Building a 1,000mph car that could break the world speed record was always going to be a challenge. But seeing the car so close to being finished at the Bloodhound Technical Centre reveals how difficult it really has been.
Originally, the body of the car was going to be made in two main sections and assembled in Bristol. The front, carbon-fibre, half was to be manufactured by the Advanced Composites Group and the back, titanium, half was going to be made by aerospace company Hampson Industries. But changes in commercial circumstances have meant that some initial commitments could not be kept, and a greater amount of the development and construction has had to take place at Bloodhound’s base, on an industrial estate at Avonmouth, Bristol.
The change in manufacturing is typical fare for such an ambitious project that involves more than 300 partners. The institution is a long term sponsor and many partners supply parts and work in kind. Bloodhound has cost £16 million since it was launched almost eight years ago. Now, however, it needs another £7 million to achieve its goal – breaking the world land speed record at the Hakskeen Pan, South Africa next year.
It may seem a lot of money but, as Bloodhound’s chief engineer Mark Chapman points out, the Bloodhound team has got this far with a fraction of the budget and resources of similar projects in motor racing or aerospace.
“This is a jet fighter glued onto a race car, with a spaceship on the back of it. Each of those would have huge teams to do. With the budget and team size we’ve had, it’s incredible what we’ve achieved so far,” he says. “I’m confident that this is the most advanced, most researched vehicle there is.”
Some of the challenges the small team has solved include the aerodynamics of keeping Bloodhound on the ground and installing the EJ200 engine. The vehicle will travel 200mph faster than the Typhoon jet fighter that this same engine powers at altitude, so getting the air intake to work, and managing the extra dynamic pressure going into it, are tough problems.
As we walk around the car – which is a masterpiece in itself and exciting to be near – Chapman says it is 95% designed and 90% structurally complete. What’s also impressive, up close, is the craftsmanship apparent in the vehicle – the nuts and bolts and precision engineering.
For example, inside the cockpit where Squadron Leader Andy Green will sit and steer the car through the sound barrier, the only things left to install are some dials being supplied by Rolex. Being up that close to the first car in the world that will travel at 1,000mph gives a sense of the approach of history in the making. There are additively manufactured parts in the vehicle, but an English wheel, rivets and glue have also been used.
“Artisans have built this car with paddles and hammers and rivet guns. It’s a riveted metal structure. We use new technology where we have to – we don’t use it for the sake of it,” says Chapman.
Rocket power
The main draw when viewing the vehicle is the EJ200 jet engine, which is fuelled by 600,000 litres of fuel held in three tanks, and which on its own can propel the car to transonic speeds of around 600mph. The rocket, in the bottom section of the car, then kicks in, and pushes it past 1,000mph.
The positions of the rocket and jet engine are an example of one of the design changes implemented over the years. The car also originally had air intakes on each of its sides, was longer and had front-operated disc brakes. The design and development plan has evolved, as further studies and computer simulations have been conducted, and as the commercial situations of partner companies in the project have changed.
Lots of further tweaks remain to be made to Bloodhound’s design and configuration during its testing and trialling. Chapman acknowledges that this will be the most challenging part of the project – the “second half” of the “engineering adventure” of developing the world’s fastest car. “There is a whole area of finding out if the car works as we thought it would,” he says.
The main challenge during the test phase will be the rapid and accurate analysis of the masses of data that Bloodhound will produce. Each of the 400 sensors onboard the car, such as accelerometers, strain gauges and thermocouples, will be recorded at 500 times a second – imagine hundreds of lines and columns of a spreadsheet endlessly updating at an incredible rate.
Bloodhound’s engineers need to find out where and when pressure sensors mounted on the car leave the boundaries expected, according to the computer simulations and studies that have already been conducted. “There will be gigabytes of data coming off this car. We don’t have the time to trawl through that. So, particularly with the aerodynamics, we have software that will compare in real time the sensor readings off the car with what the prediction is.”
The team has devised a graphical representation of the data on a computer model, or “virtual twin,” of the car. When the sensor goes out of boundary it goes green and then red, so adjustments can be prepared and made to the vehicle. Engineers may find that predictions about the sonic shockwave expected when the car breaks the sound barrier are incorrect and that the model needs to be adjusted.
“We’ll validate the models that we already have,” says Chapman. “Computationally, we know what things such as the chassis stiffness and the wheel hub frequencies are. But there’s nothing like running it. We may need different spring rates; we might want to change how we use down force to affect stability. There are a lot of things that we know we don’t know, such as how the wheels are going to interact with the desert. We can test that only by getting out and running the car.”
The front and back fins can be moved to aerodynamically balance the car. Suspension rates and dampening rates can also be changed. Another change could be accommodating a new, larger rocket, which changes the rear suspension.
The rocket is an example of just one of the possible changes between the Year One version of Bloodhound, used for the trials, and the Year Two version, which will run in the world record attempt. Such radical changes to the design, so late in a project, would fill most engineers with apprehension. But Chapman insists his team is ready to complete this last 5% of the design. “It’s not a failure of the team to not know,” he says. “A lot of the core team are ex-Thrust SSC [the vehicle that set the first supersonic land speed record].
“We’ve identified what we don’t know and have a robust plan about how to get that data.
“There are parts, such as the wheel fairings, that don’t need to be on the car when we do the low-speed testing, so we might as well wait as long as possible before we put them on.”
The pace of work must be frustrating – engineers have been designing and building the vehicle bit by bit for eight years. The last 10% won’t be finished until just before the team goes to South Africa. “It’s just-in-time design, as well as just-in-time manufacturing,” says Chapman.
Did you know? The Hakskeen Pan
The location for Bloodhound SSC’s attempt to set a 1,000mph record, the 54-square mile dried lake bed in South Africa, was selected using satellite earth observation imagery of 20,000 sites. The Hakskeen Pan floods with water almost every year, and its surface is made of 1-2cm thick plates of mud which have built up over thousands of years.
It’s taken 317 volunteers 120 days to pick up 6,000 tonnes of stones and rocks to clear the path for Bloodhound’s 12-mile track