Dynamic calibration of derivative balances in wind tunnel aircraft model - applying defined braking force to oscillated calibration model using eddy current brake and measuring load on model

摘要

The eddy current braking device (10) with a variable magnetic field source (12) applies a defined braking force to a non-magnetisable calibration element exposed to the field. A wind tunnel model (34) contains a plate (60) of the same thickness and material as the calibration element. The model is oscillated so that the plate moves like an element to be braked in the magnetic field, using knowledge of the eddy current device's braking effect based on the magnetic field strength and the speed-related instantaneous braking force opposing the model oscillation. The load on the model, which results from the braking force, is measured and the measurement system is calibrated according to the determined braking force and the measurement results produced by the measurement device. USE/ADVANTAGE - For use with equipment for performing dynamic measurements on aircraft models in wind tunnels. Aerodynamic damping can be simulated for calibration of instrumentation before measurements are made.