Aerodynamic Bicycle Helmet Design Using a Truncated Airfoil With Trailing Edge Modifications

Abstract

Aerodynamic drag contributes the majority of the resistance experienced by a competitive cyclist. Low aerodynamic drag is a key quality of high performance equipment and many aerodynamic helmets have been developed. These helmets are designed with a teardrop shape that attempts to maintain attached air flow. This shape provides a drag reduction when the athlete has their head up and is looking forward but has adverse effects if the athlete rotates their head down. A helmet design that helps maintain attached airflow while presenting reduced frontal area when the athlete’s head is down could significantly improve performance. The aerodynamic improvements of applying a truncated airfoil shape with a trailing edge modification to a helmet design were investigated. SolidWorks Flow Simulation was used to evaluate the aerodynamic forces. A common production helmet design was progressively truncated to determine the optimal truncation length and the effects of multiple trailing edge modifications were tested. A specific truncation length with a trailing edge base cavity was found to provide similar head up performance but significantly better head down performance compared to the production design. Scale models of the final improved design and the production helmet were tested in the wind tunnel to verify the computational results.

Aerodynamics Analysis for an Outdoor Road Cycling Helmet and Air Attack Helmet

“…During a long bicycle time trial or during the cycling portion of a triathlon, 80 to 90 percent of the power developed by the athlete is used to overcome aerodynamic drag. According to Peter E. Jenkins [2], many aerodynamic helmets have been developed to reduce the aerodynamic drag experienced by cyclists. Though not optimized airfoils, current helmets are designed with a tear drop shape to try and maintain attached air flow.…”

Analysis of the effect of helmet shape and head position on performance during time-trial cycling

“…Defraeye et al (2010) evaluated the aerodynamic performance of different cyclist positions by means of CFD simulations and wind tunnel measurements. Sims and Jenkins (2011) used the CFD method to improve aerodynamic design of the bicycle helmet.…”