An advanced technology 7-Component-Wind-Tunnel-Balance for the automotive industry has been developed by Carl Schenck AG, Germany and is now fully operational at the Volkswagen Wind Tunnel, Wolfsburg, Germany. The balance is based on the computer separated technology introduced by Schenck AG in the DNW wind tunnel in 1982. The seperation of the aerodynamic components inside the balance was performed -since the begining of wind tunnel testing- with mechanical separation systems. With the development of the computer technology it was possible to transfer this separation to the computer. This new computer separated balance has demonstrated outstanding performance and reliability.
Common practice in automotive wind tunnel testing is to measure the four lift forces on each wheel pad, the drag force and yawing moment. The side force acting on the front axle and rear axle are calculated with the data given by the measured yawing moment and the theoretical wheel base. The other two aerodynamic moments are calculated with the lift forces and the theoretical (or design) wheel base and wheel track. In practice wheel base and wheel track depend on tire pressure and mechanical fabrication tolerances. Therefore the calculation of the moments is subject to errors.
The Schenck AG advanced technology balance provides the ability to determine the actual wheel base and wheel track as influenced by the wind tunnel airflow. Each of the four wheels is located on four mechanically independent computerized 6-Component-Balances. The load signal of each balance combined with the load cell arrangement of each balance enables “ON-LINE” calculation of the actual wheel base and wheel track.
This new balance by Schenck AG will give to the automotive engineers more accurate test data and therefore can have a favourable result with better handling for safety and better ride quality for comfort.