ETW - High quality test performance in cryogenic environment

The capability of the European Transonic Windtunnel ETW to test simultaneously at cryogenic temperatures down to 110 K and at pressure levels up to 450 kPa allows to achieve Reynolds numbers appropriate to full scale flight from low speed up to transonic Mach numbers. This paper briefly summarises the achievements in flow quality and tunnel control to generate the prerequisites for the provision of high data quality over the full operating range. Especially, low levels in unsteady flow quantities can be demonstrated. Based on an excellent data repeatability the smallest increments in aerodynamic quantities can be measured with high confidence, leading to a relaxation on model surface quality requirements. The implementation of a unique anti-vibration system yields gains in model safety and extended pitch ranges. An extraordinary thermal stability of the new half model balance offers unique perspectives for this test technology in ETW. Improvements in the IR-imaging technique and on-model deformation measurements provide attractive tools for the analysis of the complex flow behaviour as well as the determination of aerolelastic and Reynolds number effects. Some typical results are presented for full and half models. Finally, productivity aspects are considered on the basis of recently performed complex test scenarios.