Validity and Reliability of Wind Speed Calculated by Notio in Comparison with a Hot-Wire Anemometer

Abstract

Optimizing aerodynamic efficiency is crucial in competitive cycling, where aerodynamic resistance significantly limits performance. Devices like Notio have emerged to calculate the coefficient of drag area (CDA) considering dynamic pressure data calculated by an integrated Pitot-static tube. This study aimed to evaluate the validity and reliability of Pitot-static tube calculations through wind speed (WS) data against a hot-wire anemometer (HWA). Sixty recordings were made, lasting 30 s each, in a closed-circuit wind tunnel at four different WS (≈30 to ≈60 km/h), and at five different yaw angles (0◦ to 20◦). Initially, Notio showed WS 6.44% higher than HWA. The calibration process recommended by the Notio manufacturer reduced the differences to a non-significant 0.76%. Comparison of the WS of Notio calibrated and HWA only showed significant differences in the WS group of ≈60 km/h. There were no significant differences in the comparison of yaw angles groups. The reliability of Notio was worse than that of the HWA. In conclusion, Notio calibrated at a speed close to its use allows for reliable and accurate calculation of WS over a wide range of yaw angles under controlled wind tunnel conditions without the presence of a cyclist and bicycle. However, due to the influence of WS on aerodynamic drag, small errors in WS could translate into considerable values of CDA for cycling performance.