The wind tunnel continues to be the main instrument for providing experimental aerodynamic data to the aerospace industry and the aerodynamic researcher for the purpose of load and performance evaluation and for verification of theoretical results. In both cases it is imperative that the user has confidence in the quality of the results, which means that he must have information on what accuracy to attach to the data. The quality of wind tunnel results depends upon both the accuracy of measurements and the imperfections provided by the wind tunnel environment. Great strides have been made in recent years on measurement accuracy and as a rule this need no longer be of much concern if properly attended to. However, imperfections provided by the wind tunnel environment are still with us and these are today the main sources affecting the quality and accuracy of aerodynamic data obtained in a wind tunnel. It was the purpose of this symposium to try to define what accuracy has presently been achieved in modern facilities and to compare these achievements with the actual demands of the user.

This report presents a technical evaluation and assessment of the AGARD Fluid Dynamics Panel Symposium on "Aerodynamic Data Accuracy and Quality: Requirements and Capabilities in Wind Tunnel Testing", held in September 1987 in Naples Italy. The major issues addressed were: what data accuracy do users need; what accuracy is presently achieved; and what can be done to improve the situtation? Users have asked the cruise drag be measured to a precision of one drag count for transports and two for military fighters; and it was shown that this is possible when reference methods can be used. However, one or two drag count uncertainlty is not state-of-the-art for the direct scaling concept and improvement will require a thorough understanding of all those parameters which significantly contribute to wind tunnel uncertainty, including bias and precision. A reduction in total uncertainty appears possible but a reduction to a level of one or two drag count also apprears formidable.