The Hope / Lotus track bike

blog preview

The Hope / Lotus track bike has been part-developed by Lotus Engineering for British Cycling in the quest for medals.

Richard Hill is the chief aerodynamicist for Lotus. In tandem with his regular job – which is helping to engineer future Lotus cars – he has led development on the pioneering front-end design of the new bike.

Richard has been with Lotus for more than 30 years and worked with rider Chris Boardman on the Type 108, aka the Lotus Sport pursuit bike from 1992, and the Type 110, which Boardman rode in the 1994 Tour de France prologue time trial to wear the iconic yellow jersey.

Here Richard explains the reasons for the unique design of the Hope / Lotus track bike, the differences when working with two wheels rather than four, and what’s he’s learned from the bike that will shape Lotus cars of the future.

 

How far has aerodynamics moved on in the years since you worked on the Lotus Type 108 in 1992?
The basic rules of aerodynamics haven’t changed – you can’t alter the laws of physics – but what we have learned over almost 30 years is to take a more holistic approach to every project.

What do you mean by ‘a more holistic approach’?
Back then it was simply about developing an aerodynamic bike that would go fast. But really there are two separate elements – the bike and the rider – which come together as one to move through the air. That was the approach we took with the new bike. Put simply, since 1992 we have learned how to use the bike’s design to make the rider more aerodynamic, and also vice-versa. What’s improved is our understanding of how to get a bike and its rider round the track together in the fastest possible time.

Were any specific lessons learned from the Type 108 and Type 110 incorporated into the creation of the new track bike?
They were both extremely low-drag bike frames in their own right, with every element designed as an efficient aerofoil and the monocoque frame itself acting as a 'wing sail'. The frames were designed to operate best in complete isolation from the rider. Chris Boardman’s famous 'Superman' riding position was about creating an airflow channel between the rider and the bike frame, minimising interactions. These frames are no longer allowed under track cycling regulations, so the new bike – which meets the updated regulations – is all about getting the rider and the bike to positively interact with each other. In this way they can benefit each other and cause each to lower the drag of the other. We achieve that by careful manipulation of the interference between the two.

The new bike has very wide front forks, far wider than other track bike. What is the thinking behind this design?
The geometry of the forks and handlebars lower the drag of the rider, which in turn lowers the drag of the frame. In some ways it's a similar concept to how riders position themselves in a team pursuit race – so one behind the other and very close – to benefit each other. Careful alignment of individual elements of the bike and the rider cause the drag of the two together to be lower than the sum of the individual parts. As far as track cycling goes, it’s man and machine in perfect harmony.

Are aerodynamics different depending whether you’re working on a two-wheeled Lotus or a four-wheeled Lotus?
The main difference is that with a bike you have a far greater proportion of the ‘machine’ constantly moving and changing geometry. The rider is also moving so it’s creating an unsteady air flow regime, whereas with cars you only have the wheels rotating. Another difference is the interaction with the ground. A car has a big ‘plan view’ profile, so covers and interacts with a lot of stationary road, whereas a bike has a much smaller footprint and significantly less interaction with the road. But at the end of the day physics is physics and you can’t cheat the rules on two wheels or four!

Is there any relevance of the aerodynamic performance of the bike to the next generation of Lotus sports cars?
Yes there is. Old-school aerodynamic car design was all about pushing the air around your vehicle in the most efficient way. The latest Lotus designs are all about the interactions between various elements of the airflow around a vehicle and also through the vehicle where appropriate. The Lotus Evija hypercar, with Venturi tunnels through the rear quarters, is a great example of that. It’s all become a lot more nuanced. What we have learned with the bike is absolutely having an influence on some of the features we are currently developing and testing for our future vehicles.