Balances are the most common method for measuring aerodynamic forces. Balances are in frequent demand because most organizations are familiar with translating balance data of wind tunnel models into data for the real aircraft.

 

DNW uses a wide range of high-precision balances to perform extremely accurate force measurements, including rotating and non-rotating balances. Measurements can be performed with an internal as well as an external balance,  depending on the features of the object and the testing conditions. In addition to its excellent equipment, DNW has amassed vast experience in eliminating interference from variations in wind force and temperature as well as vibrations that could affect measurements.

 

External balances excel in their extremely high levels of precision, with average deviations of less than 0.01%. Because the balances are located outside of the model and tunnel, wind effects on the support struts of models need to be avoided. DNW achieves this by carefully shielding the support struts of a model. Measurements are corrected for load shifts by taking into account wind-off measurements at the same conditions as well as zero-measurements.

 

Internal balances can either be rotating or non-rotating. These balances are located inside the model, which means that the balance moves along with the object. Measurements are, therefore, performed under a variety of angles, which require corrections in order to ensure adequate accuracy.

 

The non-rotating balances perform pseudo-static measurements on slowly moving objects. DNW developed a unique flexible airline bridge that compensates for measurement interference caused by the air supply line passing the balance (with high momentum pressurized air). This pressurized air is used to drive Turbofan Propulsion Simulators (TPS) or air motors.

 

Rotating balances involve dynamic measurements. Balances can, for instance, be located just behind propeller blades in order to measure the performance of the propeller and the interaction between the propeller and the wing of an aircraft. Thanks to its extensive experience, DNW is able to compensate the measurements for influences from centrifugal forces and the vibrations caused by unequal force distribution.