15. In-Flight Application of Pressure Sensitive Paint

A feasibility test for in-flight pressure measurement using Pressure-Sensitive Paint (PSP) techniques has been performed in the frame work of the research project Advanced In-flight Measurement Techniques (AIM). PSP was applied to a pylon surface of the VFW 614 ATTAS aircraft. In the test, three PSP measurement methods: “intensity method with LED-array”, “intensity method with Electro Luminescence (EL) foil”, and “image based lifetime method” were employed to measure pressure distributions and the results were compared. The results showed the good feasibility of PSP measurements at in-flight testing. All three methods could represent the pressure distribution on the pylon. Especially the intensity method with LED-array and EL foil could provide results in good image quality. An EL foil which was applied to the pylon surface outside of the cabin and firstly employed in flight tests worked very well even at high altitudes. From the obtained results, one can conclude that the PSP technique successfully passed the first feasibility tests. The lessons learned from the experiences in the flight test are presented in the following chapter.