Abstract: The system is used in power-assisted control systems to provide a restoring force to the control stick indicative to the pilot of the deflection of a control surface. The feel system is trimmable in that the neutral position can be altered. In prior systems trimming was accomplished by releasing a brake which permitted movement of a part of the control stick linkage toward an equilibrium position in response to the restoring force. In prior systems the released part acquired sufficient momentum to cause it to overshoot and oscillate about the equilibrium position. If the brake were engaged prematurely, the momentum was imparted to the control stick resulting in a disagreeable "kick" felt by the pilot. To overcome these problems, the brake is repetitively disengaged and engaged at a repetition rate in the range 5-40 Hz. The small amount of momentum built up in each of the successive cycles results in an almost imperceptible vibratory reaction on the control stick rather than a single large "kick".

Abstract: A skin construction suitable for use as a high temperature airfoil surface that includes a metallic member having first and second corrugations. The first corrugations have a size and spacing which permits resilient thermal expansion of the member in a direction transverse to the direction of the first corrugations. The second corrugations are positioned in a direction that is substantially transverse to the direction of the first corrugations and the second corrugations have a size and spacing which permits resilient thermal expansion of the member in a direction generally transverse to the direction of the second corrugations.An imperforate metallic surface is integral with the metallic member. Thermal stresses imposed on the skin construction are, thus, absorbed by deformation of the first and second corrugations which act as expansion joints in permitting controlled expansion of the skin construction.

Abstract: An antitorque system for use in a helicopter produces antitorque moments with efficiency comparable to that of the tail rotor it is designed to replace. The antitorque forces are generated mainly from the main rotor downwash by the circulation control effect. The downwash is deflected laterally as it passes around the tail boom by a sheet of air continuously discharged tangentially to the surface of the tail boom on one side of it at velocities in the range 30 to 120 meters per second from slots extending longitudinally along the tail boom and having a width in the range 4 to 20 millimeters. The discharged air is supplied by a relatively low-pressure-ratio fan within the fuselage which directs a stream of air rearwardly into the tail boom. The tail boom is provided at its rear end with a laterally disposed aperture through which some of the fan-supplied air is discharged to create a direct jet thrust. The flow through the aperture is throttled to vary the antitorque moment for trim and maneuvering.

Abstract: A manual radio selector switch, normally used in aircraft, is provided with a particular switch position which is connected to a cyclical stepping switch. When the manual radio selector switch is in this position, the choice of radio is effected by the cyclical stepping switch. The cyclical stepping switch is stepped under control of the pilot who changes from one radio to the next by actuating a stepping switch on his control stick, whereby, when the manual radio selector switch is in the particular switch position, the pilot can change radios without the necessity of removing his hand from the control stick. One of several indicator lamps on the instrument panel indicates which radio has been selected by the pilot. When the pilot is transmitting, the light corresponding to the radio being used will flash.

Abstract: In some helicopters power is transmitted from a gearbox adjacent the engine to the tail rotor by a long shaft. To minimize weight, a tubular shaft is used, which rotates at supercritical speeds. Vibrations resulting from shaft unbalance are magnified by resonance as the shaft passes through its critical speeds making it essential that the shaft be finely balanced. This is accomplished by slowly rotating the shaft about its axis while measuring at a chosen station along its length both the wall thickness of the tubular shaft and the distance from a fixed reference plane to the outer surface of the shaft. From these data are determined the local cross sectional area and the location of the center of gravity at the chosen station. From the latter two quantities are determined both the amount of counterweight required and its required angular location around the shaft, for the chosen station. The measurements are repeated at a large number of stations along the shaft.

Abstract: A dual passage string of pipe for use in cycling fluid from a ship to an undersea mineral aggregate gathering apparatus. The string of pipe is made up of sections of concentric inner and outer pipes. The outer pipes are screwed together and the inner pipes slide telescopingly within each other. The inner pipes are suspended in the outer pipes at their upper ends by a rigid supporting ring supported by an internal shoulder in the outer pipe. The internal shoulder is located at the base of the threads and is separated from the lower end of the male threaded section. A resilient seal ring is carried between the supporting ring and the male threaded section for preventing water from entering the threads to avoid corrosion.

Abstract: Mineral aggregates or nodules dispersed on the floor of an ocean are harvested and conveyed to a surface vessel, which tows a submerged harvesting apparatus. This apparatus is suspended from the vessel by a string of dual concentric pipes, which contains pressurized water for hydraulically conveying the aggregates to the surface. Pumps on the surface vessel force water down an annular passage between inner and outer pipes of the string. A portion of the downward flow is distributed to a feeder mechanism which collects crushed aggregates and feeds them into the return fluid flowing up the inner pipe. An inclined channel collects the aggregates from the underwater floor with water jets which dislodge and push the aggregates up the channel, where they are crushed by rollers. A portion of the downward flow of water from the surface is converted to lower pressure and higher volume downhole by using a dual piston converter to supply water to the water jets.

Abstract: An immobilized immunoadsorbent for use in immunoassay and radioimmunoassay procedures includes, in a preferred form, a mass of superficially porous refractory particles having a water insoluble polymer, such as dextran, bonded thereto. The polymer in turn has bonded to it, by covalent bonds, antibodies capable of binding a specific antigen thereto and stoichiometrically releasing the bound antigen by the use of a rinsing solution which does not adversely affect the binding of the antibody to the polymer. Preferably, each of the porous particles includes an impervious core which has joined thereto sufficient layers of microparticles to form an outer porous coating on the core. Methods of forming such an immunoadsorbent and for using the same and structure for supporting the same are also disclosed.

Abstract: An all metal, low conductivity, high performance and relatively lightweight, composite structure, in the form of an insulation blanket is operably disposed to be exposed to a high temperature zone, e.g., a high temperature fluid, or on a supporting surface exposed to high temperature. The composite includes two metal skin members spaced from each other by a metallic member functioning as a spacing member. The spacing member is preferably deformed to contact the spaced skin sheets at spaced positions, the space between the skin sheets forming a fluid space which defines a zone of substantially reduced heat transfer by convection. When deformed, the spacing member, or an array of spacers, also provides an elongated path for conduction of heat, and defines a plurality of cavities of limited volume forming stagnant gas pockets. The skin sheets may be perforated to vent the cavities and to provide expansion space for absorbing thermal growth by the metal components of the composite.

Abstract: An inertial sighting system for slaving the axis of a craft mounted movable member such as an armament system, camera, spotlight or the like to the axis of a hand held sight including two sets of inertial sensors in the form of a pair of gyroscopes for each set. One pair of gyroscopes, fixed to the craft and responsive to changes in craft attitude, provides pitch, azimuth, and roll information regarding craft attitude. The other pair of gyroscopes, fixed to the sighting device and responsive to changes in sighting device attitude, provides pitch and azimuth information regarding sight device attitude. The spin axes of the gyroscopes are initially aligned by a caging mechanism provided on a sight stowing bracket mounted on the craft and a cooperating caging mechanism on the sight.

Abstract: A thermal insulation composite includes at least a first metallic skin sheet, and a plurality of non-combustible metallic filaments randomly interlocked to form a wool and affixed to said first skin sheet. A second metallic skin sheet may be affixed to said wool and said first sheet, or the second skin sheet may be a surface of the structure to be insulated. A fluid is present in the interstices of the filaments and in the zone between the skin sheets. Each of the filaments has a significant length to cross-sectional diameter ratio to minimize its thermal conductivity. The filaments also preferably have a circular cross section to minimize the area of contact and hence the heat conducted between adjacent filaments. In this manner, the conductivity of the wool is made primarily dependent upon the thermal conductivity of the fluid in the interstices of the filaments. Heat transmission by radiation is inhibited by providing a plurality of radiation shields interposed between multiple layers of the wool.

Abstract: A device for shielding a heated surface from infrared detection through an exhaust opening adjacent the heated surface which comprises an exhaust gas conducting member adapted to receive heated exhaust gases from the exhaust opening with the member having a configuration which blocks the exhaust opening from line-of-sight view through the outlet to the member. The exhaust gas conducting member includes apparatus to inhibit heat transfer across its interior surface while promoting heat transfer through the wall of the member. Additionally there is provided a diffusion device for breaking up a main stream of heated exhaust gas into a plurality of smaller streams to reduce infrared radiation from the exhaust gas which includes a body adapted to receive heated exhaust gas with insulation apparatus to maintain the exterior surface of the body at a relatively low temperature. A plurality of openings in the body provide discharge of smaller streams of exhaust gas.