Abstract: A temperature sensitive paint comprises a binder for forming a polymer matrix, a transition metal complex embedded in the binder and displaying a temperature dependent fluorescence, the fluorescence of the transition metal complex showing a maximum relative temperature sensitivity per Kelvin at a first temperature, and a rare earth complex also embedded in the binder and displaying a temperature dependent fluorescence, the fluorescence of the rare earth complex showing a maximum relative temperature sensitivity per Kelvin at a second temperature. The second temperature is higher than the first temperature by 50 to 150 Kelvin so that the overall temperature range covered by both complexes as temperature probes is extended.

Abstract: A support (11) for a wind tunnel model (10) has a sting (12) provided with a balance (16) carrying the model (10). On the basis of deformations of the balance (16), the wind forces acting on the model (10) can be measured. The balance (16) together with the model (10) forms a vibrating mass-spring system. For elimination of the vibrations, a counter vibration generator (15) is provided, arranged in serial arrangement with the balance (16).The counter vibration generator (15) is controlled, in dependence on signals of the balance (16) or other sensors describing the movements of the model (10), to cause counter vibrations for compensating the natural vibrations of the model (10).

Abstract: A wind tunnel having a plurality of walls surrounding a test section. The walls are provided with a plurality of longitudinal slots. A channel is formed behind each slot. Each channel contains a flexible channel bottom. The shape of the flexible channel bottom may be modified by adjustment devices. The influence of the walls on air flow is thereby decreased and made easier to compute. The influence of the walls on the testing of models is reduced, wind tunnel simulation is improved, and a more accurate and reliable computation of residual influences is provided.

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.