2022 record attempt

Pushing the limits

Creating such a super-bike presents unique engineering challenges. The frame must be optimised for weight and stiffness, and tailored precisely to the individual rider’s shape and strength. The drive chain and components must operate with minimal friction and rolling resistance. All of these components must fit inside the external shell of the the vehicle, which is carefully tuned to minimise aerodynamic drag. 

Aerodynamics

The digital model used a 3mm mesh with an expanding series of 50 “inflation” layers surrounding the surface of the vehicle, starting at less than 1/100th of a mm in thickness. The simulation used a total of nearly 12 million elements. The settings used were initially validated against published empirical data from a previous record holding HPV - the Varna.

With the model thus defined, there followed an iterative process of refining the shape and curvature of each of the key areas of the vehicle, such as the nose, the footbox, the tail, and the wheel openings, and examining the effects of these changes on the airflow. Particular focus was on the “transition zone”, the region in which the airflow changes state from laminar to turbulent; this is characterised by high velocity and low pressure, resulting in high drag forces. This zone is only detected in the simulation when the roughness of the surface is also factored into the model.

A Sand Grain Roughness Height represents the sanding and polishing treatment by generating around 3 trillion microscopic hemispheres that protrude from the surface to simulate the microscopic peaks and troughs left by sanding and polishing the surface. The effect of these adds approximately 33% onto the overall viscous drag of the vehicle.

The team have worked with the Boardman Performance Centre cycle-specific wind tunnel in the past and continue to actively develop the aerodynamics for future iterations of the vehicle.

Shell and Chassis

Once the surface shape has been defined to optimise the aerodynamic performance, this must be manufactured into a stiff composite shell that will maintain it’s shape under the aerodynamic loads, and also protect the rider in the event of a collision.

The design was translated from CAD data to 3d physical form using the multi-axis KUKA CNC robot from the Digital Architecture Robotics lab at LSBU, which cut the foam bucks from which fibre-glass moulds were made (see this video)

The shell of the 2019 vehicle was shaped in these moulds from composite layers of carbon-Kevlar (for abrasion resistance and stiffness), sandwiched either side of a polyurethane foam core. The is stiffened by a monocoque carbon fibre chassis that provides a solid platform for mounting the transmission, steering, seat, and wheel assemblies, and a roll cage to protect the rider in the event of a collision.

Steering and Transmission

The goal of the power transmission design is to ensure minimal friction and maximum efficiency.

The 2022 design incorporates crossover chain drive system powering the front wheel (which is also steered) using a gear ratio of 150:14 - carefully specified with the 93mph target in mind. This presents further design challenges in minimising the Q-factor (the horizontal distance between the pedals) around the transmission system; aside from the biomechanical advantages of a low Q-factor, reduction in width plays a key role in the aerodynamics by reducing the frontal profile area of the vehicle - critical to the drag characteristics.

The team have previously worked with project sponsor Autodesk in the use of their latest generative design technology to optimise the front chainring and crank.

Stabiliser

Rider Ergonomics

The Rider Experience team’s focus is on all aspects of the ergonomics, from external vision & audio comms to correct posture in the seating. The tiny space in which our riders are encased must be optimised to allow them to perform to the highest physical level so they can focus all of their attention on breaking the Human Powered land speed record!

Number one priority is the rider vision system. The recumbent riding position and the low profile shell render windscreens ineffective. The vehicle will use a camera and monitor system provide the rider with a clear, unobstructed view of the road ahead. Learning from the drone racing industry, reliable wide angle cameras with minimal latency will feed to high definition monitors inside the cockpit.

The monitors will also provide our riders with a live data feed from Garmin sensors that track power, cadence, heart rate, and speed, allowing them to tailor their performance to our predefined programme for the track.

Rider safety is of upmost importance and as such the HPV will include a 360-degree roll cage, 3-point harness and Carbon-Kevlar shell to protect them during a crash. The team are also working on a breathing system to draw in, filter, and hydrate fresh air, ensuring a constant and optimised flow of air to the rider.

The riders are working with the LSBU Human Performance Centre to develop a bespoke hypoxia training programme for them to follow over the year, conditioning the bloodstream and muscles for optimal performance in the lower-oxygen conditions of the race venue.