Aerodynamic test results of bicycle helmets in different configurations: towards a responsive design

Within the sport of cycling, aerodynamic efficiency is a fundamental criterion for equipment such as bicycle frames, wheels, clothing and helmets. Emerging technologies continually challenge the rules governing the sport as designers, engineers, sports scientists and athletes attempt to gain the edge on their competition. This study compares the aerodynamic drag force of three 3D-printed bicycle helmet prototypes with three commercially available helmets via aerodynamic testing in a wind tunnel. One 3D printed helmet featured a mechanical mechanism allowing two states of ventilation to be examined for aerodynamic efficiency, while another featured electronically adjustable ventilation tested at five different states of ventilation opening. A third 3D printed helmet acted as a control, based on a budget-level helmet design. Data was collected using an anthropometrically accurate mannequin sitting atop a bicycle in a road cycling position. The results found that the mechanically controlled prototype offered a 4.1% increase in overall drag experienced by the mannequin with ventilation in the open position compared to closed. The electronic prototype showed an increase in drag as ventilation opening increased through the five states, with an overall difference in drag of 3.7% between closed and the maximum opening. These experimental findings indicate the significant effect variable ventilation in helmet design can play on the drag forces experienced by a cyclist, and may provide new opportunities to modify athlete performance throughout varying stages of training and competition using sensors and autonomous control systems.