely surronding a high thermal inertia rotor is provided with a support structure having low thermal inertia characteristics. The support structure is selectively exposed to different temperature mediums during transient operation by way of a thermal actuated valve so as to cause a rapid growth thereof during periods of engine acceleration and a slow shrinkage thereof during periods of deceleration of the engine. In this manner the clearance relationship between the shroud and enclosed rotor is maintained at a minimum during periods of steady-state and transitional operation to thereby increase the efficiency of the combination.

Abstract: A digital tachometer provides a signal proportional to output speed which clocks a multivibrator whose "on" time is selectively set as a function of desired speed. The output is filtered and any deviation from one-half the peak voltage becomes the speed error signal which is pulse width modulated to provide an error signal to the prime mover. Proper selection of multivibrator parameters provides for a plurality of output pulse widths which accommodate sensitive speed regulation over a low speed range.