Shape-shifting bike helmet tunes its aerodynamics on the fly
At the top end of a sport like cycling, every tiny advantage can make all the difference, whether it’s saving a gram on an ultralight bottle cage or tweaking a pedal stroke for that little bit more power. Similarly, a helmet designed for maximum ventilation won’t be the best in terms of aerodynamics, but an Australian researcher is working on a dynamic version that could offer cyclists both, by changing shape at different stages of a race.
“Most helmets are static products and don’t change to suit the race conditions,” says Dr James Novak, a research fellow at Deakin University's School of Engineering. “Specialist time trial helmets are designed with almost no ventilation to minimize drag forces but, as a result, they can only be worn for short periods before the athlete risks overheating. In races like the Tour de France, where each stage lasts four to six hours, helmets have to strike a balance between aerodynamic performance and ventilation; they are not optimized for either extreme.”
In pursuit of a helmet that can offer cyclists both some ventilation when the heat is on and optimum aerodynamics when they’re making a breakaway, Novak has designed a 3D-printed helmet that opens its vents only when needed. Called Dynaero, it uses Bluetooth to hook up to computers and sensors embedded in the bike or a smartphone. From there, it can open or close the vents in response to changes in temperature, speed or other conditions.
“It features an Arduino Uno, Bluetooth sensor, micro servo and a custom-built mobile phone application that uses a built-in accelerometer to determine speed, controlling the opening of the vents,” explains Novak. “Future versions of the helmet will also be connected to a range of cycling and wearable sensors.”
Novak’s project is very much in the early stages, but he has produced a 3D-printed prototype and tested it out in a wind tunnel alongside commercial helmets. Such a helmet wouldn’t be allowed under current cycling regulations, but the engineer says the helmet is generating a bit of interest and hopes that further down the track it could get the green tick to find a home in the peloton.
“The Dynaero is a highly responsive helmet and will close ventilation during fast down-hill descents or finish line sprints, potentially maximizing the cyclist’s aerodynamic performance by 3.7 percent,” he says. “When aerodynamics are less critical, such as during slow hill climbs, the vents open to increase airflow and keep the cyclist cool. In this way, both the performance and health of the cyclist are improved through intelligent design.”
Source: Deakin University