Advances in the Development of Wind Tunnel Balance Systems for Experimental Automotive Aerodynamics

For many reasons, external balances allow for a higher degree of accuracy and wider range of application than internal balances. By adoption of the well known mathematical force separation schemes from internal balances, and through the introduction of highly accurate master load cells, external balances have improved considerably during recent years. Further development, however, gives reason for additional new improvements: An optical ccd camera. controlled center of gravity measuring device with on-line correction of measured pitching moments; a removable rolling floor for better boundary layer simulation, with the advantage of easy exchange for boundary layer suction devices or solid floors; and a completely new developed combined platform and pyramidal balance. This development allows for a significant increase of adaptabilities to required measurements. As a result, measurements of models with a low reference point (cars), and models with a reference point in the tunnel axis (aircraft), are possible without any loss of accuracy.