Abstract: System for determining the airspeed of helicopters, having a coupled measuring device to which is supplied by the cyclic and collective control signals, the attitude angles and the rotational velocities about the axes of the helicopter. The measuring device contains two models, namely a first model of the input behaviour of the helicopter motion, on which the cyclic and collective control signals act as input, and a second model of the system behaviour of the helicopter, on which the condition parameters act as input parameters. The estimated state parameters are obtained in an integration stage by integration of the algebraic sum of the outputs of the two models and the output signal of the correction arrangement, from which the values of the the velocity components are supplied to an indication. The integration stage is connected in front of a correction arrangement for the measured parameters of the rotational velocity and the attitude angle.

Abstract: In a method in which a heterodyne-laser-Doppler method is used for the demination of the sign of the direction of a particle stream, the beam from a laser source is directed by means of an optical arrangement used as an emitter optical system to a measuring volume in an interferometer device. A frequency difference between the emitted laser beam and the laser beam returning into the optical arrangement is measured through heterodyne reception by means of the same optical arrangement used as a receiving optical system; this returning laser beam is frequency-shifted because of scattering by particles moving with the same speed in the particle stream and because of the Doppler effect. In the method according to the invention, an additional Doppler shift with a definite sign then is alternately impressed on the laser beam in exactly defined areas of beam paths, the additional Doppler shift being preferably considerably smaller than the Doppler shift generated by the particle movement.

Abstract: A measuring instrument for simultaneous in situ determination of the spectral scatting and absorption coefficient, which can also be called an extinction meter, has a modulated light source and an optical system encompassing the hemisphere; the optical system has a multiply folded ray path with a focal point in the volume to be measured, and through this system the measurement signal is projected to detectors. The scattering measurement signals, which are maximally enlarged in this way, are then separated from those for the absorption. The extinction meter also has not only an integrating nephelometer for monitoring purposes but also a transmission meter for low transmission factors. Because of the small three-dimensional size and the streamlined shape of the measuring portion of the extinction meter, the extinction meter can be carried in aircraft and surface vehicles.

Abstract: A method and an apparatus for influencing a laminar-turbulent boundary layer transition on bodies in flow is indicated. The disturbances are in this case introduced into the boundary layer in an unsteady manner. The disturbances are induced by blowing-out and sucking-off and/or by oscillations of the surface and/or by sound pressure.

Abstract: For remote aerial or satellite reconnaissance of the earth using an optoetronic camera that takes area photographs and has one or more line scanners associated with it, or a combination of such cameras, a series of overlapping individual pictures is taken at regular intervals. In the overlapping zone of adjacent individual area pictures, the positions of corresponding pixels or picture zones, so-called partial images, are then selected for mutual orientation of the photographing positions of the area camera or cameras. Finally, the orientation data from the optoelectronic area camera or cameras are transmitted to the line scanner by fixed orientation or measurement of the relative orientation.

Abstract: Method of reducing the overflying noise of airplanes having a propeller den by a piston engine. The propeller is arranged on the engine shaft in such a way that positive components of the engine sound pressure fall on negative components of the propeller sound pressure. It is preferable to use an engine/propeller combination in which the number of engine ignitions per revolution of the propeller shaft divided by the number of the propeller blades is an integer, preferably being equal to 1.

Abstract: An opto-electronic A/D converter comprises an input light source, an input nterferometer, and a plurality of parallel multistable interferometers the optical lengths of which are controlled by respective electrodes, the outputs of the parallel interferometers being converted by photodiodes into electrical signals which are used both to supply a digital output of the converter and as feedback signals to both the respective and an adjacent one of the parallel interferometers.

Abstract: A system for measuring electromagnetic radiation originating from the hemhere corresponding to a solid angle of 2.pi. is provided wherein a highly sensitive low-inertia detector is disposed below a transmissive dome and wherein the chopped light detection method is utilized. There are provided above the transmissive dome two similarly or differently designed modulators which are in the shape of dome segments and which are fitted into each other. At least one of the modulators rotates about their common vertical axis or the modulators may both rotate about the common vertical axis, either at the same or a different speed in the same direction or in opposite directions.

Abstract: A method of and device for contactless measuring of temperature of an object independently of its emissivity in infrared and/or visible range, is based on finding, by means of Planck law of radiation a curve which is the sum of the radiance or radiant intensity of a radiator having temperature and emissivity of the object and the radiance or radiant intensity of a radiator having the temperature of environment, the latter radiation being reflected by the object with the reflectivity .rho.=1-.epsilon. where .epsilon. is the emissivity of the object. The actual temperature of the object is found from the curve which is most similar to the curve of at least two values of radiance or radiant intensity detected from the object, plotted against the wavelengths.

Abstract: The distance measuring Equipment (DME) is a well-approved means for short nge navigation in international civil aviation. It utilizes the inherent capacity of the system in most applications to a relatively small degree. Therefore, additional functions can be integrated into the system such as data links, ground derived slant range measurement equipment and direction finders (growth potential). Thus, the DME can be extended to an Integrated Navigation, Communication, and Surveillance System. This system may be superior by technical, as well as by economical and operational reasons, to conventional solutions, which use separate systems for the different functions. The integrated system can be composed in different ways using different sets of the DME growth elements. A promising set is described and applied to a scenario of helicopter operations with oil rigs.

Abstract: The injection element comprises a fuel inlet, an oxidant inlet, a mixing mber for fuel and oxidant, and an ignition device for a mixture of fuel and oxidant. To ensure optimum mixing of the reaction components and efficient ignition even in the case of small reactors, the fuel inlet opens into an ignition chamber having a widened flow cross-section, the ignition chamber has an outlet having a cross-section smaller than the flow cross-section of the ignition chamber, the outlet of the ignition chamber and the oxidant inlet open into the mixing chamber, an ignition oxidant inlet opens into the ignition chamber and the ignition device is disposed in the ignition chamber immediately upstream of its outlet.

Abstract: In a method for conveying a liquid at or in the proximity of its boiling temperature, in particular, liquid hydrogen, by means of a pump which draws the liquid from a storage container through a suction entrance port, in order to prevent undesired bubble formation in the suction region, it is proposed that the pressure in the storage container be increased for a short time during the suction phase of the pump above the equilibrium pressure of the liquid in the storage container. An apparatus for performing this method is also described.

Abstract: A device for converting solar energy into process heat has a number of heat xchanging pipes traversing a heat exchanger chamber. A first partial stream of gas to be heated is delivered to inlets of the pipes via an upper distribution chamber, and the first partial stream of gas is subsequently collected from outlets of the pipes in a lower distribution chamber. An inlet aperture of the heat exchanger chamber receives sunlight radiation and a second partial stream of gas to be heated, the second partial stream of gas flowing around the heat exchanger pipes. The heat exchanging pipes absorb the solar radiation and heat both the first partial stream flowing through the pipes and the second partial stream flowing around the pipes. The heated second partial stream is collected by a heated gas outlet conduit connected to the heat exchanger chamber.

Abstract: A description is given of a tactile sensor for measuring force with fine resolution which is based on a network of glass fiber optic interferometers. The counting of interference fringes as readout method makes available an inherently digital (incremental) output signal which allows the measured signal to be passed on optically free of interference to evaluation electronics and to data processing. In conjunction with a suitable elastic skin to accept the glass fiber network, the small glass fiber diameter (125 .mu.) and the user of the strain measurement technique employing glass fiber interferometers should make possible a tactile sensor comparable with the human sense of touch. The fields of application for such tactile sensors are robotics, prostheses and advanced controls at the man-machine interface.

Abstract: An electromagnetic radiation detecting device comprises at least one radion detector for detecting electromagnetic radiation from a hemisphere, a radiation-transparent protective hood covering the or each detector, and a rotary chopper to alternately shield the or each detector and associated hood from arriving radiation and to expose the detector and hood to such radiation. The chopper comprises a carrier disc, which is rotatable about an axis parallel to a radiation-receiving area of the or each detector, and at least one hollow semicylindrical shielding member fixed at the periphery of the disc and curved in the axial direction of the semicylindrical shape. The or each shielding member is movable on a circular path by the disc to alternately shield and reveal the hood covering the or each detector.

Abstract: He--Ne gas discharge tube having a cylindrical tube body with an inside cathode cylinder and end walls which are inserted into ends of the tube body and which have for two capillary tubes, outside ends of which are closed by means of Brewster windows, exhaust pipe and connecting pin for the cathode cylinder. The tube, the end walls and the capillary tubes consist of calcium alkalisilicate glass or calcium alumosilicate glass. The end walls are sealingly connected by means of glass solder to the tube body, the capillary tubes, the exhaust pipe and the cathode connecting pin. The He--Ne gas discharge tube is characterized by a high helium tightness.

Abstract: An optical head, to which laser light is supplied, produces, in a measuring volume, at least two focusing points at which particles flowing through the measuring volume are illuminated and cause scattered radiation which is collected by the optical head. The laser beam is directed, via at least one first light guide, to the optical head. From the optical head, the radiation received from the measuring volume is supplied, via at least one second light guide, to a light receiving means. The optical head is small-sized and may be rotated about its optical axis by means of a rotating device.

Abstract: The process relates to the improvement of the static and dynamic mechanical roperties of (.alpha.+.beta.) titanium alloys by thermomechanical treatment, wherein the alloys produced by melting and forging and/or hot isostatic pressing of powders are deformed by more than 60% with simultaneous strain-hardening at a temperature just above the recrystallization temperature of the relevant alloys in one or more steps, with structure stress-relief heatings being performed without complete recrystallization between these individual steps, the shaped part is then tempered for 2 to 4 min near the transus of the alloy, quenched and then aged at temperatures in the range of from 400.degree. to 600.degree. C.

Abstract: Directly driven propeller whose propeller blades are provided with slats and which is designed for a lower blade tip Mach number in order to reduce the propeller noise. The slats are rigidly connected to the propeller blades and the slat tips lie on a diameter given by the equation ##EQU1## where LTLP=lower transonic limit of the particular blade configuration including slata.sub.o =velocity of sound in airv.sub..infin. =flight speedn=propeller rotational speed.

Abstract: The apparatus contains a dispersion means (DP) decomposing the incident laser beam into a number of colors (C1-C5) spacially separated from each other. The focusing points of said colors are subsequently traversed by particles contained in the flow. The light from the measuring volume (MV) is conducted via the dispersion means to a light receiving means (AV) in which the light is decomposed again into the individual colors. Due to a switching means (SE), the colors used for the measurment are selectible. Thus, the space of the focusing points used for the measurement may be varied.