Lodders Life Issue 9: Redefining aero testing

At the start of the century, most people walking by the Catesby Tunnel in Northamptonshire would see nothing more than a beautiful but disused Victorian railway tunnel.

But Dr Rob Lewis OBE saw something more – the opportunity to make his ambition of creating the world’s largest indoor aero test facility a reality.

Timeline of the tunnel

Construction of the Catesby railway tunnel began in 1885 as part of Great Central Railway’s London Extension. Approximately 30 million bricks were needed to build the perfectly straight tunnel, and the result was a striking piece of Victorian architecture. The line opened fully in March 1899 and operated effectively for 68 years, before its closure in September 1966 and subsequent dereliction.

Fast-forward to 2023, and the Catesby Tunnel is now a worldwide benchmark for vehicle testing, capable of providing accurate and affordable full-scale aerodynamic and performance data. 2.7km long and 8.2m wide, vehicles can maintain a constant speed of 100mph for approximately 40 seconds before braking. Full-size cars, rather than scale models, can be tested in real-world conditions.

Private, discreet, and entirely enclosed, it provides the ideal environment for customers to bring their cars to and run tests away from prying eyes.

Tunnel specification

2740m long
8.2m wide
1:176 constant gradient
40sqm working section

15 years in the making

The multi-million-pound transformation project was led by co-founder and managing director of TotalSim, Dr Rob Lewis OBE. TotalSim is a multi-disciplinary UK engineering consultancy that specialises in both computational and experimental aerodynamic development and testing. It is one of three entities that comprise Aero Research Partners – the driving force behind the transformation of the Catesby Tunnel.

Following several years of discussion, Aero Research Partners initiated the design phase back in 2013, and in 2020, the project attracted £6.2 million of investment from the government’s Local Growth Fund, secured through the South East Midlands Local Enterprise Partnership.

An unrivalled testing facility

As a closed environment, the tunnel minimises external factors that can influence an outdoor test, while simultaneously offering the repeatability of a wind tunnel. Rob explains:

“The tunnel is not affected by the weather – there is no rain or moisture on the track, no wind influencing movement, and the temperature doesn’t change. Full-scale testing under these fully controlled, ambient conditions ensures accurate, representative, and repeatable tests for companies testing at the tunnel.

We are extremely proud of what we have accomplished at Catesby. The development enriches the capabilities of the UK vehicle industry and provides a base for the commercialisation of new technology, innovation, and R&D.”

Overcoming bumps in the road

Taking the tunnel from a derelict railway to a working test facility was a huge undertaking, making its success all the more remarkable. Rob explains:

“Each challenge we faced was magnified by the sheer scale of the project. From managing drainage and persistent water ingress to setting up lighting with a voltage dip in the tunnel, everything needed not just to function correctly, but to function correctly for all 2.7km of the track. We also had to navigate our way through several significant macroeconomic factors, including the recession, Brexit, and the pandemic. From buying the land to securing funding to obtaining planning permission – I often referred to the project as a multi-miracle problem!”

On its completion, Rob was awarded the Simms Medal by the Royal Automobile Club, which recognises an outstanding contribution to motoring innovation by individuals or small companies and one that exemplifies the “spirit of adventure.” It is awarded to the most ground-breaking motoring endeavours of recent years.

Catesby Innovation Centre

Roughly half a mile away from the tunnel is the second part of the project – a four-and-a-half-acre, £4 million science park built on the site of Charwelton’s former railway station. With its design inspired by a Victorian engine shed at nearby Brackley, the Catesby Innovation Centre offers rentable, flexible offices, conference facilities and workshop space for local high-tech, innovative companies to lay down roots.

Plans for future development

The facility opened for business in 2021, but Rob and his team have plans to enhance the tunnel further. These include adding force plates in the road’s surface, which will allow engineers to instantly measure downforce, as well as an ultra-wideband indoor positioning system to enable accurate measurement of speed and location inside the tunnel.

As with the majority of the stages of the tunnel’s development, future plans will likely present further hurdles for the innovators at Catesby to overcome. However, by working with Lodders, including dispute resolution expert Jane Senior, the team is well-positioned to tackle any issues head-on and continue to drive innovation.

Click here to read Lodders Life Issue 9 in full.