Abstract: For cooling down a cryogenic model, provided for testing in a cryogenic wind tunnel, to the wind tunnel temperature and for performing mounting work and configurational changes on the cryogenic model, there is provided a working chamber which is supplied with warm air so that working personnel can enter it. The working chamber contains an insulating box, made from heat-insulating material, which has an open top and into which cold air is injected. The insulating box accommodates the cryogenic model under cold air conditions. Persons can perform manipulations on the cryogenic model while leaning over the edge of the insulating box. The cryogenic model is held on a holder which can be lifted upwardly out of the insulating box. Removal of the cryogenic model from the working chamber is possible by opening a top door.

Abstract: To generate an unpolluted high enthalpy air blast of several seconds duration a mass of feed air intended to constitute the high enthalpy air blast is preheated to a given temperature and stored at a given pressure in an elongate confinement tunnel with thermally insulative walls. A downstream orifice of the tunnel is kept closed and a blast of high-pressure air is applied to the upstream end of the mass of feed air to compress it quasi adiabatically to obtain a feed air temperature of at least 1,800K. The downstream orifice is opened and application of the high-pressure air blast is continued whereby the mass of feed air is expelled through the downstream orifice in the form of a feed blast, the temperature of which remains constant for several seconds.

Abstract: An apparatus for determining smoothness of a surface is disclosed. The apparatus has a distance wheel for determining distance travelled along the surface and two laterally spaced inclination sensors which produce signals indicative of inclination of the apparatus at locations along the surface over which the apparatus travels.

Abstract: A marine sensor mounting mechanism having a tubular sleeve in the hull of a boat; valve means mounted for pivotal movement in the sleeve from an open position when a sensor is in place to a closed position when the sensor is removed.

Abstract: Apparatus for gauging high pressure gas in particular for the supply of oxygen gas on board on aircraft, the apparatus being associated with a gas tank or with a plurality of gas tanks having their outlets interconnected, the apparatus being wherein each individual tank is provided both with a pressure regulator connected to a common outlet duct, and with a pressure sensor producing a signal proportional to the pressure in the, or each, tank, with the or each, pressure sensor being connected to a calculation and storage unit suitable for determining the content of each individual tank on the basis of the signal associated therewith and taking account of the coefficient of compressibility of the gas contained in each individual tank on the basis of data stored in the storage unit for different values of pressure, and consequently deducing the overall available content, the calculation unit further including a readout for displaying the overall available content.

Abstract: An automatic transducer selection system for fluid pressure measurement functions by using two or more transducers wtih different .Iadd.measurement .Iaddend.ranges .[.of accuracy.]. and also by incorporating comparator circuitry which automatically selects the transducer reading nearer to full scale. An electronic signal or output from the comparator is preferably nested such that a continuous voltage is generated in accordance with the fluid pressure being measured, this making the system appear to function as a single transducer with a wide .Iadd.measurement .Iaddend.range of .Iadd.high .Iaddend.accuracy.